identifier	taxonID	type	CVterm	format	language	title	description	additionalInformationURL	UsageTerms	rights	Owner	contributor	creator	bibliographicCitation
F4EB0277C0765B7ABBFF5A7170710C9B.text	F4EB0277C0765B7ABBFF5A7170710C9B.taxon	http://purl.org/dc/dcmitype/Text	http://rs.tdwg.org/ontology/voc/SPMInfoItems#GeneralDescription	text/html	en	Geosesarma De Man 1892	<div><p>Genus Geosesarma De Man, 1892</p><p>Type species.</p><p>Sesarma (Geosesarma) nodulifera De Man, 1892, subsequent designation by Serène and Soh (1970).</p></div>	https://treatment.plazi.org/id/F4EB0277C0765B7ABBFF5A7170710C9B	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	Ng, Peter K. L.	Ng, Peter K. L. (2026): Geosesarma wongi sp. nov., a distinctive new species of semiterrestrial crab from Tapah Hills in Perak, Peninsular Malaysia; with notes on G. peraccae (Nobili, 1903) and G. cataracta Ng, 1986 (Crustacea, Brachyura, Sesarmidae). ZooKeys 1266: 281-298, DOI: 10.3897/zookeys.1266.172575
91E6CB1F1BB55703B18D3EB3037717FC.text	91E6CB1F1BB55703B18D3EB3037717FC.taxon	http://purl.org/dc/dcmitype/Text	http://rs.tdwg.org/ontology/voc/SPMInfoItems#GeneralDescription	text/html	en	Geosesarma wongi Ng 2026	<div><p>Geosesarma wongi sp. nov.</p><p>Figs 1, 2, 3, 4, 5</p><p>Material examined.</p><p>Holotype: • male (12.7 × 11.3 mm) (ZRC 2025.0023), <a href="https://tb.plazi.org/GgServer/search?materialsCitation.longitude=101.3481&amp;materialsCitation.latitude=4.3491" title="Search Plazi for locations around (long 101.3481/lat 4.3491)">forest near 16 th milestone, Tapah Hill, east of Jor Main Dam, near Sungai Sekam, east of Highway 59 to Tapah</a>, Batang Padang area, Perak, Peninsular Malaysia, 4.3491°N, 101.3481°E, ca. 550 m asl, coll. aboriginal collectors, July 2025 . Paratypes: • 7 males, 11 females, 1 ovigerous female (12.6 × 11.0 mm, with 4 eggs, each ca. 1.45 mm) (ZRC 2025.0027), same data as holotype .</p><p>Comparative material.</p><p>Geosesarma peraccae (Nobili, 1903): lectotype • male (11.8 × 9.8 mm) (MRSN Cru 1421 a), Singapore, coll. Deschamps; paralectotype • female (9.1 × 7.9 mm) (MRSN Cru 1421 b), same data as lectotype; 1 male (11.8 × 10.4 mm), 1 female (12.6 × 10.7 mm) (ZRC 1990.0518), Nee Soon Swamp Forest, Singapore, coll. P. K. L. Ng, February 1990. Geosesarma cataracta Ng, 1986: holotype • male (12.4 × 10.9 mm) (ZRC 1985.1760), <a href="https://tb.plazi.org/GgServer/search?materialsCitation.longitude=100.75&amp;materialsCitation.latitude=4.7833333" title="Search Plazi for locations around (long 100.75/lat 4.7833333)">Bukit Larut</a> (<a href="https://tb.plazi.org/GgServer/search?materialsCitation.longitude=100.75&amp;materialsCitation.latitude=4.7833333" title="Search Plazi for locations around (long 100.75/lat 4.7833333)">Maxwell Hill</a>), near Taiping, Perak, 4°47'N, 100°45'E, ca. 350 m, under mats of bryophytes and algae on damp area adjacent a waterfall, coll. H. P. Ng &amp; P. K. L. Ng, September 1984; paratypes: • 3 males, 4 females (largest 10.5 × 9.5 mm), 3 juveniles (ZRC 1985.1762 – 1771), same data as holotype.</p><p>Diagnosis.</p><p>Carapace rectangular, wider than long, width to length ratio 1.11–1.14, lateral margins almost straight, gently divergent towards posterior carapace margin (Fig. 2 A, B); dorsal surfaces with well-defined regions, anterior half with prominent low, rounded tubercles and granules; postfrontal lobes distinct, median lobes with transverse row of relatively dense short setae, setae sparser on lateral lobes; epibranchial region raised; protogastric region gently convex; urogastric region raised, with gastrocardiac groove deep (Fig. 2 A, B); frontal margin distinctly deflexed, frontal lobes broad, with gently convex margins in dorsal view, separated by wide shallow median concavity; postfrontal cristae sharp, distinct (Fig. 2 A – C); external orbital angle triangular, directed anteriorly, not extending beyond lateral carapace margin, outer lateral margin gently convex; separated from first epibranchial tooth by V-shaped cleft; first epibranchial tooth distinct, wide, second epibranchial tooth just visible as low lobe (Fig. 2 A, B); merus of third maxilliped subovate; exopod slender, flagellum elongate, longer than width of merus (Fig. 5 A); outer surfaces of palm of chela covered with numerous small rounded granules (except at bases of pollex and dactylus), with cluster of closely packed larger ones on lower half, just posterior to pollex; inner surface with prominent flange-like transverse ridge lined by large rounded tubercles, surface of flange concave; fingers distinctly longer than palm, dorsal margin of dactylus with 15–17 small sharp granules arranged unevenly on surface, not in a row; dactylus with broad median molariform tooth on cutting edge; pollex with 2 distinct teeth on proximal half of cutting edge (Fig. 3 A – D); ambulatory merus with sharp subdistal spine on dorsal margin, surface weakly rugose, propodus slender, relatively long; P 4 merus length 3.0 times width; P 2 propodus and dactylus without dense tuft of setae on flexor margins (Figs 2 A, 3 E, F); pleon broadly triangular; somite 3 widest, somite 6 wide, width to length ratio 2.6–2.7, lateral margins convex; telson triangular, 0.8–0.9 times longer than broad, lateral margins gently convex (Fig. 4 B, C); G 1 relatively slender, distal part bent at angle of ca. 50 ° along longitudinal axis, outer margin of subdistal part gently convex, without any shelf-like feature, distal chitinous elongate, tapering sharply in lateral view, subspatuliform in marginal view with distinct median cleft distally (Fig. 5 B – I); vulvae positioned close to each other, opening laterally oblique (Fig. 4 F).</p><p>Females and variation.</p><p>The denser row of setae lining the median postfrontal lobes is usually distinct in this species, with those on the lateral lobes usually shorter and sparser. The carapace of the females and subadult males do not differ substantially from the holotype and have more slender chelae (Fig. 4 D). The female P 2 also lacks tufts of setae on the flexor margins of the propodus and dactylus (Fig. 4 D). The female pleon covers most of the thoracic sternum, and the semicircular telson is deeply inserted into the distal margin of somite 6 (Fig. 4 E). The vulvae are large and positioned close to each other; with each gently swollen with smooth surface, and the opening laterally oblique in position close to each other, opening laterally oblique (Fig. 4 F).</p><p>Colour.</p><p>In life, the carapace and legs are dark brown, the cheliped is dark orange, and the fingers are a lighter orange. The ventral surfaces are light brown with the cornea black (Fig. 1).</p><p>Remarks.</p><p>In the subrectangular shape and armature on the carapace, with low rounded granules and tubercles, and the presence of a well-developed transverse crista on the inner surface of the male chela, G. wongi sp. nov. belongs to the same group of Southeast Asian species as G. amphinome (De Man, 1899) [West Kalimantan], G. peraccae (Nobili, 1903) [Singapore and Johor, Peninsular Malaysia], G. sarawakense (Serène, 1968) [Sarawak], G. cataracta Ng, 1986 [Perak, Malaysia] and G. pylaemenes Ng, 2015 [West Kalimantan].</p><p>In G. wongi sp. nov., the transverse crista on the inner surface of the male chela is very prominent, especially in the holotype, being much stronger and more produced than in the other species (Fig. 3 B, C) (cf. Fig. 9 A, D, E; Ng 2015: figs 2 F, 3 D, F, 5 F). The size of the transverse crista on the inner surface of the male chela, however, varies with the size of the specimen. It is most prominent in the largest holotype male (12.7 × 11.3 mm, ZRC 2025.0023; Fig. 3 B, C) but is distinctly smaller and less well-developed in smaller males measuring 10.1 × 8.9–10.6 × 9.5 mm (ZRC 2025.0027). In these smaller males, the crista is more similar to those of the other species discussed earlier possessing this character; and as such, the differences observed may be due to the maturity of the males.</p><p>The other species in this group also have relatively lower urogastric regions and are not as raised (Fig. 9 A, B; Ng 2015: figs 1 A, B, 3 A, B, 5 A, B, 6 A, B) as in G. wongi sp. nov. (Figs 1 A, 2 B). The armature of the cutting edges of the fingers of the adult chela is also different in G. peraccae and G. wongi sp. nov. In G. peraccae, there is no median molariform tooth on the dactylar finger, and there are only uneven teeth on the proximal part of the pollex (Figs 6 C, D, 7 A, D; Ng 1988: fig. 56 B; Ng 2015: fig. 5 E, F). In G. wongi sp. nov., on the other hand, the median molariform tooth is distinct, and there are two smaller molariform teeth on the proximal part of the pollex (Fig. 3 A). The male pleon of G. wongi sp. nov. is proportionately much wider compared to most of the species in this group, especially somite 6 (Fig. 4 B, C) (cf. Ng 2015: figs 1 E, 2 C, 4 B, 7 B). Only in G. peraccae does the male pleon share similar proportions (cf. Fig. 8 A; Ng 2015: fig. 5 D). The G 1 of G. wongi sp. nov. has the distal chitinous part spatuliform, and this character is also shared by the species with a well-developed transverse crista on the inner surface of the male chela. In G. wongi sp. nov., the distal chitinous part is distinctly flatter and in lateral view, the structure appears narrow and acutely tapered to the tip (Fig. 5 B – D, G). In most other species with similar G 1 s, the distal chitinous part is more curved along the longitudinal axis, and in lateral view the structure is prominently wider (cf. Ng 2015: figs 2 G – K, 4 D – G, 7 D – F). The G 1 distal chitinous part of G. peraccae is most similar in form to that of G. wongi sp. nov., being narrow in lateral view (Fig. 8 B – E; Ng 1988: fig. 56 D, F) but in the dorso-mesial view, the structure is distinctly narrower, and the tip is entire (Fig. 8 B – F; Ng 1988: fig. 56 E). In G. wongi sp. nov., the G 1 distal chitinous part is very wide in the dorso-mesial view and there is a prominent median cleft at the tip (Fig. 5 E, F, H, I). In addition, the subdistal part of the G 1 is proportionately stouter in G. wongi sp. nov. (Fig. 5 B, C) than in G. peraccae (Fig. 8 B, C; Ng 1988: fig. 56 D, F).</p><p>The only member of the species-group known in the state of Perak is G. cataracta from Bukit Larut (= Maxwell Hill) which is about 90 km northwest of the type locality of G. wongi sp. nov. Geosesarma wongi sp. nov. can easily be distinguished by the external orbital tooth being broadly triangular, with the tip not extending beyond the lateral margin and directed anteriorly (Fig. 2 A, B) (versus external orbital tooth more acutely triangular in form, with the tip extending beyond the lateral margin and directed obliquely in G. cataracta; Ng 1988: fig. 50 A); the protogastric region is only gently convex and not raised (Figs 1 A, 2 B) (versus region raised by presence of large flattened tubercles in G. cataracta; Fig. 9 A, B); the outer face of the male palm has a distinct cluster of closely packed rounded granules on the lower half, posterior to the base of pollex, the dactylus has large molariform median tooth on the cutting edge, the dorsal margin of the dactylus has 15–17 small sharp granules arranged unevenly on surface and the pollex has two submolariform teeth on the proximal half of the cutting edge (Fig. 3 A – D) (versus outer surface of palm with uniformly distributed granules and no obvious cluster of closely packed granules, there is no molariform tooth on the cutting edge of the dactylus, the dorsal margin of the dactylus has 7 or 8 low tubercles arranged in a longitudinal row and the pollex has one rounded median tooth on the cutting edge in G. cataracta; Ng 1988: fig. 59 B); the flexor margins of the propodus and dactylus of the adult male P 2 do not possess a fringe of stiff setae (Fig. 3 E) (versus with dense fringe of stiff setae in G. cataracta; Ng 1988: fig. 59 G); the male telson is proportionately shorter (Figs 2 D, 4 B) (versus telson more elongate in G. cataracta; Fig. 10 A); the G 1 has the chitinous distal part more elongate and spatuliform (Fig. 5 B – D, G, H) (versus distal part shorter and acutely tapering in G. cataracta; Ng 1988: fig. 59 D – F); and the vulvae are relatively larger and positioned closer to each other (Fig. 4 F) (versus distinctly smaller and positioned further apart in G. cataracta; Fig. 10 E).</p><p>The type material of G. wongi sp. nov. was collected with numerous specimens of G. malayanum, indicating that both species are sympatric, although their exact habitats are unknown.</p><p>The type series of G. cataracta was re-examined, and it was determined that the largest female in the paratype series, measuring 12.3 × 10.8 mm (ZRC 1985.1761), is actually not a species of Geosesarma . It has a very smooth carapace, an almost straight front with two postorbital lobes (rather than four), broad ambulatory meri as well as more setose ambulatory propodi and dactyli (Fig. 11 A), and the vulva has a distinct structure, with two closely placed vulvar covers with a slit like opening for the opening (Fig. 11 E).</p><p>The vulva of ZRC 1985.1761, with the median slit between the two vulvar covers, is most similar to that reported for Parasesarma bengalense (Davie, 2003) from the eastern Indian Ocean by Shahdadi and Schubart (2017: fig. 10 C), although the slit for this species is slightly wider. While the carapace shape of ZRC 1985.1761 agrees with that of P. bengalense, the latter species has a much rougher and more setose carapace and the outer surface of the chela is prominently granulose, even in females (cf. Davie 2003: figs 1 C, 2 A, C) and the female telson is strongly sunk into the distal margin of somite 6 (Shahdadi and Schubart 2017: fig. 9 C). In ZRC 1985.1761, the outer surface of the chela is smooth and female telson is only partially inserted into the distal margin of somite 6 (Fig. 11 D). The carapace of ZRC 1985.1761 also resembles that of Fasciarma fasciatum (Lanchester, 1900) [Southeast Asia], a species common in back mangroves, but the ambulatory legs of this species is prominently longer and more slender (Shahdadi and Schubart 2017: fig. 15 A, B, G) and the vulva is mushroom-shaped, without a median slit (Shahdadi and Schubart 2017: fig. 10 F).</p><p>The carapace and ambulatory legs of ZRC 1985.1761 closely resembles species of Pseudosesarma Serène &amp; Soh, 1970 s. str. (cf. Schubart and Ng 2020). The relatively smooth carapace surfaces and the presence of an epibranchial tooth are associated with species like P. crassimanum (De Man, 1887) [Southeast Asia] and P. glabrum Ng, Rani &amp; Nandan, 2017 [eastern India]. Pseudosesarma crassimanum has a carapace which is somewhat more setose, the surfaces of the ambulatory legs are more rugose, the inner angle of the carpus of the cheliped has a sharp tooth (Schubart and Ng 2020: fig. 22 D). The very smooth carapace and blunt inner angle of the carpus of the cheliped of ZRC 1985.1761 is closer in form to the condition in P. glabrum but the ambulatory merus in this species is more rugose (cf. Schubart and Ng 2020: fig. 22 F). The vulvae of these Pseudosesarma species are also different in structure, with the gap between the vulvar covers much wider (Schubart and Ng 2020: fig. 44 B, C). In any case, all known Pseudosesarma species have the outer surfaces of their chelae distinctly granular in both sexes (cf. e. g., Schubart and Ng 2020: fig. 27 D, F), and as such, ZRC 1985.1761 is unlikely to be a member of the genus.</p><p>The smooth carapace and the smooth unarmed outer surface of the chela of ZRC 1985.1761 are very similar to those in Bresedium laevimanum (Zehntner, 1894) (= Sesarma sediliensis Tweedie, 1940) as rediagnosed by Schubart and Ng (2020: figs 24 E – H, 29 D – F). It cannot be B. laevimanum as the inner angle of the carpus of the cheliped of this species has a sharp tooth (Fig. 11 F; Schubart and Ng 2020: fig. 24 E – H) (blunt in the present specimen, Fig. 11 A, C) and the vulva is formed by two triangular vulvar cover plates with a wide gap between them (Fig. 11 G) (a narrow slit between the covers in the present specimen, Fig. 11 E). Specimen ZRC 1985.1761 is thus not Bresedium laevimanum but probably an allied taxon. The taxonomy of Bresedium, which now contains three species (see Li et al. 2020; Shahdadi and Ng 2025), is now being revised by H. - T. Shih and colleagues, and specimen ZRC 1985.1761 is provisionally placed there. Bresedium species like B. laevimanum are known from back mangroves and can be found some distance from the shore, but its presence in a waterfall on Bukit Larut is noteworthy as this location is about 15 km from the nearest mangroves.</p></div>	https://treatment.plazi.org/id/91E6CB1F1BB55703B18D3EB3037717FC	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	Ng, Peter K. L.	Ng, Peter K. L. (2026): Geosesarma wongi sp. nov., a distinctive new species of semiterrestrial crab from Tapah Hills in Perak, Peninsular Malaysia; with notes on G. peraccae (Nobili, 1903) and G. cataracta Ng, 1986 (Crustacea, Brachyura, Sesarmidae). ZooKeys 1266: 281-298, DOI: 10.3897/zookeys.1266.172575
