Phuket mar. biol. Cent. Res. Bull. 70: 1–6 (2011)

ON THE IDENTITY OF THE MANGROVE , ERIOPHORUM NOBILI, 1903 (CRUSTACEA: BRACHYURA: )

Peter K. L. Ng 1, 2, Cheryl G. S. Tan 2 and Rueangrit Promdam 3

1Tropical Marine Science Institute and Raffles Museum of Biodiversity Research, National University of Singapore, 14, Science Drive 4, Singapore 117543, Republic of Singapore. 2Department of Biological Sciences, National University of Singapore, 14, Science Drive 4, Singapore 119260, Republic of Singapore. 3Reference Collection, Phuket Marine Biological Center, Phuket Marine Biological Center, P.O. Box 60, Phuket, 83000, Thailand. ([email protected]) Corresponding author: P. K. L. Ng, e-mail: [email protected]

ABSTRACT: The identity of the poorly known camptandriid mangrove crab Paracleistostoma eriophorum Nobili, 1903, is clarified. It is shown to be a senior synonym of Paracleistostoma tweediei Tan & Humpherys, 1995, and the of the species is discussed, with the range of the species extended to Thailand. Notes on its ecology are also provided.

INTRODUCTION Paracleistostoma eriophorum Nobili, 1903: 23. - Manning & Holthuis, 1981: 209 (list) - Ng The camptandriid genus Paracleistostoma et al., 2008: 233, 234. De Man, 1895, is currently represented by eight Paracleistostoma wardi - Yang, 1979: 39 (list). species (Rahayu & Ng, 2003; Ng et al., 2008). - Harminto, 1988: 88 (nec P. wardi Rathbun, Ng et al. (2008: 233, 234) commented that the 1926). - Tan & Ng, 1994: 83 (list). poorly known Paracleistostoma eriophorum Paracleistostoma tweediei Tan & Humpherys, Nobili, 1903, was actually a senior synonym of 1995: 251, figs. 1–3. Paracleistostoma tweediei Tan & Humpherys, Paracleistostoma tweediei Tan & Ng, 1995: 608. 1995, but did not elaborate. We here redescribe and figure the type of Material examined. - Holotype male of P. Paracleistostoma eriophorum Nobili, 1903, and eriophorum (7.5 x 10.0 mm) (MZUT Cr1200, ex comment on its taxonomic relationships. 1531), Buntal, Sarawak, East Malaysia, don. R. Shelford, 1902. Others - SINGAPORE: 1 male MATERIALS AND METHODS (holotype of P. tweediei) (7.9 x 10.2 mm) (ZRC 1987.57), 8 males (paratypes of P. tweediei) (5.3 The terminology follows that in Tan & x 6.7 mm, 6.4 x 8.3 mm, 6.6 x 8.4 mm (ZRC Ng (1999). Measurements provided, in millimetres, 1987.60–62), 7.4 x 9.4 mm, 7.5 x 9.7 mm, 7.5 x are of the carapace length and width respectively. 10.0 mm, 8.3 x 10.7 mm, 8.8 x 11.5 mm (ZRC Specimens are deposited in the Museo Regionale 1987.57–59), Lim Chu Kang mangrove, coll. P. di Scienze Naturali (MZUT), Sezione di Zoologia, K. L. Ng & S. Harminto, 13 September 1986; 1 Turin, Italy; Zoological Reference Collection (ZRC) male (7.2 x 9.3 mm) (ZRC 1987.1382), of the Raffles Museum of Biodiversity Research, Woodlands, Singapore, coll. S, Harminto, 2 June National University of Singapore, Singapore; 1987. PENINSULAR MALAYSIA: 18 males (ZRC Phuket Marine Biological Centre (PMBC), Phuket, 1998.1007), Matang mangroves, Perak, coll. C. Thailand; and Queensland Museum (QM), G. S. Tan, 8 June 1995; 4 males (5.0–6.9 x 6.1– Brisbane, Australia. 8.8 mm) (ZRC 1998.998), Matang mangroves, Perak, coll. A. Ramli, M. Faizal, C. G. S. Tan, 10 Paracleistostoma eriophorum Nobili, 1903 June 1995. BRUNEI: 1 male (9.3 x 11.9 mm) (QM (Figs. 1, 2) W19967), Batu Marang, coll. N. A. Mackenzie, 2 Phuket mar. biol. Cent. Res. Bull.

Figure 1. Paracleistostoma eriophorum Nobili, 1903. A, holotype male (7.5 x 10.0 mm) (MZUT Cr1200, ex 1531), Sarawak; B, C, male (7.6 x 9.6 mm) (ZRC), Thailand. A, B, overall views; C, left G1 in situ.

March 1993. THAILAND: 1 male (7.6 x 9.6 mm), Type locality. - Buntal, Sarawak. 1 female (6.5 x 8.3 mm) (ZRC 2010.0071), 1 male (6.9 x 8.5 mm) (ZRC 2010.0072); 3 males (10.9 Diagnosis (holotype male of P. eriophorum). - x 8.3 mm, 10.4 x 8.0 mm, 10.0 x 7.7 mm), 3 Carapace surface smooth, slightly convex, broadly females (12.0 x 9.0 mm, 9.0 x 7.0 mm, 8.8 x 6.8 quadrangular, broader than long (1.2–1.3 times); mm) (PMBC 23738), mangroves, Khanom District, regions indistinct, epigastric lobes moderately low; Nakhon Srithammarat, Gulf of Thailand, coll. R. metagastric groove shallow. Front almost straight Promdam & A, Kaenphet, 23 June 2007. from dorsal view, upper surface slightly concave 3 Identity of the mangrove crab

Figure 2. Paracleistostoma eriophorum Nobili, 1903. A, G–I, holotype male (7.5 x 10.0 mm) (MZUT Cr1200, ex 1531), Sarawak; B–F, male (7.9 x 10.2 mm) (ZRC 1987.57), holotype of P. tweediei Tan & Humpherys, 1995, Singapore. A, B, male abdomen; C, frontal view showing epistome; D, anterior part of male thoracic sternum; E, outer view of left chela; F, G, dorsal view of right carpus of cheliped; H, I, left G1 (setae not drawn). Scales: A, G = 0.5 mm; H, I = 1.0 mm. medially, anterolateral angles of front rounded; dense setae; posterolateral margin lined with small frontomedial projection triangular, apex rounded; granules, completely obscured by pubescence; orbital margins setose; supraorbital margin weakly posterior carapace margin straight. Anterior and granular, sinuous; infraorbital margin straight, finely posterior halves of epistome separated by median granular along central third, inner infraorbital tooth transverse ridge; postero medial-tooth broadly well developed, distinct from rest of infraorbital triangular, ending in small, pointed extremity, margin; suborbital ridge defined by line of granules; posterior margin on either side almost straight; posterolateral border and surfaces of carapace with sulcus separating epistome from anterior 4 Phuket mar. biol. Cent. Res. Bull.

pterygostomian margin indistinct. Third maxilliped the appendages detached. Most of the setae on ischium broadly rectangular, outer distal margin the carapace have also been lost, although one can with row of long setae along outer half; merus discern where the main setose areas were (Fig. with well developed outer distal angle which is 1A). The distal part of the G1 of the holotype male bilobed, outer surface uneven, inverted V shaped is somewhat less swollen (Fig. 2H, I) compared sulci on outer surface indistinct. Chelipeds to the recent material (Fig. 1C), but this is almost subequal, enlarged; carpus subglobular, outer certainly because of its age and some dehydration. surface almost smooth, inner surface sparsely Paracleistostoma eriophorum appears to granular, inner dorsal edge finely beaded with be close to P. depressum and is distinguished from granules, appearing subcarinate, inner ventral edge all its congeners by the unique structure of the with large triangular granules, with short row of G1, which has the distal appendage modified to long setae.Ambulatory legs relatively long, densely form a spine like process. It is one of the two setose; first and last pairs of ambulatory legs Paracleistostoma species having the inner ventral almost equal in length, first pair with setae only on edge of the carpus lined with sharp granules, the dorsal surface of merus. Abdominal somites 2–5 only other Paracleistostoma species exhibiting this completely fused, sutures not discernible, suture condition being P. longimanum. Also, in P. between somites 2 and 3 visible only as short, eriophorum, the ridge below the infraorbital margin shallow grooves on either side of abdomen; somite is formed by a raised line of granules. This 1 broader than somite 2, with transverse mdian condition is also found in P. wardi. ridge; somite 6 shorter than telson, lateral margin Neither Nobili (1903) nor Tan & sinuous. G1 recurved, apex large, globular, with Humpherys (1991) described the epistome and the short but distinct submedian spine-like distal anterior sternal structure, and these are included appendage. in the present description (Fig. 2C, D). Only one female specimen of this species (from Thailand) Remarks. - Nobili’s (1903) description of is known. It closely resembles the male in all non- Paracleistostoma eriophorum was relatively sexual features except that the chelae are even detailed but he did not provide a figure. He more slender, and the patches of setae on the distinguished P.eriophorum from P.depressum and posterolateral regions are less clearly demarcated, P. cristatum by the unusually tomentose partially because there are also short setae on the ambulatory legs and the presence of two carinae dorsal parts of the carapace which are normally of long granules on the inferior and superior glabrous in males. The female abdomen is margins of the outer surface of the cheliped palm. subcircular, covers the thoracic sternum, and all Nobili (1903) also mentioned that the posterior the somites and telson are mobile. carapace, including the median branchial region Harminto (1988) recorded this species as and the area around the intestinal region, bears a P. wardi (Rathbun, 1926). His specimens were thick, short felt like tomentum, and the ambulatory examined and compared withAustralian specimens legs were covered with long, woolly setae with of P. wardi in the ZRC and were found to differ the dactyli bearing sulci and setae. From his significantly from the latter species in terms of comparisons, Serène (1974:64) noted “... it is the structures of the G1, epistome and male possible that eriophorum is a Leipocten or Baruna”. cheliped carpus. Tan & Ng (1994) had incorrectly After examining the type, there is no doubt recorded this species as P. wardi in their list of that P.eriophorum is a species of Paracleistostoma. mangrove Brachyura. AsnotedbyNget al. (2008), P.eriophorum Nobili, The figure of the frontal region and 1903, is a senior synonym of P. tweediei Tan & abdomen provided by Tan & Humpherys (1995) Humpherys (1995). The type specimens of both is somewhat inaccurate in that the inner infraorbital species are of similar size, and agree closely in all tooth is not clearly shown (Tan & Humpherys, characters. The holotype male of P. eriophorum 1995: Fig. 2A) and the sutures between abdominal is not in a good condition (Fig. 1A) with most of segments 3–5 are shown to be present as notches 5 Identity of the mangrove crab

on either side of the abdomen (Tan & Humpherys, 1995, priority over P. tweediei C. G. S. Tan & 1995: Fig. 2G). In fact, only the suture between Ng, 1995.” somites 3 and 4 is visible as a notch on either side of the abdomen. The above features are refigured Ecology. - In Perak, Malaysia, Paracleistostoma here (Fig. 2A, B). eriophorum was collected from the Matang As discussed by Ng et al. (2008), mangroves along with specimens of P. depressum there is a nomenclatural problem with the names and the varunid Metaplax elegans De Man, 1888. Paracleistostoma tweediei Tan & Humpherys, These were all found in burrows in soft, brown 1995, and Paracleistostoma tweediei Tan & Ng, mud, close to the edge of the river. In the Khanom 1995. Ng et al. (2008: 234) noted that “Both are District, Thailand, P. eriophorum were found in objective synonyms as they are based on the same mangrove habitats near rivers, with burrows holotype. The problem arose because C. G. S. Tan typically occurring in the areas between nearby and P. K. L. Ng originally intended to publish the mangrove trees. Sympatric species there, include new species, and the paper was prepared for a the sesarmids Episesarma palawanense (Rathbun, regional symposium in 1994 (Tan & Ng, 1995). 1914), Parasesarma ungulatum (H. Milne At the same time, P. J. F. Davie and A. Humpherys Edwards, 1853), Perisesarma eumolpe (De Man, had independently also discovered the species. As 1895) and P. indiarum (Tweedie, 1940). it was clear that the two taxa in question were conspecific, P. J. F. Davie and P. K. L. Ng left it Distribution. - Buntal, Sarawak, East Malaysia; to C. G. S. Tan and A. Humpherys to finish the Brunei, Peninsular Malaysia, Singapore, and now new species description on their own (Tan & for the first time from the eastern coast of Thailand. Humpherys, 1995). In early 1995, P. K. L. Ng asked the editors of the symposium volume to ACKNOWLEDGEMENTS have the paragraph on the new Paracleistostoma in their paper deleted, but although they agreed, The authors thank Giovanni Balma of the the changes were not made, no proofs were sent, University of Turin for his help in obtaining the and the volume was published in 1995 with the type of P. eriophorum. Part of the study was problem paragraph still intact. This mistake supported by research grants to the first author nevertheless validates P. tweediei C. G. S. Tan & from the National University of Singapore. The Ng, 1995. In any case, the symposium article third author was supported by the TOTAL came out later than the paper in the Raffles Bulletin Corporate Foundation, TOTAL E&P Thailand and of Zoology. Since the symposium volume did not the TRF/BIOTEC Special Program for Biodiversity have a publication date, under the Code, it should Research and Training Grant BRT R_149023 and be regarded as published on 31 December 2005. he would like to thank Arwut Kaenphet, staff of This gives P. tweediei C. G. S. Tan & Humpherys, Walailak University, who worked closely with him during the field trips to the mangroves of Khanom.

REFERENCES

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Manuscript received: 20 October 2009 Accepted: 9 April 2010