identifier	taxonID	type	CVterm	format	language	title	description	additionalInformationURL	UsageTerms	rights	Owner	contributor	creator	bibliographicCitation
7734DAEF363752D4A85787DF8A64B60D.text	7734DAEF363752D4A85787DF8A64B60D.taxon	http://purl.org/dc/dcmitype/Text	http://rs.tdwg.org/ontology/voc/SPMInfoItems#GeneralDescription	text/html	en	Merapohra karsticola Tan & Ooi & Ng 2026	<div><p>Merapohra karsticola sp. nov.</p><p>Figs 2, 3, 4, 5, 6, 7</p><p>Type material.</p><p>Holotype. Peninsular Malaysia • male; 37.2 × 26.7 mm; Pahang State, Merapoh, Gua Hari Malaysia; 19 Apr. 2025; Q. Ooi et al. leg.; ZRC 2024.0327 . Paratypes. Peninsular Malaysia • 3 females; 36.8 × 26.5 mm, 30.0 × 21.4 mm, 20.0 × 15.4 mm; same data for holotype; ZRC 2024.0328 .</p><p>Diagnosis.</p><p>As for new genus.</p><p>Description of male holotype.</p><p>Carapace subquadrate, anteriorly wider than long, relatively low; dorsal surfaces smooth, except for few granules around branchial regions, regions poorly demarcated, cervical grooves barely visible; H-shaped gastro-cardiac depression shallow but discernible (Fig. 2 A, B); dorsal surface (including branchial regions) gently convex, gently inflated (Fig. 2 C); epigastric cristae very low, marked by two low humps; postorbital cristae barely visible, rounded (Fig. 2 B). Frontal margin gently convex, lobes not well marked, appearing almost straight in dorsal view, contiguous with supraorbital margin (Fig. 2 B, C). Supraorbital margin gently sinuous, without clefts or fissures (Fig. 2 C). External orbital tooth, short, broad, margins distinctly concave, outer margin longer than inner margin, outer margin ~ 1.77 × length of inner margin, just before suborbital margin; barely demarcated from anterolateral margin by minute indentation (Fig. 2 B); epibranchial tooth low, present as small tubercle, weakly separated from external orbital tooth by shallow cleft; rest of anterolateral margin convex, subcristate; posterolateral margin gently sinuous, converging towards gently convex posterior carapace margin (Fig. 2 B). Orbits ovate, large; eyes nearly filling space; cornea large, pigmented black; peduncle not elongate (Fig. 2 B, C). Antennules long, folding laterally into narrow, subrectangular antennular fossa (Fig. 2 D); antennae short, shorter than peduncle (Fig. 2 D). Epistome longitudinally narrow, lateral parts covered in dense short hairs; posterior margin with low, triangular median lobe, confluent with gently sinuous lateral margins; margins of posterior epistomal margin lateral to median lobe gently sloping downwards, not parallel with frontal margin (Fig. 2 D). Suborbital margin concave, smooth, without inner tooth; suborbital region smooth; subhepatic, pterygostomial and sub-branchial regions weakly rugose to smooth (Fig. 2 C).</p><p>Third maxillipeds relatively short; merus subquadrate, shorter and narrower than ischium, surface slightly pitted, otherwise smooth and generally glabrous; ischium rectangular, length to width ratio 1.4, median sulcus shallow; exopod relatively slender, long, outer margin straight, nearly reaching to half-length of merus, with short flagellum approx. half-length of merus (Figs 2 C, 4 F).</p><p>Chelipeds elongate; right one slightly larger (Fig. 2 A, E). Basis-ischium with few granules on ventral margin; ventral margins of merus lined with tubercles, dorsal margin uneven, gently rugose; carpus with broad spine on inner angle, surface gently rugose; outer surface of chela almost smooth, surface of fingers punctate; fingers slightly shorter than palm in major chela, equal in minor chela; fingers gently curved with large cutting teeth evenly spread out (Fig. 2 A, E).</p><p>Ambulatory legs relatively long, slender, margins and surfaces smooth; second leg longest, fourth leg shortest; dorsal margins sub-cristate, appearing very weakly serrate; carpus with subdorsal ridge; propodus long, with shallow median sulcus; dactylus long, subequal in length to propodus, gently curved (Fig. 2 A).</p><p>Anterior thoracic sternum relatively narrow; surface of sternites smooth, glabrous except for dense short setae on lateral margins (Fig. 3 A, C). Sternites 1 and 2 completely fused forming triangular plate with convex lateral margins, relatively narrow, width-to-length ratio 2.87, separated from sternite 3 by distinctly convex suture (anteriorly); sternites 3 and 4 fused, s 3 / 4 present as shallow lateral groove that is medially interrupted by anterior edge of sternopleonal cavity; s 4 / 5, s 5 / 6 and s 6 / 7 medially interrupted; deep longitudinal groove between sternite 8 extending to median part of sternite 7 (Fig. 3 A, D). Somite 8 not visible when pleon closed (Fig. 3 B). Sternopleonal cavity reaching to imaginary line connecting median part of coxae of chelipeds; tubercle of male pleonal locking mechanism on posterior third of somite 5 (Fig. 3 A, D).</p><p>Pleon broadly triangular; somite 1 longitudinally narrow, reaching to edges of coxae of fourth ambulatory legs (Fig. 3 B); somite 2 of same width as somite 1; somite 3 widest; somites 4 and 5 trapezoidal; somite 6 trapezoidal, wide; telson broadly triangular, lateral margin almost straight (Fig. 3 A – C).</p><p>G 1 relatively short, stout; subterminal article relatively stout, straight, basal part distinctly broad, before tapering distally, without neck-like distal portion; terminal article elongated, slender, about 0.6 × length of subterminal article, very strongly curving outwards anteriorly before recurving posteriorly, gently tapering along length to broad tip, with relatively long, medial dorsal flap (Fig. 4 A – D).</p><p>Female paratypes.</p><p>The female specimens agree with the holotype in all non-sexual characters except for its more slender and more symmetrical chelipeds (Fig. 5 A). The thoracic sternum has the same features except that it is proportionately wider (Fig. 5 C). The pleon is ovate and covers almost the entire surface of the thoracic sternum when closed (Fig. 5 B). Vulva is very large, directed ventrally, occupying almost length of sternite 6, impinging upwards onto sternite 5, sternite 5 forming a ledge-like overhang over sternite 6 and vulvae; intervulvar distance, measured between mesial margins of both vulvae, 0.42 × vulvar distance, measured between lateral margins of both vulvae (Fig. 5 C).</p><p>Etymology.</p><p>The specific epithet is derived from a combination of the word karst (limestone) and the Latin suffix - colo for tendency to inhabit or dwell in, alluding to the karst dwelling habits of this new species.</p><p>Live colouration.</p><p>In life, the dorsal surfaces of the carapace, ambulatory legs, and the chelipeds are purple in colour. The joints of ambulatory legs, chelipeds, outer surfaces of chelipeds and margins of orbits are bright orange. The ventral surfaces largely pale off-white to light orange in colouration (Figs 6, 7).</p><p>Remarks.</p><p>Differences between morphologically close, karst-dwelling species from the region have been elaborated at length in the remarks section for the new genus (see above).</p><p>Distribution.</p><p>Merapohra karsticola sp. nov., is so far only known from the type locality, Gua Hari Malaysia, Merapoh, Pahang, Peninsular Malaysia (Figs 1, 8).</p></div>	https://treatment.plazi.org/id/7734DAEF363752D4A85787DF8A64B60D	Public Domain	No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.		Pensoft via Plazi	Tan, Zhi Wan;Ooi, Qie;Ng, Peter K. L.	Tan, Zhi Wan, Ooi, Qie, Ng, Peter K. L. (2026): On a new genus and species of karst-dwelling freshwater crab (Crustacea, Brachyura, Potamidae) from Peninsular Malaysia. ZooKeys 1277: 113-136, DOI: 10.3897/zookeys.1277.181453
B39BDD455FC25F01AA2A9B531C885980.text	B39BDD455FC25F01AA2A9B531C885980.taxon	http://purl.org/dc/dcmitype/Text	http://rs.tdwg.org/ontology/voc/SPMInfoItems#GeneralDescription	text/html	en	Merapohra Tan & Ooi & Ng 2026	<div><p>Genus Merapohra gen. nov.</p><p>Figs 2, 3, 4, 5, 6, 7</p><p>Type species.</p><p>Merapohra karsticola sp. nov. by monotypy.</p><p>Comparative material.</p><p>Erebusa calobates Yeo &amp; Ng, 1999 . Holotype. Laos • male; 20.8 × 17.8 mm; Khammouan Province, Tham Tê, near Ban Na; 11 Feb. 1998; L. Deharveng &amp; A. Bedos leg.; ZRC 1998.1073. Paratypes. Laos • 2 males; 20.0 × 17.4 mm, 19.9 × 17.5 mm; 1 juvenile; same data as holotype; ZRC 1998.1074 – 1075 • 1 ovigerous female; 23.0 × 19.3 mm; Khammouan Province, Tham Houai Say, near Ban Khen; 26 Feb. 1998; F. Brehier leg.; ZRC 1998.1076.</p><p>Johora grallator Ng, 1988 . Holotype. Peninsular Malaysia • female; 33.1 × 23.5 mm; Pahang, Pulau Tioman, <a href="https://tb.plazi.org/GgServer/search?materialsCitation.longitude=104.16028&amp;materialsCitation.latitude=2.8563888" title="Search Plazi for locations around (long 104.16028/lat 2.8563888)">Gunung Kajang</a>, 792 m asl, <a href="https://tb.plazi.org/GgServer/search?materialsCitation.longitude=104.16028&amp;materialsCitation.latitude=2.8563888" title="Search Plazi for locations around (long 104.16028/lat 2.8563888)">Ulu Lalang</a>, in insect trap baited with coconut, ca 2°51'23"N, 104°09'37"E; 18 Jun. 1962; J. A. Bullock leg.; ZRC 1989.2691. Non-type specimens. Peninsular Malaysia • 2 juvenile males; 11.2 × 8.8 mm, 11.9 × 9.0 mm; Pahang, Pulau Tioman, Gunung Kajang, under rock in dry cave; 27 Jun. 1996; T. H. T. Tan et al. leg.; ZRC 1996.1730 • 1 male; 32.7 × 23.1 mm; Pahang, Pulau Tioman, Gunung Kajang, ca 700 m asl, on trail; 8 Jul. 2024; J. Bartels leg.; ZRC 2024.0159.</p><p>Johora gua Yeo, 2001 . Holotype. Peninsular Malaysia • male; 11.4 × 8.5 mm; Pulau Tioman, Gua Tengkuk Ayer, route to Gunung Kajang from Juara, ca 900 m asl; 1 Sep. 2000; H. H. Tan &amp; T. M. Leong leg.; ZRC 2000.2236.</p><p>Johora punicea (Ng, 1985) . Holotype. Peninsular Malaysia • male; 19.7 × 15.5 mm; Pahang, Pulau Tioman, under rocks, on slope adjacent to Sungei Besar, ca 300 m asl; 20 Jun. 1984; P. K. L. Ng leg.; ZRC 1984.6803. Paratypes. Peninsular Malaysia • 1 male; 21.6 × 16.0 mm; 2 females; same data as holotype; ZRC 1984.6804 – 6806. Non-type specimens. Peninsular Malaysia • 1 female; 19.9 × 15.6 mm; Pahang, Pulau Tioman, Paya; Jul. 2018; Honours Class leg.; ZRC 2022.0102 • 1 ovigerous female; Pahang, Kampung Paya; 19 Sep. 1995; P. K. L. Ng leg.; ZRC 2018.1130 • 1 male; Pahang, Pulau Tioman, Kampung Paya; Jul. 2005; H. H. Tan leg.; ZRC 2018.1113.</p><p>Demanietta sunthorni Lheknim, Leelawathanagoon &amp; Ng, 2023 . Holotype. Thailand • male; 36.6 × 27.7 mm; <a href="https://tb.plazi.org/GgServer/search?materialsCitation.longitude=99.303764&amp;materialsCitation.latitude=6.5122" title="Search Plazi for locations around (long 99.303764/lat 6.5122)">Ao Dan</a>, south of Adang Island, unnamed creek, 6°30.732'N, 99°18.226'E, 35 m asl; 20 Oct. 2008; V. Lheknim &amp; P. Leelawathanagoon leg.; ZRC 2022.0826.</p><p>Phaibulamon stilipes Ng, 1992 . Holotype. Thailand • male; 28.5 × 22.7 mm; Kanchanaburi Province, Kwai Valley, Tham Nam Pah Khoan cave, from “ K 2 ” resurgence; 18 Aug. 1990; French Expedition Kwai 90 leg.; ZRC 1992.8325.</p><p>Terrapotamon abbotti (Rathbun, 1898) . Non-type specimens. Thailand • 3 males; 39.2 × 32.3 mm, 29.5 × 24.3 mm, 25.7 × 20.8 mm; 1 female; 33.4 × 27.8 mm; Surat Thani Province, Bon Baeng Bap, Ratthanikhom, Amphoe Khiri; 16–19 Jul. 1983; T. Sisuchat &amp; D. Kuntisit leg.; ZRC 2012.0683.</p><p>Terrapotamon longitarsus Lheknim &amp; Ng, 2016 . Holotype. Thailand • male; 47.4 × 38.6 mm; Satun Province, Muang Satun District, Tambon Khuan Po, found dead on limestone bedrock at Khao Raya Bung Sa, southernmost of Nakhon Si Thammarat mountain range, 30 m asl; 9 Sep. 1999; V. Lheknim &amp; P. Leelawathanagoon leg.; ZRC 2016.0161.</p><p>Terrapotamon palian Ng &amp; Naiyanetr, 1998 . Holotype. Thailand • male; 24.6 × 20.5 mm; Trang Province, Palian District, Ton Tok Waterfall; 21 May 1976; P. Naiyanetr leg.; ZRC 2012.0685.</p><p>Thampramon tonvuthi Ng &amp; Vidthayanon, 2013 . Non-type specimens. Thailand • 1 male; 33.9 × 27.8 mm; <a href="https://tb.plazi.org/GgServer/search?materialsCitation.longitude=100.877&amp;materialsCitation.latitude=16.8379" title="Search Plazi for locations around (long 100.877/lat 16.8379)">Baan Chompu</a> southwest of Thung Salaeng Luang National Park, Tham Phra Wangdaeng, cave entrance, 16.8379°N, 100.877°E; 8 Oct. 1997; C. Vidthayanon leg.; ZRC 2012.1126 • 1 female; 42.7 × 36.3 mm; same locality as male, in twilight zone of cave, ca 100 m from entrance, on wet rock wall, 4 m above stream above bat guano; 28 Aug. 2002; D. Smart leg.; ZRC 2012.1127.</p><p>Nemoron nomas Ng, 1996 . Holotype. Vietnam • male; 23.7 × 20.3 mm; Quang Binh Province, Hang Toi, Phong Nha, station Viet 062, 35 m asl, in cave, about 300 m inside; 11 Jan. 1995; L. Deharveng, A. Bedos &amp; Levet leg.; ZRC 1996.0094.</p><p>Tiwaripotamon edostilus Ng &amp; Yeo, 2001 . Holotype. Vietnam • male; 36.4 × 28.3 mm; Ha Long Bay, Cat Ba Island, cave at Gia Luang; 28 Sep. 1998; L. Deharveng leg.; ZRC 2000.0096. Paratype. Vietnam • male; 40.5 × 31.1 mm; same data as holotype; ZRC 2000.0097.</p><p>Diagnosis.</p><p>Carapace (Figs 2 A, 2 B, 5 A) transversely subovate, slightly wider than long, CW / CL ratio 1.30–1.40; dorsal surface gently convex, smooth, glabrous; branchial regions not prominently expanded laterally, not inflated in frontal view, lateral branchial regions not discernible in dorsal view; orbits oblique in frontal view; epigastric and postorbital cristae not clearly discernible, appearing as smooth margin with small granulations, epibranchial crista slightly anterior of postorbital crista, postorbital crista with lateral part breaking up into low striae and granules approaching but not joining anterolateral margin; postorbital, postfrontal and epibranchial regions with indistinct low granules, rugae and / or punctae (Fig. 2 D); epibranchial tooth poorly defined, weakly separated from external orbital tooth by shallow cleft; external orbital tooth well produced, narrowly triangular with concave lateral margins, outer margin ~ 1.77 × length of inner margin, just before suborbital margins; margins of posterior epistomal margin with low median lobe, lateral parts gently sloping downwards, not parallel with frontal margin (Fig. 2 E). Third maxilliped with subquadrate merus, ischium rectangular, length to width ratio 1.40, exopod relatively slender, outer margin straight, flagellum short, approx. half-length of merus (Fig. 4 F). Ambulatory legs and dactylus (Fig. 2 A) slender, elongate, margins and surfaces smooth. Male thoracic sternites 1 and 2 fused, relatively narrow, width-to-length ratio 2.87, sternites 3 and 4 fused, relatively narrow, but with shallow, visible grooves demarcating sutures; thoracic sternite 8 completely hidden when male pleon closed (Fig. 3 A, B); male pleon (Fig. 3 B, C) broadly triangular; male telson broadly triangular, lateral margins almost straight. Male sternopleonal cavity (Fig. 3 D) reaching imaginary line joining median point of cheliped coxae; press-button tubercle of male pleonal locking mechanism distinct, on posterior third of sternite 5. G 1 subterminal article (Fig. 4 A – D) relatively stout, straight; terminal article long, 0.6 × length of subterminal article, strongly curving outwards anteriorly before recurving posteriorly, gently tapering throughout to broad tip, with long, medial dorsal flap. Vulva (Fig. 5 C) conspicuously large, directed mesial-ventrally, occupying almost length of sternite 6, impinging upwards onto sternite 5, sternite 5 forming ledge-like overhang over sternite 6 and vulvae; intervulvar distance, measured between mesial margins of both vulvae, 0.42 × vulvar distance, measured between lateral margins of both vulvae.</p><p>Etymology.</p><p>The new genus is named after the town of Merapoh in Lipis district, Pahang state, Peninsular Malaysia; an area known for numerous limestone hills and caves. Gender feminine.</p><p>Remarks.</p><p>The external morphology of Merapohra gen. nov., is similar to 25 karst dwelling potamid crabs found in Southeast Asia: Cerberusa tipula Holthuis, 1979, C. caeca Holthuis, 1979 (both from Sarawak, Borneo, Malaysia); Erebusa calobates Yeo &amp; Ng, 1999 (Khammouan Province, central Laos); Kanpotamon duangkhaei Ng &amp; Naiyanetr, 1993 (Kanchanaburi Province, western Thailand); Nemoron nomas Ng, 1996 (Quang Binh Province, central Vietnam); Ngan mayla Guinot &amp; Rodríguez Moreno, 2024 (East Kalimantan, Borneo, Indonesia); Phaibulamon stilipes Ng, 1992 (Kanchanaburi Province, western Thailand); Schubartamon serenum Guinot &amp; Rodríguez Moreno, 2024 (Vientiane Province, central Laos); Terrapotamon longitarsus Lheknim &amp; Ng, 2016, Te. thungwa Promdam, Yeesin &amp; Ng, 2017 (both from Nakhon Si Thammarat, Satun, Surat Thani, Trang Provinces, southern Thailand); Thampramon tonvuthi Ng &amp; Vidthayanon, 2013 (Phetchabun Province, central Thailand: one species); and 14 species of Tiwaripotamon Bott, 1970 (from northern Vietnam and Guangxi Province, southern China); especially with regards to their dolichopodous form which are likely adaptations for life in karstic habitats. Of these taxa, Erebusa Yeo &amp; Ng, 1999, Kanpotamon Ng &amp; Naiyanetr, 1993, Ngan Guinot &amp; Rodríguez Moreno, 2024, Phaibulamon Ng, 1992, Schubartamon Guinot &amp; Rodríguez Moreno, 2024, and Thampramon Ng &amp; Vidthayanon, 2013, are monotypic genera, while Cerberusa Holthuis, 1979, only has two known species. Terrapotamon Ng, 1986, has five known species but only the two listed here have long ambulatory legs, the other possessing short legs and are not found near caves (see Ng 1988; Leelawathanagoon et al. 2010; Promdam et al. 2017).</p><p>Merapohra can be immediately distinguished from Cerberusa, Ngan, Nemoron Ng, 1996, and Phaibulamon by the presence of a distinct albeit short flagellum on the exopod of the third maxilliped, a character absent in the latter four genera (Fig. 4 F, Table 1; cf. Holthuis 1979; Ng 1992 c: fig. 2 A; Ng 1996: fig. 2 A; Guinot and Rodríguez Moreno 2024 a). Among the remaining taxa that possess a flagellum on the third maxilliped exopod, Erebusa and Schubartamon differ markedly from Merapohra in possessing very short eyestalks; in Merapohra, the longer eye stalks are distinctly longer, sporting well developed and corneas pigmented, suggesting a more epigean or trogophilic lifestyle (Fig. 2 B, C, Table 1; cf. Yeo and Ng 1999: fig. 1 E; Guinot and Rodríguez Moreno 2024 b: figs 3 B, 7 B, 8).</p><p>* Original description based on female only.</p><p>Kanpotamon duangkhaei, Terrapotamon longitarsus, Te. thungwa, Thampramon tonvuthi, and members of Tiwaripotamon all have short to very short flagella on the exopods of their third maxillipeds and large pigmented eyes on longer eye stalks, which are more similar to Merapohra . The two Terrapotamon species are the most dissimilar, distinguishable by its higher, more subquadrate carapace, that is more strongly covered in rugosities and granules particularly around branchial, sub-branchial, pterygostomial regions, and anterolateral margins (cf. Lheknim and Ng 2016: fig. 1 A; Promdam et al. 2017: fig. 2 A); and a more strongly defined epigastric, postorbital cristae, anterolateral margin, and epibranchial tooth (cf. Lheknim and Ng 2016: fig. 1 A, B, C; Promdam et al. 2017: fig. 2 A, B). In Merapohra, the carapace is relatively flatter, more transversely sub-ovate, that is very weakly rugose or completely smooth on both dorsal and ventral surfaces (Fig. 2 B, C), with a much more weakly defined epigastric, postorbital cristae, anterolateral margin, and epibranchial tooth (Fig. 2 B) (Table 1).</p><p>In comparison to the species of Kanpotamon, Thampramon, and Tiwaripotamon, the new genus Merapohra can be differentiated by the following morphological differences: 1) carapace is transversely sub-ovate, relatively smooth, except for few gentle rugosities and granules around branchial regions (Fig. 2 B) (vs carapace less transverse, more strongly rugose around branchial regions in Thampramon, while in Kanpotamon and Tiwaripotamon, it is completely smooth, cf. Ng and Naiyanetr 1993: fig. 21; Ng and Yeo 2001: figs 1 A, 3 A, 4 A; Ng and Vidthayanon 2013: fig. 2; Shih and Do 2014: figs 4 A, 6 A; Do et al. 2016: figs 3 A, 4 A, 5 A; Do et al. 2017: figs 2 A, 5 A; Ng and Ngo 2022: fig. 2 A; Ng 2024: fig. 1 A; Dang and Do 2025: fig. 2 A); 2) anterolateral margin sub-cristate, very weakly serrated (Fig. 2 B) (vs anterolateral margins strongly cristate, appearing raised and serrated in Kanpotamon and Thampramon, while in Tiwaripotamon, the anterolateral margins can appear smooth to serrated, cf. Ng and Naiyanetr 1993: fig. 21; Ng and Yeo 2001: figs 1 A, 3 A, 4 A; Ng and Vidthayanon 2013: fig. 2; Shih and Do 2014: figs 4 A, 6 A; Do et al. 2016: figs 3 A, 4 A, 5 A; Do et al. 2017: figs 2 A, 5 A; Ng and Ngo 2022: fig. 2 A; Ng 2024: fig. 1 A; Dang and Do 2025: fig. 2 A); 3) epibranchial tooth less well-defined, appearing as a nodule, confluent with external orbital tooth (Fig. 2 B) (vs epibranchial tooth large, triangular, clearly separated from external orbital tooth by deep cleft in Kanpotamon and Thampramon, that in Tiwaripotamon, varies in size, from broad angle to triangular, still clearly separated from external orbital tooth, cf. Ng and Naiyanetr 1993: fig. 21; Ng and Yeo 2001: figs 1 A, 3 A, 4 A; Ng and Vidthayanon 2013: fig. 2; Shih and Do 2014: figs 4 A, 6 A; Do et al. 2016: figs 3 A, 4 A, 5 A; Do et al. 2017: figs 2 A, 5 A; Ng and Ngo 2022: fig. 2 A; Ng 2024: fig. 1 A; Dang and Do 2025: fig. 2 A); 4) both epigastric and postorbital cristae poorly developed, appearing smooth except for few granules at lateral margins (Fig. 2 B) (vs epigastric and postorbital cristae well-developed, appearing sharp in Kanpotamon and Thampramon, that in Tiwaripotamon is even more poorly defined, completely smooth, cf. Ng and Naiyanetr 1993: fig. 21; Ng and Yeo 2001: figs 1 B, 3 B, 4 B; Ng and Vidthayanon 2013: fig. 3; Shih and Do 2014: figs 4 B, 7 B; Do et al. 2016: figs 3 B, 4 B, 5 B; Do et al. 2017: figs 2 B, 5 B; Ng and Ngo 2022: fig. 3 B; Ng 2024: fig. 2 F, G; Dang and Do 2025: fig. 2 A); and 5) epistomal medial lobe, well produced, narrowly triangular (Fig. 2 D) (vs epistomal median lobe lower, appearing as broad triangle in Thampramon and Tiwaripotamon, cf. Ng and Yeo 2001: figs 1 A, 3 A, 4 A; Ng and Vidthayanon 2013: fig. 2; Shih and Do 2014: figs 4 A, 6 A; Do et al. 2016: figs 3 A, 4 A, 5 A; Do et al. 2017: figs 2 A, 5 A; Ng and Ngo 2022: fig. 2 A; Ng 2024: fig. 1 A; Dang and Do 2025: fig. 2 B).</p><p>Perhaps the most significant feature of Merapohra gen. nov., is in its unique G 1 morphology, where the terminal article is relatively long, about 0.6 × length of subterminal article, strongly curving outwards proximally, and nearly recurved 180 ° distally, with a large semi-circular dorsal flap (Fig. 4 B, D). No other potamid crab possesses a G 1 with such a strongly recurved distal terminal article. This contrasts with other long-legged karst dwelling species in Southeast Asia, which typically possess a terminal article that is proportionally shorter, about 0.2–0.4 × length of subterminal article, which in Kanpotamon, Terrapotamon, and Thampramon, is not recurved, while in Tiwaripotamon, it can range from curving downwards to being gently recurved, either without a dorsal flap, or if present, is always small and low, cf. Ng and Naiyanetr 1993: fig. 55; Ng and Yeo 2001: figs 2 D – H, 5 D – K; Leelawathanagoon et al. 2010: fig. 1 F, H; Ng and Vidthayanon 2013: fig. 7 C, D; Shih and Do 2014: fig. 3 A – H; Do et al. 2016: fig. 2 A – F; Lheknim and Ng 2016: fig. 5; Do et al. 2017: fig. 4 A – C, 7 A – D; Promdam et al. 2017: fig. 4; Ng and Ngo 2022: fig. 5 A – D; Ng 2024: fig. 5 A – D, F – H; Dang and Do 2025: fig. 5 B, C, E – G).</p><p>The only other cavernicolous potamid crab species from Peninsular Malaysia is Johora gua Yeo, 2001, described from Gua Tengkuk Ayer, near the summit of Gunung Kajang, Pulau Tioman. Johora gua is an unusual species, for the genus, featuring troglomorphic features, including distinctly elongated legs and reduced cornea size (Yeo 2001), that is unlike most species of Johora, which typically have stouter ambulatory legs and regular sized cornea (Ng 1988, 2020). Nevertheless, Merapohra differs from Johora gua and all other species of Johora by its very poorly developed, rounded epigastric and postorbital cristae; nearly indiscernible epibranchial tooth; and a G 1 terminal article that is strongly recurved with a pronounced dorsal flap (Fig. 4 B, D). This contrasts with all Johora species that are characterised by their well-defined epigastric cristae, postorbital cristae, and epibranchial tooth; and a G 1 terminal article that ranges from being straight to curving downwards, never recurved, typically without dorsal flap, if ever present, is very low (cf. Ng 1988: figs 13–23; Yeo 2001: figs 1 A, 2 C – F; Leelawathanagoon et al. 2005: fig. 2; Ng 2020: figs 2, 6–12).</p><p>There are some potamids that have been collected in karstic caves in Southeast Asia that have relatively short ambulatory legs, but these species do not have any characters that suggest they are troglophiles or troglobites. For example, Isolapotamon bauense Ng, 1987 (Sarawak, Malaysia), Shanphusa ywarngan Ng &amp; Whitten, 2017, and Demanietta burmanica Ng, 2018 (both Myanmar), were collected from caves but none have cave adapted features (Ng 1987, 2018 b; Ng and Tan 1998; Ng and Whitten 2017) and are now regarded as troglophiles at most. The holotype of Xestomon tacu Ng, 2021, was collected from a cave in southern Vietnam; and the species is overall pale orange in colour, but the corneas are fully pigmented, and specimens have also been collected in several epigeal habitats (Ng 2021).</p></div>	https://treatment.plazi.org/id/B39BDD455FC25F01AA2A9B531C885980	Public Domain	No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.		Pensoft via Plazi	Tan, Zhi Wan;Ooi, Qie;Ng, Peter K. L.	Tan, Zhi Wan, Ooi, Qie, Ng, Peter K. L. (2026): On a new genus and species of karst-dwelling freshwater crab (Crustacea, Brachyura, Potamidae) from Peninsular Malaysia. ZooKeys 1277: 113-136, DOI: 10.3897/zookeys.1277.181453
