THE RAFFLES BULLETIN OF ZOOLOGY 1996 44(1): 109-134

REVISION OF THE ANCHIALINE VARUNINE CRABSOF THE GENUS ORCOVITA NG & TOMASCIK, 1994
(CRUSTACEA: DECAPODA: BRACHYURA: GRAPSIDAE),WITH DESCRIPTIONS OF FOUR NEW SPECIESPeter K. L. Ng, Daniele Guinot and Thomas M. Iliffe

ABSTRACT. - Four new species of the varunine crab genus Orcovita Ng & Tomascik,
1994, viz. O. gracilipes, O. mollitia, O.fictilia and O. angulata are described from the Pacificislands of Niue, Guam and the Philippines. The genus was previously considered monotypic,
with only the Indonesian type species, O. saltatrix Ng & Tomascik, 1994. A key to thegenus is provided. All known Orcovita species are anchialine and/or cavernicolous crabs.

INTRODUCTION
Ng & Tomascik (1994) described an unusual new genus and new species of grapsid
crab, Orcovita saltatrix, from an anchialine lagoon in a raised atoll in Kakaban, between
Borneo and Sulawesi in Indonesia. Although Orcovita clearly belongs to the subfamily
Varuninae, it is very distinct with regards to its broad and rectangular carapace, well developed
frontal median triangle, broadly triangular external orbital angle, elongate and slenderpereiopods, and a short and stout G 1.
The third author, in his investigations of the anchialine fauna in the Pacific, obtained
numerous crabs which were subsequently referred to the first and second authors for study(see Ng et aI., 1994). Among the crabs collected from caves and sinkholes in the islands ofNiue, Guam and the Philippines archipelago are a good series of specimens clearly referrable
to the genus Orcovita. The study of this material showed that they contained representativesof four species, all of which are undescribed. The present paper serves to describe these four
new species and provides a key to the genus.

Peter K. L. Ng - Department of Zoology, National University of Singapore, Kent Ridge, Singapore
119260, Republic of Singapore. Daniele Guinot - Laboratoire de Zoologie (Arthropodes), Museum
National d'Histoire Naturelle, 61 rue Buffon, 75231 Paris cedex OS, France. Thomas M. Iliffe Department of Marine Biology, Texas A & M University at Galveston, Mitchell Campus, P.O. Box
1675, Galveston, Texas 77553, USA.

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Ng et al.: Revision of the anchialine crab genus Orcovita
MATERIALS AND METHODS
The abbreviations Gland G2 are used for the male first and second pleopods respectively;
M, D and P refer to the ambulatory merus, propodus and dactylus respectively, the number
preceding it referring to the respective ambulatory leg. Measurements are of the carapace
width and length respectively. The terms used essentially follow those used by Crosnier(1965). The term anchialine is used in the sense of HoIthuis (1973).
Specimens are deposited in the Museum national d'Histoire naturelle (MNHN), Paris,
France; Zoological Reference Collection (ZRC), Department of Zoology, National Universityof Singapore; Museum Zoologicum Bogoriense (MZB), Bogor, Indonesia; United States
National Museum of Natural History (USNM), Smithsonian Institution, Washington D.C.;
National Museum (NMCR), Manila; Zoological Collection of the University of Ljubljana,
Slovenia (ULS); and the Nationaal Natuurhistorisch Museum (NNM), Leiden, The
Netherlands.

TAXONOMYFAMILY GRAPSIDAE MACLEAY, 1838
SUBFAMILY VARUNINAE H. MILNE EDWARDS, 1853

Orcovita Ng & Tomascik, 1994
Orcovita Ng & Tomascik, 1994: 939.
Type species. - Orcovita saltatrix Ng & Tomascik, 1994, by original designation andmonotypy.
Diagnosis. - Carapace rectangular to subrectangular, distinctly broader than long; dorsal
surface smooth; regions poorly defined; epigastric cristae very low; postorbital cristae very
low to not discernible. External orbital angle very broad, outer margin distinctly convex;
frontal median triangle present, formed by 3 granuliform ridges. Antennal segments entering
orbital hiatus. Antennules broad. Eyes well developed, cornea pigmented. Third maxillipedwith very broad, stout exopod, as wide or slightly wider than ischium; anteroexternal angleof merus strongly auriculiform. Chelipeds relatively long, with distinct pulvinus (swollen
area with thin, membranaceous cuticle) with setose surrounding areas present at base of
fingers of both male chelae; pulvinus usually also present in females although relatively
smaller, setae varies from dense and long to sparse to almost undiscernible. Ambulatory legs
subcylindrical in cross-section, segments long, slender; dorsal and ventral margins gently
serrated in first ambulatory merus, progressively less serrated from first to third ambulatory
merus, appearing rough to uneven in fourth 'ambulatory merus. Male abdomen not retainedby a "bouton-pression" (cf. Guinot, 1979), with only a sternal ridge surrounding telson. G Iwith truncate tip. G2 very short, no distal segment present (modified from Ng & Tomascik,
1994: 939).
Remarks. - Ng & Tomascik (1994: 940) have discussed the affinities of Orcovita withother varunine genera and there is no need to elaborate on this here. Externally, Orcovita
most closely resembles Ptychognathus Stimpson, 1858, especially with regards to the pulvinus

110THE RAFFLES BULLETIN OF ZOOLOGY 1996 44(1)Fig. 1. a, Orcovita saltatrix Ng & Tomascik, 1994, paratype male (17 .0 by 13.0 mm) (MNHN B22891); b, O. gracilipes, new species, holotype male (18.5 by 13.1 mm) (MNHN B-22892); c, O.
mollitia, new species, holotype male (12.6 by 9.6 mm) (MNHN B-22895).

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Ng et a1.: Revision of the anchialine crab genus Orcovita
and setose parts of the chela. In terms of the carapace, frontal margin, anterolateral margins,and pereiopods however, there is not much resemblance.
Sexual dimorphism is quite marked in members of this genus. Ng & Tomascik (1994:
943) noted that the chelipeds of males are longer and the chelae relatively stouter comparedto females for O. saltatrix, and this is also valid for the other four species recognised here.
The tooth on the inner distal angle of the chelipedal carpus is low and obtuse in males but
distinctly more developed and much stronger in females. The outer surface of the chela inmales in all known species is smooth, but in females, there is a low but visible submarginal
longitudinal ridge near the ventral margin which extends across the pollex. This submarginal
ridge is present in all five species although it is very weak in O. gracilipes.

Fig. 2. a, Orcovitafictilia, new species, holotype male (21.5 by 15.3 mm) (NMCR); b, O. angulata,
ho1otype female (16.7 by 13.0 mm) (USNM 3643 lOb).

112

THE RAFFLES BULLETIN OF ZOOLOGY 1996 44(1)One ovigerous specimen of O. gracilipes was obtained and it has small eggs (ca. 0.3 mm
diameter) , suggesting that the first zoeae are small and the larval stages have a relatively
long planktonic life.

Fig. 3. Live colours. A, Orcovita saltatrix Ng & Tomascik, 1994, in Kakaban Lake, specimen notcollected (photograph: G. R. Allen); B, O. jictilia, new species, female (17.0 by 13.0 mm) (USNM
36431Oa).

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Ng et al.: Revision of the anchialine crab genus Orcovita

Orcovita saltatrix Ng & Tomascik, 1994
(Figs. la, 3A, 4, 5)
Orcovita saltatrix N g & Tomascik, 1994: 937, Figs. 3-7.

Material examined. - Holotype - male (19.0 by 14.0 mm) (MZB), ca. 11 m depth, Kakaban,
Indonesia, colI. T. Tomascik, 27 Sep.1993.
Paratypes - 7 males (largest 23.0 by 16.1 mm), 2 females (19.4 by 14.9 mm, 19.4 by 14.6 mm)(ZRC 1994.4220),2 males (MNHN B-22891), 1 male (NNM), ca. 10 m depth, same locality as holotype,
coIl. T. Tomascik, 29 Sep.1993 .

Diagnosis. - Carapace broader than long (width ca. 1.4 times length). External orbital
angle separated from anterolateral margin by distinct, V -shaped cleft; posterolateral margins
minutely granular, appearing smooth, gently concave to straight, converging gradually towards
posterior margin of carapace. Outer surface of male major chela smooth, without any traceof a longitudinal sulcus, outer surface of female chela with weak submarginal longitudinalridge adjacent to ventral margin; areas adjacent to male pulvinus with well developed setae,
female pulvinus very small to undiscernible, with very short or no setae; outer surfaces oftips of fingers glabrous. 3M length ca. 5.8 times width, 3P length ca. 4.3 times width, 3D
length ca. 7.8 times width, 4M length ca. 4.4 times width, 4P length ca. 3.1 times width, 4D
length ca. 5.5 times width. Width of segment 6 of male abdomen ca. 2.1 times length; lengthof telson ca. 1.3 times length of segment 6.
Remarks. - Orcovita saltatrix has been described and discussed in detail by Ng &Tomascik (1994), and there is no need to elaborate upon the species here. Ng & Tomascik(1994) commented that there is some variation in the density and length of the setae at thebase of the cutting edges of the fingers of the chela in this species, with the outer margin of
the external orbital angle varying from arcuate to gently convex. Orcovita saltatrix has theshortest third and fourth ambulatory dactylus (length 7.8 and 5.5 times width respectively)
and longest third ambulatory merus (length 5.8 times width).
Colour. - "In life, carapace greyish-brown to dark grey, with blotches of reddish-brown
on anterior half, H-shaped central depression white to dirty-white; ambulatory legs grey tobrown; chelae in smaller specimens grey with dark grey longitudinal streaks; greyish-white
in adults; cutting teeth white; ventral surfaces dull grey to dirty white ..... " (after Ng &Tomascik, 1994: 943). A colour photograph of this species (as an unidentified grapsid) was
published in Allen (1995: 77) and is reproduced here (Fig. 3).
Notes on the habitat and biology. - "Kakaban (02°08'35"N, 118°31' 13 "E) is a raised
atoll island approximately 2.5 km wide and 7.5 km long. It is situated on a depositional
basin that stretches from the Simporna Peninsula (Sabah, East Malaysia) to the Mangkalihat
Peninsula (East Kalimantan, Indonesia) along the northeast coast of Borneo in the Sulawesi
Sea ..... The former lagoon of the uplifted atoll of Kakaban may be classified as an anchialinelake as it is completely surrounded by a heavily vegetated coral ridge that rises to a heightof approximately 50-60 m above sea level. There is is no surface connection with the open
sea. The lake has an approximate area of 3.9 km2 , an average depth of 8.5 m and a tidal
amplitude of about 0.19 m, with the estimated total tidal flushing (per tidal cycle) less than
2.5% of the total lake volume. The pH and salinity of the lake water are lower than that of
the surrounding sea water (pH 7.6-7.8 against average of pH 8.3, salinity 26-28 ppt against
32-35 ppt). The average water temperature is distinctly higher than the surrounding waters

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THE RAFFLES BULLETIN OF ZOOLOGY 1996 44(1)(surface 32°C, 31 °C at a depth of about 10 m, against 26°-28°C). The dissolved oxygen(measured at mid-afternoon) was 6.6 mg/l at the surface and 5.6 mg/l at a depth of about 10
m, against that of seawater which ranges from 6.0-6.4 mg/I. The lake at Kakaban is fringed
by a narrow mangrove belt about 3-5 m wide ..... The sediments in the lake can be roughly
grouped into three types. Type 1 is a dark sediment found exclusively under the stilt roots

(

(

8\
A~

····t
· · · · · · ··f

. :,...: -'... :...:..... .

------------------~

F

GI

-H

Fig. 4. Orcovita saltatrix Ng & Tomascik, 1994. Holotype male (J 9.0 by 14.0 mm) (MZB). A, carapace;B, left third maxillipeds; C, frontal view of carapace; D, antennae, antennules and orbits (frontalview); E, frontal median triangle; F, posterior margin of epistome; G, distal part of merus , carpus andproximal part of chela (dorsal view); H, left chela; I, anterior thoracic sternites. Scales = 1.0 mm.

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Ng et al.: Revision of the anchialine crab genus Orcovita
of Rhizophora and consists mainly of mangrove detritus, some weathered 'beach' rock andfragments from Halimeda and the bivalve Brachydontes variabilis which are very abundanton the stilt roots. Type 2 sediment is a fine mud covering most of the lake bottom. Type 3
sediment consists mostly of Halimeda fragments and is dominant in the lake's extensive
Halimeda meadows. Orcovita saltatrix were observed only on Type I and Type 2 sediments.
Preliminary observations indicate that the crabs are found only at depths greater than 2 m.
The crabs move gently over the bottom and when disturbed, swiftly burrow into the softmud." (after Ng & Tomascik, 1994: 944-947). Allen (1995: 77) notes that the crab lives in" ... silty burrows".

A

B

----~

IG
H

Fig. 5. Orcovitasaltatrix Ng & Tomascik, 1994. Holotype male (19.0by 14.0 mm) (MZB). A, abdomen;

B, right third ambulatory leg; C, left fourth ambulatory leg; D-I, left G 1; G-I, distal part of left G 1;
J, left G2. D-E, with setae; A, F-I, denuded. Scales: A-C = 1.0 mm; D-J = 0.5 mm.

116

THE RAFFLES BULLETIN OF ZOOLOGY 1996 44(1)Orcovita gracilipes, new species(Figs. 1b, 7, 8)
Material examined. - Holotype - male (18 .5 by 13.1 mm) (MNHN B-22892), station 88-006,
Vaikona Chasm, Niue, colI. T. M. IIiffe, 6 Feb.1988, with plastic bottle baited with fish and left
overnight at 13 m depth.
Paratypes - 3 males, 2 females (larger, ovigerous, 17.4 by 12.5 mm) (MNHN B-22893), 1 female(NNM), 1 male, 1 female (ZRC 1996.96-97), same data as holotype.
Others - 1 female (19.6 by 13 .9 mm) (MNHN B-22894), station 88-009, Anatuku Chasm, Niue,
colI. T. M. IIiffe, 12 Feb.1988, with plastic bottle baited with fish and left overnight at 20 m depth.

Diagnosis. - Carapace broader than long (width ca. 1.4 times length). External orbital
angle separated from anterolateral margin by distinct, V -shaped cleft; posterolateral margins
distinctly granulated, concave, converging distinctly towards posterior margin of carapace.
Outer surface of male major chela smooth, with a shallow but clear longitudinal sulcus on
the upper half in large males, outer surface of female chela with very weak: submarginal
longitudinal ridge adjacent to ventral margin; areas adjacent to male and female pulvinus
with long setae, often completely obscuring pulvinus; outer surfaces of tips of fingers glabrous;
border strongly corneous. 3M length ca. 5.7 times width, 3P length ca. 5.1 times width, 3D
length ca. 10.8 times width, 4M length ca. 4.7 times width, 4P length ca. 3.2 times width,
4D length ca. S.9 times width. Width of segment 6 of male abdomen ca. 2.1 times length;
length of telson ca. 1.1 times length of segment 6.
Etymology. - The name alludes to the long and slender ambulatory legs of the species(from the Latin "gracilis" for long, slender and "pes" for foot).
Remarks. - With regards to the elongate ambulatory legs and dense setose areas
surrounding the pulvinus on the chela, O. gracilipes seems to be closest to O. saltatrix, butthere are several key differences. Orcovita gracilipes can be separated from O. saltatrix inthe structure and shape of the posterolateral margin of the carapace, proportions of theambulatory merus and propodus, degree of granulation on the inner distal margin of thechelipedal carpus, proportions of the male abdominal segment 6 (Table 1). The external
orbital angle of O. gracilipes is also usually less strongly arcuate compared to that on O.
saltatrix (Fig. 3A vs. SA), but, in at least one specimen of O. gracilipes (Fig. SK), this is not
the case. Orcovita gracilipes is also the only species in the genus in which the outer surfaceof the major chela in large males has a shallow but discernible longitudinal sulcus on theupper half.
The degree of pubescence around the pulvinus of the chela in O. gracilipes is very marked- more so than for any other species. In both males and females, the setae are very long anddense, often completely obscuring the pulvinus. These setae are distinctly longer than thosein male O. saltatrix or O. mollitia. In other Orcovita species, the setae around the pulvinusof female chelae are very weak to absent. The density and length of the setae are correlatedwith the strength of the pulvinus, particularly in females. In females of species in which thesetae are very sparse and short, the pulvinus is frequently small to indistinct (e.g. O. saltatrix
and o.fictilia). In O. gracilipes, the pulvinus in males and females are equally well developed.
Even in juvenile specimens (e.g. male 12.1 by 9.0 mm, MNHN B-22893), the pulvinus iswell developed and the setae long and dense.
The proportions of the elongate ambulatory legs ally O. gracilipes with O. angulata, but

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Ng et al.: Revision of the anchialine crab genus Orcovita
the carapace of O. gracilipes is very different, appearing proportionately longer, the lateral
margins are distinctly more rounded, the third and fourth ambulatory propodus and dactylus
is proportionately much longer, the outer surface of the chela is smooth and has no longitudinalridge, the area surrounding the pulvinus on the chela is covered with long setae and the tipsof the fingers of the chela are glabrous (Table l).
The submarginal longitudinal ridge present near the ventral margin of the female chela
is very weak in O. gracilipes compared to other species. In larger female specimens, theridge almost cannot be discerned.

Colour. - Not known. The preserved specimens are a uniform yellowish white.
Notes on the habitat and biology. - Niue is a single, 259 km2 , raised limestone atoll
located 386 km east of Vava'u, Tonga, in the south Pacific at 19°04'S 169°53'W (Fig. 6).
A 20 m high sea cliff at the inner edge of a narrow reef platform surrounds the island, andinland, a second terrace rises to become a central plateau about 60 m above sea level. Faulting
during uplift has produced many deep chasms that run parallel to the coastline. Well developed
karst relief is present all around the margins of the island.

,.

'¥o'~.

Fiji. .... }New
C:uh:_dml.b)

ANATUKU
CHASM

N

2

r

4km

Fig. 6. Map of Niue showing the locations of Vaikona and Anatuku Chasms.

118

THE RAFFLES BULLETIN OF ZOOLOGY 1996 44(1)~~..

. .. .. ,"" ' "

i

\

\\

d\1

o

#

~t . ~~
A _....

=====

Fig. 7. Orcovita graciUpes, new species. A-E, holotype male (18.5 by 13.1 mm) (MNHN B-22892);
F, paratype female (16.8 by 12.2 mm) (NNM); G, paratype female (15.5 by 11.1 mm) (MNHN B22893); H, paratype female (ovigerous, 17.4 by 12.5 mm) (MNHN B-22893). A, H, carapace; B, rightfourth ambulatory leg; C, F, carpus and proximal part of right chela (dorsal view); D, G, left chela;E, right third ambulatory leg. Scales = 1.0 mm .

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Ng et al.: Revision of the anchialine crab genus Orcovita
The type locality, Vaikoma Chasm, is located 150 m inland from the east coast of theisland, 1.7 km southeast of the village of Liku. The chasm is reached by a well marked, 1.5
km long path from the coastal road, and is about 20 m deep to the water level with sheer
vertical walls. One enters the rift through a small hole on one side with a series of drops
negotiated with the aid of a handline. In the main open section of the rift is a clear deep pool.
At the far side of this pool is a chamber in total darkness with a dry section containing
pyramid-like cairns 1 m high. After the cairns is another dark lake with two narrow rift
passages which taper off. The length of the main part of the chasm is 200 m. Salini ties were
8.5 ppt at 0 and 1 m, 10 ppt at 3 m, 15 ppt at 10 m, and 30 ppt at 16 m depth. The watertemperature was constant at 23°C above 10 m, but increased to 27°C at 16 m. Fish andshrimps were also collected from the pool.
A single female specimen was also collected from Anatuku Chasm. Anatuku is 150 m
inland from the east coast, 1 km southeast of the village of Hakupu. This chasm is on thesouth side of the road from the village to the Tuhia-atua landing place, between the upperand lower cliffs. The steep-walled entrance rift is visible from the road. This rift first descends
along a breakdown floor, then ascends over a mound beneath a surface opening, before
finally dropping down to a clear deep pool. The pool is over 100 m long by 0.5 to 4 m wide.
At the bottom of the entrance slope, the pool is 24 m deep, while farther along the rift,
depths of 32 m are reached. Around the pool, the chasm is mostly roofed over, but at midday, shafts of sunlight briefly illuminate the pool. The bottom of the pool consists ofbreakdown, organic detritus, silt and some larger logs. Underwater stalactites and draperies
are present on the walls. Salinity was constant at 1.5 ppt for the first 10 m, increasing to 24
ppt at 20 m and 31 ppt at 24 m. Visible haloclines were observed at II and 21 m. Water
temperature was uniform with depth at 22°C. Shrimps and copepods were also collectedfrom the deeper waters of the pool.

B

A

ill I
;j

!

0

I
E

I I

I I,

o

J '

\\1/
I
\

,

,I

IF

Fig. 8. Orcovita gracilipes, new species. A-E, holotype male (18.5 by 13.1 mm) (MNHN B-22892).
A, abdomen; B-F, left Gl; D-F, distal part ofleft Gl. B, D, ventral view; C, E, dorsal view; F, dorsomarginal view. B-C, with setae; A, D-F, denuded. Scales: A = 1.0 mm; B, C = 0.5 mm; D-F = 0.25
mm.

120.

THE RAFFLES BULLETIN OF ZOOLOGY 1996 44(1)Orcovita mollitia, new species(Figs. 1c, 10, 11)Material examined. - Holotype - male (12.6 by 9.6 mm) (MNHN B-22895), station 85-015, Faifai
Beach Cave, Guam, call. T. M. Iliffe, 27-28 Jan.1985, with plastic bottle trap baited with crab partsand left overnight in 3 m water depth.
Paratypes - 5 males, 4 females (MNHN B-22896), 2 males, 2 females (largest 12.8 by 9.7 mm)(ZRC 1996.98-101), same data as holotype.
Others - 1 male (14.9 by 10.9 mm) (USNM 364310c), station 85-009, Marbo Cave, in cave pool ,Guam, in 0-5 m water depth, colI. T. M. Iliffe, 20 Jan.1985, with plastic bottle trap baited with hermit
crab and left overnight in 3 m water depth.

Diagnosis. - Carapace broader than long (width ca. 1.3-1.4 times length). External orbital
angle separated from anterolateral margin by small notch (sometimes indistinct), epibranchial
tooth very small to indistinct; posterolateral margins gently granulated, gently concave,
converging towards posterior margin of carapace. Outer surface of male major chela smooth,
without any trace of a longitudinal sulcus, outer surface of female chela with low but distinct
submarginal longitudinal ridge adjacent to ventral margin; areas adjacent to male and female
pulvinus with short setae, sometimes almost glabrous; outer surfaces of tips of fingers glabrousin small specimens, with short setae in larger specimens. 3M length ca. 5.7 times width, 3P
length ca. 5.2 times width, 3D length ca. 12.9 times width, 4M length 4.2-4.7 times width,
4P length 2.8-3.2 times width, 4D length ca. times 7.6 width. Width of segment 6 of maleabdomen ca. 3.0 times length; length of tel son ca. 1.4 times length of segment 6.
Etymology. - The name alludes to the small size and delicate appearance of the species(from the Latin "mollitia" for weakness).
Remarks.- Orcovita mollitia seems to be closest to O. fictilia, especially with regards
to the shape of the carapace and anterolateral margins. They differ clearly however, in theform of their chela and proportions of their ambulatory legs (Table 1).
Orcovita mollitia is also the smallest of the known species of Orcovita, with the largest
mature male only 14.9 by 10.9 mm (USNM 36431Oc), and the largest mature female 12.9
by 9.7 mm (paratype, ZRC 1996.100).
The degree of pubescence surrounding the pulvinus of the chela varies a great deal inthis species, from almost glabrous to highly setose. In general however, the setae in males
tend to be longer. The tips of the fingers of the chelae are usually glabrous, although in thelargest male (14.9 by 10.9 mm, USNM 364310c), it is setose. This suggests that this charactermight be associated with size. This is interesting, as in O. fictilia, setae are present on thetips of the chelae in small specimens and are lost in large individuals. This large male has
an unusual coloration in that many of its ambulatory legs and one of its chelipeds is whiteand not grey. This suggests that these appendages are recently regenerated structures.
The holotype male has a rather short fourth ambulatory dactylus (length 5.7 times width)
compared to those in other specimens (length ca. 7.6 width), and suggests that it may havepreviously been damaged.
Colour. - Not known. The preserved specimens vary from grey to greyish-brown.

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Ng et al.: Revision of the anchialine crab genus Orcovita

Notes on the habitat and biology. - Guam is the largest and southernmost of the Mariana
Islands, and is located in the western Pacific at 13°28'N and l44°45'E (Fig. 9). The islandis 50 km long, 6-18 km wide, and 541 km2 in area. The northern part of Guam consists ofa rolling upland plateau of emerged limestone with no permanent rivers or streams, bounded
by towering cliffs along much of the coastline. The southern part of Guam is a mountainous
volcanic upland fringed with limestone along the east coast. Exposed rocks range in age
from late Eocene to Recent. Most of the northern plateau and the fringing limestone along
the east coast of southern Guam are Pliocene and Pleistocene age Mariana limestone, theyoungest widespread formation on the island. During the recent Pleistocene, the island was
uplifted and the terraces were cut by shifting glacial levels.
The type locality, Faifai Beach Cave, is on the west coast of Guam. It is located at thebase of a cliff about 100 m inland from the beach south of Two Lover's Point. A clump ofprehistoric latte stones lie in front of the cave. The cave is divided into two small chambers,
each containing an anchialine pool. Surface water temperature and salinity were 25.2°C and2.6 ppt respectively, with maximum water depth at 5 m. Shrimps and amphipods were alsocollected from the pools.

GUAM
FAIFAI BEACH
CAVE

N

i
o

5

Fig. 9. Map of Guam showing the location of Faifai Beach Cave.

122

10 km

THE RAFFLES BULLETIN OF ZOOLOGY 1996 44(1)

c

E
G

~
,/

'---"."i">:, ':.===---H
Fig. 10. Orcovita mollitia, new species. A-D, holotype male (12.6 by 9.6 mm) (MNHN B-22895); E,F, paratype male (12.9 by 9.6 mm) (ZRC 1996.98); G, male (14.9 by 10.9 mm); H, J, paratype female(12.9 by 9.7 mm) (ZRC 1996.100); 1, paratype male (12.8 by 9.7 mm) (ZRC 1996.99). A, I, carapace;B, carpus and proximal part of right chela (dorsal view); C, right chela; D, F, G, right fourth ambulatoryleg; E, right third ambulatory leg; H, left chela; J, right carpus and proximal part of right cheliped(dorsal view). Scales = 1.0 mm.

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Ng et al.: Revision of the anchialine crab genus Orcovita

A

o

B

F
E
Fig. 11. Orcovita mollitia, new species A-D, holotype male (12.6 by 9.6 mm) (MNHN B-22895). A,
abdomen; B-F, left 01; D-F, distal part ofleft 01. B, D, ventral view; E, dorso-marginal view; C, F,
dorsal view. B-C, with setae; A, D-F, denuded. Scales: A = 1.0 mm; B, C = 0.5 mm; D-F = 0.25 mm.

The other locality where the species was collected was Marbo Cave, which is on the east
coast near Andersen South Air Force Base. The cave is located at the base of a hill some 300
m inland. It consists of a collapse chamber divided by breakdown into four pools at varying
light levels. Surface water temperature and salinity were 26.3°C and 4.3 ppt respectively,
while maximum water depth was 6 m. Also collected from the pool were amphipods andthree species of shrimps.

Orcovita jictilia, new species(Figs. 2a, 3B, 13-15)
Material examined. - Holotype - Male (21.5 by 15.3 mm) (NMCR), station PH I, Hinagdanan
Cave, -3 m, Binag-Dauis, Panglao Island, Bohol, Philippines, colI. B. Sket, 2 Jan.1995.
Paratypes - I male (17.2 by 12.3 mm) (ZRC 1996.102), 1 female (15.0by 11.0mm) (NNM), samedata as holotype. - 1 male (18.0 by 13.0 mm), 2 females (larger 18.7 by 14.0 mm) (ZRC), 1 male,
2 females (MNHN B-22897), 1 male, 1 female (ULS), 2 females (NMCR), Hinagdanan Cave, -0.5 m,
Binag-Dauis, Panglao Island, Bohol, Philippines, colI. B. Sket, 2 Jan.1995.
Others - 2 males (larger 14.1 by 10.6 mm), 6 females (largest 14.9 by 10.3 mm) (MNHN B22898),2 males, 2 females (ZRC 1996.106-109), station 85-62, Tauala Cave, Panglao Island, Bohol,
Philippines, with dipnet from 0-1 m depth, colI. T. M. Iliffe, 3 Apr. 1985 . - 4 males (largest l7. 7 by
12.7 mm) (MNHN), 1 male, 1 female (15.7 by 11.6 mm) (ZRC 1996.110-111), station 85-62, Tauala
Cave, Panglao Island, Bohol, Philippines, call. T. M. Iliffe, 3 Apr. 1985, with dipnet from 0-1 m depth.
- 1 female (17.0 by 13.0 mm) (USNM 36431Oa), station 85-61, Cansista Cave, Panglao Island,
Bohol, Philippines, colI. T. M. Iliffe, 2 Apr. 1985, with plastic bottle trap left overnight in 1 m water
depth.

Diagnosis. - Carapace broader than long (width 1.4-1.5 times length). External orbital
angle separated from anterolateral margin by small but distinct cleft (occasionally only a124

THE RAFFLES BULLETIN OF ZOOLOGY 1996 44(1)notch present), epibranchial tooth small, low; posterolateral margins gently to minutely
granulated, gently concave, converging towards posterior margin of carapace. Outer surfaceof male major chela smooth, without any trace of a longitudinal sulcus, outer surface offemale chela with low but distinct submarginal longitudinal ridge adjacent to ventral margin;
areas adjacent to male and female pulvinus with short to very short setae, sometimes almost
glabrous; tips of fingers corneous, outer surfaces of tips of fingers with short setae in small
specimens, obscure to absent in larger specimens. 3M length ca. 5.3 times width, 3P length
ca. 4.2 times width, 3D length ca. 9.1 times width, 4M length 4.2-4.4 times width, 4P length
2.6-3.0 times width, 4D length 6.2-6.9 times width. Width of segment 6 of male abdomenca. 2.2 times length; length of telson ca. 1.3 times length of segment 6.

Etymology. - The name alludes to delicate appearance of the carapace (from the Latinnoun "fictilia" for pottery). Used as a noun in apposition.
Remarks. - Orcovitafictilia seems to be closest to O. angulata with regards to the very
short setae present on the areas surrounding the pulvinus and the setose tips of the fingersof the chela. In all other aspects of the carapace proportions, anterolateral margin armature,
structure of the chela and proportions of the ambulatory legs, however, the two species differ
significantly (Table 1).

PHILIPPINES-(I

PACIFIC OCEAN
SOUTH CHINA SEA

BUSUANGA~SAMAR

KORON~'Ni

PALWANo 200400 . .
,

,

.

., .
Fig. 12. Map of the Philippines showing the locations of Koron and Panglao Islands.

125

Ng et al.: Revision of the anchialine crab genus Orcovita

.. '

"

i

/
)J

c) ,~•... ..... ,...
tJ/;'1/,/.
.'--4t.l
~~

i)

,
'~\

\.

F
\,
\

B -~

-===============~--------_ ...........

o,\~.~-......
~! ,~\--- ••

= ."}

-

"'-'.

,

"~
... . ..............
~'"

Fig. 13. Orcovitafictilia, new species. A, C, D, G, ho1otype male (21.5 by 15.3 mm) (NMCR); B,
paratype male (18.0 by 13.0 mm) (ZRC 1996.103); E, paratype female (18.7 by 14.0 mm) (ZRC); F,
female (14.1 by 10.6 mm) (ZRC 1996.108). A, B, carapace; C, E, right carpus of cheliped; D, rightchela; E, left chela. Scales = 1.0 mm.

126

THE RAFFLES BULLETIN OF ZOOLOGY 1996 44(1)

F

B

H

G

E

I

Fig. 14. Orcovitajictilia, new species. A-E, male (14.1 by 10.6 mm) (MNHN B-22898); F, paratypemale (14.2 by 9.8 mm) (MNHN-B22897); G, H, male (15.1 by 11.2 mm) (ZRC 1996.106). A, carapace;B, carpus and proximal part of right chela (dorsal view); C, right chela; D, right fourth ambulatoryleg; E, abdomen; F, carapace; G, carpus and proximal part ofleft cheliped (dorsal view); H, left chela.
Scales = 1.0 mm.

127

Ng et al.: Revision of the anchialine crab genus Orcovita

c

B

A

o

E

~
,:,r

~ ~~
"

I

II,

IJ

"

I'

, I,

,,," ,," , I,,, ",, ', I
, ,

"

l-

K

Fig, 15, Orcovitafictilia, new species, A-E, holotype male (21.5 by 15,3 mm) (NMCR); F, G, I-L,
male (14.1 by 10.6 mm) (MNHN B-22898); H, male (17,0 by 13.0 mm) (USNM 36431Oa). A-E, 1L, left Gl; C-E, J-L, distal part ofleft Gl; F, right third ambulatory leg; G, H, right fourth ambulatoryleg, A, C, I, J, ventral view; D, K, dorso-marginal view; B, E, L, dorsal view, A, B, I, with setae; CE, J, denuded, Scales: A, B, I = 0,5 mm; C-E, J-L = 0,25 mm; F-H = 1.0 mm,

128THE RAFFLES BULLETIN OF ZOOLOGY 1996 44(1)Orcovitafictilia also closely resembles O. mol/itia, especially with regards to the shapesof the carapace and anterolateral margin, but differs clearly in ambulatory leg proportions
and structure of the chela (Table 1).

The degree of granulation on the posterolateral margin is strongest in smaller specimens,
becoming more obscure in large males and females. In the holotype and largest females, theposterolateral margin appears almost smooth, not unlike O. saltatrix. The degree of concavity
and convergence of the posterolateral margin however, does not change significantly between
size-groups.
One female (17.0 by 13.0 mm, USNM 3643 lOa) from Cansista Cave differs from all theother specimens in having a relatively flatter dorsal carapace surface, especially on the gastricand branchial regions, but in all other aspects, it agrees with O. fictilia, and is tentatively
referred to this species. With regards to the relatively flatter carapace, this female specimen
resembles O. angulata from Koron Island, but this species differs markedly from O. fictilia
in lateral armature and proportions of the ambulatory legs (Table 1).

Colour. - Not known. The preserved specimens are a uniform yellowish white.
Notes on the habitat and biology. - Panglao Island is situated in the south-central
Philippines about 500 krn south of Manila at 9°35'N 123°50'W (Fig. 12). This low limestoneisland, which is located only 1 km off the southwest corner of Bohol Island, has numerous
anchialine sinkholes and small caves. Orcovitafictilia was obtained from two different cavesystems here, Tauala and Cansista Caves.
The type locality, Tauala Cave, is a sinkhole containing a pool regularly used by the
local villagers for bathing and washing laundry. Salinity and temperature were 4 ppt and
29°C respectively. Amphipods, cyclopoid copepods, isopods (species of Gnathiidea) andmolluscs were also collected.
Cansista Cave, where one large female was collected, is a collapse sinkhole containing
a pool in darkness about 8 to 10m below the surface of the ground. Salinity in the pool was
6 ppt and maximum water depth about 4 m. Shrimps, amphipods, cyclopoid copepods, isopods(Gnathiidea sp.), molluscs and polychaetes were also collected in this pool.

Orcovita angulata, new species(Figs. 2b, 16)Material examined. - Ho1otype - Female (16.7 by 13.0 mm) (USNM 364310b), station 85-56,
Raft Cave, Koron Island, Philippines, colI. T. M. Iliffe, 28 Mar.1985, with a dipnet from the water
surface, from a floating log.
Paratype - 1 female (15.8 by 12.2 mm) (ZRC 1996.112), same data as holotype.

Diagnosis. - Carapace broader than long (width ca. 1.3 times length); posterobranchialregion flat. External orbital angle separated from anterolateral margin by distinct cleft;
posterolateral margins gently granulated, almost straight, converging gradually towards
posterior margin of carapace. Chelipedal carpus with very well developed serrated tooth on
inner distal angle. Outer surface of female chela with low but distinct submarginal longitudinal129

Ng et al.: Revision of the anchialine crab genus Orcovita
ridge adjacent to ventral margin; areas adjacent to female pulvinus with very short setae;
outer surfaces of tips of fingers with short setae. 3M length ca. 5.4 times width, 3P length
ca. 5.4 times width, 3D length ca. 16.1 times width, 4M length ca. 4.6 times width, 4P length
ca. 3.7 times width, 4D length ca. 6.6 times width. Gl not known.

Etymology. - The Latin name "angulata" alludes to the angular appearance of the junction
at the antero- and posterolateral margins.
Remarks. - Orcovita angulata is very distinctive among the known Orcovita species
with regards to its proportionately less broad carapace, the angular antero-posterolateraljunction and the very elongate third and fourth ambulatory propodus and dactylus(proportionately the longest for any known Orcovita species). Although only females are............ ~-~-~

I,c._-_._------ --",

Fig. 16. Orcovita angulata, new species. Holotype male (16.7 by 13.0 mm) (USNM 36431Ob). A,
carapace; B, carpus and proximal part ofleft chela (dorsal view); C, left chela; D, right fourth ambulatoryleg; E, right third ambulatory leg. Scales = 1.0 mm.

130THE RAFFLES BULLETIN OF ZOOLOGY 1996 44(1)known (both are mature specimens), the differentiating characters are taxonomicallysignificant and independent of sex. The length of the ambulatory legs allies O. angulata
with O. graci/ipes, but, in its proportions and all other aspects, they differ markedly (Table
1).

The dorsal carapace surface of O. angulata also appears distinctly flatter, especially on
the branchial and gastric regions, compared to the other Orcavita species, but the value of
this character is difficult to assess with just two specimens. The dorsal carapace surface of
one female specimen of o. fictilia (17.0 by 13.0 mm) (USNM 36431Oa) is also relatively
flat, but still less so compared to O. angulata.

Colour. - Not known. The preserved specimens are a uniform yellowish white.
Notes on the habitat and biology. - Koron Island is about 250 km southwest of Manila
in the central Philippines at 11 °55 ' N l20 15'W (Fig. 12). It is situated at the southeasterncomer of the larger island of Busuanga. The island consists of highly karstified limestone
with elevations to over 600 m. Numerous caves on this island are exploited as commercially
important sources of valuable birds' nests made by cave swiftlets.
0

In the type locality, Raft Cave, located on the north side of Koron Island, a large bamboo
raft and platform have been constructed to provide access to crevices near the ceiling where
the birds usually nest. The cave entrance consists of a small crevice that drops vertically for
10 m into the center of a totally dark lake chamber which is 30 m long by 18 m wide. Water
depth was at least 15 m. Also collected from this lake were shrimps, copepods, ostracods
and polychaetes.

GENERAL DISCUSSION
Although the GIs have not been used in the present study to separate the five species of
Orcovita, they are nevertheless useful. They are rather difficult to use because the distalmost
part is twisted at slightly but distinctly different angles. The rest of the G 1 structure also
differs in stoutness and slight differences in curvature. These differences, however, are difficult
to appreciate and use unless one places the GIs side by side for direct comparisons. All fivespecies, however, can easily be separated on the basis of their external morphologies.
It is important to note that all five species occur in anchialine habitats. Orcavita saltatrix
inhabits an anchialine open lagoon, whereas the other four species have all been found incaves or sinkholes. The distribution of the species are very disjunct (Kakaban - between
Borneo and Sulawesi, Niue, Guam and Philippines), but all agree so well in the main charactersthat we have little doubt that they are congeneric.

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Ng et al.: Revision of the anchialine crab genus Orcovita
Table 1. Differences between known species of Orcovita
O. saltatrix

O. gracilipes

O. mollitia

O. fictilia

O. angulata

Carapace
proportions(width vs.
length)ca. 1.4

ca. 1.4

ca. 1.3

1.3-1.5

ca. 1.3

External
orbitalangle

separated fromanterolateral
margin by
distinct,
V -shaped cleft

separated fromanterolateral
margin by
distinct,
V-shaped cleft

separated fromanterolateral
margin bysmall notch(sometimes
indistinct),
epibranchial
tooth verysmall toundiscernible

separated fromanterolateral
margin bysmall notch(sometimes
indistinct),
epibranchial
tooth small toalmostundiscernible

separated fromanterolateral
margin by
distinct cleft

Posterolateral
marginssmooth, gently
concave tostraight, notdistinctly
converging

granulated,concave,distinctly
converging

gentlygentlygentlygranulated,
granulated,
granulated,gently concave, gently concave, almost straight,
gentlygentlynot distinctly
converging
converging
converging

Area aroundmalepulvinuswith welldeveloped
setaewith long,with shortwell developed setae
setae

3M

ca. 5.8

ca. 5.7

ca. 5.7

ca. 5.3

ca. 5.4

3P

ca. 4.3

ca. 5.1

ca. 5.2

ca. 4.2

ca. 5.4

3D

ca. 7.8

ca. 10.8

ca. 12.9

ca. 9.1

ca. 16.1

4M

ca. 4.4

ca. 4.7

4.2-4.7

4.2-4.4

ca. 4.6

4P

ca. 3.1

ca. 3.2

2.8-3.2

2.6-3.0

ca. 3.7

4D

ca. 5.5

ca. 5.9

ca. 7.6

6.2-6.9

ca. 6.6

Width ofmale
abdominal
segment 6(vs. length)

ca. 2.1

a.2.1

ca. 3.0

ca. 2.2

Length ofmale telson(vs. segment
6)

ca. 1.3

ca. 1.1

ca. 1.4

ca. 1.3

ProvenanceKakaban(Indonesia)

Niue

Guam

Panglao(Philippines)

with very short with very short
to short setae setae

NB. Proportions of ambulatory legs based on maximum length against width.

132

Koron
(Philippines)

THE RAFFLES BULLETIN OF ZOOLOGY 1996 44(1)KEY TO THE GENUS ORCOVITA
1. Carapace appearing distinctly rectangular; posterolateral margins almost straight, subparallel, notdistinctly convergent towards posterior carapace margin (Indonesia; Philippines) ................. 2
Carapace appearing more hexagonal; posterolateral margins concave, distinctly convergent towards
posterior carapace margin (Niue; Guam; Philippines) .............................................................. 3
2. Junction between antero- and posterolateral margins rounded; posterolateral margin smooth; lengths
ofthird and fourth ambulatory propodus 4.3 and 3.1 times width respectively, lengths of thirdand fourth ambulatory dactylus 7.8 and 5.5 times width respectively (Kakaban: Indonesia) ..
..................................................................................................................................... O. saltatrix
Junction between antero- and posterolateral margins angUlar; posterolateral margin granulated;
lengths of third and fourth ambulatory propodus 5.4 and 3.7 times width respectively, lengthsof third and fourth ambulatory dactylus 16.1 and 6.6 times width respectively (Koron: Philippines).................................................................................................................................... O. angulata
3. Posterolateral margins strongly convergent; external orbital tooth always clearly separated fromrest of anterolateral margin by deep, distinct cleft, margin never entire; pulvinus on chela partiallyto completely obscured by long setae in males and females; length of fourth ambulatory dactylus
5.9 times width (Niue) ............................................................................................ O. gracilipes
Posterolateral margins gently convergent; external orbital tooth separated from rest of anterolateral
margin by small cleft, sometimes absent, with margin appearing almost entire; pulvinus onchela in males and females surrounded by short setae, sometimes appearing almost glabrous;
length of fourth ambulatory dactylus more than 6.5 times width ............................................. 4
4. Length o,f third ambulatory propodus 5.2 times width, lengths of third and fourth ambulatory
dactylus 12.9 and 7.6 times width respectively; G1 relatively stout (Fig. lIB, C) (Guam) .....
... ........................... ..... ........................ ......... ..................................... ................... .......... O. mollitia
Length of third ambulatory propodus 4.2 times width, lengths of third and fourth ambulatory
dactylus 9.1 and 6.2-6.9 times width respectively; G1 relatively slender (Fig. 15A,B) (Panglao:
Philippines) .................................................................................................................... O. fictilia

ACKNOWLEDGEMENTS
The third author's work in Niue was supported by grants from the National Science
Foundation (BSR-8700079) and National Geographic Society (3412-86); and that in
Philippines and Guam by a National Science Foundation grant (BSR-8417494). The firstauthor was partially supported by a research grant (RP 900360) from the National Universityof Singapore. The third author thanks Yolanda Iliffe for help during all his collections; John
A. Maciolek and Lucius G. Eldredge for information, and Terry Coe (Niue Adventures) for
diving logistics in Niue; Lu Eldredge and staff of the Guam Marine Laboratory who provided
accomodations, laboratory space and boats in Guam; and Pedro Gonzales and staff of the
National Museum for providing logistical assistance for the cave investigations in thePhilippines. Thanks are also due to Boris Sket of the University of Ljubljana for sending us
his material of Orcovita from his explorations in Bohol, which were also supported by the
National Museum of the Philippines. The first author thanks Gerry Allen for permission touse his colour photograph of O. saltatrix. Comments on the manuscript by Lipke B. Holthuis
and Raymond B. Manning are much appreciated.

133

Ng et a1.: Revision of the anchialine crab genus Orcovita
LITERA TURE CITED
Allen, G. R., 1995. Kakaban. Aqua Geographia, 10: 66-78.
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ORSTOM, Paris, 143 pp, 11 pis.
Guinot, D., 1979. Donnees nouvelles sur la morphologie, la phylogenese et 1a taxonomie des Crustaces
Decapodes Brachyoures. Mem. Mus. natn. Hist. Nat., Paris, (A)Zool., 112: 1-354, pIs. 1-27, tables 15.
Holthuis, L. B., 1973. Caridean shrimps found in land-locked saltwater pools at four Indo-West Pacificlocalities (Sinai Peninsula, Funafuti Atoll, Maui and Hawaii Islands), with the description of one new
genus and four new species. Zool. Verh., Leiden, 128: 1-48, pIs. 1-7.
MacLeay, W. S., 1838. Illustrations of the Annulosa of South Africa; being a portion of the objectsof natural history chiefly collected during an expedition into the interior of South Africa, under the
direction of Dr. Andrew Smith, in the years 1834, 1835, and 1836; fitted out by the "Cape of Good
Hope Association for Exploring Central Africa". In: A. Smith, Illustrations of the Zoology of South
Africa Investigations, London, Sith, Elder and Co., pp. 1-75, pIs. 1-4.
Milne Edwards, H., 1853. Memoires sur la famille des Ocypodiens, suite. Ann. Sci. Nat., Paris,(3)(Zool.) 20: 163-228, pIs. 6-11. [A continuation of H. Milne Edwards, 1852, and reprinted with itin the undated Melanges Carcinologiques pp. 129-196]
Ng, P. K. L., D. Guinot & T. M. Iliffe, 1994. Sesarmoides ultrapes new species, aremarkab1e sesarmine
crab from caves in the Solomon Islands (Decapoda: Brachyura: Grapsidae). Crust. Res., Tokyo, 23:
12-22.
Ng, P. K. L. & T. Tomascik, 1994. Orcovita saltatrix, a new genus and species of anchialine varuninecrab (Crustacea: Decapoda: Brachyura: Grapsidae) from Kakaban Island, Indonesia. Raffles Bull. Zoo I.,
42(4): 937-948.
Stimpson, W., 1858. Prodromus descriptionis animalium evertebratorum quae in Expeditione ad
Oceanum Pacificum septentrionalem, a Republica Federata Missa, Cadwaladaro Ringgold et Johann
Rodgers Ducibus, observavit et descripsit - Part V, Crustacea Ocypodoidea. Proc. Acad. nat. Sci.,
Philadelphia, 10: 93-110.
Received 02 Jan 1996
Accepted 27 Feb 1996

134