identifier	taxonID	type	CVterm	format	language	title	description	additionalInformationURL	UsageTerms	rights	Owner	contributor	creator	bibliographicCitation
FEBCE5AD8B235E49A60056E5B8027C78.text	FEBCE5AD8B235E49A60056E5B8027C78.taxon	http://purl.org/dc/dcmitype/Text	http://rs.tdwg.org/ontology/voc/SPMInfoItems#GeneralDescription	text/html	en	Megapleonum falx Huang & Shih & Ahyong 2025	<div><p>Megapleonum falx sp. nov.</p><p>Figs 1, 2</p><p>Type material.</p><p>Holotype: • SYSBM 002142, male (19.6 × 15.8 mm), <a href="https://tb.plazi.org/GgServer/search?materialsCitation.longitude=115.07&amp;materialsCitation.latitude=23.03" title="Search Plazi for locations around (long 115.07/lat 23.03)">Baima Village</a>, Huidong County, Huizhou City, Guangdong Province, China, 23.03°N, 115.07°E, hill stream under rock, coll. Song-Bo Wang, August 2019.</p><p>Diagnosis.</p><p>Carapace broader than long, dorsal surface slightly convex, lateral margins covered in dense setae; postorbital, epigastric cristae confluent (Fig. 1 A). Maxilliped 3 sparsely covered in long setae; merus width ~ 1.4 × length; ischium width ~ 0.7 × length; exopod reaching beyond anterior edge of ischium, flagellum as long as merus width (Fig. 2 A). Ambulatory legs with dense setae; pereiopod 5 dactylus ~ as long as propodus (Fig. 1 A). Male anterior thoracic sternum very broad, width ~ 1.8 × length (Fig. 1 C). Male pleon large, broadly triangular, pleonite 6 width ~ 2.6 × length, telson width ~ 1.8 × length (Fig. 1 D). G 1 large, strongly sinuous, tip exceeding suture between thoracic sternites 4 / 5 in situ (Fig. 1 E); subterminal segment length ~ 3.2 × length of terminal segment (Fig. 2 C). Subterminal segment outer margin strongly concave; terminal segment strongly curved inwards, strongly tapering, sickle shaped, tip pointed downwards in dissected view (Fig. 2 C, F, G). G 2 subterminal segment tapering, bent outwards distally, flagelliform terminal segment ~ 1.8 × length of subterminal segment, apex blunt (Fig. 2 B).</p><p>Description of male holotype.</p><p>Carapace broader than long, ~ 1.2 × as wide as long; regions not pronounced, dorsal surface slightly convex, finely pitted; dense setae along lateral margins (Fig. 1 A). Frontal margin almost straight, deflexed (Fig. 1 A, B). Epigastric cristae and postorbital cristae relatively smooth, confluent; bifurcated groove between epigastric cristae (Figs 1 A, 2 A). Branchial regions not swollen (Fig. 1 A, B). Cervical groove shallow but visible (Fig. 1 A). Mesogastric region flat (Fig. 1 A). External orbital angle broadly triangular, outer margin slightly convex, confluent with anterolateral margin (Fig. 1 A, B). Epibranchial tooth granular, indistinct (Fig. 1 A, B). Anterolateral margin lined with indistinct single or partially fused granules; posterolateral margin posteriorly convergent (Fig. 1 A); posterolateral surface slightly rugose (Fig. 1 A). Orbits regular; supraorbital margins weakly cristate, infraorbital margins lined with fused granules (Fig. 1 B). Eyes normal (Fig. 1 A, B). Sub-orbital, pterygostomial and sub-hepatic regions generally smooth, pitted (Fig. 1 B). Antennules large, folded within broad fossae; antennae very short (Fig. 1 B). Median lobe of epistome buccal margin broadly triangular, lateral margins slightly sinuous (Fig. 1 B).</p><p>Maxilliped 3 sparsely covered in long setae, merus subtrapezoidal, with slight median depression, width ~ 1.4 × length; ischium subtrapezoidal with shallow median sulcus, distomesial margin rounded, width ~ 0.7 × length. Exopod reaching proximal one-third of merus; flagellum as long as merus width (Fig. 2 A).</p><p>Chelipeds (pereiopod 1) subequal (Fig. 2 D, E). Merus trigonal in cross-section, surfaces generally smooth; outer dorsal and ventral margins slightly crenulated, inner margin lined with large granules (Fig. 1 A, B). Carpus dorsal surface slightly rugose, with large spike at inner-distal angle, spinule at base (Fig. 1 A). Major cheliped palm length ~ 1.5 × height; dactylus 0.7 × palm length (Fig. 2 D, E). Palm surface pitted, occlusal margin of fingers with 7–9 irregular blunt teeth, with small gape when closed (Fig. 2 D, E).</p><p>Ambulatory legs (pereiopods 2–5) slender, covered with setae (Fig. 1 A). Pereiopod 3 merus 0.6 × CL (Fig. 1 A). Pereiopod 5 propodus length 1.7 × height, approximately as long as dactylus (Fig. 1 A).</p><p>Male thoracic sternum generally smooth, pitted, setae at margins and sparsely on sternites; sternites 1–4 width ~ 1.8 × length; sternites 1, 2 fused to form broad triangle; fused sternites 1, 2 demarcated from sternite 3 by sinuous transverse sulcus, sulcus lined with setae; sternites 3, 4 fused without obvious demarcation other than a line of setae (Fig. 1 C). Male sterno-pleonal cavity reaching anteriorly slightly beyond mid-length of cheliped coxa (Fig. 1 C). Male pleonal locking tubercle positioned at mid-length of sternite 5 (Fig. 1 E).</p><p>Male pleon large, broadly triangular; somites 3–6 progressively narrower, not entirely confluent with each other; somite 6 width approximately 2.6 × length; telson width 1.8 × length; lateral margins almost straight, apex rounded (Fig. 1 D).</p><p>G 1 large, strongly sinuous, tip exceeding suture between thoracic sternites 4 / 5 in situ (Fig. 1 E); subterminal segment length ~ 3.2 × length of terminal segment (Fig. 2 C). Subterminal segment outer margin strongly concave; terminal segment strongly curved inwards, strongly tapering, sickle shaped, tip pointed downwards in dissected view (Fig. 2 C, F, G). G 2 subterminal segment tapering, bent outwards distally, flagelliform terminal segment ~ 1.8 × length of subterminal segment, apex blunt (Fig. 2 B).</p><p>Colour in life.</p><p>Generally camouflage-brown all over.</p><p>Habitat.</p><p>Unknown. The only specimen collected was found in the lower reaches of the hill stream, but further collection efforts in the same area and further upstream yielded no crabs at all. We consider it likely that the primary habitat of this species is higher up the mountain, which reaches above 1000 m above sea level, and that this lone specimen that was collected was washed downstream in a flooding event.</p><p>Distribution.</p><p>Baima Village, Huidong County, Huizhou City, Guangdong Province, China.</p><p>Etymology.</p><p>The species name is the Latin word falx which means sickle-shaped. It alludes to the sickle-shaped G 1 terminal segment of this species.</p><p>Remarks.</p><p>The wide male anterior thoracic sternum, large and broadly triangular male abdomen and large and sinuous G 1 of Megapleonum falx sp. nov. fit the diagnosis of the genus. In possessing thick setae on the carapace margins and ambulatory legs, M. falx sp. nov. is most similar to M. ferrumequinum sp. nov. The sickle-shaped G 1 terminal segment of M. falx sp. nov., however, is unlike any other congener and immediately distinguishes it (Fig. 2 C, F, G). Apart from the G 1, M. falx sp. nov. also has a flatter carapace dorsal surface when compared to M. ferrumequinum sp. nov. (Figs 1 B, 3 B). The flagellum of the maxilliped 3 exopod is present in M. falx sp. nov. whereas it is absent in M. ferrumequinum sp. nov. (Fig. 2 A vs Fig. 4 A). The male abdomen is also obviously wider in M. falx sp. nov., with the somite 6 width approximately 2.6 × length (Fig. 1 D) (vs narrower in M. ferrumequinum sp. nov., sixth somite width approximately 2.5 × length, Fig. 3 D). The relative length of the pereiopod dactylus to the propodus is also different, being approximately the same length in M. falx sp. nov. and in M. ferrumequinum sp. nov., having a shorter dactylus (Figs 1 A, 3 A). More detailed comparisons can be found in Table 1.</p></div>	https://treatment.plazi.org/id/FEBCE5AD8B235E49A60056E5B8027C78	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	Huang, Chao;Shih, Hsi-Te;Ahyong, Shane T.	Huang, Chao, Shih, Hsi-Te, Ahyong, Shane T. (2025): Four new freshwater crab species of the genus Megapleonum Huang, Shih & Ahyong, 2018 (Crustacea, Decapoda, Potamidae) from Guangdong, China. ZooKeys 1244: 1-27, DOI: 10.3897/zookeys.1244.148112
7FB5A7F23BF559619415E29FCBFBB8C3.text	7FB5A7F23BF559619415E29FCBFBB8C3.taxon	http://purl.org/dc/dcmitype/Text	http://rs.tdwg.org/ontology/voc/SPMInfoItems#GeneralDescription	text/html	en	Megapleonum ferrumequinum Huang & Shih & Ahyong 2025	<div><p>Megapleonum ferrumequinum sp. nov.</p><p>Figs 3, 4, 13 A</p><p>Type material.</p><p>Holotype: • SYSBM 002143, male (16.6 × 13.1 mm), <a href="https://tb.plazi.org/GgServer/search?materialsCitation.longitude=111.22&amp;materialsCitation.latitude=22.29" title="Search Plazi for locations around (long 111.22/lat 22.29)">Datianding</a>, Dawuling Nature Reserve, Maoming City, Guangdong Province, China, 22.29°N, 111.22°E, dirt road near the summit at night, coll. Jian Wang, June 2018.</p><p>Diagnosis.</p><p>Carapace broader than long, dorsal surface convex, lateral margins covered in dense setae; postorbital, epigastric cristae weak, almost confluent (Fig. 3 A). Maxilliped 3 merus width ~ 1.3 × length; ischium width ~ 0.7 × length; exopod reaching slightly beyond anterior edge of ischium, without flagellum (Fig. 4 A). Ambulatory legs densely setose; pereiopod dactylus shorter than propodus (Fig. 3 A). Male anterior thoracic sternum very broad, width ~ 1.9 × length (Fig. 3 C). Male pleon large, sublinguiform, pleonite 6 width ~ 2.5 × length; telson width ~ 1.7 × length (Fig. 3 D). G 1 large, slightly sinuous, tip exceeding suture between thoracic sternites 4 / 5 in situ (Fig. 3 E); subterminal segment length ~ 2.5 × length of terminal segment (Fig. 4 C). Subterminal segment outer margin slightly concave, outer distal margin bulging; terminal segment curved inwards, tip pointed upwards in dissected view, connected to a large mesoanterior-facing horseshoe shaped structure, large thick proximal pad on dorsal side (Fig. 4 C, F, G). G 2 subterminal segment tapering, slightly bent outwards distally, flagelliform terminal segment thick, ~ 1.6 × length of subterminal segment, apex blunt (Fig. 4 B).</p><p>Description of male holotype.</p><p>Carapace broader than long, ~ 1.3 × as wide as long; regions not pronounced, dorsal surface convex; surface finely pitted, dense setae at lateral margins (Fig. 3 A). Frontal margin almost straight, deflexed (Fig. 3 A, B). Epigastric cristae and postorbital cristae rugose, low, almost confluent; bifurcated shallow groove between epigastric cristae (Fig. 3 A). Branchial regions not swollen (Fig. 3 A, B). Cervical groove shallow, barely visible (Fig. 3 A). Mesogastric region flat (Fig. 3 A). External orbital angle broadly triangular, outer margin slightly convex, confluent with anterolateral margin (Fig. 3 A, B). Epibranchial tooth granular, indistinct (Fig. 3 A, B). Anterolateral margin lined with indistinct single or partially fused granules; posterolateral margin posteriorly convergent (Fig. 3 A); posterolateral surface smooth (Fig. 3 A). Orbits regular; supraorbital margins weakly cristate, infraorbital margins lined with fused granules (Fig. 3 B). Eyes normal (Fig. 3 A, B). Sub-orbital, pterygostomial and sub-hepatic regions generally smooth, pitted (Fig. 1 B). Antennules large, folded within broad fossae; antennae very short (Fig. 3 B). Median lobe of epistome buccal margin broadly triangular, lateral margins straight (Fig. 3 B).</p><p>Maxilliped 3 merus subtrapezoidal, with slight median depression, width ~ 1.4 × length; ischium subtrapezoidal with shallow median sulcus, distomesial margin rounded, width ~ 0.7 × length. Exopod reaching proximal one-third of merus; flagellum absent (Fig. 4 A).</p><p>Chelipeds (pereiopod 1) subequal (Fig. 4 D, E). Merus trigonal in cross section, surfaces generally smooth, margins lined with long setae; outer dorsal margin slightly crenulated margins slightly crenulated, inner and ventral margin lined with large granules (Fig. 3 A, B). Carpus dorsal surface slightly rugose, with large spike at inner-distal angle, spinule at base (Fig. 3 A). Major cheliped palm length ~ 1.5 × height; dactylus 0.7 × palm length (Fig. 2 D, E). Palm surface pitted, occlusal margin of fingers with 7–9 irregular blunt teeth, with small gape when closed (Fig. 2 D, E).</p><p>Ambulatory legs (pereiopods 2–5) covered with setae, especially dense on pereiopods 2–3 (Fig. 3 A). Pereiopod 3 merus 0.6 × CL (Fig. 3 A). Pereiopod 5 propodus length 1.7 × height, longer than dactylus (Fig. 3 A).</p><p>Male thoracic sternum generally smooth, pitted, setae at margins and sparsely on sternites; sternites 1–4 width ~ 1.9 × length; sternites 1, 2 fused to form broad triangle; fused sternites 1, 2 demarcated from sternite 3 by sinuous transverse sulcus, sulcus lined with setae; sternites 3, 4 fused without obvious demarcation (Fig. 3 C). Male sterno-pleonal cavity reaching anteriorly slightly beyond mid-length of cheliped coxa (Fig. 3 C). Male pleonal locking tubercle positioned slightly posterior to mid-length of sternite 5 (Fig. 3 E).</p><p>Male pleon large, sublinguiform; somites 3–6 progressively narrower; somite 6 width approximately 2.5 × length; telson width 1.7 × length; lateral margins almost straight, apex rounded (Fig. 3 D).</p><p>G 1 large, slightly sinuous, tip exceeding suture between thoracic sternites 4 / 5 in situ (Fig. 3 E); subterminal segment length ~ 2.5 × length of terminal segment (Fig. 4 C). Subterminal segment outer margin slightly concave, outer distal margin bulging; terminal segment curved inwards, tip pointed upwards in dissected view, connected to a large meso-anterior-facing horseshoe shaped structure, large thick proximal pad on dorsal side (Fig. 4 C, F, G). G 2 subterminal segment tapering, slightly bent outwards distally, flagelliform terminal segment thick, ~ 1.6 × length of subterminal segment, apex blunt (Fig. 4 B).</p><p>Colour in life.</p><p>Generally drab camouflage-brown all over (Fig. 13 A).</p><p>Habitat.</p><p>Typical habitat unknown. The only specimen collected was found at night on the side of a dirt road near the summit at approximately 1600 m above sea level. Multiple subsequent attempts to find this species in the same area failed to locate any more specimens with only Megapleonum wangjiani sp. nov. and Eurusamon guangdongense being found. The true habitat of this species remains elusive.</p><p>Distribution.</p><p>Dawuling Nature Reserve, Maoming City, Guangdong Province, China.</p><p>Etymology.</p><p>The species name is the Latin word ferrumequinum, meaning horseshoe. It alludes to the horseshoe-shaped structure on the G 1 terminal segment of this species. Used as a noun in apposition.</p><p>Remarks.</p><p>Megapleonum ferrumequinum sp. nov. is unique in its genus by its sublinguiform male abdomen (Fig. 3 D, vs broadly triangular in all other congeners) and its peculiar G 1, which is only slightly sinuous (Fig. 4 C, vs more strongly sinuous in all other congeners) with a horseshoe-shaped structure in the terminal segment (Fig. 4 F – H, vs absent in all other congeners). In possessing dense setation on the carapace margins and ambulatory legs, M. ferrumequinum sp. nov. is most similar to M. falx sp. nov. (see remarks for M. falx sp. nov.). More detailed comparisons can be found in Table 1.</p></div>	https://treatment.plazi.org/id/7FB5A7F23BF559619415E29FCBFBB8C3	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	Huang, Chao;Shih, Hsi-Te;Ahyong, Shane T.	Huang, Chao, Shih, Hsi-Te, Ahyong, Shane T. (2025): Four new freshwater crab species of the genus Megapleonum Huang, Shih & Ahyong, 2018 (Crustacea, Decapoda, Potamidae) from Guangdong, China. ZooKeys 1244: 1-27, DOI: 10.3897/zookeys.1244.148112
5B3B1E37FE7C52C9956DD1C067AFCC3A.text	5B3B1E37FE7C52C9956DD1C067AFCC3A.taxon	http://purl.org/dc/dcmitype/Text	http://rs.tdwg.org/ontology/voc/SPMInfoItems#GeneralDescription	text/html	en	Megapleonum Huang, Shih & Ahyong 2018	<div><p>Megapleonum Huang, Shih &amp; Ahyong, 2018</p><p>Diagnosis.</p><p>Carapace broader than long, dorsal surface slightly convex; postorbital, epigastric cristae confluent or almost confluent; external orbital angle bluntly triangular, confluent or almost confluent with anterolateral margin. Epistome buccal margin with triangular median lobe. Maxilliped 3 ischium longitudinally subquadrate, length ~ 0.7 × width; exopod reaching slightly beyond distal edge of ischium, flagellum absent to well-developed. Male anterior thoracic sternum very broad, width 1.8–2.0 × length. Male pleon large, broadly triangular to sublinguiform, tip of telson rounded. Female pleon linguiform to subovate. G 1 large, sinuous, reaching beyond male pleonal locking tubercle, subterminal segment outer margin slightly to strongly concave, terminal segment highly variable. G 2 subterminal segment tapering, bent to slightly bent outwards distally, thin to thick flagelliform terminal segment. Vulvae ovate, large, reaching suture of sternites 5 / 6, relatively widely separated.</p><p>Composition.</p><p>Megapleonum ehuangzhang Huang, Shih &amp; Ahyong, 2018 (type species), Megapleonum falx sp. nov., M. ferrumequinum sp. nov., Megapleonum shenzhen Huang &amp; Mao, 2021, M. yangdongense sp. nov., and M. wangjiani sp. nov.</p><p>Remarks.</p><p>With the description of four new species herein, the diagnosis of the genus has to be revised. The significant variation within the genus, particularly in the form of the G 1 poses challenges to establishing a uniform diagnosis. However, the key distinguishing features include the confluent or almost confluent postorbital and epigastric cristae, and external orbital angle and anterolateral margin, very broad male anterior thoracic sternum, large male pleon and the ovate, large vulvae, which extend to the suture of sternites 5 / 6 and are relatively widely spaced.</p></div>	https://treatment.plazi.org/id/5B3B1E37FE7C52C9956DD1C067AFCC3A	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	Huang, Chao;Shih, Hsi-Te;Ahyong, Shane T.	Huang, Chao, Shih, Hsi-Te, Ahyong, Shane T. (2025): Four new freshwater crab species of the genus Megapleonum Huang, Shih & Ahyong, 2018 (Crustacea, Decapoda, Potamidae) from Guangdong, China. ZooKeys 1244: 1-27, DOI: 10.3897/zookeys.1244.148112
C80D0340D9645FCD8913422A01FB4647.text	C80D0340D9645FCD8913422A01FB4647.taxon	http://purl.org/dc/dcmitype/Text	http://rs.tdwg.org/ontology/voc/SPMInfoItems#GeneralDescription	text/html	en	Megapleonum wangjiani Huang & Shih & Ahyong 2025	<div><p>Megapleonum wangjiani sp. nov.</p><p>Figs 5, 6, 7, 11 A, B, 13 B, C</p><p>Type material.</p><p>Holotype: • SYSBM 002144, male (11.7 × 9.7 mm), <a href="https://tb.plazi.org/GgServer/search?materialsCitation.longitude=111.22&amp;materialsCitation.latitude=22.29" title="Search Plazi for locations around (long 111.22/lat 22.29)">Datianding</a>, Dawuling Nature Reserve, Maoming City, Guangdong Province, China, 22.29°N, 111.22°E, under rocks in small seepage, coll. Chao Huang, November 2018 . Paratypes: • SYSBM 002145 –002147, 3 males (11.6 × 9.5 mm, 10.9 × 9.0 mm, 8.3 × 6.9 mm), same data as holotype. SYSBM 002148 –002151, 4 females (16.7 × 12.8 mm, 15.0 × 11.3 mm, 14.6 × 11.4 mm, 9.3 × 7.5 mm), same data as holotype . • NNU 16 C-201811 MW, 1 male (10.3 × 8.3 mm), 1 female (14.6 × 11.4 mm), same data as holotype .</p><p>Diagnosis.</p><p>Carapace broader than long; dorsal surface slightly convex, postorbital, epigastric cristae weak, rugose, almost confluent (Fig. 5). Maxilliped 3 merus width ~ 1.2 × length; ischium width ~ 0.7 × length; exopod reaching slightly beyond anterior edge of ischium, without flagellum (Fig. 7 A). Ambulatory legs with dense setae; pereiopod dactylus shorter than propodus (Fig. 7). Male anterior thoracic sternum very broad, width ~ 2.0 × length (Fig. 6 B). Male pleon large, broadly triangular, pleonite 6 width ~ 2.6 × length; telson width ~ 1.8 × length (Fig. 6 C). Female pleon subovate (Fig. 6 E). G 1 large, strongly sinuous, tip exceeding suture between thoracic sternites 4 / 5 in situ (Fig. 6 D); subterminal segment length ~ 2.3 × length of terminal segment (Fig. 7 C – E). Subterminal segment outer margin strongly concave; terminal segment short, rounded, distoventrally with long setae, directed inwards, inner-proximal margin concave; tip presenting as protrusion on higher two-thirds of outer margin (Figs 7 C – E, 11 A, B). G 2 subterminal segment slightly bent outwards distally, flagelliform terminal segment thick, ~ 1.7 × length of subterminal segment, apex blunt, slightly swollen (Fig. 7 B).</p><p>Description.</p><p>Carapace broader than long, ~ 1.2 × as wide as long in males (n = 4), ~ 1.3 × as wide in mature females (n = 4); regions not pronounced, dorsal surface convex; surface finely pitted, anterolateral regions slightly rugose (Fig. 5). Frontal margin slightly sinuous, deflexed (Fig. 5). Epigastric cristae and postorbital cristae rugose, low, almost confluent; bifurcated shallow groove between epigastric cristae (Fig. 5). Branchial regions not swollen (Fig. 5). Cervical groove shallow (Fig. 5). Mesogastric region flat (Fig. 5). External orbital angle broadly triangular, outer margin slightly convex, confluent with anterolateral margin (Figs 5, 6 A). Epibranchial tooth granular, indistinct (Figs 5, 6 A). Anterolateral margin lined with 10–14 granules; posterolateral margin posteriorly convergent (Fig. 5); posterolateral surface smooth (Fig. 5). Orbits regular; supraorbital margins weakly cristate, infraorbital margins lined with fused granules (Fig. 6 A). Eyes normal (Figs 5, 6 A). Sub-orbital, pterygostomial and sub-hepatic regions generally smooth, pitted (Fig. 6 A). Antennules large, folded within broad fossae; antennae very short (Fig. 6 A). Median lobe of epistome buccal margin triangular, lateral margins straight (Fig. 6 A).</p><p>Maxilliped 3 merus subtrapezoidal, with slight median depression, width ~ 1.2 × length; ischium subtrapezoidal with shallow median sulcus, distomesial margin rounded, width ~ 0.7 × length. Exopod reaching proximal one-third of merus; flagellum absent (Fig. 4 A).</p><p>Chelipeds (pereiopod 1) subequal (Fig. 7 F – I). Merus trigonal in cross section, surfaces generally smooth; outer dorsal margin slightly crenulated, inner and ventral margin lined with large granules (Figs 5, 6 A). Carpus dorsal surface slightly rugose, with small blunt spine at inner-distal angle, spinule at base (Fig. 5). Major cheliped palm length ~ 1.3–1.4 × height in males (n = 2), 1.4–1.5 × height in females (n = 4); dactylus 0.9 × palm length in males (n = 2), 0.9–1.0 × palm length in females (n = 4) (Fig. 7 F – I). Palm surface pitted, occlusal margin of fingers with 8–11 irregular blunt teeth, with very small gape when closed (Fig. 7 F – I).</p><p>Ambulatory legs slender (pereiopods 2–5) covered with setae, especially dense on pereiopods 2, 3 (Fig. 5). Pereiopod 3 merus 0.6–0.7 × CL in both sexes (n = 8, Fig. 5). Pereiopod 5 propodus length 1.9–2.2 × height in males (n = 4), 2.1–2.4 × height in females (n = 4), shorter than dactylus (Fig. 5).</p><p>Male thoracic sternum generally smooth, sparsely pitted; sternites 1–4 width ~ 2.0 × length; sternites 1, 2 fused to form broad triangle; fused sternites 1, 2 demarcated from sternite 3 by almost straight transverse sulcus; sternites 3, 4 fused without obvious demarcation (Fig. 6 B). Male sterno-pleonal cavity reaching anteriorly slightly beyond mid-length of cheliped coxa (Fig. 6 B). Male pleonal locking tubercle positioned at mid-length of sternite 5 (Fig. 6 D). Female vulvae ovate, large, reaching suture of sternites 5 / 6, relatively widely separated (Fig. 6 F).</p><p>Male pleon large, broadly triangular; somites 3–6 progressively narrower; somite 6 width ~ 2.6 × length; telson width 1.8 × length; lateral margins almost straight, apex rounded (Fig. 6 C). Female pleon sub-ovate (Fig. 6 E).</p><p>G 1 large, strongly sinuous, tip exceeding suture between thoracic sternites 4 / 5 in situ (Fig. 6 D); subterminal segment length ~ 2.3 × length of terminal segment (Fig. 7 C – E). Subterminal segment outer margin strongly concave; terminal segment short, rounded, distoventral region with long setae, directed inwards, inner-proximal margin concave; tip presenting as protrusion on higher two-thirds of outer margin (Figs 7 C – E, 11 A, B). G 2 subterminal segment slightly bent outwards distally, flagelliform terminal segment thick, ~ 1.7 × length of subterminal segment, apex blunt, slightly swollen (Fig. 7 B).</p><p>Colour in life.</p><p>Generally drab camouflage-brown all over, some individuals exhibit a reddish hue (Fig. 13 B, C).</p><p>Habitat.</p><p>Little is known about the ecology of this new species, aside from its occurrence at high elevations, where it inhabits seepages and is occasionally seen roaming the forest floor. Megapleonum ferrumequinum sp. nov. and Eurusamon guangdongense are also found on the same mountain, but the three species apparently occupy different niches.</p><p>Distribution.</p><p>Dawuling Nature Reserve, Maoming City, Guangdong Province, China.</p><p>Etymology.</p><p>This species is named in honour of its discoverer, Jian Wang, in recognition of his contribution to this study.</p><p>Remarks.</p><p>Like many species in this genus, Megapleonum wangjiani sp. nov. can immediately be distinguished by its distinctive G 1, especially in the rounded terminal segment with the tip presenting as a protrusion on the higher two-thirds of the outer margin (Figs 7 C – E, 11 A, B). Apart from the G 1, M. wangjiani can be separated from the sympatric M. ferrumequinum sp. nov. by its slenderer legs, with the pereiopod 5 propodus length 1.9–2.4 × height, shorter than dactylus, whereas in the latter the pereiopod 5 propodus length is 1.7 × height, longer than dactylus (Fig. 5 A, B vs Fig. 3 A). Megapleonum wangjiani sp. nov. also has a broader male abdomen than M. ferrumequinum n. sp. (Fig. 6 C vs Fig. 3 D). More detailed comparisons can be found in Table 1.</p><p>There is noticeable sexual dimorphism in Megapleonum wangjiani sp. nov., with males being smaller and maturing at a smaller size than females (the male SYSBM 002147 at CW 8.3 mm has a full length G 1 whereas the female SYSBM 002151 at CW 9.3 mm has an immature narrow abdomen). Females also have a proportionally wider carapace (1.2 × as wide as long in mature males vs ~ 1.3 × in mature females) and more slender legs than females (pereiopod 5 propodus length 1.9–2.2 × height in males vs 2.1–2.4 × height in females), but these differences might also be related to size and are only obvious due to the apparent inability for the males to reach the size of females. Interspecific variation of the G 1 is small, with the tip opening varying slightly in size and shape (Fig. 7 C – E).</p></div>	https://treatment.plazi.org/id/C80D0340D9645FCD8913422A01FB4647	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	Huang, Chao;Shih, Hsi-Te;Ahyong, Shane T.	Huang, Chao, Shih, Hsi-Te, Ahyong, Shane T. (2025): Four new freshwater crab species of the genus Megapleonum Huang, Shih & Ahyong, 2018 (Crustacea, Decapoda, Potamidae) from Guangdong, China. ZooKeys 1244: 1-27, DOI: 10.3897/zookeys.1244.148112
9E1C850AB36F51BD922339DC594E89F8.text	9E1C850AB36F51BD922339DC594E89F8.taxon	http://purl.org/dc/dcmitype/Text	http://rs.tdwg.org/ontology/voc/SPMInfoItems#GeneralDescription	text/html	en	Megapleonum yangdongense Huang & Shih & Ahyong 2025	<div><p>Megapleonum yangdongense sp. nov.</p><p>Figs 8, 9, 10, 11 C, D, 13 D</p><p>Type material.</p><p>Holotype: • SYSBM 002152, male (17.8 × 14.5 mm), <a href="https://tb.plazi.org/GgServer/search?materialsCitation.longitude=112.07&amp;materialsCitation.latitude=21.97" title="Search Plazi for locations around (long 112.07/lat 21.97)">Gaozhai</a>, Yangdong County, Yangjiang City, Guangdong Province, China, 21.97°N; 112.07°E, under rocks in hillstream, coll. Chao Huang, Hsi-Te Shih and Bernhard Bein, 1 June 2019 . Paratypes: • SYSBM 002153, male (17.3 × 13.7 mm), same data as holotype. SYSBM 002154 –002155, 2 females (16.0 × 12.4 mm, 15.3 × 12.0 mm), same data as holotype . IHB, 2 males (16.0 × 12.7 mm, 15.4 × 12.0 mm), same data as holotype . NCHUZOOL 15306, 2 males (16.0 × 13.1 mm, 14.9 × 11.8 mm), 1 female (16.0 × 12.6 mm), NCHUZOOL 15307, 1 male (16.7 × 13.8 mm), same data as holotype .</p><p>Diagnosis.</p><p>Carapace broader than long, dorsal surface slightly convex, postorbital, epigastric cristae confluent, sharp (Fig. 8). Maxilliped 3 merus width ~ 1.3 × length; ischium width ~ 0.7 × length; exopod reaching slightly beyond anterior edge of ischium; flagellum short, as long as dactylus (Fig. 10 A). Ambulatory legs without long setae, pereiopod dactylus shorter than propodus (Fig. 8). Male anterior thoracic sternum very broad, width ~ 1.9 × length (Fig. 9 B). Male pleon large, broadly triangular, pleonite 6 width ~ 2.4 × length, telson width ~ 1.8 × length (Fig. 9 C). Female pleon subovate (Fig. 9 E). G 1 large, sinuous, tip exceeding suture between thoracic sternites 4 / 5 in situ (Fig. 9 D); subterminal segment length ~ 2.7 × length of terminal segment (Fig. 10 C – E); subterminal segment thick, outer margin strongly concave, distal end slanted with outer-distal section highest; terminal segment short, both lateral margins slightly convex, bifurcated with one point being opening tip and other a smaller projection on outer margin, both pointing upwards (Figs 10 C – E, 11 C, D). G 2 subterminal segment thick, slightly bent outwards distally, flagelliform terminal segment thin, ~ 2.3 × length of subterminal segment (Fig. 10 B).</p><p>Description.</p><p>Carapace broader than long, males ~ 1.2–1.3 × as wide as long (n = 6); regions not all visible, dorsal surface slightly convex; surface pitted, anterolateral regions slightly rugose (Fig. 8). Frontal margin sinuous, deflexed (Fig. 8). Epigastric cristae and postorbital cristae confluent, sharp; bifurcated shallow groove between epigastric cristae (Fig. 8). Branchial regions not swollen (Fig. 8). Cervical groove obvious (Fig. 8). Mesogastric region flat (Fig. 8). External orbital angle broadly triangular, outer margin slightly convex, almost confluent with anterolateral margin (Figs 8, 9 A). Epibranchial tooth granular, indistinct (Figs 8, 9 A). Anterolateral margin lined with 10–14 granules; posterolateral margin posteriorly convergent (Fig. 8); posterolateral with weak striae (Fig. 8). Orbits regular; supraorbital margins cristate, infraorbital margins lined with fused granules (Fig. 9 A). Eyes normal (Figs 8, 9 A). Sub-orbital, pterygostomial and sub-hepatic regions generally smooth, pitted (Fig. 9 A). Antennules large, folded within broad fossae; antennae very short (Fig. 9 A). Median lobe of epistome buccal margin broadly triangular, lateral margins straight (Fig. 9 A).</p><p>Maxilliped 3 merus subtrapezoidal, with slight median depression, width ~ 1.3 × length; ischium subtrapezoidal with very shallow median sulcus, distomesial margin rounded, width ~ 0.7 × length. Exopod reaching proximal one-third of merus; flagellum short (Fig. 10 A).</p><p>Chelipeds (pereiopod 1) subequal (Fig. 10 F – I). Merus trigonal in cross section, surfaces generally smooth; outer dorsal margin slightly crenulated, inner and ventral margin lined with large granules (Figs 8, 9 A). Carpus dorsal surface slightly rugose, with small blunt spine at inner-distal angle, spinule at base (Fig. 8). Major cheliped palm length ~ 1.4–1.5 × height in males (n = 3), 1.4 × height in females (n = 2); dactylus 0.9 × palm length in males (n = 3), 0.8–0.9 × palm length in females (n = 2) (Fig. 10 F – I). Palm surface pitted, occlusal margin of fingers with 9–13 irregular blunt teeth, with very small gape when closed (Fig. 10 F – I).</p><p>Ambulatory legs slender (pereiopods 2–5), with only very short setae on margins (Fig. 8). Pereiopod 3 merus 0.7 × CL in both sexes (n = 5, Fig. 8). Pereiopod 5 propodus length 1.7–2.0 × height in males (n = 3), 1.8–1.9 × height in females (n = 2), longer than dactylus (Fig. 8).</p><p>Male thoracic sternum generally smooth, sparsely pitted; sternites 1–4 width ~ 1.9 × length; sternites 1, 2 fused to form broad triangle; fused sternites 1, 2 demarcated from sternite 3 by slightly sinuous sulcus; sternites 3, 4 fused with distinct sulcus (Fig. 9 B). Male sterno-pleonal cavity reaching anteriorly slightly beyond mid-length of cheliped coxa (Fig. 9 B). Male pleonal locking tubercle positioned at mid-length of sternite 5 (Fig. 9 D). Female vulvae ovate, large, reaching suture of sternites 5 / 6, relatively widely separated (Fig. 9 F).</p><p>Male pleon large, broadly triangular; somites 3–6 progressively narrower; somite 6 width approximately 2.4 × length; telson width 1.8 × length; lateral margins almost straight, apex rounded (Fig. 6 C). Female pleon sub-ovate (Fig. 9 E).</p><p>G 1 large, sinuous, tip exceeding suture between thoracic sternites 4 / 5 in situ (Fig. 9 D); subterminal segment length ~ 2.7 × length of terminal segment (Fig. 10 C – E). Subterminal segment thick, outer margin strongly concave, distal end slanted with outer-distal section highest; terminal segment short, both lateral margins slightly convex, bifurcated with one point being opening tip and other being smaller projection on outer margin, both pointing upwards (Figs 10 C – E, 11 C, D). G 2 subterminal segment thick, slightly bent outwards distally, flagelliform terminal segment thin, ~ 2.3 × length of subterminal segment (Fig. 10 B).</p><p>Colour in life.</p><p>Generally camouflaged in light mottled brown overall (Fig. 13 D).</p><p>Habitat.</p><p>This is a typical aquatic hill stream species that can be found residing under rocks in the shallows of the hillstream. The sympatric Eurusamon guangdongense is also aquatic but can grow to a much larger size and mature individuals occupy the deeper areas of the hillstream.</p><p>Distribution.</p><p>Yangdong County, Yangjiang City, Guangdong Province, China.</p><p>Etymology.</p><p>This species is named after the type locality, Yangdong County.</p><p>Remarks.</p><p>This new species is closest to Megapleonum ehuangzhang and especially M. shenzhen in terms of carapace and gonopodal morphology, and the three are no doubt closely related. Megapleonum yangdongense sp. nov., however, can be distinguished from the other two by its prong-shaped G 1 terminal segment (vs folded terminal segment in M. ehuangzhang, Huang et al. 2018: fig. 3 C, and goose-head-shaped terminal segment in M. shenzhen, Huang and Mao 2021: fig. 3 C – E). Otherwise, it can further be separated from the two aforementioned congeners in having a slightly narrower male abdominal somite 6, with the width ~ 2.4 × length (vs 2.6 × in both M. ehuangzhang and M. shenzhen, Huang et al. 2018; Huang and Mao 2021). More detailed comparisons can be found in Table 1. Interspecific variation of the G 1 is minimal, with the terminal segment slightly varying in size and the outer projection of the terminal segment slightly varying in sharpness and angle (Fig. 10 C – E).</p></div>	https://treatment.plazi.org/id/9E1C850AB36F51BD922339DC594E89F8	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	Huang, Chao;Shih, Hsi-Te;Ahyong, Shane T.	Huang, Chao, Shih, Hsi-Te, Ahyong, Shane T. (2025): Four new freshwater crab species of the genus Megapleonum Huang, Shih & Ahyong, 2018 (Crustacea, Decapoda, Potamidae) from Guangdong, China. ZooKeys 1244: 1-27, DOI: 10.3897/zookeys.1244.148112
