Three New Crustaceans

from La Media Luna,

San Luis Potosi, Mexico

ALEJANDRO VILLALOBOS FIGUEROA

and

HORTON H. HOBBS, JR.

m

SMITHSONIAN CONTRIBUTIONS TO ZOOLOGY • NUMBER 174
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SMITHSONIA N CONTRIBUTIO N T O ZOOLOGY • NUMBER 174

Three New Crustaceans

from La Media Luna,

San Luis Potosi, Mexico

Alejandro Villalobos Figueroa

and Horton H. Hobbs, Jr.

SMITHSONIAN INSTITUTION PRESS

City of Washington

1974
ABSTRACT

Villalobos Figueroa, Alejandro, and Horton H. Hobbs, Jr. Three New Crustaceans from La Media Luna, San Luis Potosi, Mexico. Smithsonian Contributions to Zoology, number 174, 18 pages, 8 figures, 1 table, 1974.—Representatives

of three families of crustaceans are described from La Media Luna, San Luis

Potosi, Mexico: Ankylocythere barbouri representing the ostracod family Entocytheridae, Procambarus (Pennides) roberti, the decapod family Cambaridae, and

Palaemonetes (Palaemonetes) lindsayi belonging to the decapod family Palaemonidae. All three are known only from the vicinity of the type-locality and seem to

have affinities with species occurring in the southeastern part of the United

States. A key to the freshwater representatives of the genus Palaemonetes, together with a summary of their diagnostic features, is appended.

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

in the Institution's annual report, Smithsonian Year. SI PRESS NUMBER 5080. SERIES COVER

DESIGN: The coral Montastrea cavernosa (Linnaeus).

Library of Congress Cataloging in Publication Data

Villalobos Figueroa, Alejandro.

Three new crustaceans from La Media Luna, San Luis Potosf, Mexico.

(Smithsonian contributions to zoology, no. 174)

Supt. of Docs, no.: SI 1.27:174.

1. Ankylocythere barbouri. 2. Procambarus roberti. 3. Palaemonetes lindsayi. 4. Crustacea—

Mexico—San Luis Potosf (State). I. Hobbs, Horton Holcombe, 1914- joint author. II.

Title. III. Series: Smithsonian Institution. Smithsonian contributions to zoology, no. 174.

QL1.S54 no. 174 [QL441.2] 591\08s [595'.384] 74-879

For sale by the Superintendent of Documents, U.S. Government Printing Office, Washington, D.C. 20402

Price 30 centi (paper cover)

ii
Contents

Page

Introduction 1

Procambarus (Pennides) roberti, new species 3

Ankylocythere barbouri, new species 7

Palaemonetes (Palaemonetes) lindsayi, new species 9

Discussion 15

Key to the North and Middle American Freshwater Species of the

Genus Palaemonetes 16

Literature Cited 17

in

Three New Crustaceans

from La Media Luna,

San Luis Potosi, Mexico

Alejandro Villalobos Figueroa

and Horton H. Hobbs, Jr.

Introduction

Three new crustaceans, a crayfish of the genus

Procambarus, which harbors an entocytherid ostracod of the genus Ankylocythere, and a shrimp

belonging to the genus Palaemonetes may now be

added to the faunal list of aquatic animals frequenting the springs and drainage ditches of La

Media Luna, San Luis Potosi.

The presence of the crayfish in this headwater

tributary of Rio Panuco was discovered by Salvador Contreras on 15 June 1968, and a year later,

Clyde D. Barbour collected a single female there,

which he sent to the Smithsonian Institution. Being aware of the active fieldwork of Robert R.

Miller in Mexico, we asked him to try to get additional specimens for us, should he be collecting in

the area. To our delight, he and Kinji Kurawaka

obtained seven specimens of the new crayfish, together with two shrimp. Dr. Contreras also secured

five additional crayfish in December 1971. After it

was realized that the shrimp represented an undescribed species, the senior author visited La

Media Luna where, on 14 February 1972, more

than 500 additional shrimp were taken in canals

and springs of Ejido Las Palomas.

Alejandro Villalobos Figueroa, Instituto de Biologia, Universidad Nacional Autdnoma de Mixico, Apartado Postal

70-233 Mixico 20, D. F., Mixico. Horton H. Hobbs, Jr., Department of Invertebrate Zoology, National Museum of Natural History, Smithsonian Institution, Washington, D.C.

20560.

Miller (1956), in describing the endemic cyprinodontid Cualac tessellatus from La Media Luna,

presented the following account of the habitat:

La Media Luna is the name given to an extensive warmspring area that lies in a broad meadow about seven airline

miles south-southwest of the town of Rio Verde. A large,

constant volume of water rises principally from two rather

deep holes in a crescent-shaped pond (laguna) and provides

all the water for three muniripios. The approximate area of

the laguna has been estimated to be 24,800 square meters

The water is blue, very clear, and has a strong sulfur odor.

Water temperatures taken at various stations during different seasons indicate a variation from about 83° to 86.5° F

The pH varied from 6.9 to 7.3 .. . hardness was recorded as

92 p.p.m. of CaCO3. There was no trace of CO, and no

reaction to phenolphthalein. According to our altimeter, the

elevation is 3,580 feet . . . the correct altitude of La Media

Luna may be closer to 3,350 feet ... .

The vegetation of the region is arid, with few trees on the

valley floor and a close growth of xerophytic plants on the

hills. Mesquite and creosote bush are characteristic, along

with large acacias, yuccas, and numerous cacti. Principal

crops are sugar cane, corn, beans, citrus fruits, and bananas ... . Although the vegetation zone of the area is

classified in a general way as desert .. . it is markedly

different from the other desert areas of northeastern Mexico,

and reflects the peculiar position of a depression lying between the relatively low crest (5,500 ft.) of the Sierra Madre

Oriental, just to the east and the much higher ranges (8,000

ft.) to the west ... . The mean annual rainfall of the depression may approach 15 to 20 inches.

In the field notes that accompanied the specimens received from Dr. Miller, he included the

following additional information. The ditch (Fig-
ure 1) from which the material was collected was

some 8 to 35 feet in width and situated in a

cultivated area with few trees and shrubs along

the bank. The moderately strong current of clear

water (78°F) flowed over a bottom consisting of

rocks, boulders, gravel, and deep mud, and supported dense beds of submergent aquatic plants,

Scirpus, and a few water lilies. The crayfish and

shrimp were taken by seine and hand net along

the undercut bank at depths of two to three feet.

The fishes secured in the same area included

Astyanax fasciatus mexicanus (de Filippi), Dionda

SMITHSONIAN CONTRIBUTIONS TO ZOOLOGY

rasconis (Jordon and Snyder), Cichlasoma bartoni

(Bean), Cichlasoma steindachneri Jordon and

Snyder, Ataeniobius toweri (Meek), and the endemic Cualac tessellatus Miller. Only two other

fishes, Ictalurus mexicanus (Meek) and Cichlasoma

labridens (Pellegrin), are known to occur in the

area.

ACKNOWLEDGMENTS.—We wish to thank Clyde D.

Barbour, Salvador Contreras, Robert R. Miller,

and Kinji Kurawaka for their kindness in collecting many of the specimens on which the descriptions are based. Dr. Miller also provided us with

F if a RE 1.—Ditch from La Media Luna, San Luis Potosf, Mexico, the type-locality of Procambarus roberti, Palaemonetes lindsayi and Ankylocythere barbouri. (Photo courtesy of Robert

R. Miller.)
NUMBER 174

the photograph of the type-locality and read an

early draft of the manuscript. We are also grateful

to Isabel Pe"rez Farfante, Fenner A. Chace, Jr., and

Margaret A. Daniel for their criticisms of the

manuscript and to Ned E. Strenth for his critical

reading of the key.

Procambarus (Pennides) roberti, new species

FIGURE 2

DIAGNOSIS.—Body pigmented, eyes well developed. Rostrum with marginal spines. Areola 31.1 to

34.5 percent of entire length of carapace, and 7 to

10 times longer than wide. Two cervical spines

usually present. Suborbital angle rounded and

weak. Postorbital ridge with apical spine. Hepatic

region tuberculate but lacking spines. Antennal

scale approximately 2.3 times longer than wide,

broadest near midlength. Ischia of third and

fourth pereiopods of first form male with simple

hooks overreaching basioischial articulation proximally. First pleopods of male asymmetrical, lacking cephalic shoulder, provided with conspicuous

array of subterminal setae, and reaching coxae of

third pereiopods; distal extremity bearing (1)

slender, caudomesially situated mesial process extending caudodistally and somewhat laterally,

slightly beyond other terminal elements; (2) small,

curved, platelike, corneous cephalic process on

cephalodistal surface; (3) subtriangular, laterally

grooved, corneous caudal process on caudodistal

surface abutting caudal base of centrally located

central projection; and (4) corneous, central projection extending distally about same distance as

cephalic process, slightly farther than caudal

process, and consisting of subspatulate centrocephalic process and smaller subtriangular centrocaudal process. Annulus ventralis subspindle-shaped,

broader than long, with broad median elevated

portion marked by sigmoid sinus cutting caudal

0.8 length of annulus. Sternum immediately

cephalic to annulus with few low tubercles, but

with caudal margin entire.

HOLOTYPIC MALE, FORM I.—Body (Figure 2c,/)

subovate, somewhat compressed laterally. Abdomen

slightly narrower than thorax (10.3 and 11.5 mm).

Width of carapace slightly less than height at caudodorsal margin of cervical groove (10.9 and 11.5

mm). Areola 7.4 times longer than broad with 2

punctations across narrowest part. Cephalic section

of carapace 2.1 times as long as areola (latter 32.2

percent of entire length of carapace). Rostrum

excavate dorsally with unthickened margins slightly

convex at base and tapering to marginal spines;

dorsal surface with submarginal row of setiferous

punctations and others scattered between; spines

at base of acumen moderately strong; acumen subtriangular, longer than wide between marginal

spines (1.7 and 1.4 mm), and constituting approximately 25 percent of total length of rostrum. Subrostral ridges weak and scarcely evident in dorsal

aspect. Postorbital ridges strong, grooved dorsolaterally, with setiferous punctations, and terminating cephalically in corneous-tipped spines.

Suborbital angle very weak and rounded. Branchiostegal spine prominent and acute. Carapace punctate dorsally, with conspicuously large pits from

base of rostrum posteriorly over most of gastric

region; hepatic region mostly tuberculate; branchiostegites granulate laterally and with tubercles

ventral to cephalic portion of cervical groove. Two

cervical spines on each side of carapace subequal

in size. Abdomen slightly longer than carapace

(27.4 and 25.2 mm). Cephalic section of telson with

3 spines in each caudolateral corner. Epistome

(Figure 2k) subcordiform, broader than long; well

defined fovea present. Antennules of usual form

with prominent spine on ventral surface of proximal segment near midlength. Antennae extending

caudally to near midlength of telson. Antennal

scale (Figure 2o) about 2.4 times longer than broad,

broadest near midlength, with broadest lamellar

area about 1.6 times wider than thickened lateral

portion, latter terminating in strong acute spine.

Right chela (Figure 2p) moderately depressed,

with palm somewhat inflated; lateral margin with

row of subsquamous tubercles along proximal half;

dorsal and ventral surfaces of palm with ciliated

squamous tubercles, mesial margin with irregular

row of 6 or 7 tubercles flanked dorsally by irregular row of 8, ventral surface with prominent

tubercle opposite base of dactyl. Fixed finger with

moderately well-developed median longitudinal

ridge flanked by setiferous punctations, and proximomesial surface with several tuberosities; opposable margin with row of 8 rounded tubercles along

proximal 0.6 subtended by row of conspicuously

setiferous punctations, third and fourth tubercles

from base largest, and large tubercle on lower level

at base of distal third; crowded minute denticles
SMITHSONIAN CONTRIBUTIONS TO ZOOLOGY

V

FICURE 2.—Procambarus (Pennides) roberti (a, c, e-g, i-l, o, p from holotypic male. Form I;

b, d, h, m, n from morphotypic male, Form II): a, mesial view of first pleopod; b, mesial view

of distal part of first pleopod; c, lateral view of carapace; d, caudoiateral view of distal part

of first pleopod; e, lateral view of first pleopod; /, caudal view of first pleopods; g, annulus

ventralis of allotype; h, dorsal view of cephalic region; i, basal podomeres of third, fourth, and

fifth pereiopods; /, lateral view of first pleopod with pubescence; k, epistome; I, dorsal view

of carapace; m, ventral view of basal podomeres of third, fourth, and fifth pereiopods; n, dorsal

view of distal podomeres of cheliped; o, antennal scale; p, dorsal view of distal, podomeres of

cheliped.
NUMBER 174

along almost entire length, sublinearly arranged

basally but forming broad band distally; ventral

surface with submedian ridge, otherwise with

setiferous punctations. Dactyl with low submedian

longitudinal ridges dorsally and ventrally, flanked

proximally by tubercles and distally by setiferous

punctations; mesial surface with tubercles along

proximal fourth and setiferous punctations distally;

opposable margin with row of 9 low, rounded

tubercles along proximal three-fifths, interspersed

in band of crowded minute denticles extending

almost entire length of finger.

Carpus of right cheliped longer than broad (6.4

and 4.3 mm), with dorsal and dorsomesial surfaces

tuberculate and that lateral to oblique furrow

punctate; distal dorsomesial surface with prominent

spine; mesial surface with 1 very large spine

slightly distal to midlength and several small

tubercles proximal to it; ventrodistal margin with

2 spines, 1 on ventral articular condyle and other

submedian.

Merus of left cheliped mostly punctate; dorsal

margin with row of tubercles along proximal half

and more irregularly arranged ones distally, two

subdistal ones spiniform; ventrolateral margin with

row of 10 tubercles proximal to fork and 5 in each

ramus of fork; ventromesial margin with row of

16 tubercles; distal tubercles in mesial and lateral

rows strongly spiniform; other smaller tubercles

present mesial and lateral to 2 rows. Ischium

with row of 4 small tubercles on ventromesial

margin.

Hooks on ischia of third and fourth pereiopods

(Figure 2t) simple, and both overreaching basioischial articulation, neither opposed by conspicuous

prominence on basis, instead by large pit, bearing

tuft of setae; hook on third subconical and longer

than somewhat flattened hook on fourth. Coxa of

fourth pereiopod with prominent caudomesial

boss; that of fifth with slender, rounded, subspatulate prominence on ventral caudomesial margin.

Sternum between second through fifth pereiopods

moderately deep and bearing prominent fringe of

setae on ventrolateral margins.

First pleopods (Figure 2a^,f,j) as described in

diagnosis.

ALLOTYPIC FEMALE.—Differing from holotype in

following respects: acumen of rostrum subequal

in length and width at base; postorbital spines

longer; ventral members of paired cervical spines

distinctly larger than dorsal ones; cephalic section

of telson with only 2 spines in right caudolateral

corner; epistome with paired anterolateral obtuse

angles; opposable margin of both fingers of chela

with minute denticles reduced to very narrow band,

with maximum of 3 denticles in broadest portions; carpus of cheliped with small spiniform

tubercle immediately proximal to large spine on

dorsal mesiodistal angle, and with additional spiniform tubercles proximal to spine on mesial surface;

several tubercles ventral to large spine also spiniform; ventral surface of merus with mesial row of

13 or 14 tubercles and lateral row of 9 or 11, with

2 or 3 in distomesial ramus of lateral row. (See

'' Measurements.'')

Sternum cephalic to annulus ventralis (Figure

2g) comparatively shallow, with caudal margin entire; surface of winglike plates between fourth

pereiopods with few very low tubercles, otherwise

unadorned.

Annulus ventralis freely movable, broader than

long, subspindle-shaped in outline, with median

portion elevated ventrally and bearing broadly

S-shaped sinus, latter beginning on median line,

approximately 0.2 length of annulus from cephalic

margin, extending caudodextrad, then turning

gently caudosinistrad to median line before bending slightly caudodextrad to caudal margin. Median

sternite immediately caudal to annulus in form

of half-ellipse, with horizontal caudal margin and

with transverse elevation, highest medially, slightly

cephalic to midlength.

First pleopods uniramous and reaching cephalic

margin of annulus when abdomen flexed.

MORPHOTYPIC MALE, FORM II.—Differing from

holotype in following respects: width of cephalothorax and abdomen 10.3 and 8.5 mm, respectively;

width and height of cephalothorax at level of

caudodorsal margin of cervical groove 10.3 and 9.5

mm, respectively; areola 4.9 times longer than

broad; cephalic section of carapace twice as long

as areola and constituting 33 percent of total length

of carapace; surface of rostrum (Figure 2/i) grooved

and with fine punctations, marginal spines well

defined, acumen triangular, length less than distance between spines (1.3 and 1.6 mm) and constituting 23.2 percent of total length of rostrum;

postorbital ridge well defined, terminating anteriorly in spine; branchiostegal spine conical and

sharp; only 1 cervical spine present; abdomen
SMITHSONIAN CONTRIBUTIONS TO ZOOLOGY

slightly longer than carapace (23.0 and 20.7 mm);

antennal scale 2.4 times longer than wide and with

greatest width at midlength; right chela (Figure

2n) slenderer than that of holotype and with opposable margins of fingers less pubescent, immovable finger with 6 small, somewhat hemispherical

teeth along dorsal region of margin and 1 large

subconical tubercle situated ventrally at base of

distal 0.33 of dactyl, movable finger with 6 denticles; carpus of cheliped with 2 spines on mesial

surface, 1 near midlength and other subdistal;

ischia of third and fourth pereiopods (Figure 2m)

with hooks represented by angular prominences.

First pleopod (Figure 2b,d) with mesial process

conical, broad basally, and maintaining its caudomesial position; cephalic process forming broad

plate; central projection consisting of subconical

tubercle; caudal process absent.

COLOR.—Mostly bleached after several weeks'

preservation in formalin and alcohol; however,

palm of chela reddish purple dorsally, reddish

orange ventrally; fingers black dorsally and ventrally, with reddish orange tips. Distal half of merus

and entire carpus reddish purple.

TYPE-LOCALITY.—"Ditch from La Media Luna,

4.8 miles (6.6 km) south of Rfo Verde (on highway to Pedro Montoya) and 2.5 miles (4 km) west

on dirt road to Mina El Refugio, San Luis Potosi,

Mexico" (Miller, in litt.). See Figure 1 and "Introduction" for description.

DISPOSITION OF TYPES.—The holotypic male,

Form I, allotype, and morphotypic male, Form II,

are deposited in the National Museum of Natural

History, Smithsonian Institution, under the catalog

numbers of the United States National Museum

(USNM), 132345, 132346, and 144826, together with

2 females and 1 juvenile female paratype. The remaining para types consisting of 4 males, Form I,

2 females, and 2 juvenile females are in the collections of the Instituto de Biologia, Universidad

Nacional Aut6noma de Mexico.

RANGE AND SPECIMENS EXAMINED.—All of the

specimens available are from Laguna de la Media

Luna: 2cfl, 9 km southwest of Rio Verde, 15 June

1968, Salvador Contreras, coll.; 1$, type-locality,

9 June 1969, Clyde D. Barbour and R. J. Douglass,

coll.; 2tfI, 39, 1 juv. $, type-locality, 8 March

1971, Robert R. Miller and Kinji Kurawaka, coll.;

1 cf I, 1 cfll, 1 9 , 2 juv. $ , 7 km southwest of Rio

Verde, 23 December 1971, F. C, coll.

SIZE AND VARIATION.—The largest specimen available is a paratypic first form male that has a carapace length of 29.6 mm, 4.4 mm longer than the

holotype. The largest female, the allotype, has a

corresponding length of 27.0 mm.

Most of the variations noted seem rather insignificant and some, at least, are associated with

size and/or possible injury. Chief among them is

the presence of only 1 cervical spine on each side

in the largest male; all of the spines are heavier and

more tubercle-like in this specimen than in any of

the others. The epistome varies from subcordiform

to subtriangular, some specimens having anterolateral angles. The number of tubercles along the

mesial margin of the palm of the chela ranges from

6 to 8. The boss on the coxa of the left fifth pereiopod of the largest male consists of a broad plate

rather than a subspatulate one as on the right

pereiopod and in the holotype. The spines on the

caudolateral corner of the cephalic section of the

telson vary from 2 to 4. There may be 1 or 2 subdistal spines on the dorsal surface of the merus. The

sinus on the annulus ventralis may be a mirrored

image of that in the allotype and may also be more

strongly curved.

RELATIONSHIPS.—Procambarus roberti is a member of the subgenus Pennides Hobbs (1972:10) and

has its closest affinities with those crayfishes that

have formerly been assigned to the Spiculifer Group

(Ortmann, 1905:100). Among them (see Hobbs,

1969), it resembles most closely P. natchitochae

Penn (1953:5), P. ablusus Penn (1963:121), P. elegans Hobbs (1969:329), and P. penni Hobbs (1951:

273). In all of them, the first pleopod of the first

form male has a full complement of terminal elements, and the central projection is directed distally

or subdistally. Too, the sternum immediately anterior to the annulus ventralis is not produced into

tuberculiform or fingerlike lobes. It differs from all

of the species of the subgenus in possessing an

areola that is 7 to 10 times longer than wide; in

none of the other members is it more than 6 times

longer, and in most less than 5. It is the only member of the subgenus in which the cephalic process

is in the form of a curved, corneous plate. This

platelike cephalic process and the large punctations on the dorsal surface of the carapace, particularly between the postorbital ridges, are unique

in the subgenus Pennides and resemble characteristics that are more typical of the members of the
NUMBER 174

Mexican subgenus Villalobosus Hobbs (1972:12)

(= "section riojae" Villalobos, 1955:94).

ETYMOLOGY.—This species is named in honor of

Robert R. Miller, who has contributed greatly to

our knowledge of the Mexican crayfishes by sending many collections to the Smithsonian and who

made a special effort to obtain specimens of this

new Mexican species.

MEASUREMENTS (mm).—

CharactersCarapace

Height

Width

Length

Areola

Width

Length

Rostrum

Width

Length

Left chela

Length of mesial

margin of palm

Width of palm

Length of lateral

margin

Length of dactyl

Holotype

11.5

10.9

25.2

1.1

S.I

4.2

7.0

8.0

6.4

20.7

11.1

Allotype

11.8

12.2

27.0

0.<)

8.8

4.8

7.7

6.7

5.0

16.3

8.8

Morphotype

9.5

10.3

20.4

1.4

6.9

3.5

5.6

5.3

3.5

13.5

7.5

Ankylocythere barbouri, new species

FIGURE 3

DIAGNOSIS.—Shell length: tf, 0.36 mm; 9, 0.40-

0.41 mm. Shell height: tf. 0.19-0.20 mm; ?, 0.22

mm.

Clasping apparatus with talon represented by

very slight excrescence near midlength of external

border of horizontal ramus; internal border with 2

teeth, larger tooth above talon and small one immediately distal to larger; apex with 2 upturned

denticles. Ventral portion of peniferum subtruncate

with anteroventral angle produced ventrally in

short spinelike projection and with short fingerlike

thickening at posterior end of truncate ventral

extremity.

MALE.—Eye situated at anterodorsal 0.2 of shell.

Shell (Figure $e) oblong with greatest height

slightly posterior to midlength; ventral margin only

slightly curved, lacking concavity; submarginal

setae almost evenly spaced except dorsally, and few

additional setae on posterolateral surface.

Copulatory complex (Figure $a<) with peniferum

slightly arched posteriorly, subtruncate ventrally,

with short spinelike projection anteroventrally supported by elevated flange extending dorsally almost

FIGURE 3.—Ankylocythere barbouri: a, copulatory complex of paratypic male; b, c, clasping

apparatus of same; d, lateral view of shell of allotypic female; e, lateral view of shell of holotype. (Scales in mm.)
8 SMITHSONIAN CONTRIBUTIONS TO ZOOLOGY

to level of penis; small fingerlike thickening directed anteriorly on posteroventral extremity. Penis

much longer than half anteroposterior diameter of

peniferum at level of penis and curved with proximal and distal ends directed at angle of approximately 130 degrees. Dorsal and ventral fingers

moderately heavy and both terminating in simple

setiform tips; ventral finger gently curved throughout its length. Clasping apparatus with indistinctly

delimited horizontal and vertical rami disposed at

angle of approximately 50 degrees. Pre- and postaxial borders of vertical ramus entire; postaxial

border of horizontal ramus with slight excrescence

near midlength (excrescence more clearly defined,

with horizontal ramus directed somewhat laterally);

preaxial border of horizontal ramus with 2 teeth:

proximal one larger and situated opposite excrescence, smaller tooth located slightly distal to larger

one and with distinct curved ridge extending proximoventrally from apex; distal extremity of ramus

with 2 denticles directed somewhat dorsally.

TRIUNGUIS FEMALE (Figure 3d).—Eye situated

anterodorsally at anterior 0.17 of shell length. Shell

oblong, slightly higher in posterior half than in

anterior, greatest height distinctly posterior to midlength; submarginal setae as in male.

Genital complex consisting of 2 posterodorsally

situated elements: posterior one subdigitiform,

hyaline, and grooved laterally; anterior sclerotized

and cylindroid.

MEASUREMENTS.—Holotype: length 0.36 mm,

height 0.20 mm. Allotype: length 0.41 mm, height

0.22 mm. See "Diagnosis" for ranges.

TYPE-LOCALITY.—Ditch from La Media Luna,

4.8 miles (6.6 km) south of Rio Verde (on highway to Pedro Montoya) and 2.5 miles west on dirt

road to Mina El Refugio, San Luis Potosi, Mexico.

(See Figure 1 and "Introduction" for description).

DISPOSITION OF TYPES.—The type-series, consisting of the holotypic male, USNM 149159, allotypic

female, USNM 149160, a dissected paratypic male,

a paratypic female, and 6 juvenile specimens, is

deposited in the National Museum of Natural

History, Smithsonian Institution, under the catalog

numbers of the United States National Museum

(USNM). No other specimens are available.

RANGE AND HOST.—Known only from the typelocality, where it is the sole entocytherid infesting

the crayfish Procambarus (Pennides) roberti, described above.

ETYMOLOGY.—This ostracod is named in honor

of its discoverer, Clyde D. Barbour, who has contributed a number of Mexican crayfishes to the

Smithsonian Institution.

RELATIONSHIPS.—Ankylocythere barbouri exhibits characteristics that indicate its close relationships with two geographic neighbors currently

assigned to different genera: Ankylocythere toltecae

Hobbs (1971:36) from the states of Hidalgo, San

Luis Potosi, and Tamaulipas, and Uncinocylhere

bicuspide (Rioja, 1943:565) from Hidalgo, Puebla,

and Veracruz. It differs most strikingly from the

former in possessing two teeth on the preaxial

border of the horizontal ramus of the clasping apparatus of the male and from the latter in bearing

a rudimentary talon (excrescence) on the postaxial

border of the ramus (see Hobbs, 1971, for summaries of our knowledge of both species). Whereas

the excrescence in A. toltecae is markedly reduced

in size as compared with that of many members of

the genus, it is even more rudimentary in A. barbouri. The latter differs from both in being larger;

for example, its shell length in the male is 0.36 mm,

whereas the corresponding lengths in A. toltecae

and U. bicuspide range from 0.29 to 0.31 mm in

both species. The penifera of the three are markedly similar, and the clasping apparatus are basically similar, differing essentially only in the

characteristic pointed out immediately above.

Those of us concerned with the interrelationships of entocytherids have been aware of the fact

that as additional species were added to the two

genera, their distinctness became less well defined.

With the discovery of Ankylocythere barbouri

(linking the Mexican species assigned to the genus

Uncinocythere with Ankylocythere toltecae, and it,

in turn, through the various "talirotundi" forms of

A. heterodonta, to those members of Ankylocythere

having a well-developed talon on the clasping

apparatus of the male), the advisability of maintaining the two genera does indeed become questionable. Nevertheless, the divergence that has occurred

within the two is so great that uniting them does

not seem fully justified. Furthermore, the two

genera may still be recognized on the basis of the

presence or absence of a talon or excrescence on the

horizontal ramus of the clasping apparatus of the

male.

In reference to the assumed relationships with

members of the genus Uncinocythere, it is note-
NUMBER 174

worthy that the presence of only two apical denticles on the clasping apparatus is limited to the

three Mexican species [U. bicuspide, U. cuadricuspide (Rioja, 1945:422), and U. dobbinae (Rioja,

1943:560)] and two [U. equicurva (Hoff, 1944) and

U. lucifuga Walton and Hobbs, 1959] from the

southeastern part of the United States [within

the range of the crayfish subgenus Pennides, and the

former occurring on Procambarus (Pennides) spiculifer (LeConte, 1956)]. Perhaps it is significant that

the peniferum of U. lucifuga is remarkably similar

to that of A. barbouri, and, in some individuals

of both U. equicurva and U. lucifuga, there are two

teeth on the preaxial border of the horizontal

ramus of the clasping apparatus that are arranged

much as they are in A. barbouri, thus differing from

the latter chiefly in lacking an excrescence on the

horizontal ramus of the clasping apparatus.

Palaemonetes (Palaemonetes) lindsayi, new species

FIGURES 4-7, 8e

DIAGNOSIS.—Rostrum dentate: 1) 6 — 7; in gen2 - 4

eral reaching extremity of antennal scale. Telson

with 4 dorsal spines; distal margin with 4 spines

and 2 setae, none of which exceeding distal end

of uropod. Ventral ramus of lateral flagellum of

antennule with 3 or 4 free articles. Antennal scale

3.5 times longer than wide. Endopodite of first

maxilla with 3 spines. First maxilliped with unilobulate gill. Second maxilliped with mesial border

of branchial ramus entire. Third maxilliped with

2 podobranchs, proximal one very small. Appendix

masculina as long as endopodial ramus of pleopod

and bearing 4 apical and 2 (including distal member of row) subapical spines.

DESCRIPTION.—Rostrum gently curved and reaching extremity of antennal scale in 39.3 percent of

individuals examined, in others (24.4 percent) projecting beyond scale, and in remaining specimens

(36.3 percent) rostrum not quite reaching distal

end of scale; dorsal margin armed with 6 or 7

teeth, latter number predominant; ventral margin

with 2, more usually 3, or rarely 4, teeth; single

dorsal tooth situated posterior to orbit (Figures 4,

5). Antennal and branchiostegal spines quite long

and sharp, former implanted submarginally, latter

on margin. Hepatic groove extending to anterior

border of carapace, slightly above antennal spine.

Pleuron of second abdominal somite rounded

both antero- and posteroventrally, its width in females equal to length of tergum of third somite,

and in males 0.75 length of latter. Tergal length of

sixth somite equal to that of telson not including

distal spines (Figure 4).

Telson with 2 pairs of dorsal spines in posterior

0.25 somewhat asymmetrically arranged, but posterior pair situated about midway between anterior

pair and posterolateral angle; posterior margin,

prolonged in median acute angle, provided with

pair of short posterolateral spines, pair of longer

more median ones, and pair of plumose setae inserted mesial to long spines (Figure 6a-e).

Eye well developed, cornea and peduncle together pyriform (Figure 6/).

Antennular peduncle with apex of stylocerite

reaching midlength of first article. Lateral flagellum of antennule bifurcate at thirteenth to fifteenth article from base; ventral ramus, consisting

of 3 or 4 free articles, about 0.33 length of basal

undivided portion of flagellum (Figure 6g, h) .

Antennal scale 3.5 times longer than wide; lateral border weakly concave, free portion of scale,

from base of spine to distal margin, 0.2 total length

of scale; length of distal article of antennal peduncle equal to greatest width of scale (Figure

6/,;).

First maxilla (Figure 6/, m) with bifurcate palp;

distal margin of lateral lobe lacking setae or spines,

that of mesial, or more proximal, lobe armed with

3 spines bent at angle. Gnathal lobules as illustrated.

Second maxilla (Figure 6n) with extremities of

scaphognathite rounded, its width almost uniform.

Palp with distal half naked. Gnathal lobules as

illustrated.

First maxilliped (Figure 7a) with branchial

epipodite bearing slight lateral emargination. Second maxilliped (Figure 76) with branchial epipodite bilobed, one lobe entire, other with digitiform

processes. Third maxilliped (Figure 7c) with 2

podobranchs, large distal one with digitiform

processes, and proximal one small with irregular

margins.

First pair of pereiopods reaching base of distal

third of antennal scale. Carpus and merus subequal

in length (Figure Id). Setiferous organs present on

ventrodistal part of carpus, ventroproximal region
10 SMITHSONIAN CONTRIBUTIONS TO ZOOLOGY

FIGURE 4.—Palaemonetes (Palaemonetes) lindsayi: a, lateral view of holotypic male; b, lateral

view of ovigerous paratypic female. (Scale in mm.)
NUMBER 174 11

of propodus, and on dactyl of chela (Figure 7e);

length of palm equal to that of dactyl; opposable

margin of fingers without teeth, single marginal

row of setae on both sides of margin in each

finger.

Second pair of pereiopods overreaching rostrum

by length of distal third of carpus and chela; merus

equal in length to chela, and dactyl shorter than

palm (Figure 7/,g); opposable margins of fingers

without teeth.

Third pair of pereiopods (Figure Ih) with 3

spines on ventral margin of propodus and 1 spine

at ventrodistal extremity. Fourth pair of pereiopods

with 4 spines on ventral margin of propodus and

another ventrodistally (Figure li), and, in addition,

series of lateral spines on lateral surface. Fifth pair

of pereiopods (Figure 7/) with 6 spines on ventral

margin of propodus; ventrodistal portion of latter

with setiferous organ as depicted (Figure It).

Ventral border of dactyl of third through fifth

pereiopods in females regularly curved, in males

with subdistal, almost angular excavation (Figure

Ik).

Second pleopod of male (Figures 7n,o, 8e) with

appendix masculina as long as endopod and provided with row of spines along almost its entire

length; distal extremity with group of 4 apical

spines and 2 (including distal member of row) subapical spines.

MEASUREMENTS (mm).—

Characters

Carapace length,

including rostrum

Telson length

Pereiopod length

First

Second

Holotypic

male

7.0

2.1

6.0

8.5

8.4

3.7

6.3

10.2

Paratypic

8.2

2.5

5.8

9.0

7.3

2.6

6.3

8.2

males

7.9

2.6

5.8

9.5

2.6

2.1

4.8

7.2

10.0#

3.0

7.6

12.5

Paratypic females

11.2#

3.4

8.1

13.5

11.0*

3.5

9.8

11.6

7.4

2.4

5.5

8.2

7.2

2.2

5.4

7.6

Ovigerous

FIGURE 5.—Palaemonetes (Palaemonetes) lindsayi: variation in rostrum. (Grid in mm.)
12 SMITHSONIAN CONTRIBUTIONS TO ZOOLOGY

FIGURE 6.—Palaemonetes (Palaemonetes) lindsayi: a, telson and uropods of male; b, e, telson

of adult females; c, d, telson of adult males; /, dorsal view of antennule and eye; g, ventral

view of antennule; h, ventral view of external and accessory flagella of antennule; i, dorsal

view of basal portion of antenna; ;', ventral view of same; k, mandibles; /, first maxilla; m,

details of palp of same; n, second maxilla, (a-e to scale 1; /, g to scale 2; i, j to scale 3; k, I, n to

scale 4; scales in mm.)
NUMBER 174 13

FIGURE 7.—Palaemonetes (Palaemonetes) lindsayi: a, first maxilliped; b, second maxilliped; c,

third maxilliped; d, first pereiopod; e, chela of first pereiopod; /, second pereiopod; g, chela of

second pereiopod; h, i, j , third, fourth, and fifth pereiopods; k, distal extremity of dactyl of

pereiopods 3-5; /, distal extremity of propodus of fifth pereiopod of male; m, same of female;

n, second pleopod of male; o, distal portion of appendix masculina. (a-d, f, h-j to scale 1;

e, k-m to scale 2; g to Scale 3; n to Kale 4; scales in mm.)
14 SMITHSONIAN CONTRIBUTIONS TO ZOOLOGY

HABITAT.—Margins of irrigation canals, among

the submerged vegetation where the current is more

sluggish.

TYPE-LOCALITY.—Springs and canals in the

watershed of Laguna de la Media Luna, 4.8 miles

(6.6 km) south of Rio Verde (on the road to Pedro

Montoya) and 2.5 miles (4 km) to the west on a

road to the Mina El Refugio, San Luis Potosi,

Mexico.

DISPOSITION OF TYPES.—The type-series consists

of the holotypic male, USNM 149161, the allotypic

female, USNM 149162, and 25 males and 25 females, all deposited in the National Museum of

Natural History, Smithsonian Institution; the remaining paratypes are in the collection of Crustacea

in the Instituto de Biologia, Universidad Nacional

Aut6noma de Mexico, and the collection of Crustacea of the Facultad de Ciencias Biol6gicas, Universidad Nacional Aut6noma de Nuevo Le"on,

Mexico.

DISTRIBUTION.—Known only from the typelocality.

ETYMOLOGY.—This species is dedicated to George

E. Lindsay, eminent student of cacti and director

of the California Academy of Sciences.

RELATIONSHIPS.—Our knowledge of the genus

Palaemonetes in Mexico is so fragmentary, and that

of the limits of variations in the four freshwater

representatives in the United States so inadequately

known, the affinities of the species described here

cannot be properly assessed. Overlooking the lack

of pigment in P. (P.) cummingi Chace, 1954, all

five of the known species belonging to the nominate

subgenus are remarkably similar, and few characTABLE 1.—Diagnostic features of Xorth and Middle American freshioater Palaemonetes

Shrimp

P. antrorum

P. cummingi

P. kadiakensis

P. paludosus

P. lindsayi

P. suttkusi

Rostral length9

not reaching

level of spine

reaching

level of spine

reaching or

slightly overreaching level

of spine

overreaching

level of spine

reaching

level of spine

reaching or almost reaching

level of spine

Branchiostegal

spine

posterior to margin and ventral

to branchiostegal groove

marginal and adjacent to

branchiostegal

groove

usually posterior

to margin and

ventral to

branchiostegal

groove

marginal or submarginal and

adjacent to

branchiostegal

groove

marginal or submarginal and

adjacent to

branchiostegal

groove

marginal or submarginal and

adjacent to

branchiostegal

groove

Posterodorsal

spines of

telson

nearer to posterior

than to anterodorsal spines

nearer to posterior

than to anterodorsal spines

usually much

nearer posterior

than to anterodorsal spines

almost midway

between anterodorsal spines

and posterior

spine

almost midway

between anterodorsal spines

and posterior

spine

almost midway

between anterodorsal spines

and posterior

spine

Spines on

lateral

ramus of

uropod

1

2

2

2

1

1

Setae on

palp of

first

maxilla

0

3

0

2

3

0

Appendix masculina

12 setae: 4 apical and 1 sub

apical (counting distal

member of lateral row);

apical setae not reaching

apex of endopod

8 setae: 5 apical and 2 sub

apical (counting distal

member of row) ; apical

setae not reaching apex of

endopod

11 setae: 3 apical and 1 sub

apical; apical setae not

reaching apex of endopod

11 setae: 4 apical and 1 sub

apical (counting distal

member of row); 1 or

more apical setae reaching

apex of endopod

16 setae: 5 apical and 2 subapical (counting distal member of row); apical setae

reaching or slightly overreaching apex of endopod

15 setae: 6 apical and 2 sub

apical (counting distal

member of row); apical

setae almost reaching apex

of endopod

•In relation to distal spine on antennal scale.
NUMBER 174 15

a

FIGURE 8.—Distal portions of appendices masculinae in postaxial view: a, Palaemonetes (Alaocaris) antrorum; b, Palaemonetes (Palaemonetes) kadiakensis; c, P. (P.) cummingi; d, P. (P.)

paludosus; e, P. (P.) lindsayi; f, P. (P.) suttkusi. (Not drawn to same scale.)

ters have been found that serve to separate them.

Holthuis (1952), in monographing the American

Palaemoninae, summarized the ranges of the three

known freshwater species and used spination of the

carapace, telson, and uropods as the primary characters for distinguishing between the two epigean

members. Subsequently, some specimens from the

southeastern part of the United States could not,

on the basis of those characters, be identified.

Fleming (1969), investigating the secondary sexual

characters of certain members of the genus, found

that a reliable characteristic for distinguishing between P. (P.) paludosus (Gibbes, 1850) and P-. (P.)

kadiakensis Rathbun, 1902, exists in the number

and distribution of the setae of the apical region

of the appendix masculina.

The characteristics presented in Table 1 include

most of those that we have found to be useful in

assessing probable relationships and in distinguishing between the six known freshwater species of the

genus occurring in North America and Middle

America. The overlap in most of the other characters that we have investigated is such that one must

conclude that, excluding P. (Alaocaris) antrorum,

Benedict, 1896, the remaining species comprise a

closely allied group. Of the previously described

species, adequate series are available of only P. (A.)

antrorum, P. (P.) kadiakensis, and P. (P.) paludosus.

There are only 4 specimens of P. (P.) cummingi

known to us, and only 13 specimens of P. (P.) suttkusi Smalley, 1964, have been reported.

Utilizing the limited data available, and perhaps

emphasizing the resemblance existing between the

appendices masculinae (Figure 8a-/), we believe

that the closest relatives of P. (P.) lindsayi are P.

(P.) suttkusi (Coahuila Province, Mexico) and P.

(P.) paludosus (New Jersey to Florida).

The key on page 16 will assist in recognizing the

species mentioned above.

Discussion

As has been pointed out in the sections devoted

to relationships of the three crustaceans, the affinities of the crayfish, Procambarus roberti, seem

clearly to be with species occurring principally in

the southeastern part of the United States, and the

discovery of the geographically disjunct member of

the stream-dwelling subgenus Pennides in a stream

within the Sierra Madre Oriental, so far south in

Mexico, came as a great surprise.

Certain resemblances of P. roberti to members

of the subgenus Villalobosus (a group of crayfishes

confined to a relatively small area north of the

Cordillera Volcanica Transversal in the states of

Hidalgo, Puebla, and Veracruz) were noted above.

Both the morphological similarities and geographic
16 SMITHSONIAN CONTRIBUTIONS TO ZOOLOGY

Key to the North and Middle American Freshwater Species

of the Genus Palaemonetes

1. Pigmented; lateral minus of antennule with mesial free portion longer than basal fused

portion Salt and brackish water species

Pigmented or albinistic; lateral ram us of antennule with mesial free portion distinctly shorter

than basal fused portion except in P. (A.) antrorum Freshwater species. ... 2

2. Body and eyes without pigment; rostrum short and lacking teeth on ventral margin; chela

of first and second pereiopods subequal in size

Palaemonetes (Alaocaris) antrorum Benedict, 1896

Body and eyes with or without pigment; rostrum long and with teeth on ventral margin;

chela of second pereiopod distinctly longer than that of first S

3. Lateral ramus of uropod with small movable spine at mesial base of lateral spine 4

Lateral ramus of uropod lacking small movable spine at mesial base of lateral spine ... . 6

4. Body and eyes without pigment; mesial lobe of palp of first maxilla with S setae

Palaemonetes (Palaemonetes) cummingi Chace, 1954

Body and eyes with pigment; mesial lobe of palp of first maxilla without or with 2 setae . 5

5. Branchiostegal spine marginal or only slightly posterior to margin and adjacent to branchiostegal groove; posterodorsal pair of spines on telson situated almost midway between

anterodorsal pair and posterolateral angle of telson; appendix masculina (Figure 8d) with

4 apical and 1 subapical setae; mesial lobe of palp of first maxilla with 2 curved setae

Palaemonetes (Palaemonetes) paludotut (Gibbes, 1850)

Branchiostegal spine never marginal and somewhat removed ventrally from branchiostegal

groove; posterodorsal pair of spines on telson usually situated much closer to posterior

margin of telson than to anterodorsal spines; appendix masculina (Figure 8b) with only

3 apical and 1 subapical setae; mesial lobe of palp of first maxilla lacking setae

Palaemonetes (Palaemonetes) kadiakensis Rathbun, 1902

6. Rostrum extending distinctly beyond level of spine on antennal scale; appendix masculina

(Figure He) with 5 apical and 2 subapical setae (counting distal member of row of setae);

mesial lobe of palp of first maxilla with 3 curved setae

Palaemonetes (Palaemonetes) lindsayi, new species

Rostrum extending only to level of spine on antennal scale; appendix masculina (Figure 8/)

with 6 apical and 2 subapical setae (counting distal member of row of setae); mesial lobe

of palp of first maxilla without setae

Palaemonetes (Palaemonetes) suttkusi Smalley, 1964

position of P. roberti suggest that it was derived

from the ancestral stock that was the forerunner

of Villalobosus. If Hobbs' views concerning the invasion of Mexico by crayfish stocks from the north

prove to be admissible (Hobbs, 1971:12, 13; see

summary table and Figure 6b), then P. roberti

represents a relict of one of the three stocks ("5B")

migrating southward into Mexico during the

Pliocene.

With the assumed passive migration (Hobbs,

1971:10) of the ostracod on crayfish hosts, and if

the suggested relationships of the hosts, as pointed

out above, are valid, one might assume that the

ostracods occurring on P. roberti would show affinities with those ostracods infesting members of the

subgenus Villalobosus, and this is precisely what

we believe has been found. Ankylocythere barbouri

indeed is markedly similar to Uncinocythere bicuspide (Rioja, 1943), which infests six crayfishes

belonging to the subgenus Villalobosus. Its importance in linking the previously recognized

genus Uncinocythere with Ankylocythere has been

discussed in the paragraphs devoted to its relationships.

In discussing the origin of the Mexican entocytherid fauna, Hobbs (1971:15-17) stated that the

Uncinocythere stock, "generally considered to be

the most primitive of the subfamily [Entocytherinae], apparently was brought into Mexico during

the Pliocene by one or more of the three stocks of

crayfishes (one of which is rather primitive [P.

roberti is believed to be a descendant of that stock])

that moved southward across the Northern Gulf

Slope [1971:10-11] to populate the interjacent

area." He further indicated that Ankylocythere

toltecae,
NUMBER 174 17

which is restricted to a small area in southern Tamaulipas,

eastern San Luis Potosi, and extreme northern Hidalgo . . .

is associated with only two hosts, P. toltecae and P. villalobosi . . . remnants of the Pliocene crayfish migration

passing through the Northern Gulf Slope southward. In fact,

these two represent the only suspected traces of the Pliocene

crayfish stock that have remained in that area [P. roberti is

the third]. Why they should harbor a member of the genus

Ankylocythere while their close relatives to the south are

infested by members of the genus Uncinocythere poses a

problem in itself.

After exploring possible explanations, he "favored"

the hypothesis, "that A. toltecae is viewed as a relict

of the pioneering [pre-Pliocene] Ankylocythere

stock which, before the extinction of its original

hosts, managed to gain access to certain members

of the Pliocene crayfish invaders as alternative

hosts."

With the discovery of A. barbouri in the Northern

Gulf Slope, linking A. toltecae to U. bicuspide,

one could hardly overlook the possibility of an independent acquisition of the excrescence on the

clasping apparatus by their immediate ancestors

from the Pliocene Uncinocy there stock that gave

rise to the Mexican members of Uncinocy there.

While this would suggest at least a diphyletic origin

of Ankylocythere from the more primitive Uncinocythere, it would permit a strong parallel with the

assumed migrations of the host stocks, and, in addition, it would provide an explanation for the

marked similarities betwen A. barbouri and the two

members of Uncinocythere (U. equicurva and U.

lucifuga) occurring in the southeastern part of the

United States. Even though such an explanation

is in keeping with our present knowledge, until

more conclusive evidence for the di- or polyphyletic

origin of Ankylocythere becomes available, recognition of the two generic groups does not seem inappropriate.

As pointed out above, there are so few data on

the range of the genus Palaemonetes in Mexico,

and one of the American species is so poorly

known, there is little to suggest the source of the

stock from which this new species was derived. If

our tentative conclusion—that Palaemonetes (P.)

lindsayi is most closely allied to P. (P.) suttkusi and

P. (P.) paludosus—proves to be tenable, then there

exists a similar pattern of relationships (Mexico

and the southeastern part of the United States)

parallel to that postulated for the crayfish and entocytherid frequenting the waters of La Media Luna.

It seems highly probable to us that the crayfish and its ostracod commensal (also possibly the

shrimp), in contrast to most of the fish fauna (see

Miller, 1956:15), have affinities with the nearctic

faunas rather than with tropical ones.

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Species of Crustaceans from an Artesian Well at San

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1954. Two New Subterranean Shrimps (Decapoda: Caridea) from Florida and the West Indies, with a Revised Key to the American Species. Journal of the

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Fleming, Laurence E.

1969. Use of Male External Genitalic Details as Taxonomic

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18 SMITHSONIAN CONTRIBUTIONS TO ZOOLOGY

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Smalley, Alfred E.

1964. A New Palaemonetes from Mexico (Decapoda, Palaemonidae). Crustaceana, 6(3):229-232, 1 figure.

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62 plates. Tesis, Facultad de Ciencias, Universidad

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•Ct U. S. GOVERNMENT PRINTING OFFICE: 1974 346-362/17


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