THE RAFFLES BULLETIN OF ZOOLOGY 2012
THE RAFFLES BULLETIN OF ZOOLOGY 2012 60(2): 461–465
Date of Publication: 31 Aug.2012© National University of Singapore

ON A NEW SPECIES OF PHRICOTELPHUSA ALCOCK, 1909,
FROM A LIMESTONE CAVE IN PERLIS, PENINSULAR MALAYSIA(CRUSTACEA: DECAPODA: BRACHYURA: GECARCINUCIDAE)Peter K. L. Ng
Raffles Museum of Biodiversity Research, Faculty of Science, National University of Singapore
14 Science Drive 4, 117543 Singapore
Email: dbsngkl@nus.edu.sg

Patrick K. Y. Lee
Division of Ecology and Biodiversity, Institute of Biological Sciences, Faculty of Science
University of Malaya, 50603 Kuala Lumpur, Malaysia
Email: patrick@um.edu.my

ABSTRACT. — A new species of the freshwater crab genus Phricotelphusa Alcock, 1909 (Gecarcinucidae)
is described from a limestone cave in Perlis, northern Peninsular Malaysia. The new species is characterisedby its very long ambulatory legs, and differs from congeners in the structure of its carapace, male abdomen
and gonopods. This brings to four the number of Phricotelphusa species now known from Malaysia.
KEY WORDS. — Crustacea, Brachyura, Gecarcinucidae, Phricotelphusa, new species, cave, Malaysia

INTRODUCTION(ZMUM); Zoological Survey of India, Calcutta, India (ZSI);and Zoological Reference Collection of the Raffles Museumof Biodiversity Research, National University of Singapore(ZRC). The abbreviations G1 and G2 are for the male first andsecond gonopods, respectively. The terminology used follows
that in Ng (1988) . Measurements provided (in millimetres)
are of the carapace width and length, respectively.

The Indo-Chinese gecarcinucid genus Phricotelphusa Alcock,1909 (type species Telphusa callianira De Man, 1887), isrepresented by 11 species (Ng et al., 2008). Three species ofPhricotelphusa are currently known from northern Peninsular
Malaysia: P. amnicola Ng, 1994 (Kedah), P. gracilipes Ng &H. P. Ng, 1987 (Langkawi Island), and P. hockpingi Ng, 1986
(Perak; Ng, 2004; Ng & Yeo, 2007). Another six species arepresent in nearby southern Thailand: P. aedes (Kemp, 1923),
P. callianira (De Man, 1887), P. deharvengi Ng, 1988, P.
limula (Hilgendorf, 1882), P. ranongi Naiyanetr, 1982, andP. sirindhorn Naiyanetr, 1989 (see Ng & Naiyanetr, 1993;
Lheknim & Leelawathanagoon, 2009). One southern Thai
species Phricotelphusa yongchindaratae Naiyanetr, 1988,
was transferred to a new genus, Thaksinthelphusa, by Ng& Naiyanetr (1993).

TAXONOMYFamily Gecarcinucidae Rathbun, 1904
Phricotelphusa Alcock, 1909
Type species. — Telphusa callianira De Man, 1887, by original
designation; gender feminine.

Recently, an unusual long-legged species of Phricotelphusa
was collected from a limestone cave in Perlis. While
superficially similar to P. aedes, it differed in the form of
the carapace, ambulatory leg proportions as well as general
structure of the male abdomen and gonopods. It is here
referred to a new species. The present paper describes thisnew species and compares it with congeners.

Phricotelphusa hymeiri sp. nov.
(Figs. 1–3)
Material examined. — Holotype male (20.5×16.5 mm) (ZMUM),
inside Loposang Cave, Wang Mu Forest Reserve, Perlis, Peninsular
Malaysia, coll. K. Hymeir, Mar.2008. Comparative materialof P. aedes (Kemp, 1923): Holotype female (25.8×18.6 mm)(ZSI C 602/1) (photographs examined), Khao Ram, Nakhon Si
Thammarat mountains, southern Thailand, coll. M. Smith, no date;1 male (17.5×13.2 mm), 1 female (ZRC), Phrommalok waterfall,

Specimens examined are deposited in the Zoology Museumof the University of Malaya, Kuala Lumpur, Malaysia461

Ng & Lee: New species of Phricotelphusa from Perlis, Malaysia
Phrommakhiri District, Nakhon Si Thammarat Province, southern
Thailand, coll. P. Naiyanetr, 8 Mar.1965.

and laterally. Frontal margin distinct, protruding anteriorly
beyond level of external orbital tooth, gently sinuous,
median part distinctly gently deflexed downwards, without
any trace of median pseudo-frontal triangle. Anterolateral
margin distinctly convex, not clearly demarcated fromposterolateral margin; epibranchial tooth spiniform, small
but distinct, sharp, separated from external orbital angle
by narrow notch; external orbital angle broadly triangular,outer margin ca. 3 times length of inner margin; epigastricand postorbital cristae sharp, distinct, rugose, separated byshallow oblique groove; epigastric cristae relatively stronger,
anterior of postorbital cristae, separated by median groove.
Posterior margin of carapace gently concave. Epistome
relatively wide longitudinally; posterior margin with distinct
median triangular lobe, lateral margins gently sinuous. Eyes
relatively large, completely filling orbits; cornea large, fully
pigmented. Antennular fossa relatively broad, rectangularin shape. Third maxilliped quadrate; ischium with shallow
oblique median sulcus; exopod reaches beyond distal edgeof ischium, flagellum absent. No suture between thoracic
sternal segments 2 and 3.

Diagnosis. — Carapace subovate, broader than long; dorsal
surfaces gently granulose to rugose; branchial regions inflated
dorsally and laterally; frontal margin protruding anteriorly
beyond level of external orbital tooth; anterolateral margin
distinctly convex; epibranchial tooth spiniform, small but
sharp, separated from external orbital angle by narrow notch;
epistome relatively wide longitudinally; third maxillipedischium with shallow oblique median sulcus; exopod reaches
beyond distal edge of ischium; antennular fossa relatively
broad, rectangular in shape; ambulatory legs very long; maleabdomen broadly T-shaped, reaching imaginary longitudinalline joining median edge of bases of chelipeds; telson shorter
than somite 6 with gently concave lateral margins; somites
5 and 6 relatively broad; G1 relatively straight, terminal
segment cone-shaped, ca. 0.3 times subterminal segment; G2
distal segment ca. 0.3 times length of basal segment.
Description of holotype. — Carapace subovate, broader
than long; regions distinct; dorsal surfaces gently granulose
to rugose; antero- and posterolateral regions lined withshort but strong oblique striae; cervical grooves broad;pterygostomial, suborbital and sub-branchial regions rugose
to granulose. Branchial regions gently inflated dorsally

Left cheliped larger; outer surfaces of both chelipeds rugose,
without sharp spines or spinules; inner margin of merus with
distinct granules; carpus with sharp inner distal tooth andsmaller sub-basal spine; outer surface of palm gently rugose
to granulose, especially lower half; ventral margin of pollex
with numerous small denticles, outer surface with 2 rows ofFig. 2. A, B, Phricotelphusa hymeiri sp. nov., holotype male
(20.5×16.5 mm) (ZMUM), Perlis, Malaysia; C, Phricotelphusa aedes(Kemp, 1923), male (17.5×13.2 mm) (ZRC), southern Thailand. A,
ventral view of carapace showing anterior thoracic sternum andabdomen; B, outer view of chelae; C, overall dorsal view.

Fig. 1. Phricotelphusa hymeiri sp. nov., holotype male (20.5×16.5mm) (ZMUM), Perlis, Malaysia. A, overall dorsal view; B, dorsal
view of carapace; C, frontal view of carapace.

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low tubercles and 2 shallow longitudinal grooves; cuttingedges of both fingers with blunt teeth and denticles.

G1 relatively straight, terminal segment cone-shaped, ca.
0.3 times subterminal segment; distal part covered withnumerous very small scale-like spines and setae on outermargin, tip rounded. G2 distal segment ca. 0.3 times lengthof basal segment.

Ambulatory legs very long, slender; second pair longest;merus unarmed, dorsal margin gently serrated but notspiniform; outer surfaces in first to third pairs rugose;
propodus with row of small movable ventral spines; dactylus
gently curved, with 2 rows of strong spines on dorsal andventral margins.

Colour. — According to the collector, the live specimen isdark orange, with the chelipeds and legs darker coloured. The
ventral surfaces are a pale yellow. The corneas are black.

Male abdomen broadly T-shaped, reaching imaginarytransverse line joining median edge of bases of chelipeds;
telson shorter than somite 6 with gently concave lateral
margins, tip rounded; somites 5 and 6 relatively broad.

Habitat. — Loposang Cave and others like it in the Wang Mu
area are natural limestone structures that have been exploitedby man. The sediment in these caves is rich in tin ore and assuch, they have been mined since the early part of the 20th

Fig. 3. Phricotelphusa hymeiri sp. nov., holotype male (20.5×16.5 mm) (ZMUM), Perlis, Malaysia. A, left third maxilliped; B, abdomen; C,
left G1 (ventral view); D, distal part of left G1 (ventral view); E, left G1 (dorsal view); F, distal part of left G1 (dorsal view); G, proximal
lower margin of subterminal segment of left G1 (dorsal view); H, left G2. Scales bars = 1.0 mm for A; 2.0 mm for B; 0.5 mm for C–H.

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Ng & Lee: New species of Phricotelphusa from Perlis, Malaysia
century. However, tin mining ceased in the 1980s, and theecosystem in the cave has since been allowed to recover.

species (see also Naiyanetr, 1988b, 1992, 1998; Ng, 1988b;
Ng & Naiyanetr, 1993; Yeo & Ng, 1999; Ng et al., 2008).

Loposang Cave is an active speleothem and is essentiallya small, narrow to medium-sized passage (Fig. 4). Small
streams flow on a rocky calcited bed through most sections of
Loposang Cave. The upper section of the cave is comprisedof vertical steep passages that form cascades and small
waterfalls. The lower section is composed of predominantly
horizontal passages with a calcited stream bed covered withsmall loose rocks. Due to the many streams, there is not much
detritus in the cave, which is relatively warm and humid.
Access into the cave is not easy due to the steep sections,and specialised caving skills and equipment are required toenter the system.

Phricotelphusa aedes differs from P. hymeiri in having
the carapace more transversely subrectangular, being
proportionately broader (Fig. 2C; Kemp, 1923: pl. 4, Fig. 12)(vs. carapace subovate and proportionately less broad in P.
hymeiri, Fig. 1A, B); the granules on the dorsal surface of thecarapace are low and relatively obscure (vs. prominent in P.
hymeiri, Fig. 1A, B); the front is shorter and does not protrude
anteriorly as far as P. hymeiri (Fig. 2C; Kemp, 1923: pl. 4,
Fig. 12 vs. Fig. 1A, B); the postorbital and postfrontal regions
are relatively narrower (Fig. 2C) (vs. relatively broader in
P. hymeiri, Fig. 1); the outer margin of the external orbital
tooth is subtruncate and separated from the epibranchial
tooth by broad, prominent triangular cleft (Fig. 2C; Kemp,
1923: pl. 4, Fig. 12) (vs. margin almost straight, separated
from epribranchial tooth by small notch in P. hymeiri, Fig.
1A, B); the epibranchial tooth is prominent and sharp (Fig.
2C; Kemp, 1923: pl. 4, Fig. 12) (vs. short and spiniform in
P. hymeiri, Fig. 1A, B); the carapace branchial regions are
gently convex to almost flat (Fig. 2C) (vs. distinctly convex
and appears inflated in P. hymeiri, both from the dorsal aswell as frontal views, Fig. 1A, B); the antennular fossa are
relatively narrower (versus broader, more rectangular in P.
hymeiri, Fig. 1B); the epistome is relatively narrow (vs.
wider longitudinally in P. hymeiri, Fig. 1B); the exopod of
the third maxilliped does not reach the distal margin of theischium (vs. reaches beyond ischium margin in P. hymeiri,
Fig. 3A); the ambulatory meri are relatively shorter (Fig.
2C; Kemp, 1923: pl. 4, Fig. 12) (vs. relatively longer in P.
hymeiri, Fig. 1A); the male abdominal somites 5 and 6 are
relatively narrower and more slender (vs. proportionately
longer in P. hymeiri, Fig. 2A); the male telson is relatively
shorter with the lateral margins more deeply concave (vs.
relatively longer with gently convex lateral margins, longer
in P. hymeiri, Figs. 2A, 3B); and the G1 has the distal marginof the subterminal segment part slightly more angular (vs.
more rounded in P. hymeiri, Fig. 3C–F).

The crab was first seen in 1997 during the Perlis limestone
caves survey conducted by the World Wide Fund for Nature(WWF)-Malaysia (Fig. 4; Hymeir, 1998). It was observed(but not collected) at the upper section with steep to verticalpassages, less than 50 m from the entrance. The secondsighting in 2008 (present specimen collected) was on thelower horizontal section of the cave, enroute to the adjacent
Baba Cave section (Fig. 4). The specimen was collected
relatively deep inside the cave, approximately 150–160 m(vertical distance) and 300–400 m (horizontal distance) fromthe entrance. In both cases, the crabs were observed out inthe open but near holes or rocks. When approached, theyscuttled away for shelter.
Etymology. — The species is named after the collector,
Mr. K. Hymeir, the past President of the Malaysian Karst
Society, who is actively involved in raising awareness andpromoting conservation of limestone caves and karst outcrops
in the country.
Remarks. — In general appearance, P. hymeiri sp. nov. closely
resembles P. aedes (Kemp, 1923) (type locality Nakhon Si
Tammarat, southern Thailand), especially with regard to
its long ambulatory legs. Parathelphusa (Phricotelphusa)
aedes Kemp, 1923, was synonymised under P. limula by
Bott (1970) but Ng (1988a) commented that it is a distinct

Phricotelphusa hymeiri does not display any of the features
normally associated with a true troglobite (sensu Holthuis,
1986; Guinot, 1988), and its presence in the Perlis cave,must be regarded as incidental or facultative, even though it
was collected deep inside the cave. There are some species(e.g., the Sarawakian gecarcinucid Stygothelphusa bidiensis(Lanchester, 1900)) which are known to be closely associatedwith caves but have apparently not developed any caveadapted features like loss of pigmentation and reduced eyes(see Ng, 1989; Ng & Yusof, 1990; Ng & Sket, 1996).

ACKNOWLEDGEMENTS
The authors thank Hymeir Kamarudin for kindly catching
this interesting species for the present study and sharing withus his observations of the species. The first author thanks
Darren Yeo for checking the type of P. aedes in ZSI and for
passing the photographs to him for use here. Tan Heok Huikindly photographed the type specimen of P. hymeiri. Tohru

Fig. 4. Map of Loposang Cave, Wang Mu Forest Reserve, Perlis,
Peninsular Malaysia, showing the plan and profile views of cavepassage. Scales bars are in metres.

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Naruse and Paul Clark kindly commented on the manuscript.
The second author thanks Zarris Kem for providing technicalassistance and logistic support during the second survey.
The survey was partially supported by University of Malaya
research grant FS299/2008 to the second author.

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Ng, P. K. L., 1986. Phricotelphusa hockpingi sp. nov., a new
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