A Summary of the Branchiobdellid

(Annelida: Clitellata)

Fauna of Mesoamerica

PERRY C. HOLT

m

SMITHSONIAN CONTRIBUTIONS TO ZOOLOGY • NUMBER 142
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A Summary of the Branchiobdellid

(Annelida: Glitellata)

Fauna of Mesoamerica

Perry C. Holt

SMITHSONIAN INSTITUTION PRESS

City of Washington

1973
ABSTRACT

Holt, Perry C. A Summary oi the Branchiobdellid (Annelida: Clitellata) Fauna

of Mesoamerica. Smithsonian Contributions to Zoology, number 142, 40 pages,

19 figures, 1973.—The branchiobdellid fauna of Mesoamerica consists of sixteen

species, assigned to four genera. Of these, all are endemic to the area except

the widespread species, Bdellodrilns illuminatus and Pterodrilus mexicanus. The

latter is considered to be a doubtful occupant of the region. Of the fourteen

remaining species, three are assigned to the genus Sathodrilus, one newly described, and eleven to Cambarincola, ten of which are newly described. The

names of thirteen species of the genus Cambarincola are emended to conform

to the masculine gender of the generic name. The report of the presence in

Mexico of Cambarincola macrodontus and C. pliiladelphicus (Rioja, 1943) is

not accepted. A brief review of the pertinent literature is followed by discussions of methods and sources of materials, some remarks on taxonomic characters

relevant to the Mesoamerican branchiobdellids, cross-referenced lists of species

of branchiobdellids, their hosts and entocytherid ostracod associates, a short

account of the ecology of the worms and an attempt to relate the distribution of

Mesoamerican branchiobdellids with that of their hosts and associates. The

conclusion is reached that representatives of all the main stocks of branchiobdellids reached southern Mexico in pre-Pliocene times and that there is no completely satisfactory way of differentiating between any subsequent invasions. The

treatment of the species include keys, synonomies, bibliographic references,

diagnoses, distribution and hosts, with all new species illustrated and fully

described.

OFFICIAL PUBLICATION DATE is handstamped in a limited number of initial copies and is recorded

in the Institution's annual report, Smithsonian Year. SI PRKSS NUMBER 4772. SERIES COVER

DESIGN: The coral Montastrea cavernosa (Linnaeus) .

Library of Congress Cataloging in Publication Data

Holt, Perry C, 1912

A summary of the branchiobdellid (Annelida: Clitellata) fauna of Mesoamerica.

(Smithsonian contributions to zoology, no. 142)

1. Branchiobddlida. 2. Clitellata—Central America. 3. Clitellata—Mexico. I. Title. II. Series:

Smithsonian Institution. Smithsonian contributions to zoology, no. 142.

QL1.S54 no. 142 [QL391.04] 591'.08s [595'. 146] 72-13965

For sale by the Superintendent of Documents,

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Contents

Page

Introduction 1

Acknowledgments 1

Review of the Literature 1

Methods and Disposition of Materials 2

Taxonomic Characteristics 2

Lists Pertaining to Mesoamerican Branchiobdellida . 3

Species List of Branchiobdellids 3

List of Hosts . 3

List of Known Branchiobdellid Associates 4

List of Entocytherid Associates . 4

Ecological Notes 4

Zoogeographical Considerations 5

Faunal Regions of Mexican Branchiobdellids 7

Order Branchiobdellida Holt, 1965 7

Key to the Mesoamerican Genera of the Branchiobdellida 8

Genus Bdellodrilus Moore, 1895 8

Bdellodrihis illuminatus (Moore, 1894) 8

Genus Cambarincola Ellis, 1912 9

Key to the Mesoamerican Species of the Genus Cambarincola ...... 10

Cambarincola acudentatus, new species 11

Cambarincola carcinophilus, new species . 13

Cambarincola ellisi, new species 14

Cambarincola hoffmani, new species 16

Cambarincola jamapaensis, new species 17

Cambarincola micradenus, new species 20

Cambarincola nanognathus, new species 22

Cambarincola olmecus, new species 24

Cambarincola smalleyi Holt, 1964 26

Cambarincola susanae, new species . 27

Cambarincola toltecus, new species 29

Genus Ptemdrilus Moore. 1895 31

Pterodrihis rnexicanus Ellis, 1919 31

Genus Sathodriius Holt, 1968 32

Key to the Mesoamerican Species of the Genus Sathodriius . . 33

Sathodriius prostates, new species 33

Sathodriius veracntzicus Holt, 1968 . . . . 36

Sathodriius villalobosi Holt, 1968 . 36

Literature Cited 38

in

A Summary of the Branchiobdellid

(Annelida: Glitellata)

Fauna of Mesoamerica

Perry C. Holt

Introduction

Brief references to, and more or less isolated descriptions of, new species of branchiobdellids, symbionts of freshwater crustaceans, from Mesoamerica

have been published in the past. There is, however, no account of this fauna that treats together

all of the known taxa. To record what is known

of the Mesoamerican branchiobdellids is the objective of this paper.

The record must of necessity be incomplete and

is likely to remain so. Earlier acquired material

was collected incidentally by students of crayfishes

and is in a generally poor state of preservation.

Much of it has been lost in the curating of crayfish

collections. My attempts to collect branchiobdellids by visiting many of the recorded localities for

crayfish in Mexico during the summer of 1962 were

usually unsuccessful, in spite of the devoted help

of Professor Alejandro Villalobos of the Universidad Nacional Aut6noma de Mexico. The area is

at the limits of the range of astacids in a land that

is either semiarid with few streams or well watered

but tropical and where the crayfishes must compete

with freshwater crabs and shrimps. Some branchiobdellids have managed to take up a life on these

hosts. More importantly, there is the apparent absence of crayfishes from many localities where Horton H. Hobbs, Jr., and Alejandro Villalobos once

Perry C. Holt, Department of Biology, Virginia Polytechnic

Institute and State University, Blacksburg, Virginia 24061.

took them in relative abundance: an absence that

I cannot explain.

So, with little hope that much additional material will be forthcoming, what is available, to my

knowledge, is described and discussed herein.

ACKNOWLEDGMENTS.—I am deeply indebted to

Dr. Alejandro Villalobos Figueroa, who first sent

me Mexican branchiobdellids many years ago and

who later went into the field with me. He has also

most generously allowed me to remove all the

branchiobdellids from the crayfish collections of

the Instituto de Biologia de la Universidad Nacional Aut6noma de Mexico. His hospitality and

friendship is deeply appreciated. Dr. Horton H.

Hobbs, Jr., made available to me several collections of Mexican branchiobdellids. He and Dr.

Villalobos have identified the host animals for me

and Dr. Hobbs and Dr. Marian H. Pettibone have

read the manuscript. Dr. Hobbs, also, helped

greatly in compiling crayfish and ostracod records

and with discussions of distributional problems.

My wife, Virgie F. Holt, my daughter, Susan E. H.

West, and Sefior Patricio Gonzales Kipper, assisted

me in field work in Mexico. Mrs. Susan S. Settle's

assistance in preparing the manuscript is appreciated. My studies of branchiobdellid taxonomy, including my field work in Mexico, were supported

for a number of years by National Science Foundation grants G-4439, G9828, and GB-372.

REVIEW OF THE LITERATURE.—The first reference

to a branchiobdellid from Mesoamerica was by

Ellis (1919:254), who described Pterodrilus mexi-
SMITHSONIAN CONTRIBUTIONS TO ZOOLOGY

canus from Mirador, Veracruz, Mexico. Rioja

(1940) recorded the presence of Bdellodrilus illuminatus in Mexico and later (1943) that of Cambarincola macrodontus and C. philadelphicus.

Goodnight (1940) had also reported C. philadelphicus in Mexico. (Since the name Cambarincola

is masculine in gender, but traditionally has been

treated as feminine, the emendation of several specific taxa of the genus is required.) Hobbs and

Villalobos (1958) reported the presence of unidentified branchiobdellids on freshwater crabs in Mexico. Holt (1964) described Cambarincola smalleyi

from Costa Rica and later (1968b) Sathodrilus villalobosi and S. veracruzicus from Mexico. Mesoamerican species from nonastacid hosts (Hobbs and

Villalobos' records and C. smalleyi) were briefly referred to in a review paper (Holt, 1968a). Holt

(1969:214) also discussed the geographical and

phylogenetic relationships of these species and two

Mexican members of the genus Sathodrilus. Much

use is made, herein, of Hobbs' (1971) treatment of

the entocytherid ostracods of Mexico and Cuba,

animals that as epizoites share the same hosts.

If any other mention of branchiobdellids from

Mesoamerica occurs in the primary literature on

the order, it is either an incidental and passing

reference or I am unaware of it.

METHODS AND DISPOSITION OF MATERIALS.—Materials collected by others than myself and field

companions and used in this study were preserved

in 70 percent ethyl alcohol. My collecting methods

and procedures have been described elsewhere

(Holt, 1960a:57), though it may be well to point

out that I often turn my slides upside down in

order to view a specimen from both sides, using for

this purpose the flourite objective previously mentioned. Drawings, made with the aid of a camera

lucida, often reflect this practice and are reversed

in appearance from that of the specimen viewed

from the cover slip side of the slide. In all cases,

drawings are made so that the anterior of the animal and its illustrated parts are directed towards

the reader's right and the reproductive systems

are always presented in lateral view.

Keys to species presented herein apply only to

the Mesoamerican members of the order and should

not, therefore, be used in any attempt to identify

branchiobdellids from north of the Rio Grande.

Except for some paratypes and a small number

of specimens retained in my personal collections at

Virginia Polytechnic Institute and State University,

the materials are deposited in the National Museum of Natural History, Smithsonian Institution,

and the collections of the Instituto de Biologia,

Universidad Nacional Autonoma de Mexico. All

holotypes are in the collections of the National

Museum of Natural History whose catalog numbers

(USNM: United States National Museum collections) and my personal catalog numbers (PCH) are

listed with the locality data given for a species.

Unless otherwise indicated, the collector of all materials was Dr. Alejandro Villalobos.

Fifty-six out of eighty-five collections of branchiobdellids contained material that was well enough

preserved for use in this study. Only species represented in this material are included in the maps

of distribution, though some of the previous records of other authors are accepted. Ostracod and

branchiobdellid associates are not repeated in the

treatments of species; they can be found in the

lists.

TAXONOMIC CHARACTERISTICS.—The terminology

used in branchiobdellid taxonomy and the taxonomic value of various characteristics have been

discussed before (Holt, 1953, 1960a, 1965, 1968a,

1968b; Holt and Hoffman, 1959). Certain organ

systems of the branchiobdellids appear invariant

within the order, for instance, the location of

ovaries and ovipores, the number and location

of testes in the American members, features of

the nervous system and, with minor exceptions,

the digestive system. Among characters considered to be diagnostic of genera, the manner

of discharge of the anterior nephridia—one

or two dorsal nephridiopores opening on the third

trunk segment—is constant among Mesoamerican

members of the order: one nephridiopore opens

middorsally on the dorsum of segment III. Parenthetically, the trunk segments are numbered separately from those, presumably four, which compose

the head. Many features are intergenerically variable, among them, the number of denticles (teeth)

borne by the pharyngeal placoids (jaws), though

the overall facies of the jaws is usually characteristic of a genus; the lobation or tentaculation of the

upper and lower lobes of the peristomium (upper

and lower lips); the presence or absence of dorsal

supernumerary longitudinal segmental muscles
NUMBER 142

(Holt, 1960b: 171-172) which, in the contracted

state, produce a greater diameter of the anterior

(major) annulus of a segment and cause "dorsal

ridges" upon all or some of the trunk segments, in

the former case conferring a sawlike appearance to

the animal in lateral view; and the presence or

absence of fanlike or finger-like projections on dorsal ridges in some genera.

Secondary sexual organs, the male efferent apparatus and the spermatheca, furnish the most

useful taxonomic characteristics. These organs have

been described in detail for some species (Moore,

1895b; Holt, 1949, 1960a). An eversible penis (one

that consists of a tube capable of being turned inside out) or a protrusible one (i.e., a conelike

muscular mass that is capable of being projected

through the gonopore surrounded by the partially

everted atrial portion of the bursa) is considered a

generic character and separates, for instance, the

genus Cambarincola Ellis (1912) from Bdellodrilus

Moore (1895b) and Sathodrilus Holt (1968b).

The presence or absence of a prostate, or

its rudimentary character, may be of generic value,

as may other components of the male system and

stable structures of the spermatheca; but in general a constellation of genitalic characteristics are

used in the diagnosis of a genus (cf. Holt, 1960a, b,

1968b). Most of these structures are labeled in

Figure 16.

A good deal of parallelism exists among the

branchiobdellids, and a species of one genus may

exhibit features that appear identical to those in

members of otherwise very distinct genera. In general, important features for the characterization of

these species are the shape and proportions of the

jaws and the number and arrangement of the teeth

they bear, the lobation of the lips, the proportions

and structure of the male efferent apparatus (particularly the presence or absence of an ental bulb

of the prostate which may or not be composed

of histologically distinct cells—i.e., filled with large

vacuoles of presumably secreted materials—from

those of the spermiducal gland), and variations in

the structure of the spermatheca.

For clarification of the zoogeographical relationships of Mesoamerican branchiobdellids a brief

tabulation of some primitive features (characteristic of ancestral stocks as opposed to those considered to be advanced, more specialized, or

characteristic of more recently evolved stocks)

follows:

Primitive

Eversible penis

Spermiducal gland

without prostate

Prostatic protuberance

Nondifferentiated prostate

Spermiducal gland with

deferent lobes

Deferent ducts enter ental

end of spermiducal gland

Spermatheca with

glandular ental process or

thickened glandular wall

of bulb

Jaws subequal in size

with several (5 or more)

similar teeth

No supernumerary

segmental muscles

Advanced

Protrusible penis

Prostate or "prostatic

protuberance" present

Fully or partially

separated prostate

Differentiated prostate

Spermiducal gland

without deferent lobes

Deferent ducts enter

spermiducal gland ectad

to ental end

Spermatheca consisting of

ectal duct and thin-walled

bulb

Jaws and teeth variously

modified

Supernumerary segmental

muscles present

Lists Pertaining to Mesoamerican

Branchiobdellida

SPECIES LIST OF BRANCHIOBDELLIDS

Numbers following each taxon refer to the

number of the species' hosts indicated in the following list.

1. Bdellodrilus illuminatus, Mexico and United States: 9

2. Cambarincola acudentatus, Mexico: 1, 2

3. Cambarincola carcinophilus, Mexico: 16, 21

4. Cambarincola ellisi, Mexico: 17

5. Cambarincola hoffmani, Mexico: 7, 12

6. Cambarincola jamapaensis, Mexico: 5, 12, 14

7. Cambarincola micradenus, Mexico: 4

8. Cambarincola nanognathus, Mexico and Nicaragua: 18,

19, 21

9. Cambarincola olmecus, Mexico: 5, 6, 14

10. Cambarincola smalleyi, Costa Rica: 20

11. Cambarincola susanae, Mexico: 5, 11, 13, 17

12. Cambarincola toltecus, Mexico: 16, 21

13. Pterodrilus mexicanus, (?) Mexico and United States: 14

14. Sathodrilus prostates, Mexico: 5, 12, 16, 21

15. Sathodrilus x'eracruzicus, Mexico: 8, 12, 15

16. Sathodrilus villalobosi, Mexico: 4, 8, 10, 15

LIST OF HOSTS

Numbers following each taxon refer

branchiobdellids in the list above.

to the
SMITHSONIAN CONTRIBUTIONS TO ZOOLOGY

ISOPODA: CIROLANIDAE

1. Speocirolana bolivari (Rioja, 1953): 2

2. Speocirolana pelaezi (Bolivar y Pieltain, 1950): 2

DECAPODA: ASTACIDAE

3. Cambarellus montezumae montezumae (Saussure 1857) : 1

4. Paracambarus paradoxus (Ortmann, 1906) : 7, 16

5. Procambarus acutus cuevachicae (Hobbs, 1941): 6, 9,

11, 14

6. Procambarus aztecus (Saussure, 1957) : 9

7. Procambarus caballeroi (Villalobos, 1944) : 5

8. Procambarus contrerasi (Creaser, 1931) : 15, 16

9. Procambarus digueti (Bouvier, 1897) : 1

10. Procambarus erichsoni Villalobos, 1958: 16

11. Procambarus gonopodocristatus Villalobos, 1958: 11

12. Procambarus hoffmanni (Villalobos, 1944): 5, 6, 14, 15

13. Procambarus llamasi Villalobos, 1954: 11

14. Procambarus mexicanus (Erichson, 1946) : 6, 9, 13

15. Procambarus riojai (Villalobos, 1944) : 15, 16

16. Procambarus ruthveni zapoapensis Villalobos, 1954: 3,

12, 14

17. Procambarus simulans regiomontanus Villalobos, 1954:

4, 11

18. Procambarus vazquezae Villalobos, 1954: 8

DECAPODA: PSEUDOTHELPHUSIDAE

19. Polamocarcinus nicaraguensis Rathbun, 1893: 8

20. Pseudothelphusa tumimanus Rathbun, 1898: 10

21. Pseudothelphusa (Tehuana) veracruzana Rodriquez and

Smalley, 1970: 3, 8, 12, 14

LIST O F KNOWN BRANCHIOBDELLID ASSOCIATES

Numbers following each taxon refer to the "Species List of Branchiobdellids."

1. Bdellodrilus illuminatus: none

2. Cambarincola acudentatus: none

3. Cambarincola carcinophilus: 12, 14

4. Cambarincola ellisi: none

5. Cambarincola tioffmani: none

6. Cambarincola jamapaensis: 14

7. Cambarincola micradenus: 16

8. Cambarincola nanognatha: 12, 14

9. Cambarincola olmecus: 11

10. Cambarincola smalleyi: none

11. Cambarincola susanae: 9, 16

12. Cambarincola toltecus: 3, 8, 14

13. Pterodrilus mexicanus: none

14. Sathodrilus prostates: 12

15. Sathodrilus veracruzicus: none

16. Sathodrilus villalobosi: 7

LIST OF ENTOCYTHERID ASSOCIATES

(See Hobbs, 1971:3)

Numbers following each entocytherid species refers to the "Species List of Branchiobdellids."

1. Uncinocythere bicuspide (Rioja, 1943): 6, 7, 9,# 14,

15, 16

2. Uncinocy'there caudricuspide (Rioja, 1945) : 6, 7, 16

3. Uncinocythere dobbinae (Rioja, 1943): 5, 6, 7, 14, 15, 16

4. Uncinocythere zaruri Hobbs, 1971: 3, 8, 12, 14

5. Anhylocythere bidentata (Rioja, 1949): 3, 9, 12, 14

6. Ankylocythere heterodonta (Rioja, 1940): 1

7. Ankylocythere sinuosa (Rioja, 1942) : 4, 11

8. Entocythere claytonhoffi Rioja, 1942: 3, 9, 11, 12, 14

9. Entocythere mexicana Rioja, 1943: 5, 6, 14, 15

10. Sphaeromicola cirolanae Rioja, 1951: 2

•Questioned by Hobbs, 1971:22.

Ecological Notes

The ecology of the branchiobdellids, which was

summarized by Holt (1968a), offers little help in

considering the evolution of the Mesoamerican

fauna; only five papers (Berry and Holt, 1959; MeManus, 1960; Brown, 1961; Young, 1966; Bishop,

1968) have been devoted explicitly to the ecology

of the branchiobdellids. It is known that some species occupy particular niches on their crustacean

hosts, that some {Bdellodrilus illuminatus and

Cambarincola alienus Holt, 1963) may be considered as true parasites, the former living in the gill

chambers of crayfish, the latter in the brood

pouches of isopods. More usually the worms occupy "preferred" areas on the exoskeleton of the

host (Brown, 1961). Those branchiobdellids that

live on protected parts of their hosts, such as those

mentioned above, and in general, those that live

on hosts other than astacids (e.g., Cambarincola

smalleyi and C. nanognathus on crabs, C. alienus

and C. acudentatus on isopods) seem more primitive than most of their congeners. It is as if these

four species just mentioned early escaped the more

rigorous competition offered by life on the exterior

of astacid crayfishes. Consequently, other than

showing some signs of specialization for a parasitic

life, they have retained more primitive features

than other members of the genus. But that this

need not be so, is indicated by Blackford's (1966)

finding of Cambarincola vitreus on the crab, Callinectes sapidus Rathbun, 1892, that has become

acclimated to freshwater lagoons in Louisiana. In

addition, Blackford (1966:6) showed that branchi-
NUMBER 142

obdellids are quite intolerant of salt water and I

have never taken them from brackish water. Therefore, freshwater routes of invasion must be assumed for them.

The diet of the branchiobdellids seems to be any

organic matter that they can find in their grazing

on the host animals; the vast majority are not

parasites, they are not species specific and, though

it is known that some are intolerant of warm

waters (Berry and Holt, 1959), essentially nothing

is known of other aspects of their ecology or life

cycles.

Zoogeographical Considerations

As previously emphasized, the knowledge of

Mesoamerican branchiobdellids is too scanty to

allow for anything but the most tentative theories

of their history and origins. It is hoped that what

little is known of their distribution and evolution

will help in the evaluation of the theories proposed

by Hobbs (1971). The lists above of hosts and associates are presented for this reason. Since his

knowledge of the crayfishes and entocytherids of

Mexico is based on a much greater body of knowledge than mine of the branchiobdellids, it is necessary to take his conclusions into careful account in

formulating any theories of the origins of the Mesoamerican branchiobdellid fauna.

The seemingly near total lack of host specificity

on the part of both the entocytherids and the

branchiobdellids (Hobbs, Holt, and Walton, 1967;

Hart and Hart, 1969; Holt, 1969; Hobbs, 1971),

except that both are confined to crustacean hosts,

complicates any attempt to correlate the evolution

of these symbionts and their hosts. In spite of their

passive means of dispersal as obligate epizoites that

can go only where their hosts do, the ability of

both groups of commensals to move readily

from one host to another produces distributional

patterns that seem to be the results of three independent lines of evolution. Though Hobbs (1971:

7-18) has produced a plausible theory of the migration of entocytherid stocks into Mexico, I cannot do so in such detail for the branchiobdellids.

There are several reasons for this other than

paucity of materials. The known hosts of branchiobdellids in Mesoamerica are twenty members of

two orders and three families of crustaceans; on

the other hand Hobbs (1917:3) lists forty hosts

from the same orders and families for the entocytherids of Mexico and Cuba. The two species

of branchiobdellids from Nicaragua (Carnbarincola nanognathus, new species) and Costa Rica

(C. smalleyi) are offset by three species of entocytherids on two hosts known from Cuba, so that

there are twice as many hosts known for the entocytherids in Mexico as there are for the branchiobdellids, though there is one more (14 as opposed to

13) branchiobdellid species in Mexico than entocytherid ones. Nonetheless, I believe that I have only

a minimal representation of the original Mexican

branchiobdellid fauna before me. That the missing

members of this fauna might well have contained

species crucial to the reconstruction of the history

of the order in Mesoamerica will, I hope, be

assumed.

In my analysis of the zoogeography of the Mesoamerican branchiobdellid fauna. I have adopted

Hobbs' (1971:7-18) faunal regions and accept the

reality of the barrier imposed by the formation of

the Cordillera Volcanico Transversal.

Bdellodrilus illuminatus is the only branchiobdellid of which I have seen a specimen from the

Central Plateau region. Rioja (1940) reported it

from "Xochimilco, Texcoco y de las Lagunas de

Zempoala" on Cambarellus montezumae monteznmae and C. m. zempoalensis for the latter locality. There is no reason to doubt these records.

The species is distinctive and, though primitive

(Holt, 1969:195-196), has been found at many

widely separated localities on the continent. It

must have reached the Central Plateau region on

either the ancestor of the disjunct Procambarus

digueti or the stock that gave rise to the Mexican

members of the genus Cambarellus in pre-Pliocene

times.

Ellis (1919) described Pterodrilus mexicanus

on the basis of a single poorly preserved

specimen presumably from Mirador, Veracruz, on

Procambarus mexicanus. The genus Pterodrilus is

common in the Appalachian and Ozarkian uplands

of the United States, but I have not found any

member of the genus in the Mexican collections

and have been unable to locate Mirador with certainty. I suspect it is in the Southern Gulf Slope

region and, hence, south of the Cordillera Volcanica Transversal. If so, and if Ellis' record is

correct, then the genus Pterodrilus is of consider-
SMITHSONIAN CONTRIBUTIONS TO ZOOLOGY

able antiquity. There are Ozarkian worms that I

have assigned to P. mexicanus, which are indistinguishable in external features from the poorly

preserved type. As stated earlier (Holt, 1968c: 18),

I doubt that Ellis' specimen was collected in Mexico. In any case, P. mexicanus must be disregarded

in any consideration of the zoogeography of Mesoamerican branchiobdellids.

There are two species of Sathodrilus in the

United States: S. carolinensis, the type-species from

Anderson County, South Carolina, and 5. megadenus from Haralson County, Georgia. Of the three

Mexican species, S. villalobosi and S. veracrnzicus

occur north of the Cordillera Volcanico Transversal, but only S. prostates, newly described herein,

is found on both sides of this barrier (Figure 19)

in the Interjacent Gulf Slope and the upland area

around Lake Catemaco in the Southern Gulf Slope.

Sathodrilus is presumably the most primitive genus

among the dominant group of North American

branchiobdellids (Holt, 1969:196-197) and S. veracruzicus the most primitive species of the genus.

S. prostates possesses characteristics which ally

Sathodrilus with the genus Tettodrilus Holt,

1968b, and hence with Cambarincola. One possibility is that members of the genus Sathodrilus

reached the Southern Gulf Slope with the first wave

of pre-Pliocene crayfish invasions (Hobbs, 1971:11)

and that the ancestors of the more primitive of the

surviving members, S. veracruzicus and S. villalobosi, were left to the north by the formation of the

Cordillera Volcanico while the somewhat more advanced S. prostates has survived on both sides of

the barrier. On the other hand, Hobbs (pers.

comm.) has suggested that the Sathodrilus stock,

because of the similarities of its distribution to that

of Uncinocy there (Hobbs, 1971:15, 17), represents,

as does the latter, a Pliocene invasion into the

Interjacent area. His U. zaruri, from the Southern

Gulf Slope, may have reached there by sea with

its crab host; S. prostates, occurring on the same

crab species in the same area, could not have done

so. Hobbs' suggestion (pers. comm.) that 5. prostates crossed the divide with its host crab, which

walked overland from stream to stream, is a possible but dubious explanation of the distribution

of the species of Sathodrilus.

Tettodrilus friaufi Holt, 1968a, may have descended from the ancestors of S. prostates: T. friaufi,

known only from streams of the Nashville basin

in Middle Tennessee, is a relict species that can

be derived from a somewhat advanced member of

the Sathodrilus stock that survives today as S.

prostates.

The genus Cambarincola is composed of 22 nominal species and 10 more are described below. It

contains more species than any other known genus

of the order, and I have in my collections a number of undescribed species from the southeastern,

Ozarkian, and Pacific slope regions of the United

States. Other than noting that the apparently primitive Mesoamerican species, e.g., C. nanognathus,

new species, appears in the Southern Gulf Slope

region and beyond into Nicaragua, there is little

relationship between any phyletic lineages that

might be proposed and their distribution. The only

species with a differentiated prostate (C. toltecus,

new species, and C. smalleyi) are known only from

the Southern Gulf Slope and Costa Rica, respectively, and would appear, on the basis of the nature

of their prostates, to be related to the more advanced Philadelphicus section of the genus (Hoffman, 1963:320). This may be an example of

parallelism, and the overall impression conveyed by

the Mesoamerican species of Cambarincola is that

they are related to some element or elements of the

more primitive cambarincoloid stock. One new

species, C. susanae, ranges from the Northern Gulf

Slope in the Rio Grande basin far south into

Campeche. Cambarincola susanae resembles in

some respects, C. vitreus, a widespread Central and

Coastal Plains member of the Philadelphicus section, but differs from the latter in its undifferentiated prostate and perhaps specialized jaws.

Cambarincola susanae resembles in its distribution

Entocy there claytonhoffi (cf. Hobbs, 1971:15)

and is without doubt a representative of the

early pre-Pliocene invasion. Cambarincola olmecus,

new species, known from the Northern Gulf Slope

regions, in features of the jaws, the presence of

dorsal ridges of the major annuli, and the thinwalled spermathecal bulb is perhaps an advanced

member of the Mesochoreus section (Hoffman,

1963). Its ancestors, however, were present on

both sides of the Cordillera Volcanico Transversal,

so it, too, has a pre-Pliocene origin. Cambarincola

jamapaensis, new species, found on both sides

of the barrier, likewise is closer to the Mesochoreus
NUMBER 142

section. Cambarincola ellisi, new species, known

only from the Rio Grande drainage of the Northern Gulf Slope, with its affinities with the Mesochoreus section, is the only species of the

Mesoamerican fauna that may represent a Pleistocene or Recent invasion.

To summarize: The branchiobdellid fauna of

Mesoamerica is ancient; many of its members

reached the southern limits of the area in prePliocene times. Although only 3 of the 13 known

genera of American branchiobdellids are known

from Mesoamerica, the three that are there, on the

basis of any concept of the phylogenetic relationships

of the branchiobdellid genera, indicate that in the

evolution of the order many of the modern genera

and some of the species are of pre-Pliocene origin.

All evidence indicates that the Mesoamerican

branchiobdellids are derived from stocks that arose

in the uplands of the southern United States. Most

or all members of the genus Cambarincola in Mesoamerica are derived from primitive stocks that

today are represented by the Mesochoreus section.

Members of this section are confined mostly to the

Central Plains of the United States and areas immediately adjacent to the plains. If this be the case,

however, such species as C. toltecus, new species,

and C. smalleyi, with their similarities to the northern members of the genus with differentiated prostates, are examples of an amazing amount of parallelism in the evolution of the genus. Until all

extant species of Cambarincola are studied in much

more detail than they have been until now, these

puzzles must remain unresolved.

The available data do not allow me to go beyond

these speculations. I cannot correlate the migrations

of any post-Miocene invaders with Hobbs' (1971:

10-14) postulated Pliocene and Pleistocene-Recent

crayfish invasions. Nothing said, however, contradicts his theories of the sources, migration routes,

and times of arrival in Mesoamerica of the crayfish hosts and the branchiobdellids' fellow travelers,

the entocytherid ostracods. Certainly I concur enthusiastically with his approval of the statement

by Martin and Harrell (1957:497) that "interpreting the eastern temperate (Arctotertiary) element

in the Mexican montane biota exclusively in terms

of Pleistocene dispersal raises more distributional

problems than it solves." I might even go further

and say, on the basis of my attempts to understand

the distribution of the branchiobdellids, that this

statement applies to the entire southeastern part

of North America.

FAUNAL REGIONS OF MEXICAN BRANCHIOBDELLIDS

(as proposed by Hobbs, 1971:10)

Initials following the name of a species are those

of another faunal region in which the species also

occurs.

SOUTHERN GULF SLOPE (SCS)

Cambarincola carcinophilus

Cambarincola jamapaensis (IGS)

Cambarincola nanognathus (Nicaragua)

Cambarincola olmecus (NGS)

Cambarincola smalleyi (only from Costa Rica)

Cambarincola susanae (ics, NGS)

Cambarincola toltecus

Pterodrilus mexicanus

Sathodrilus prostates (ics)

INTERJACENT GULF SLOPE (IGS)

Cambarincola hoffmani

Cambarincola jamapaensis (SGS)

Cambarincola micradenus

Cambarincola susanae (SGS, NCS)

Sathodrilus prostates (scs)

Sathodrilus veracruzicus

Sathodrilus villalobosi (NCS)

NORTHERN GULF SLOPE

Cambarincola acudentatus

Cambarincola ellisi

Cambarincola olmecus (SGS)

Cambarincola susanae (scs, IGS)

Sathodrilus villalobosi (IGS)

CENTRAL PLATEAU

Ddellodrilus illuminatus

Order BRANCHIOBDELLIDA Holt, 1965

DISCODRILIDAE Vejdovsky, 1884:38-40.—Pierantoni, 1912:1-

17—Ellis, 1912:481.

BRANCHIOBDELLIDAE Ludwig, 1886:782-783.—Hall, 1914:190.—

Ellis [by implication], 1919:241.—Stephenson, 1930:795-

802.—Goodnight, 1940:27—Hoffman, 1963:271.

BRANCHIOBDELLOIDEA Hall, 1914:190—Goodnight, 1940:27.

BRANCHIOBDELLIDA Holt, 1965:30-31.

DIAGNOSIS (from Holt, 1965:30-31).—

Clitellate annelids with constant number of segments (15) ;

without setae or prostomium; with the peristomium modi-
8 SMITHSONIAN CONTRIBUTIONS TO ZOOLOGY

fied as an anterior sucker; with a posterior sucker; a pair

of dental placoids (a dorsal and ventral one) in the

pharynx; the body divided into a head of four segments and

a trunk of eleven; anus dorsal and subterminal; two pairs

of nephridia, an asymmetrical pair in segments 5 to 8 and

a pair in segments 12 and 13; muscles non-syncytial, composed of cells with outer contractile and inner undifferentiated cytoplasm; testes in segments 9 and 10 or in segment

9 only; paired male funnels and ducts in each testicular

segment, with the ducts uniting in each such segment to

form an unpaired deferent duct, or if two such ducts they

fuse in segment 10 and open in any case by means of an

elaborate glandular and muscular apparatus through an

unpaired pore on the venter of segment 10; a pair of

ovaries and ovipores without free oviducts and funnels in

segment 11; an unpaired spermatheca in segment 9; clitellum

on segments 10 and 11; epizoites on freshwater crustaceans;

holoarctic in distribution, extending into neotropical Central

America.

The order has not yet been successfully divided

into families. Goodnight (1940:27-28), accepting

Hall's (1914:190) proposal that the group be considered a monotypic superfamily, proposed two

subfamilies: the Branchiobdellinae, to be a monotypic group based on the Eurasian genus Branchiobdella Odier, 1823; and the Cambarincolinae,

with the genus Cambarincola Ellis, 1912, as the

type, to include the remainder of the family.

Branchiobdella, with species from eastern Asia and

Europe is distinctive in having lost a pair of testes

and male funnels and ducts, but otherwise is too

close in morphological characters to separate from

a number of eastern Asian and North American

genera. The order for the present is composed of

the single family Branchiobdellidae.

Key to the Mesoamerican Genera of the Branchiobdellida

1. Penis protrusible 2

Penis eversible 3

2. Without appendages borne on dorsal ridges Cambarincola

With at least one dorsal ridge bearing appendages Pterodrilus

3. With bifid spermatheca, deferent ducts enter spermiducal gland ectally to its ental end

Bdellodrilus

Spermatheca never branched, deferent ducts always unite at ental end of

spermatheca Sathodrilus

XOTE: This key is applicable only to the known Mesoamerican branchiobdellids and is not

adequate to separate these genera from some of those of the United States.

Genus Bdellodrilus Moore, 1895

Bdellodrilus Moore, 1895b:497.

DIAGNOSIS (emended from Hobbs, Holt, and

Walton, 1967:51).—

Head elongated and less in diameter than anterior body

segments; peristomium without lobes, body wall thin

and glandular (parasitic facies); posterior sucker small

and weak; two pairs of testes, no prostate [deferent ducts

enter spermiducal gland ectally to its ental end], penis

eversible; spermatheca bifid; lateral glands present in

trunk segments I through IX; anterior nephridia open by

Common pore; upper jaw longitudinal ridge bearing

three teeth, lower jaw deep trough in which dorsal one fits;

inhabitants of gill chambers.

TYPE-SPECIES.—Bdellodrilus illuminatus (Moore,

1891), by subsequent designation (Goodnight,

1940:53).

Bdellodrilus illuminatus (Moore, 1894)

FIGURES 1, 19

liranchiobdella illuminaia Moore, 1894:421-423.

Bdellodrilus illuminatus.—Moore, 1895b:497.

TYPE-SPECIMENS.—No longer extant, but taken

at Philadelphia, Pennsylvania, and Watauga County,

North Carolina, on Cambarus bartonii (Fabricius,

1798), by J. Percy Moore.

HOSTS.—UNITED STATES: B. illuminatus is known

(Goodnight, 1940:54; Hobbs, Holt, and Walton,

1967:51) to occur on seven species of the genus

Cambarus and there are several unpublished records in my collections. MEXICO: Procambarus digueti, Cambarellus montezumae montezumae (Rioja,

1940).

DISTRIBUTION.—Bdellodrilus illuminatus probably ranges over the continent wherever its astacid
NUMBER 142

FIGURE 1.—lidellodrilus illuminatus: a, animal from Giles

County, Virginia; b, reproductive systems; c, jaws, (a and c

from Hobbs, Holt, and Walton, 1967; b, redrawn from Moore,

1895b.)

hosts occur. Goodnight (1940:54) records it from

Illinois; Hobbs, Holt, and Walton (1967:51-52)

found it abundantly in their study of the Mountain

Lake, Virginia, area; and I have scattered, unpublished records from many parts of the United

States. It is an ancient and primitive species with

specializations for a parasitic way of life in the gill

chambers of its hosts. It probably reached the Central Plateau region of Mexico in pre-Pliocene times

on either the ancestor of Procambarus digneti or

the ancestors of the Mexican members of Cambarellus (Hobbs, 1917:12). Its apparent absence from

the other faunistic regions of Mexico (and many

parts of the United States) is probably an artifact

of collecting. Most of the specimens of Mesoamerican branchiobdellids were removed from the sediments in museum jars containing crayfish collections; curators of such collections do not like to

have their specimens damaged in a search for gillinhabiting worms.

MATERIAL EXAMINED.—One specimen (PCH

1620) taken on Procambarus digueti at Jacona,

Rancho Nueva Espana, km 470 carretera MexicoGuadalajara, Michoacan, by Dieter Enkerlin, 18

July 1950.

Genus Cambarincola Ellis, 1912

Astacobdella Leidy, 1851:206.

Branchiobdella.—Moore, 1894:427 [in part].

Bdellodrilus.—Pierantoni, 1912:24 [in part].

Cambarincola Ellis, 1912:481; 1919:263—Hall, 1914:190—

Stephenson, 1930:801.—Yamaguchi, 1933:191; 1934:189.—

Goodnight, 1940:30.—Holt and Hoffman, 1959:97—Hoffman, 1963:271.—Hobbs, Holt, and Walton, 1967:52—Holt,

1969:197.

DIAGNOSIS (from Hobbs, Holt, and Walton,

1967:52).—"Body terete without specialized projections; anterior nephridia opening through common

pore on dorsum of segment III; deferent ducts

entering ental end of spermiducal gland; prostate

and ejaculatory duct both present; penis noneversible; bursa subpyriform to obcordate; spermatheca never bifid."

TYPE-SPECIES.—Cambarincola macrodonta Ellis,

1912, by original designation.

RANGE.—North America. Species of the genus

Cambarincola are the dominant components of

the branchiobdellid fauna in all parts of North

America where branchiobdellids occur (except

from some streams of the Coastal Ranges and Cascade Mountains of the Pacific drainage), ranging

from Ontario and Quebec to Costa Rica; and west

to the Pacific coast of California, Oregon, Washington, and British Columbia.

NOMENCLATURAL EMENDATIONS.—The examples

given under Article 30 (a), (i), (2) of the International Code of Zoological Nomenclature, adopted

by the XV International Congress of Zoology,

dearly prescribes that the generic name Cambarincola is masculine. Of the twenty-two validly published species names in the genus, the following

13, therefore, required emendation:

Cambarincola philadelphica (Leidy) (1851:209) to

C. philadelphicus

Cambarincola macrodonta Ellis (1912:481) to C.

macrodontus

Cambarincola vitrea Ellis (1918:49) to C. vitreus

Cambarincola chirocephala Ellis (1919:263) to C.

chirocephalus
10 SMITHSONIAN CONTRIBUTIONS TO ZOOLOGY

Cambarincola floridana Goodnight (1941:73) to C.

floridanus

Cambarincola macrocephela Goodnight (1943:100)

to C. macrocephelus

Cambarincola branchiophila Holt (1954:168) to C.

branchiophilus

Cambarincola aliena Holt (1963:97) to C. alienus

Cambarincola mesochorea Hoffman (1963:307) to

C. mesochoreus

Cambarincola virginica Hoffman (1963:322) to C.

virginicus

Cambarincola holostoma Hoffman (1963:359) to C.

holostomus

Cambarincola heterognatha Hoffman (1963:362) to

C. heterognathus

Cambarincola demissa Hoffman (1963:365) to C.

demissus

By provision of Article 31 (a) of the International

Code of Zoological Nomenclature, the following

emendation is required:

Cambarincola osceola Hoffman (1963:330) to C.

osceolai

REMARKS.—Less than a decade ago, Hoffman

(1963) accorded monographic treatment to the then

known members of the genus, including within it

21 species of which 12 were newly described and 3

species formerly assigned to the genus were excluded. Since then two additional species (C.

alienus Holt, 1963, and C. smalleyi Holt, 1964) have

Key to the Mesoamerican Species of the Genus Cambarincola

1. Prostate differentiated 2

Prostate not differentiated 3

2. Spermatheca with thick-walled bulb; dental formula 14; dorsal ridges present

C. tolectus, new species

Spermatheca with thin-walled bulb, ental process; dental formula 6/6; dorsal ridges

absent C. smalleyi

3. Dorsal ridges present 4

Dorsal ridges absent, i.e., body outline smooth 5

4. Prostate equal to or exceeding spermiducal gland in length; prostatic bulb prominent

C. olmecus, new species

Prostate shorter than spermiducal gland; prostatic bulb obscure . C. jamapaensis, new species

5. Spermiducal gland shorter than prostate, subequal to latter in diameter; middle segments

of body not greatly exceeding head in diameter C. micradenus, new species

Spermiducal gland longer than prostate; or, if not, body corpulent, middle segments of

body much exceeding head in diameter 6

6. Spermiducal glancj with large deferent lobes; dental formula 7/6

C. acudentatus, new species

Spermiducal gland without large deferent lobes; dental formula less than 7/6 7

7. Spermiducal gland long, slender, bent back upon itself 8

Spermiducal gland relatively short, never reflexed 9

8. Upper jaw noticeably larger than lower (ratio 5:3); prostate with obvious ental bulb;

spermathecal bulb globular C. susanae, new species

Upper and lower jaws not so unequal in size (ratio 3:2); prostate without an ental bulb;

spermathecal bulb elongate ovoid C. ellisi, new species

9. Spermiducal gland shorter than prostate, less in diameter, body corpulent, diameter of

midsegments much exceeding that of head C. hoffmani, new species

Spermiducal gland longer than prostate, latter arising some distance entad to junction

with ejaculatory duct 10

10. Jaws thin, delicate, small; cells of ental portion of spermiducal gland finely granular;

prostate approximately one-half diameter of spermiducal gland

C. nanognathus, new species

Jaws of more nearly normal size, teeth prominent; spermiducal gland large, without two

types of cells; prostate gland less than one-fourth of diameter of spermiducal gland

C. carcinophilus, new species

Note: Cambarincola macrodontus Ellis, recorded from Mexico by Rioja (1940) is not

included, since the record is considered doubtful; the record of C. philadelphicus (Leidy) by

Rioja (1940) is tentatively included under C. jamapaensis.
NUMBER 142 11

been placed in the genus. Despite the excellence

of Hoffman's treatment, the genus is again badly

in need of revision. In addition to the ten new

species from Mesoamerica described below, I have

in my collections an unknown, but large, number of

unnamed ones from the southern Appalachians,

the Ozarks, and the Pacific slope regions of the

United States. The known existence of these undescribed forms renders futile any attempt to improve upon Hoffman's effort to divide the genus

into "sections" and "groups." As will be shown,

some of the criteria he used for these infrageneric

groupings are no longer valid. It is still more futile,

then, to speculate on the historical zoogeography

of the genus, though I accept Hoffman's (1963:298)

belief that the genus was widespread and speciose

by late Miocene times and have briefly discussed

above these ideas as applied to the Mesoamerican

members of the genus.

Rioja (1943) recorded the presence in Mexico

of Cambarincola macrodontus and C. philadelphicus. I have no animals remotely resembling C macrudontits in my materials, but consider the possibility that specimens of C. jamapaensis, new species,

may have been the animals (which are no longer

available) identified by Rioja as C. philadelphicus.

Cambarincola acudentatus, new species

FIGURES 2, 7

TYPE-SPECIMENS.—Holotype and one paratype

(USNM 45435), six para types (PCH 489), four

paratypes, Instituto de Biologia, Universidad de

Mexico, taken on Speocirolano bolivari and S. pelaezi, from Grutas de Quintero, 11 km SW of Ciudad Mante, Tamaulipas, Mexico, 14 May 1950.

DIAGNOSIS.—M e d i u m - s i zed branchiobdellids

(known specimens approximately 3.0 mm in

FIGURE 2.—Cambarincola acudentatus. new species: a, holotype; b, obliquely en face view of

jaws; c, reproductive systems.
12 SMITHSONIAN CONTRIBUTIONS TO ZOOLOGY

length); body outline smooth (no dorsal ridges);

jaws light in color, delicate; dental formula 7/6,

teeth sharp, prominent; bursa small, approximately

1/4 body diameter in length; spermiducal gland

short, 3/4 length of bursa, with prominent deferent

lobes; prostate subequal to spermiducal gland in

length and diameter, its epithelial cells highly granular, different from those of spermiducal gland,

with ental bulb; spermatheca with long ectal duct,

expanded oval bulb, approximately 3/4 to 4/5

body diameter in total length.

ETYMOLOGY.—From Latin acus (needle) plus

dens (tooth) in reference to the sharply pointed

teeth.

DESCRIPTION.—Cambarincola acundentatus is a

medium-sized worm of normal proportions. Only

the holotype is unbroken or not too distorted to

measure; posteriorly it is bent back upon itself. It

has the following approximate dimensions: total

length, 3.0 mm; greatest diameter (segment VII),

0.6 mm; head length, 0.7 mm; head diameter, 0.5

mm; diameter, segment I, 0.3 ram; diameter, sucker,

0.2 mm.

The lips are entire with the usual lateral indentations separating upper and lower ones. There

is no evidence of oral papillae. The external furrow

setting off the peristomium (lips) is not of unusual

prominence. There is only one pharyngeal sulcus.

The body outline is smooth. The clitellar glands

of segments VI and VII are only moderately developed. The sucker is somewhat less in diameter

than segment I.

The jaws are distinctive. They are triangular in

en face view, extremely light in color, delicate in

appearance and approximately 40 by 40 microns in

size. The dental formula is 7/6; the teeth are long

and sharply pointed, the median tooth of the upper

jaw and the paramedian ones of the lower jaw

are larger than the others.

The spermiducal gland is provided with large

deferent lobes and is short and of relatively small

size, its length less than that of the bursa. The

prostate is subequal to the spermiducal gland in

both length and diameter, has a small ental bulb

(i.e., the blind end is occupied by a noncellular,

fluid-filled space) and is composed of cells that are

not highly vacuolated but are granular, as is the

case in some other Mesoamerican species. The

ejaculatory duct is not unusual in its proportions

or length. The bursa is disproportionately small

and the penial sheath makes up approximately 3/7

of its total length, the bursal atrium the remainder.

The penis is less clearly a protrusible cone of

muscular tissue than in most species of the genus,

but is not an obviously eversible tube.

The spermatheca is of ordinary shape and proportions: the ectal duct is a long muscular tube;

the bulb is ovoid and thin-walled; there is no ental

process; the total length approximates the diameter

of segment V. Its only noteworthy feature is the

disproportion between its size and the overall size

of the male reproductive system; the spermatheca

is not usually so much the larger.

VARIATION.—Other than subtle differences in size

and appearance of the organs of the reproductive

systems that are accounted for by differences in the

aspects from which they are viewed, there are no

detectable variations in my material.

AFFINITIES.—The closest relatives of Cambarincola acudentatus appear to be among the members

of Hoffman's Mesochoreus section of Cambarincola and another isopod-inhabiting species, C.

alienus Holt (1963).

All members of the Mesochoreus section have

undifferentiated prostates without ental bulbs and

spermiducal glands with variously developed deferent lobes. Cambarincola acudentatus differs

from these species, exemplified by C. mesochoreus,

in the apparent histological differences between its

prostate and spermiducal gland; the prostate is

granular, but the granules are smaller and apparently much more numerous than those of the

spermiducal gland while, in C. mesochoreus and its

relatives, the prostate is histologically indistinguishable from the spermiducal gland.

The ental bulb, present in C. acudentatus, is

found in members of Hoffman's Philadelphicus

section that have differentiated prostates, in C.

demissus Hoffman (1963) with an undifferentiated

prostate, and in several species newly described

herein.

Cambarincola acudentatus, C. demissus, and C.

alienus have remarkably small male reproductive

systems. The prostate of C. alienus is undifferentiated without an ental bulb and there are no deferent

lobes of its spermiducal gland. Cambarincola smalleyi Holt lacks the ental bulb of the prostate and

deferent lobes of the spermiducal gland, but the
NUMBER 142 13

prostate is differentiated. Its dental formula is 6/6,

close to that of C. acudentatus, but the jaws of C.

smalleyi are subrectangular in form and the teeth

are subequal in length.

The spermatheca varies within the species discussed: it possesses an ental process in C. mesochoreus, C. alienus and C. smalleyi, a structure that

is absent in C. acudentatus, the other members of

the Mesochoreus section, and in C. demissus.

The penis of C. acudentatus is somewhat puzzling and seems to be intermediate in some respects

between that of Tettodrilus friaufi, a representative

of the postulated ancestral stock of the genus

Cambarincola (Holt, 1968b:314-317), and the presumably more advanced species of Cambarincola.

In T. friaufi the penis is composed of an investing

cuticle and a layer of epithelial cells that are not

obviously muscular; in C. acudentatus the penis is

muscular and differs from that of other species of

Cambarincola in that it is proportionately longer.

Cambarincola acudentatus further differs from T.

friaufi in the nature of the prostate, which is incompletely separated from the spermiducal gland

in the latter.

Nonetheless, it is difficult to find a near relative

of C. acudentatus. Its affinities lie with a somewhat

diverse group of species that, for one reason or

another, have been considered as primitive members of the genus (Hoffman, 1963; Holt, 1963, 1964,

1968b, c). The jaws of C. acudentatus, with their

large number of teeth, are diagnostic and clearly

differentiate the species from any known others of

the genus.

HOSTS.—Speocirolana bolivari, S. pelaezi. (C.

acudentatus material came from a collection containing both of these isopods; therefore, I have no

way of knowing whether it occurs on only one or

both.)

MATERIAL EXAMINED.—The type-series.

Cambarincola carcinophilus, new species

FIGURES 3, 7

TYPE-SPECIMENS.—Holotype (USNM 45439), one

paratype, Instituto de Biologia, one paratype (PCH

698), taken on Pseudothelphusa veracruzana from

Rio Tapalapa, Santiago Tuxtla, Veracruz, Mexico

by A. Villalobos and Horton H. Hobbs, Jr., 1957.

DIAGNOSIS.—Medium sized branchiobdellids

(about 3.0 mm in length); body outline smooth;

jaws subequal in size, small; dental formula 5/4;

teeth prominent, sharp-pointed; bursa small (about

0.3 body diameter in length); spermiducal gland

L-shaped, prominent, without deferent lobes;

prostate undifferentiated, slender (its diameter

1/5-1/4 that of spermiducal gland), short reaching

to about midlength of spermiducal gland, tapering

entally; spermatheca spatulate, ectal duct expanded

at juncture with bulb; latter thick-walled, small

broad ental process present.

ETYMOLOGY.—From the Greek karkinos (a crab)

plus philos (love) for this species' association with

freshwater crabs.

FIGURE 3.—Cambarincola carcinophilus, new species: a, holotype; b, lateral view of jaws, from paratype, PCH 698;

c, reproductive systems.
14 SMITHSONIAN CONTRIBUTIONS TO ZOOLOGY

DESCRIPTION.—Cambarincola carcinophilus is a

medium-sized member of the genus. The holotype

has the following dimensions: total length, 3.3 mm;

greatest diameter, 0.6 mm; head length, 0.5 mm;

head diameter, 0.4 mm; diameter, segment I, 0.4

mm; diameter, sucker, 0.3 mm. Only one other

specimen from the type-series is fully mature; it is

3.0 mm in length. Other subadult specimens also

designated as paratypes are about 2.0 mm long.

The lips each have a shallow median emargination. Oral papillae are absent. There is one prominent pharyngeal sulcus internally, externally the

peristomial sulcus and one other at the level of

the pharyngeal one are present, but not prominent.

Supernumerary longitudinal muscles of the body

wall are absent or weakly developed. Consequently

the major annulations of the body segments are

only slightly, if at all, raised above the minor ones.

The anterior nephridiopore presents no unusual

features.

The jaws are small and approximately equal in

size, their length somewhat less than 1/12 that of

the head. In the larger specimens they are rather

dark in color. The dental formula is 5/4 and the

teeth, though the jaws appear hardly different in

proportions from most members of the genus with

a 5/4 dental formula, are large and distinct.

The ectal half of the spermiducal gland usually

lies horizontally; the ental half vertically, i.e., the

organ is bent so that it forms a right angle at its

midlength. It is about 3/5 of the body diameter

in length and about 1/4 of its own length in diameter. There are no deferent lobes. The prostate is

short, ending entally at the midlength of the spermiducal gland in a narrowed, very obscure, ental

bulb. Its diameter is at most 1/4 that of the spermiducal gland, an unusually small size of the organ

among members of the genus, and it is undifferentiated, i.e., histologically indistinguishable from the

spermiducal gland.

The ejaculatory duct is relatively long and the

ovoid bursa correspondingly short: the latter is

about 3/10 of the body diameter in length. The

penial sheath region is not externally marked; the

penis is of the typical cone-shaped, muscular protrusible type characteristic of the genus.

The spermatheca as a whole is spatulate in

shape; the ectal duct widening entally to its juncture with the thick-walled bulb which ends entally

in a short, broad and obscure ental process.

VARIATION.—Other than differences attributable

to the age of the animals and degree of extension

of the body at death, there are no detectable variations among my limited number of specimens.

The unusually large diameter of the type-specimens

may be due to an artifact of fixation and, if so, the

relative sizes of the reproductive organs as given

above would not be representative of the species.

AFFINITIES.—Cambarincola carcinophilus cannot

be readily associated with any of the species of the

genus that have an undifferentiated prostate. Its

affinities are to be sought among the Mesoamerican

species discussed herein. Among these it is perhaps

closest to C. nanognathus, from which it differs in

the larger jaws with more prominent teeth; in the

larger spermiducal gland that is not narrowed ectally, regionally differentiated, or provided with

deferent lobes; and in the relatively smaller prostate that is more completely separated, i.e., arises

nearer the junction of the spermiducal gland and

the ejaculatory duct.

HOSTS.—Pseudothelphusa veracruzana, Procambarus ruthveni zapoapensis.

DISTRIBUTION.—Cambarincola carcinophilus is

only known from two localities in the lowlands of

southern Veracruz in the Southern Gulf Slope

region.

MATERIAL EXAMINED.—The type-series; three

specimens (PCH 700) taken on Pseudothelphusa

veracruzana and Procambarus ruthveni zapoapensis

from Arroyo de Zapoapan de Cabana, Verucruz, by

A. Villalobos and H. H. Hobbs, Jr., 1957. Temnocephalids were associated with the branchiobdellids

at the latter locality.

Cambarincola ellisi, new species

FIGURES 4, 7

TYPE-SPECIMENS.—Holotype (USNM 45443),

taken on Procambarus simulans regiomontanus

from Rio San Juan, San Juan, Nuevo Leon, by

Salvador Contreras, 18 April 1964. Paratype (PCH

1844), taken on P. s. regiomontanus from Arroyo

de la Cruz, km 245 de la carretera MexicoMonterrey, 14 February 1964.

DIAGNOSIS.—Small branchiobdellids (holotype,

1.8 mm in length); body outline smooth; jaws
NUMBER 142 15

small, dark, upper jaw larger than lower (ratio

3:2), dental formula 5/4; bursa small, spherical,

diameter approximately 1/5 that of body; spermiducal gland long, slender, subequal in length to

body diameter, bent completely back upon itself,

without deferent lobes; prostate undifferentiated,

slender, entally ending at bend of spermiducal

gland, without prostatic bulb; spermatheca with

long ectal duct (exceeding 1/2 body diameter in

length), bulb cylindrical to subovate.

ETYMOLOGY.—Named in honor of the late Max

M. Ellis, who first denned the genus Cambarincola.

DESCRIPTION.—Only the types of C. ellisi are

known. The holotype has the following dimensions: total length 1.8 mm; greatest diameter, 0.26

mm; head length, 0.3 mm; head diameter, 0.16 mm;

diameter, segment I, 0.16 mm; diameter, sucker

0.16 mm. The paratype is of closely comparable

dimensions.

The lips are entire; oral papillae are questionably present; the peristomium is well delimited by

an external sulcus. The head shows one other

€

FIGURE 4.—Cambarincola ellisi, new species: a, holotype;

b, obliquely lateral view of jaws; c, reproductive systems.

very shallow external furrow, and there is only

one internal pharyngeal sulcus.

The body outline is remarkably smooth with very

shallow intersegmental furrows and secondary furrows, which demarcate the minor annulations. C.

ellisi is a small gracile worm.

The jaws are darker than is usual for such small

animals, otherwise, with their 5/4 dental formula,

they are similar to those of most, but by no means

all, members of the genus.

The spermiducal gland is extremely long and

slender, without deferent lobes. The gland runs

dorsad from the junction of the deferent ducts to

the dorsal border of the gut, where it is sharply

reflexed in the holotype so that the two portions

actually are in contact, but a small space separates

the ental and ectal portions of the gland in the

paratype. In total length the gland is subequal to

the body diameter. The prostate is undifferentiated, subequal in diameter to the spermiducal

gland, lacks an ental bulb and ends entally at the

point of flexure of the spermiducal gland.

The bursa is small, scarcely extending inward

beyond the inner face of the body wall, spherical,

about 65 microns in diameter (between 1/4 and

1/5 of the body diameter). The ejaculatory duct is

correspondingly short, but not mensurable in my

specimens and distinctly dilated along its midlength.

The ectal duct of the spermatheca is only slightly

less than 1/2 the body diameter in length and

composes 0.6 of the total length of the spermatheca.

The spermathecal bulb is subcylindrical in the

holotype and apparently the wall is thickened, but

in the paratype it is globose and thin-walled, as is

usually the case when full of sperm, and there is

no evidence of an ental process.

VARIATION.—Since only the two types are known

and both are described above, nothing can be said

of variability in the species.

AFFINITIES.—Cambarincola ellisi differs in no important respect from C. vitreus Ellis, 1918, except

for the undifferentiated prostate without an ental

bulb, the apparently smaller size of the entire worm

and the more nearly spherical shape and smaller

size of the bursa (Hoffman, 1963:326). The histological features of the prostate and the presence

or absence of an ental prostatic bulb have proven

to be reliable taxonomic characters in the past and
16 SMITHSONIAN CONTRIBUTIONS TO ZOOLOGY

can usually be detected in poorly preserved material. The types of C. ellisi are not well preserved

and I do not entirely discount the possibility that

subsequent collecting will reduce C. ellisi to

synonymy with C. vitreus. Among Mesoamerican

members of the genus, C. ellisi is closest to C. susanae from which it differs in the shapes and proportions of the jaws, in its proportionately much

longer spermiducal gland and prostate, and in the

absence of deferent lobes of the spermiducal gland.

HOST.—Procambarus simulans regiomontanus.

DISTRIBUTION.—The basin of the Rio San Juan,

which is a tributary to the Rio Grande. C. ellisi is,

therefore, geographically the closest of the Mesoamerican branchiobdellids to those of the United

States.

MATERIAL EXAMINED.—The type-series.

Cambarincola hofimani, new species

FIGURES 5, 7

TYPE-SPECIMENS.—Holotype (USNM 45447),

taken on Procambarus hoffmanni at Los Estajos,

6 km NE of Zihuateutla, Arroyo de Tlatentiloyan,

Puebla, Mexico, 11 November 1949; two paratypes

(PCH 1622), taken on Procambarus caballeroi at

Villa Juarez, Puebla, Mexico, May 1944.

DIAGNOSIS.—Small, corpulent branchiobdellids

(holotype, 2.3 mm in length), body outline smooth;

upper jaw much larger than lower, dental formula

1/2; bursa about 0.3 body diameter in length,

pyriform, atrial fold prominent; spermiducal gland

short, about 2/3 length of bursa, without deferent

lobes; prostate undifferentiated, slightly longer and

greater in diameter than spermiducal gland, rudimentary prostatic bulb present; spermatheca with

long ectal duct, ovoid bulb.

ETYMOLOGY.—It is a pleasure to name this species

in honor of the eminent diplopodologist, Professor

Richard L. Hoffman, in recognition of his contribution to our knowledge of the genus Cambarincola.

DESCRIPTION.—Cambarincola hoffmani is a small

worm. The holotype has the following dimensions:

total length, 2.3 mm; greatest diameter, segment

VII, 0.7 mm; head length 0.4 mm; head diameter,

0.3 mm; diameter, segment I, 0.3 mm; diameter,

sucker, 0.4 mm. The two paratypes from a different

locality are of comparable size, but, since they have

FIGURE 5—Cambarincola hoffmani, new species: a, holotype; b, obliquely lateral view of jaws; c, male reproductive system; d, spermatheca.

suffered some distortion in preservation, were not

measured.

The peristomium, except for the usual lateral

emarginations, appear to be undivided into lobes,

but this point is not firmly determinable in my

material. A number of oral papillae are present.

The body is smooth in outline, i.e., there are no

or very weak supernumerary muscles, but is distinctive in its proportions. The reproductive segments are much greater in diameter than usual,

although the reproductive systems themselves are

not of unusual proportional size. The anterior

nephridiopore, in its usual position, is clearly visible.

The jaws are distinctive. The upper jaw bears a

single large median tooth and is produced anteriorly and laterally in large wing-like extensions.

The lower jaw is roughly rectangular and bears
NUMBER 142 17

two paramedian teeth. The upper jaw is almost

three times the lower in size. The ratio of the

greatest measurable dimensions of the upper to the

lower jaw is 5:2. Both jaws are dark brown in

color, but the teeth are almost colorless.

The spermiducal gland lacks deferent lobes and

is short and thick with a definite lumen in the

holotype that appears to be filled with a granular

material. The prostate is both longer and greater

in diameter than the spermiducal gland and indistinguishable from the latter in appearance, except

that entally there is a clear space that seems comparable to the prostatic bulb of some other species.

The ejaculatory duct is relatively short and thick.

Although the pyriform bursa is relatively small,

there is a distinct atrial fold present and the muscular penis fills the inner penial sheath portion and

extends, in the holotype, into the atrial portion

through the opening in the atrial fold.

The spermatheca is provided with a long ectal

duct that is bent laterad and then dorsad, ending

at the ventral border of the gut in an ovoid "bulb."

(In the holotype, the spermatheca is pressed backward against septum 5/6 so that it actually lies

lateral to and at the same level as the spermiducal

gland.) The bulb, except that its rather small lumen contains spermatozoa, has the appearance of

the ental processes of the spermathecae of some

other branchiobdellids, with a remarkably thick

and apparently nonglandular wall. More unusual,

yet, spermatozoa are present in the ental portion

of the ectal duct, whose wall is clearly muscular,

so that it is possible that the "bulb" of the spermatheca of C. hoffmani is homologous to the ental

process of other species and that the ental portion

of the ectal duct represents the true spermathecal

bulb.

VARIATION.—None in the material examined.

AFFINITIES.—Body shape, size, and the proportionally small reproductive organs are similar to

those of C. demissus Hoffman, 1963, but C. hoffmani differs in the much larger prostate and details

of the spermatheca, bursa, and jaws. The undifferentiated prostate may indicate a primitive status

for both species, the other similarities are more

likely paralellisms associated with similar habits or

habitats (Hoffman, 1963:365, postulated, on the basis of appearance, that C. demissus inhabits the gill

chambers of the host, and without any real evidence, I concur in this guess for both species).

Most, not all Mesoamerican members of the genus

lack differentiated prostates (but cf. C. smalleyi

Holt, 1964, and C. toltecus, new species, described

herein). Cambarincola micradenus, new species, in

the thickened wall of its spermatheca and similar

jaws, may well be closest to C. hoffmani, but the

differences in body proportions—those of C. micradenus are more typical of the genus—and those of

the male reproductive systems clearly separate the

two species.

HOSTS.—Procambarus hoffmanni, P. caballeroi.

DISTRIBUTION.—The Interjacent Gulf Slope in

Puebla, Mexico.

MATERIAL EXAMINED.—The type-series.

Cambarincola jamapaensis, new species

FIGURES 6, 7

TYPE-SPECIMENS.—Holotype and five immature

paratypes (USNM 45438); one paratype (PCH

1592), taken on Procambarus mexicanus from the

Rio Jamapa at 7 km NE of Coscomatepec, Veracruz, Mexico, by P. C. and V. F. Holt, 9 July 1962.

DIAGNOSIS.—Small branchiobdellids, about 2.0

mm in length; major annulations of body segments

greater in diameter than minor ones; jaws dark,

triangular; dental formula 5/4; bursa ovate, approximately 1/3 body diameter in length, penial

sheath portion short; spermiducal gland slightly

longer than bursa, without prominent deferent

lobes; prostate only slightly shorter than spermiducal gland, its cells more densely granular than those

of latter, with small ental bulb; spermatheca with

long ectal duct, expanded ovoid bulb.

ETYMOLOGY.—This species is named for the typelocality, the Rio Jamapa.

DESCRIPTION.—Cambarincola jamapaensis is a

small branchiobdellid, approximately 2.0 mm in

length. The holotype and paratype are the only

mature animals among the type-material and they

are of approximately the same size. The holotype

has the following dimensions: total length, 2.0

mm; greatest diameter, segment VII, 0.3 mm; head

length, 0.45 mm; head diameter, 0.3 mm; diameter,

segment I, 0.3 mm; diameter, sucker, 0.3 mm.

The upper lip bears four blunt lobes, often obscured by the extension of the animal or fixation

while attached by the mouth; the lower lip is di-
18

SMITHSONIAN CONTRIBUTIONS TO ZOOLOGY

FIGURE 6.—Cambarincola jamapaensis, new species: a, holotype; b, lateral view of

jaws; c, reproductive systems.

vided into two lobes by a slight median emargination; laterally, in the indentation between upper

and lower lips on each side there are two much

smaller lobes. Oral papillae are absent. The peristomial sulcus is not unusually prominent and internally there is only one prominent pharyngeal sulcus

that is marked externally by a shallow furrow that

encircles the head.

The major annulations of the body segments are

greater in diameter than the minor ones. The anterior nephridiopore is prominent in the holotype,

the "nephridial vesicle" (Moore, 1897) is large and

surrounded by glandular cells, but is obscured by

the orientation of the animal on the slide in the

paratype. The clitellum, as usual in species with

raised ridges on the dorsa of major annulations, is

not noticeably well developed.

The jaws are triangular in both en face and

lateral aspects, dark brown in color and approximately 1/6 of the head diameter in width. The

dental formula is 5/4; the median teeth are strong,

somewhat blunt; the much smaller lateral ones are

obscure in lateral view.

The spermiducal gland is between 1/3 and 1/2
NUMBER 142

of the body diameter in length, straight (not bent

back upon itself), without deferent lobes. The

prostate is approximately 4/5 the length of the

spermiducal gland and 3/5 its diameter. Its

cells are more densely granular than those

of the spermiducal gland, but not differentiated.

An ental prostatic bulb is present. The bursa is

ovoid in length with a short, externally nonde19

limited penial sheath region. The penis is an

almost spherical muscular mass.

The spermatheca has a long ectal duct portion

and an oval thin-walled spermathecal bulb (not

expanded nor filled with spermatozoa in the holotype).

VARIATION.—Only two of my specimens are sexually mature and, except for the difference in the

• Cambarincola

• Cambarincola

• Cambarincola

• Cambarincola

• Cambarincola

acudentatatus

carcinophilus

ellisi

hoffmani

jamapaensis

= Cordillera Volcanico Transversal

FIGURE 7.—Distribution of five Mexican members of the genus Cambarincola.
20

SMITHSONIAN CONTRIBUTIONS TO ZOOLOGY

degree of expansion of the spermathecal bulb, there

are no detectable differences between them that

cannot be accounted for by the usual differences in

position and degree of contraction of the bodies at

death.

AFFINITIES.—Cambarincola jamapaensis is very

similar in appearance to the Appalachian members

of the Philadelphicus section. Indeed Rioja (1943)

has recorded C. philadelphicus from localities in

Puebla (Hauchinango, Necaxa, and Villa Juarez).

It is extremely unlikely that C. philadelphicus occurs in Mexico and if Rioja was dealing with C.

jamapaensis (one of the more likely possibilities),

the mistake is understandable. Most students of

the branchiobdellids of that time would have unhesitatingly assigned my specimens to C. philadelphicus on the basis of peristomial and jaw characters, body form and an overall resemblance of

the reproductive systems. Yet the animals are not

so large, and the lobes of the upper lip and the

raised major annulations of C. jamapaensis are not

so prominent as they are in C. philadelphicus and

the prostate is markedly different in the two species. The prostate is composed of vacuolated cells

in C philadelphicus and densely granular ones in

C. jamapaensis, a difference earlier considered to be

of fundamental importance and one upon which

Hoffman (1963) based his subgeneric sections. Although this grouping of species, with the addition

to our knowledge of the Mesoamerican branchiobdellids, may no longer be tenable, the histological

characteristics of the prostate are constant within a

species and clearly justify according species status

to the animals from the Rio Jamapa.

Among Mesoamerican congeners of C. jamapaensis, C. olmecus and C. toltecus have dorsal ridges.

Cambarincola olmecus has a much longer prostate

with a larger ental bulb than does C. jamapaensis;

C. toltecus has a differentiated prostate and a thick

walled spermatheca, neither of which are present in

C. jamapaensis.

HOSTS.—Procambarus mexicanus, P. hoffmanni,

P. acutus cuevachicae.

DISTRIBUTION.—Cambarincola jamapaensis is

known with certainty only from the type-locality

in the Southern Gulf Slope. With some hesitation

I have assigned specimens (see below) from north

of the Cordillera Volcanico in the Interjacent Gulf

Slope to the species. It is likely that these worms,

if this assignment is correct, are conspecific with

those from Puebla identified as C. philadelphicus

by Rioja (1943).

MATERIAL EXAMINED.—The type-series; three

specimens (PCH 702), on Procambarus hoffmanni

at Mi Ranchito, Villa Juarez, Puebla, Mexico, by

A. Villalobos and H. H. Hobbs, Jr., 4 April 1957;

one (PCH 703), taken on P. acutus cuevachicae at

El Ajenjibre, Mesa de San Diego, km 262 de la

carretera Mexico-Tuxpan, Puebla, Mexico, by A.

Villalobos and H. H. Hobbs, Jr., 12 April 1957.

Cambarincola micradenus, new species

FIGURES 8, 14

TYPE-SPECIMENS.—Holotype and two paratypes

(USNM 45448), one paratype (PCH 1615), taken

on Paracambarus paradoxus at La Canada y Tetela

de Ocampo, Puebla, Mexico, May 1944.

DIAGNOSIS.—Small branchiobdellids (known

specimens approximately 2.5 mm in length); body

outline smooth (no raised dorsal ridges); dental

formula 1/2; upper lip with four, lower lip with

two, low indistinct lobes; bursa small, about 3/7

body diameter in length; spermiducal gland very

small, hardly more than 1/3 length of bursa, without deferent lobes; prostate slender, subequal to

spermiducal gland in diameter, twice latter in

length, undifferentiated; with ental bulb; spermatheca club-shaped with long ectal duct, short

thick-walled bulb, approximately 1/2 diameter of

body in length..

ETYMOLOGY.—From Greek mikros (little) plus

adenus (gland) in reference to the remarkably

small spermiducal gland.

DESCRIPTION.—Cambarincola micradenus, as is

true of most Mesoamerican branchiobdellids, is a

small worm. The holotype has the following dimensions: total length, 2.7 mm; greatest diameter,

0.5 mm; head length, 0.4 mm; head diameter, 0.3

mm; diameter, segment I, 0.3 mm; diameter, sucker,

0.4 mm. The other known specimens are smaller;

the smallest is 1.8 mm in total length.

The peristomium is rather weakly lobed and

there are no oral papillae.

The body wall is thin and there are no, or very

weak, supernumerary muscles, hence the body outline is smooth and the major annulations are only

very slightly greater in diameter than the minor
NUMBER 142 21

FIGURE 8.—Cambarincola micradenus, new species: a, holotype; b, lateral view of jaws; c,

reproductive systems.

ones, even in strongly contracted specimens. The

single anterior nephridiopore is clearly visible on

the dorsum of segment III. The posterior segments

are provided with a large number of glands (apparently more, or more prominently, than is common)

that appear to empty to the outside through the

sucker.

The jaws are prominent and distinctive. The

upper is more than twice the lower in its greatest

dimension and bears a single large tooth; the lower

bears two much smaller teeth.

The gut of some of the specimens is filled with

a coagulum that may be the blood of the host.

The spermiducal gland is remarkably small in

proportion to the relatively small male reproductive system as a whole. It is about 1/3 the length

of the bursa and lacks deferent lobes. The prostate

exceeds by approximately 1/3 its length that of the

spermiducal gland and is undifferentiated, although its cells appear slightly more granular than

those of the spermiducal gland. It ends entally in

a thick-walled bulb that is quite different in appearance from the usual thin-walled prostatic bulbs

of other branchiobdellids with such a feature.

The ejaculatory duct is relatively long, exceeding

slightly the spermiducal gland in length, with an

expanded lumen and a relatively thin muscular

wall. The penis is difficult to interpret in the available material, but appears to consist of the protrusible muscular cone characteristic of the genus.

If so, it is rather thin-walled, but there is no observable evidence of an eversible cuticular lining.

The bursa is elongate pyriform in shape, about 3/7,

or less, the body diameter in length, and is marked

internally by a well-developed atrial fold.

Any accurate estimation of the length of the

spermatheca is not possible, since it is normally

bent to the side, but in side view its ental end

barely reaches the ventral border of the gut. The

ectal duct, however, approximates half the total

length of the organ and the bulb is lined with a

glandular epithelium which confers upon the entire spermathecal bulb the appearance of the ental

process of the spermatheca known from some other

species. The clitellum, in the better preserved

specimens, is unusually well developed, particularly

on segment VII.

VARIATION.—Other than in size and quality of

preservation, there are no detectable differences

among the available material.

AFFINITIES.—The spermiducal gland and prostate

of Cambarincola micradenus are peculiar and reminiscent of those of Tettodrilus friaufi (cf. Holt,

1968b:313, 315). The jaws, however, are specialized

and the animal has the general facies of a gillinhabiting species, although nothing is known of

its microhabitat. The most that can be said of the

relationships of C. micradenus is that it is a primitive member of the genus, apparently close to

Tettodrilus friaufi, which has been postulated to

represent the group from which Cambarincola

arose (Holt, 1968b:313-314). Indeed, at first, I was
22

SMITHSONIAN CONTRIBUTIONS TO ZOOLOGY

inclined to place micradenus in Tettodrilus, but

the protrusible penis of micradenus as opposed to

the eversible one of the latter and, to a much lesser

extent, the specialized features of the jaws seem

to argue for retaining it among the members of

Cambarincola. Its closest relative within the genus

is C. hoffmani, new species, primarily because of

the nature of the spermiducal gland and prostate,

the thick-walled spermathecal bulb and the similar

jaws. The addition of this species and that of the

others herein assigned to the genus Cambarincola

will require a revision of the groupings proposed

by Hoffman (1963:300-301).

HOSTS.—Paracambarus paradoxus.

DISTRIBUTION.—Cambarincola micradenus is

known only from the type-locality in the Interjacent Gulf Slope.

MATERIAL EXAMINED.—The type-series.

Cambarincola nanognathus, new species

FIGURES 9, 14

TYPE-SPECIMENS.—Holotype (USNM 45444); one

paratype (PCH 1830); one paratype, Instituto de

Biologia, Universidad de Mexico, on Potamocarcinus nicaraguensis taken at Isleta de Granada, Lago

de Nicaragua, Nicaragua, by G. Alvil^z, 13 July

1964.

DIAGNOSIS.—Small branchiobdellids (known

specimens approximately 2.0 mm in length); body

outline smooth (no dorsal ridges); jaws light in

color, small, dental formula 5/4; bursa small, approximately 1/4 or less body diameter in length;

spermiducal gland slender, approximately 1.8 times

bursal length, cells of ental half finely granular,

without prominent deferent lobes; prostate incompletely divided from spermiducal gland, approximately 1/2 as long as latter, undifferentiated, with

ental bulb; spermatheca approximately 2/3 body

diameter in length, ectal duct and bulb subequal

in length, ental portion of bulb thick-walled.

ETYMOLOGY.—From Greek nanos (dwarf) plus

gnathos (jaw) in reference to the small size of the

jaws.

DESCRIPTION.—Cambarincola nanognathus is a

small member of the genus. The holotype has the

following dimensions: total length, 2.1 mm; greatest diameter, segment VII, 0.4 mm; head length,

0.3 mm; head diameter, 0.25 mm; diameter, segFIGURE 9.—Cambarincola nanognathus, new species: a, holotype; b, lateral view of jaws; c, en face view of jaws; d,

reproductive systems.

ment I, 0.3 mm; diameter, sucker, 0.2 mm. (Many

specimens of the series are poorly preserved, partially macerated and grossly extended; none of

these were measured.) The average dimensions of

the holotype and four paratypes, with ranges given

in parentheses, are as follows: total length, 1.9 mm

(1.6-2.1 mm); greatest diameter, segment VII, 0.4

mm (0.3-0.5 mm); head length, 0.3 mm (0.25-0.5

mm); head diameter, 0.2 mm (0.2-0.3 mm); diameter, segment I, 0.3 (0.2-0.3 mm); diameter, sucker,

0.2 (0.2-0.2 mm). The undistorted specimens studied are of rather uniform size and proportions.

The lips are entire without median indentations.

There are no oral papillae. The peristomium is

set off by a deep sulcus. Internally, there is only

one prominent pharyngeal sulcus.

The body outline is smooth, although intersegmental grooves are prominent. The anterior nephridiopore, usually difficult to detect in entire

animals, is obvious in almost all specimens. The
NUMBER 142 23

clitellum, especially on segment VII, is well developed.

The jaws are of the usual form for members of

the genus. They are triangular in lateral view and

subrectangular in en face view. They are lightly,

though distinctly colored. But their small size is

notable. The upper jaw illustrated (from a poorly

preserved specimen) measures 26 by 15 microns;

the lower (from the same specimen), 22 by 15 microns. The dental formula is 5/4 and the median

teeth of each jaw are longer than the lateral ones.

The spermiducal gland is relatively long and

slender and without obvious deferent lobes. The

glandular cells of its ental portion are filled with

small granules; ectally they lack such granules. The

prostate is undifferentiated, noticeably less in diameter than the spermiducal gland, about 1/2 its

length and incompletely separated, i.e., it unites

with the spermiducal gland about 1/3 the length

of the latter entad to its union with the ejaculatory

duct. A distinct ental prostatic bulb is present.

The ejaculatory duct is not remarkable in any way,

nor is the bursa except for its small size (about

100 microns in length).

The spermatheca, about 2/3 of the body diameter in total length, has a relatively long ectal

duct. The middle portion, the spermathecal bulb,

is of usual appearance, but the ental part, somewhat less in diameter than the bulb in many specimens, has a wall composed of a taller columnar

epithelium than the bulb proper—a condition suggestive of the ental process of the spermatheca in

some species (Holt, 1960a:64).

VARIATION.—Some apparent variation in the

number of teeth borne by the jaws occurs, but most

likely this is due to the breaking of lateral teeth.

In any case, it is difficult in such small animals to

determine the number and arrangement of the

teeth, but there is little doubt that the normal dental formula of the species is 5/4.

AFFINITIES.—Cambarincola nanognathus appears

to be closely related to C. acudentatus, new species, and C. smalleyi. It differs from C. acudentatus

in the smaller size of its jaws and its dental formula, in the absence of deferent lobes and in the

finely granular ental portion of its spermiducal

gland (unique among known members of the

genus), in the incompletely separated prostate and

in the ental process (if the thicker wall of the

ental portion of the spermatheca may be called an

ental process) of its spermatheca. It differs from

C. smalleyi in dental formula (6/6 in the latter),

in its undifferentiated prostate and prostatic bulb

(the prostate of C. smalleyi is differentiated but

lacks the ental bulb) and perhaps, most uncertainly, in the ental process of the spermatheca (distinct in C. smalleyi). Cambarincola nanognathus

is a primitive member of the genus on the basis

of the prostate, differentiated ental part of the

spermatheca, and, perhaps, in its small size, delicate

jaws, and lack of dorsal ridges. The histological

differences along the course of the spermiducal

gland canot be accounted for now. Such differences

are characteristic of some branchiobdellids without a prostate, e.g., species of Xironogiton Ellis

(Holt, 1949), but were unknown among species of

Cambarincola and those of related genera with

prostates. In the small size of the animal itself, the

jaws and the male reproductive system, in the incompletely separated and undifferentiated prostate

with an ental bulb and in the thick-walled ental

part of the spermatheca, C. nanognathus resembles

putatively primitive species of Pterodrilus Moore

(Holt, 1968c), but lacks any dorsal ridges, of which

at least one is present in all known species of

Pterodrilus. Perhaps it stands near the point of divergence of the two closely related genera. But the

combination of characters discussed above, particularly the spermiducal gland, clearly differentiates

it from any species of these two genera.

HOSTS.—Potamocarcinus nicaraguensis, Pseudothelphusa veracruzana, Procambarus vazquezae.

DISTRIBUTION.—Cambarincola nanognathus

ranges from the Rfo Tapalapa and Laguna de Catemaco in southern Veracruz, Mexico, to the typelocality in Nicaragua, which is the second southernmost locality from which a branchiobdellid has

been recorded. It, thus, partially fills the gap between its closest relatives, C. acudentatus and C.

smalleyi, the southernmost known branchiobdellid.

MATERIAL EXAMINED.—The type-series; 39 others

from the type-locality (PCH 1830); 25 specimens

(PCH 696) taken on Procambarus vazquezae from

Laguna de Catemaco, Playa Azul, Veracruz, Mexico

by A. Villalobos and H. H. Hobbs, Jr., 15 April

1957; 22 (PCH 697) taken on Pseudothelphusa

veracruzana, from the Rio Tapalapa, Santiago

Tuxtla, Veracruz, Mexico by A. Villalobos and H.

H. Hobbs, Jr., 9 April 1957.
24 SMITHSONIAN CONTRIBUTIONS TO ZOOLOGY

Cambarincola olmecus, new species

FIGURES 10, 14

TYPE-SPECIMENS.—Holotype (USNM 45445), one

paratype (USNM 45446), one paratype (PCH 201),

and one paratype, Instituto de Biologia, Universidad de Mexico; taken on Procambarus aztecus at

Tomatldn, Veracruz, Mexico, 3 November 1948.

DIAGNOSIS.—Medium-sized branchiobdellids (2-3

mm in length); major annulations of body segments

greater in diameter than minor ones; jaws triangular, dark; dental formula 5/4; bursa pyriform,

approximately 1/3 body diameter in length; spermiducal gland slender, curved, with small deferent

lobes; prostate with finely granular cells (nondifferentiated), equal to or exceeding spermiducal

gland in length, with prominent expanded ental

bulb, often curved away from spermiducal gland;

spermatheca with large, approximately ovoid, bulb,

without ental process.

ETYMOLOGY.—This species is named for the Olmecs, one of the early peoples of Mexico.

DESCRIPTION.—Cambarincola olmecus ranges

from about 2.0 to 3.0 mm in length, somewhat

larger than most Mesoamerican members of the

genus but moderately small for the genus as a

whole. The holotype has the following dimensions:

total length, 2.9 mm; greatest diameter; 0.46 mm;

head length, 0.5 mm; head diameter, 0.3 mm; diameter, segment I, 0.26 mm; diameter, sucker, 0.3

mm. The average dimensions, with ranges given

in parentheses, of five specimens from Ciudad MenFIGURE 10.—Cambarincola olmecus, new species: a, holotype; b, en face view of upper jaw;

c, en face view of lower jaw; d, reproductive systems.
NUMBER 142 25

doza, Veracruz, are as follows: total length, 2.3 mm

(1.9-2.5 mm); greatest diameter, 0.4 mm (0.35-0.5

mm); .head length, 0.4 mm (0.4-0.5 mm); head

diameter, 0.3 mm (0.3-0.3 mm); diameter, segment

I, 0.3 mm (0.3-0.3 mm); diameter, sucker, 0.3 mm

(0.2-0.3 mm).

The dorsal lip is divided into four short, blunt

lobes by very shallow indentations and the lower

lip into two. Between the upper and lower lips

there are small medial lobes, each of which may

appear subdivided in some specimens. There are

no oral papillae. Internally, there is only one

prominent pharyngeal sulcus. Externally, the

peristomial sulcus is prominent in dorsal view and

another shallow furrow encircles the head at the

level of the pharyngeal sulcus.

The major annulations are marked dorsally by

raised ridges which are not usually prominent. The

anterior nephridiopore is not easily seen.

The brown jaws are triangular in both en face

and lateral views. The dental formula is 5/4, but

the lateral teeth of both jaws in larger (? older)

animals are often obscure or worn away so that the

dental formula may appear to be 1/2.

The spermiducal gland, approximately 1/2 the

body diameter in length and slightly curved, is

provided with deferent lobes of which the anterior

is the larger. The prostate frequently exceeds and

always appears to be at least subequal in length

and is about 1/2 the diameter of the spermiducal

gland. Its ental end is often bent back upon itself

or away from the spermiducal gland. It is always

provided with a large, often expanded, ental bulb

formed by a reduction of the prostatic epithelium

to a thin layer of nonglandular cells, which enclose

an expansion of its lumen. The glandular cells of

the prostate are not markedly vacuolated as in the

differentiated type of a prostate, but often appear

to be more finely granular than those of the spermiducal gland.

The ejaculatory duct, penis, and bursa present

no significant features. The bursa is about 1/3 the

body diameter in length and the penial sheath

portion, approximately 1/2 of the total length, is

somewhat reduced in diameter; the organ is, therefore, pyriform.

The ectal duct of the spermatheca is somewhat

thick and about 1/3 the total length of the organ;

the bulb is subovoid with a suggestion of an ental

process produced by the lesser diameter of its ental

end, but the wall of this narrowed portion of the

bulb is not histologically distinct from that of its

middle portion and contains spermatozoa.

VARIATION.—The dental formula of C. olmecus,

as mentioned above, appears to vary from 5/4 to

1/2. Apparently in older animals the lateral teeth,

always relatively small, wear away with age. The

prostate is always as long as the spermiducal gland

and in many specimens appears to be longer, but

its ental end is not closely bound by its peritoneal

investment to the latter and is often bent in various

directions away from it. The ental bulb of the

prostate may be expanded to differing degrees, although it is always unusually prominent. Likewise,

though not rare among the branchiobdellids, the

bulb of the spermatheca, and particularly its ental

part, may be distended to a greater or lesser extent

so that in some, presumably younger animals, the

spermatheca may appear to have an ental process.

None of these variations seem to be correlated with

the geographical distributions of the populations

from which they come. No other variations were

noted, except the usual differences in size and proportions that are dependent upon age and differing concentrations of fixatives.

AFFINITIES.—Cambarincola olmecus, as is true of

C. jamapaensis, new species, is in many respects

similar to species previously assigned to the Philadelphicus section of the genus; C. jamapaensis,

then, may be its closest relative. Cambarincola olmecus is slightly larger; the prostate is longer and

its ental bulb much more prominent; the bursa is

pyriform rather than ovoid; and the spermathecal

bulb is less obviously ovoid with a suggestion of

an ental process. These two species are closely

related and if further collecting were possible, it is

conceivable that they could be shown to be local

variants of the same species, yet, for now, the length

of the prostate serves to sharply separate the two.

Cambarincola ingens Hoffman, 1963, is similarly

separated from C. philadelphicus (Leidy, 1851),

and there is no doubt that they are distinct, though

largely sympatric, species.

HOSTS.—Procambarus aztecus, P. mexicanus, P.

acutus cuevachicae.

DISTRIBUTION.—Cambarincola olmecus, though

not, apparently, a primitive member of the genus,

at least among the Mesoamerican ones, is found
26 SMITHSONIAN CONTRIBUTIONS TO ZOOLOGY

on both sides of the Cordillera Volcanica Transversal in the Northern Gulf Slope in San Luis

Potosi and in the Southern Gulf Slope in Veracruz.

It probably occurs, or has occurred, in the Interjacent Gulf Slope.

MATERIAL EXAMINED.—The type-series; over seventy specimens (PCH 1601) taken on Procambarus

mexicanus at Ricon de la Doncella, Ciudad Mendoza, Veracruz, 18 May 1956; seven (PCH 1621,

1625) taken on P. acutus cuevachicae at Aquism6n,

km 419 de la carretera Mexico-Valles, San Luis Potosi, 6, 7 April 1956.

Cambarincola smalleyi Holt, 1964

FIGURES 7, 11

Cambarincola smalleyi Holt, 1964:1.

TYPE-SPECIMENS.—Holotype (USNM 30940); one

paratype (USNM 30941); one paratype in the collections of Tulane University (Dr. A. E. Smalley);

one paratype (PCH 1702) taken on Pseudothelphusa tumimanus from Rio Hondura, eight miles

north of San Jeronimo de Moravia, San Jose Province, Costa Rica, by A. E. Smalley, 9 July 1962.

DIAGNOSIS (from Holt, 1964:1).—

Medium-sized members of the genus; head approximately

equal in diameter to that of segment I and the sucker, showing external evidence of being composed of four segments;

prosomites of body segments not appreciably greater in

diameter than metasomites; jaws homodont and isomorphic,

dental formula 6/6. Male reproductive system: the prostate

about two-thirds the size of the spermiducal gland in length

and diameter and histologically different [differentiated, with

large vacuolated cells] from the latter, the prostate lacking

an ental bulb; the spermiducal gland without deferent lobes;

the bursa elongate pyriform in shape. Female reproductive

system: spermatheca with a long ectal duct and an ental

process.

AFFINITIES.—Cambarincola smalleyi and C. toltecus, new species, are the only Mesoamerican members of the genus with differentiated prostates, otherwise they differ in the raised dorsal ridges and the

unusual spermatheca of the latter. The jaws are

unusual and are most like those of C. acudentatus,

new species. The latter, however, differs from C.

smalleyi in the lack of an ental process of the spermatheca, in its nondifferentiated prostate and the

presence of large deferent lobes of its spermatheca.

Perhaps C. nanognathus, new species, the next

southernmost branchiobdellid, is closest to C.

FIGURE 11—Cambarincola smalleyi: a, holotype; b, dorsal

jaw, paratype; c, ventral jaw, paratype; d, reproductive systems. (From Holt, 1964.)
NUMBER 142 27

smalleyi, but they differ in dental formulae and the

nature of the prostate.

HOST.—Pseudothelphusa tumimanus.

DISTRIBUTION.—Known only from the typelocality.

REMARKS.—With the discovery of several other

branchiobdellids, including C. nanognathus, new

species, which has been taken from both crabs and

crayfish in southern Mexico and Nicaragua, I cannot be as sure as I was when I said of C. smalleyi

(Holt, 1964:3): "Yet cambarine crawfishes must

have carried them to Costa Rica, lost in competition with tropical crabs, and passed their commensals to their conquerors." It is possible that the

transferral of branchiobdellids to crabs occurred

much farther north in Mexico, and that they were

then carried (by crabs) in Mexico to Nicaragua

and Costa Rica—beyond the southernmost regions

ever reached by crayfish.

Cambarincola susanae, new species

FIGURES 12, 14

TYPE-SPECIMENS.—Holotype and two paratypes

(USNM 45441), ten paratypes (PCH 1629), three

paratypes, Instituto de Biologia, Universidad de

Mexico, taken on Procambarus acutus cuevachicae

at Cueva Chica, El Pujal, 3 km northeast of Valles,

San Luis Potosi, Mexico, 9 May 1950.

DIAGNOSIS.—Small branchiobdellids (known

FIGURE 12.—Cambarincola susanae, new species: a, holotype; b, paratype (contracted); c, reproductive systems; d, obliquely en face view of jaws; e, lateral view of jaws.
28 SMITHSONIAN CONTRIBUTIONS TO ZOOLOGY

specimens approximately 2 mm in length); body

outline smooth (no raised dorsal ridges); upper jaw

larger than lower (ratio of length to width in both

upper and lower jaw approximately 5:3), dental

formula 5/4; bursa small, spermiducal gland long,

bent back upon itself, with small deferent lobes,

prostate undifferentiated, ental end extending to

bend of spermiducal gland, with small ental bulb;

spermatheca with expanded bulb, no ental process.

ETYMOLOGY.—This species is named in honor of

my daughter, Mrs. Susan E. H. West, who in her

childhood was assiduous and courageous in assisting me in collecting branchiobdellids.

DESCRIPTION.—Cambarincola susanae is a small

branchiobdellid. The holotype, greatly extended

and selected for clarity with which its internal

structures may be seen rather than for its typical

proportions, has the following dimensions: total

length, 3.2 mm; greatest diameter, segment VII,

0.4 mm; head length, 0.5 mm; head diameter, 0.25

mm; diameter, segment I, 0.2 mm; diameter, sucker,

0.25 mm. The average dimensions of the holotype

and four other specimens, each from a different

locality, with ranges given in parentheses, are as

follows: total length, 2.3 mm (1.6-3.2 mm); greatest

diameter, segment VII, 0.4 mm (0.3-0.5 mm); head

length, 0.35 mm (0.25-0.5 mm); head diameter, 0.2

mm (0.2-0.3 mm); diameter, segment I, 0.2 mm

(0.2-0.3 mm); diameter, sucker, 0.2 mm (0.2-0.3

mm). The usual proportions of the animals in a

contracted state, as it would normally be collected,

are illustrated in Figure 126.

The dorsal lip is divided into four very short

and broad lobes by shallow indentations; the lower

lip is entire. There are no oral papillae. The

peristomial sulcus is shallow. The body, smooth

in outline, presents no unusual features.

The jaws are distinctive. The upper jaw, almost

twice the length and width of the lower one, consists of a triangular tooth-bearing ridge set upon a

larger base. The lower jaw is deeply concave on its

free (internally facing) surface with a deep indentation or sulcus between the median teeth. Both

jaws are distinctly brown, though not extremely

dark. The dental formula is 5/4.

The deferent ducts expand slightly to form

rather small deferent lobes before they unite to produce the spermiducal gland. The latter is long

and bent back upon itself at its midlength. The

prostate is approximately half the length of the

spermiducal gland and ends entally in a small,

often narrowed, ental bulb at the flexure of the

spermiducal gland. It is not histologically distinct

from the spermiducal gland; the cells of the glandular epithelium of both are finely granular throughout the length of both organs.

The ejaculatory duct is not remarkable. The

bursa is short, almost spherical in shape, and approximately 1/4 the body diameter in length (0.1

mm).

The ectal duct of the spermatheca, curved

around the gut in the holotype, is approximately

2/3 the body diameter in length. The bulb of the

spermatheca is expanded, subspherical in shape,

and lacks an ental process.

VARIATION.—There is considerable variability in

size and proportions among the specimens that compose my material, ascribed to the various concentrations of the alcohol used in the collection and

storage of the host crayfish. Many specimens are

greatly extended and often badly macerated. No

significant differences in the reproductive systems

occur, except that the spermathecal bulb is cylindrical and unexpanded in some animals. There is

some variability in the relative size of the jaws

and among the specimens of a collection from the

Rio San Juan, Nuevo Leon (PCH 1606), the ratio

of the anteroposterior length of the upper to the

lower jaw varies from approximately 2:1 to 6:5.

AFFINITIES.—The jaws of C. susanae are most

nearly like those of C. heterognathus Hoffman, but

the latter is an Appalachian member of the Philadelphicus section of the genus with a short spermiducal gland and a very short and differentiated

prostate; it is not likely that the two are closely

related. C. vitreus Ellis has a long spermiducal

gland that is bent back upon itself, as is that of

C. susanae, but this inhabitant of the Mississippi

Valley and the Coastal Plains of the United States

is likewise a member of a group of species with a

differentiated prostate and otherwise is unlike C.

susanae. The relationships of C susanae would appear, therefore, to lie with other members of the

genus from Mesoamerica, from all of which, except

for C. ellisi, new species, it is easily distinguished

by the marked dissimilarity in the size of the upper

and lower jaws and the length of the spermiducal

gland.
NUMBER 142 29

HOSTS.—Procambarus gonopodcristatus, P. acutus cuevachicae, P. simulans regiomontanus, P.

llamasi.

DISTRIBUTION.—Cambarincola susanae occurs in

five states in Mexico, ranging from the Rio Grande

drainage in Nuevo Leon (Rio San Juan) to western

Campeche in the Yucatan Peninsula and hence, in

all of Hobbs' faunistic regions except the Central

Plateau.

MATERIAL EXAMINED.—The type-series and 17

others (PCH 1629); one specimen (PCH 1627)

taken on Procambarus llamasi at 10 km S of Escarcega, Campeche, 14 January 1953; 8 (PCH 1606)

taken on P. simulans regiomontanus at San Juan,

Rio San Juan, Nuevo Leon, by Laura Trevino

Rodriguez, 22 May 1960; 3 (PCH 1628) taken on

P. acutus cuevachicae at El Ajenjibre, Mesa de San

Diego, km 262 de la carretera M£xico-Tuxpan,

Puebla, 9 May 1950; 18 (PCH 1621) taken on P.

acutus cuevachicae at Aquism6n, km 419 de la

carretera Mexico-Valles, San Luis Potosf, 6 April

1956; 7 (PCH 1625) taken on P. acutus cuevachicae

at 4 kms E Aquism6n, San Luis Potosi, 7 April

1950; 16 (PCH 1604) taken on P. gonopodocristatus at Mana de Casse, Veracruz, 18 July 1957.

REMARKS.—Cambarincola susanae may be an inhabitant of the gill chamber of the hosts (the host

animals were museum material and I did not examine the branchial chambers of any of them).

The body wall is thin and delicate as in known

inhabitants of the gill chambers and unlike, in

this respect, most other branchiobdellids; the gut

is often, though not always, filled with a homogeneous material that may be the blood of the host.

Most gill-dwelling branchiobdellids probably are

ectoparasites, feeding on the host's blood.

Cambarincola toltecus, new species

FIGURES 13, 14

TYPE-SPECIMENS.—Holotype (USNM 45436); two

paratypes (USNM 45437); two paratypes, Instituto

de Biologia, Universidad National Aut6noma de

Mexico; two paratypes (PCH 697); taken on Pseudothelphusa veracruzana from Rio Tapalapa, Santiago, Tuxtla, Veracruz, Mexico, by A. Villalobos

and H. H. Hobbs, Jr., 17 April 1957.

DIAGNOSIS.—Small to medium-sized branchiobdellids; major annulations of body segments greater

in diameter than minor ones; jaws dark, dental

formula 1/4, lateral teeth of lower jaws minute, obscure; bursa globose, small, approximately 1/7 body

diameter in length, penial sheath approximately

1/2 bursal length; spermiducal gland without deferent lobes, approximately \\/2 times bursa in

length; prostate differentiated, subequal to spermiducal gland in diameter, 2/3 latter in length, with

rudimentary prostatic bulb; spermathecal bulb

with thickened wall, irregularly spatulate in shape.

ETYMOLOGY.—This species is named for the

Toltecs, a people of presumably northern origin

who invaded Mexico in earlier times.

DESCRIPTION.—Cambarincola toltecus is perhaps

a little larger than most Mesoamerican members of

the genus, but is small for the genus as a whole.

The holotype has the following dimensions: total

FIGURE 13. Cambarincola toltecus, new species: a, holotype;

b, lateral view of jaws; c, reproductive systems.
30 SMITHSONIAN CONTRIBUTIONS TO ZOOLOGY

length, 2.7 mm; greatest diameter, 0.5 mm; head

length, 0.5 mm; head diameter, 0.3 mm; diameter,

segment I, 0.3 mm; diameter, sucker, 0.25 mm. The

average dimensions of five specimens (the holotype

and four paratypes), with ranges given in parentheses, are as follows: total length, 2.4 mm (2.1-2.7

mm); greatest diameter, 0.4 mm (0.4-0.5 mm);

head length, 0.5 mm (0.4-0.5 mm); head diameter,

0.3 mm (0.25-0.3 mm); diameter, segment I, 0.3

mm (0.3-0.3 mm); diameter, sucker, 0.25 mm

(0.2-0.25).

The dorsal lip always projects beyond the lower

one and bears four blunt lobes; the lower lip has

a shallow median emargination; the lateral emargination, which divides the peristomium into upper

and lower lips, is broad and deep and often appears

to contain a small lateral lobe. An indeterminate

number of oral papillae are present. As usual,

there is only one prominent internal pharyngeal

sulcus, but externally the head shows no signs of

segmentation.

The major annulations of most body segments

are markedly greater in diameter than the minor

ones which are indistinct. The anterior nephridiopore is difficult to detect in available material.

The jaws are subrectangular in lateral view. The

upper is slightly the larger: the ratio of the length

of the upper to the lower jaw is 5:4 in the holotype

(54 to 43 microns). The upper jaw bears a single

large tooth; the lower, two paramedian ones and

often two minute indistinct lateral denticles. Both

jaws are distinctly brown in color, but not unusually dark.

There are no deferent lobes of the spermiducal

gland, which is about U/2 times the bursa in

length and L-shaped with the short arm of the

"L" ental and directed ventrad. The histology of

the gland is indistinguishable from that of more

northern and better known species of the Philadelphicus section of the genus. The same is true of

the differentiated prostate which is about 2/3 the

length of the spermiducal gland and subequal to it

in length. There is apparently a rudimentary or

small prostatic bulb present, which appears to be

filled with a granular material in the holotype.

There are no notable features of the ejaculatory

duct and bursa. The former is rather short and the

later globose in shape with the penial sheath portion composing approximately half the organ.

The irregularly spatulate spermatheca extends

almost to the dorsal border of the gut. The ectal

duct composes about 1/3 of the organ; the bulb

has a thickened wall that histologically resembles

the ental processes of species which have them, but

spermatozoa are present within the rather narrow

lumen of the bulb to its ental end.

VARIATION.—There is some question about the

presence of oral papillae; they can be seen in the

holotype with difficulty, but not distinctly enough

to count. In some other specimens they cannot be

detected. My material is poorly preserved, though

adequate for the diagnosis of the species. It is not

macerated, but, rather, it has the appearance of

having been preserved in methanol. The lower jaw

often seems to bear minute lateral teeth, but these

minute denticles can easily be overlooked and it is

not at all certain that they occur in all specimens.

AFFINITIES.—Cambarincola toltecus has a closer

relationship to members of the Philadelphicus section of the genus than do the other Mesoamerican

members. Except for the structure of the prostatic

bulb, the male reproductive system is much like

that of C. philadelphicus (Leidy, 1851), as is the

lobation of the peristomium. The raised annulations approach in their distinctness those of C.

fallax Hoffman, 1963, and several other more northern species. Cambarincola toltecus, however, differs

from these species in its dental formula and particularly in the peculiarities of its spermatheca.

None of the known members of the Philadelphicus

section have spermathecae with thickened bulbular

walls or spermathe^cal ental processes. Among the

Mesoamerican species of the genus, C. smalleyi

Holt has a differentiated prostate, but lacks the

raised major annulations, while C. olmecus, new

species, and C. jamapaensis, new species, have them;

all differ in details of the spermatheca and jaws.

Cambarincola toltecus, along with C. olmecus and

C. jamapaensis, appear to form a group of southern, and presumably more primitive, relatives of

the northern Philadelphicus section.

HOSTS.—Procambarus ruthveni zapoapensis,

Pseudothelphusa veracruzana.

DISTRIBUTION.—The type-locality and Arroyo de

Zapoapan de Cabana, Veracruz, Mexico. Both localities are in the Southern Gulf Slope region in

the tropical lowlands of Veracruz.

MATERIAL EXAMINED.—The type-series and four-
31

A Cambarincola

• Cambarincola

• Cambarincola

• Cambarincola

• Cambarincola

micradenus

nanognathus

olmecus

susanae

toltecus

1 1 Cordillera Volcanica Transversal

A

FIGURE 14—Distribution of five Mexican members of the genus Cambarincola.

teen others (PCH 697); fifteen specimens (PCH

700); taken on Procambarus ruthveni zapoapensis

and Pseudothelphusa veracruzana from Arroyo de

Cabana, Veracruz, Mexico.

Genus Pterodrilus Moore, 1895

Pterodrilus Moore, 1895a:449.—Holt, 1968c: 1

DIAGNOSIS (from Holt, 1968c: 3).—

Small branchiobdellids (known forms less than 2.0 mm in

length) of delicate appearance; cylindrical; prosomite of

segment VIII always with elevated dorsal ridge, those of other

segments often so, dorsal ridges often bearing fan- or fingerlike projections; jaws delicate, light in color or colorless.

triangular in shape, dental formula 5/4; prostate present,

incompletely divided from spermiducal gland; bursa ovoid

to pyriform, penis sheath short, penis non-eversible; spermatheca with long ectal duct, bulb clavate or spatulate;

anterior nephridia open by common dorsal pore on segment

III.

TYPE-SPECIES.—Pterodrilus alcicornus Moore,

1895a:449-450, by subsequent designation (Goodnight, 1940:58).

Pterodrilus mexicanus Ellis, 1919

FIGURE 15

Pterodrilus mexicanus Ellis, 1919:254.—Goodnight, 1940:63

Causey, 1955:44.—Holt, 1968c: 15.
32 SMITHSONIAN CONTRIBUTIONS TO ZOOLOGY

TYPE-SPECIMEN.—Holotype (USNM 17654),

taken on Proccnnbarus mexicanus at Mirador, Mexico, by Nelson and Goldman (date unknown).

DIAGNOSIS (from Holt, 1968c: 15).—"Dorsal ridge

on segment VIII, typically bearing four conical

projections, remainder of segments without ridges;

bursa large, elongate, length exceeding 1/2 body

diameter; ejaculatory duct short; prostate about

1/2 diameter of and subequal in length to spermiducal gland, undifferentiated; spermatheca shorter

than body diameter, bulb thick-walled."

HOSTS.—Procambarus mexicanus in Mexico (Ellis, 1919) and eight species of Orconectes Cope,

1872, in the Ozark plateau region of Arkansas, Oklahoma and Missouri (Holt, 1968c: 16).

FIGURE 15.—Pterodrilus mexicanus: a, reproductive systems;

b, animal from Wayne County, Missouri. (From Holt, 1968c.)

REMARKS.—The genus Pterodrilus has been revised recently (Holt, 1968c). The status of P. mexicanus, based upon a unique specimen, was discussed

in this revision and approximately 100 specimens

from Arkansas, Missouri, and Oklahoma were assigned to it (Holt, 1968c: 15-18). The holotype has

four prongs borne on a single dorsal ridge on segment VIII, as do the Ozarkian animals. I could

not locate Mirador while in Mexico; all attempts

to collect near the suspected locality from which

Ellis' specimen came failed. Of the hundreds of

specimens from Mexico that I have seen, not any

could possibly be considered as a member of the

genus Pterodrilus. Whether or not P. mexicanus,

or a very similar species (since the number and

arrangement of the "dorsal appendages" of Pterodrilus show little intraspecific variability), exists or

once existed in Mexico probably may never be

known. If P. mexicanus or a similar form did or

does exist in Mexico, the probability is great that

it was there in pre-Pliocene times (cf Hobbs, 1971:

10-12). The genus Pterodrilus is believed to be derived from some early cambarincoloid stock (Holt,

1968c:4-5) and there are relatively advanced species

of Cambarincola south of the Cordillera Volcanico

Transversal.

Genus Sathodrilus Holt, 1968

Sathodrilus Holt, 1968b:294.

DIAGNOSIS (emended from Holt, 1968b: 294).—

Medium-sized worms (known species 1.6-4.6 mm

in length) with two pairs of testes; unpaired nephridiopore on dorsum of segment III; body terete,

without peristomial tentacles or dorsal projections

on trunk segments, though dorsal ridges may be

present; spermiducal gland with vasa deferentia entering entally; prostate ranging from absent

through bulb-like prostatic protuberance to large

one that arises considerably entally to junction of

spermiducal gland with ejaculatory duct; ejaculatory duct present; penis eversible, but attached by

cytoplasmic strands to inner wall of penial sheath,

without cuticular hooks; spermatheca with or without ental process.

TYPE-SPECIES.—Sathodrilus carolinensis by original designation (Holt, 1968b:294).

RANGE.—From the southeastern borders of the

Appalachian uplift in South Carolina and Georgia
NUMBER 142 33

Key to the Mesoamerican Species of the Genus Sathodrilus

1. Spermiducal gland with prostatic protuberance or prostate 2

Spermiducal gland without prostatic protuberance or prostate S. veracruzicus

2. Spermiducal gland with prostatic protuberance S. villalobosi

Prostate present S. prostates, new species

to the Interjacent and Southern Slope faunistic

regions of Mexico. This range is discontinuous;

representatives of the genus are not known to occur between northwestern Georgia and northern

San Luis Potosf.

Sathodrilus prostates, new species

FIGURES 16, 19

TYPE-SPECIMENS.—Holotype (USNM 4532), on

Procambarus acutus cuevachicae taken at El Ajenjibre, Messa de San Diego, km 262 de la carretera

M&cico-Tuxpan, Puebla, Mexico, by A. Villalobos

and H. H. Hobbs, Jr., 12 April 1957; two paratypes

(USNM 45432), on Pseudothelphusa veracruzana

taken at Rio Tapalapa, Veracruz, Mexico, by A.

Villalobos and H. H. Hobbs, Jr.; one paratype

(USNM 45433), on Procambarus ruthveni zapoapensis at Arroyo de Zapoapan de Cabana, Veracruz,

Mexico; one paratype, Instituto de Biologia, Universidad de Mexico, from the latter locality; seven

paratypes (PCH 700), from the latter locality.

DIAGNOSIS.—Small branchiobdellids, average

length about 1.8 mm; body outline smooth except

for raised major annulation of segment VIII; jaws

small, light in color, dental formula 5/4; bursa

large, somewhat more than 1/2 body diameter in

length, penial sheath about 2/5 bursal length, penis

eversible; spermiducal gland subequal to bursa in

length, 3/10 its length in diameter, with prominent

anterior deferent lobe; prostate present, arising

approximately at junction of ectal and median

thirds of spermiducal gland, subequal in diameter

to latter, undifferentiated, with small prostatic

bulb; spermatheca with ectal spermathecal bursa,

short ectal duct, wall of spermathecal bulb glandular, ental process prominent and glandular.

ETYMOLOGY.—From Greek prostates (one who

stands before) in reference both to the presence of

a prostate gland in this species and its possible

phylogenetic position as a remnant of the sathodriloid stock that gave rise to the genus Cambarincola and its relatives.

DESCRIPTION.—Sathodrilus prostates is a small

worm, exceeded in size by all known members of

the genus except S. veracruzicus. The holotype has

the following dimensions: total length, 2.0 mm;

greatest diameter, 0.4 mm; head length, 0.4 mm;

head diameter, 0.2 mm; diameter, segment I, 0.2

mm; diameter, sucker, 0.2 mm. The average dimensions of the holotype and four of the paratypes

chosen randomly, with ranges given in parentheses,

are as follows: total length, 1.8 mm (1.1-2.0 mm);

greatest diameter, 0.3 mm (0.25-0.4 mm); head

length, 0.3 mm (0.25-0.4 mm); head diameter, 0.2

mm (0.15-0.2 mm); diameter, segment I, 0.2 mm

(0.2-0.2 mm); diameter, sucker, 0.2 mm (0.15-0.2

mm).

Lobes, if present, of the lips are obscurely delimited. Oral papillae are present. The peristomial

sulcus is present, but there is no other external

sign of segmentation of the head and internally

only one pharyngeal sulcus. The body is smooth

in outline, except in some specimens where the

intersegmental furrows are strongly marked and a

prominently raised ridge is present on the major

annulation of segment VIII.

The jaws, light brown in color and with a dental

formula of 5/4, are unremarkable.

The anterior deferent duct enters the spermiducal gland ventral to and at some distance from

the point of entry of the posterior deferent duct

producing an anterior deferent lobe (Hoffman,

1963:287). The spermiducal gland is approximately

1/2 the body diameter in length and about 2/5 its

own length in diameter. A large prostate arises

from the spermiducal gland near the ectal 1/3 of

the latter and terminates in a small narrowed bulb

near the ectal part of the anterior deferent lobe.

It is histologically similar to the spermiducal

gland.

The ejaculatory duct is relatively long and frequently curves dorsally over the gut in its course

from the spermiducal gland to the bursa, but otherwise presents no unusual features.

The bursa, which is large (more than 1/2 the
34

SMITHSONIAN CONTRIBUTIONS TO ZOOLOGY

FIGURE 16 Sathodrilus prostates, new species: a, holotype; b, en face view

of jaws (from PCH 700 = USNM 45433); c, lateral view pf jaws; d, reproductive systems [b=bursa; ejd=ejaculatory duct; ep=ental process

of spermatheca; pr=prostate; sb=bulb of spermatheca; sd=spermathecal

duct; spb=spermathecal bursa; spz=spermatozoa; sg=spermiducal gland;

vd=vas deferens].

body diameter in length and usually inclined posteriorad in the segment) is composed of a large

penial sheath region which encloses what appears

(in the limited available material) to be an eversible penis connected along its length by strands of

muscle to the muscular wall of the penial sheath.

An atrial fold is present at the inner portion of the

bursal atrium.

The spermatheca is composed of four distinct

regions. Ectally a very short duct leads into a muscular walled enlargement of a type previously designated as a spermathecal bursa (Holt, 1960a:64),

which is lined with cuticle and is essentially

spherical in shape. The spermathecal bursa leads

entally into another subspherical portion, which is

not lined with cuticle, but which has strands of

presumably glandular cells projecting inward from

its walls. This appears to be the main sperm storage portion of the organ and is, hence, the spermathecal bulb. A large portion of the spermatheca

follows entally with glandular cells projecting into

its lumen and, in some specimens, with a few(?)
NUMBER 142 35

spermatozoa stored within. The ental end of the

spermatheca consists of a narrowed ental process,

composed of large granulated glandular cells, but

lacks an obvious lumen.

VARIATION.—All my specimens are mounted entire. Apparent differences among them are best

accounted for by the degree of extension and contraction of the animals at death, their overall sizes,

and the relative positions of the reproductive

organs. After several false starts, it became obvious

that they all conform, except for differences in

size and stage of maturity, to the description of the

holotype. In addition, though always present, the

distinctness of the raised annulation on segment

VIII may be obscured in greatly extended and

younger specimens; also, the lateral teeth of the

jaws may be difficult to see. In only a few specimens have spermatozoa been detected in the third

(unnamed, but presumably outer part of the ental

process) portion of the spermatheca. Therefore,

although I am not sure of their presence in the

holotype, they are indicated in that position in Figure 16d. There can be no doubt as to the conspecificity of the material I have assigned to this

somewhat unusual species.

AFFINITIES.—It is with considerable reluctance

that I assign this species, with its obvious similarities to members cf several other genera, to the

genus Sathodrilus. I have discussed the relationships of these genera previously (Holt, 1968b: 294-

295) and herein I need only refer to some of the

peculiarities of S. prostates. In body form, particularly in the raised major annulation of segment

VIII, S. prostates resembles certain species of Pterodrilus, notably P. choritonamus Holt (1968c:26-28).

The only reason for not including prostates in

Pterodrilus as a close relative of P. choritonamus

is the eversible penis of the former. They differ

otherwise chiefly in the more elaborate differentiations of the spermatheca of S. prostates. The

genera Sathodrilus, Magmatodrilus, and Ceratodrilus form a remarkably similar group of animals

and now (with the discovery of S. prostates) are

most clearly separated by features of body ornamentation, jaw structure, and geographical isolation

(cf. Holt, 1960a, b, 1967, 1968b, 1969:197-198).

Figure 2 (in Holt, 1969:196) illustrating the relationships of branchiobdellid genera reflects greater

phyletic distances between these genera and the

others of the Sathodrilus lineage than objectively

exists. The problem is confounded by the apparent

parallelism in such structures as peristomial projections, raised annulations of body segments, some

of which bear finger- or fan-like projections, the

degree of development of the prostate, and wide

ranges in body size. Sathodrilus prostates must,

therefore, on the basis of our present knowledge

be considered as close to, or representative of the

stock that, perhaps almost simultaneously, gave

rise to the genera Ceratodrilus, Magmatodrilus,

Tettodrilus, Pterodrilus, and Cambarincola, with

Oedipodrilus and Ellisodrilus regarded as composed

of more specialized groups of derivative species.

Within the genus Sathodrilus, S. prostates is

closer to S. carolinensis in features of the bursa,

penis, and rudimentary prostatic bulb, but in the

differentiated nature of the spermatheca S. prostates is closer to S. megadenus. Both S. carolinensis

and S. megadenus are from the piedmont regions

at or near the southern borders of the Appalachians. Among the apparently more distantly related

Mexican members of the genus, S. villalobosi

possesses a prostatic protuberance, but the penis

has evolved towards the condition found among

the species of Oedipodrilus, as has that of S. veracruzicus which, however, entirely lacks any rudiment of a prostate. None of the other species of

Sathodrilus have prominently raised major annulations of the body segments (the first three segments of S. megadenus have slightly raised major

annulations), so the raised annulation of segment

VIII of S. prostates is distinctive. Except for S.

villalobosi, which has heavy and dark jaws and

presumably a dental formula of 1/4, the jaws and

dental formulae of the species of Sathodrilus are

remarkably similar to each other and to those of

Pterodrilus and many species of Cambarincola.

HOSTS.—Procambarus acutus cuevachicae, P. hoffmanni, P. ruthveni zapoapensis, Pseudothelphusa

veracruzana.

DISTRIBUTION.—From the lower slopes of the

Sierra Madre Oriental in Puebla, the Interjacent

Gulf Slope, to the lowlands of Veracruz south of

the Cordillera Volcanica Transversal, the Southern

Gulf Slope. S. prostates is one of the species that

is found on both sides of the barrier produced

by th? Cordillera Volcanica Transversal, though

so far to the south of the barrier only in streams
36 SMITHSONIAN CONTRIBUTIONS TO ZOOLOGY

that drain the flanks of the volcanic mountain,

San Martin, which stands on the coastal plain.

MATERIAL EXAMINED.—The type-series; several

specimens (PCH 702) taken on Procambarus hoffmanni at Mi Ranchito, Villa Juarez, Puebla, Mexico, 4 April 1957.

Sathodrilus veracruzicus Holt, 1968

FIGURES 17, 19

Sathodrilus veracruzicus Holt, 1968b:305.

TYPE-SPECIMENS.—Holotype (USNM 37105); six

para types (USNM 37106 and 45440), taken on

Procambarus hoffmanni at Coyutla, Veracruz,

Mexico, 16 April 1949.

DIAGNOSIS (from Holt, 1968b:305).—

Small, slender, terete worms; lips entire; dental formula

5/4; bursa long, exceeding body diameter in length, penial

sheath about 3/4 total length, less in diameter than bursal

atrium; eversible penis with thickened wall attached by few

strands to penial sheath; ejaculatory duct short, about 1/3

length of spermiducal gland; spermiducal gland small, about

1/3 as long as bursa; no prostatic protuberance; spermatheca

long, spermathecal duct subequal to body diameter in length,

bulb cylindrical, long, no ental process.

AFFINITIES.—See Sathodrilus prostates.

HOSTS.—Procambarus contrerasi, P.' hoffmanni,

P. riojai.

DISTRIBUTION.—Sathodrilus veracruzicus is known

from the states of Puebla and Veracruz in the Interjacent Gulf Slope region.

Sathodrilus villalobosi Holt, 1968

FIGURES 18, 19

Sathodrilus villalobosi Holt, 1968b:299.

TYPE-SPECIMENS.—Holotype (USNM 37101), four

para types (USNM 37102), and four paratypes

(PCH 208), taken on Paracambarus paradoxus at

Tetela de Ocampo, 35 km NE of Zacapoaxtla,

Puebla, Mexico, May 1944 (erroneously recorded

as May 1941 in Holt, 1968b:299).

FIGURE 17.—Sathodrilus veracruzicus: a, reproductive systems; b, holotype; c, en face

view of jaws; d, lateral view of jaws. (From Holt. 1968b.)
NUMBER 142 37

DIAGNOSIS (emended from Holt, 1968b:299).—

Medium-sized, terete branchiobdellids; upper lip

entire, lower with shallow median indentation;

jaws heavy, dark, dental formula 1/4 or 5/4; bursa

large, subequal to body diameter in length, bursal

atrium less than 1/3 total bursal length; eversible

penis composed of tube attached by few strands to

inner wall of penial sheath; ejaculatory duct short,

about 1/2 length of spermiducal gland; length of

spermiducal gland about twice its diameter, about

1/3 that of bursa, tapering toward each end from

prostatic protuberance, without deferent lobes;

spermatheca with long narrow ectal duct, bulb

globose.

AFFINITIES.—See Sathodrilus prostates.

HOSTS.—Paracambarus paradoxus, Procambarus

contrerasi, P. erichsoni, P. riojai.

DISTRIBUTION.—Sathodrilus villalobosi is known

from the states of Hidalgo and Puebla in the Interjacent Gulf Slope region of Mexico.

REMARKS.—A contradiction appears in my original treatment of this species. In the diagnosis (Holt,

1968b:299) it is said that S. villalobosi lacks oral

papillae; in the discussion of the affinities of the

FIGURE 18.—Sathodrilus villalobosi: a, holotype; b, jaws; c, reproductive systems; d, longitudinal section of ectal part of penis and bursa. (From Holt, 1968b.)
38 SMITHSONIAN CONTRIBUTIONS TO ZOOLOGY

• Bdellodrilus

• Sothodrilus

• Sathodrilus

• Sathodrilus

illuminatus

prostates

veracruzicus

villalobosi

= Cordillera Volcanica Transversal

FIGURE 19.—Distribution of four species of Mexican branchiobdellids.

species then known (Holt, 1968b: 307) it is said that

S. villalobosi and S. veracruzicus possess such papillae. The paratypes, somewhat overcontracted, do

not appear to have oral papillae. The much better

preserved material from Aqua Fria (PCH 1593),

collected by me and my field companions, have oral

papillae. It is likely that these structures are often

impossible to see in specimens that are overly contracted or poorly preserved and it is not known

whether there is intraspecific variability in the presence or absence of them or whether or not they are

of any real taxonomic value.

The dental formula is also apparently more

variable than the original description would indicate (Holt, 1968b:301). In some, presumably

younger specimens, the dental formula is 5/4, but

the lateral teeth are small and perhaps wear away

with age.

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Transferred into a Japanese Lake. Proceedings of

the Imperial Academy [of Japan], 9(4): 191-193,

figures 1-2.

1934. Studies on Some Japanese Branchiobdellidae with

some Revisions on the Classification. Journal of the

Faculty of Science, Hokkaido Imperial University,

series 6, 3(3) :177-219, figures 1-17, plates 12, 13.

Young, Willard

1966. Ecological Studies of the Branchiobdellidae (Oligochaeta) . Ecology, 47 (4) :571-578, figures 1-3.

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