Alcolyra alcocki ( Kemp, 1915 ) Trivedi & Mitra & Ng, 2022

Trivedi, Jigneshkumar N., Mitra, Santanu & Ng, Peter K. L., 2022, Alcolyra, a new genus of leucosiid crab (Crustacea: Decapoda: Brachyura) from India, Zootaxa 5091 (2), pp. 383-392 : 390-392

publication ID	https://doi.org/ 10.11646/zootaxa.5091.2.9
publication LSID	lsid:zoobank.org:pub:FB74A1EA-B149-48C9-92B7-BD4E519002C0
DOI	https://doi.org/10.5281/zenodo.5847313
persistent identifier	https://treatment.plazi.org/id/0B2C4772-FFA8-FFC5-30A4-FB5EFE5AFEA3
treatment provided by	Plazi
scientific name	Alcolyra alcocki ( Kemp, 1915 )
status	comb. nov.

Treatment

Alcolyra alcocki ( Kemp, 1915) View in CoL n. comb.

( Figs. 1–5 View FIGURE 1 View FIGURE 2 View FIGURE 3 View FIGURE 4 View FIGURE 5 )

Philyra alcocki Kemp 1915: 212 View in CoL , pl. 12 fig. 2, text figure 2, 3; Takeda & Nakasone 1991:23 (in discussion); Deb 1995: 349; Mohapatra et al. 2007: 247 (in list); Dev Roy & Nandi 2008: 498 (in list); Ng et al. 2008: 93 (in list); Sahoo et al. 2008: 178 (in list); Galil 2009: 281 (in list); Mahapatro et al. 2015: 9 (in list); Dev Roy 2017: 209 (in list): Dev Roy & Rath 2017: 93 (in list); Trivedi et al. 2018: 49 (in list): Ng 2021: 370 (in discussion)

Material examined. Types: Lectotype (herein selected), male (CL 12.5 mm; CW 11.9 mm) ( ZSI. C8944 /10), sandy or muddy bottom, 1.5 to 3 m, Chilika Lake , Odisha state, India, coll. S. Kemp. Paralectotype, female (CL 13.3 mm; CW 11.6 mm)( ZSI. C8944 /10), same data as lectotype .

Others: 2 males (CL 12.7 mm; 12.1 CW mm; 12.4 CL mm;11.7 CW mm) ( ZSI. C7734 /2), sandy bottom, 1.5 to 2 m, Kapuda Ghat, Chilika Lake , Odisha state, India, 4 February, 2016, coll. S. Mitra ; 1 male (CL 12.0 mm; CW 11.0 mm), 1 female (CL 15.3 mm; CW 13.7 mm) ( LFSC. ZRC- 69), muddy bottom, 1.5 to 2 m, Chilika Lake , Odisha state, India, 1 March, 2020, coll. K. Patel.

Description. Males: Carapace suborbicular, slightly longer than broad. Dorsal surface convex,covered with punctae, regions relatively distinct; cardiac, branchial, intestinal regions elevated, median ridge relatively faint, extending from frontal region and merging with elevated intestinal region; protogastric region depressed, less punctate ( Figs. 1A, B View FIGURE 1 , 2A, B View FIGURE 2 ); cardio-gastric region separated from branchial region on both sides by shallow depression; intestinal and cardiac regions with patch of tubercles, more strongly developed in males ( Figs.1A, B View FIGURE 1 , 2A, B View FIGURE 2 ); branchial region with 2 tuberculated ridges originating from posterolateral margin, longitudinal anteriorly, oblique posteriorly, posterior branchial ridge merging anterior branchial ridge longitudinally ( Figs.1A, B View FIGURE 1 , 2A, B View FIGURE 2 ); hepatic region excavated, forming broad shallow depression margins not merging anteriorly, extended till outer limit of orbit, posteriorly joins anterolateral margin at well-marked obtuse angle, floor of depression smooth with scattered punctae, lower margins of the depression finely beaded, strongly convex inferiorly ( Figs.1A, B View FIGURE 1 , 2A, B View FIGURE 2 ). Anterolateral, posterolateral, posterior margins beaded; epibranchial angle obtuse; posterolateral margin sinuous, convex ( Figs.1A, B View FIGURE 1 , 2A, B View FIGURE 2 ). Front anterior margin almost straight with single median tooth projecting beyond visible margin of epistome, small notch on margin of epistome beneath eye ( Figs.1A, B View FIGURE 1 , 2A, B View FIGURE 2 ). Posterior margin concave in male, broadly triangular blunt teeth on lateral sides ( Figs.1A, B View FIGURE 1 , 2A, B View FIGURE 2 ).

Third maxilliped surface with numerous punctae; merus 0.9 times as long as ischium along inner margin; ischium 1.8 times longer than wide ( Figs. 1C View FIGURE 1 , 2C View FIGURE 2 , 5B View FIGURE 5 ); propodus and dactylus not visible in external view when reposed, articulating on inner surface of merus, dactylus apex with long setae ( Figs. 1C View FIGURE 1 , 2C View FIGURE 2 , 5B View FIGURE 5 ). Exopod outer margin convex, much longer than wide, almost twice length of merus, outer and inner margins of ischium, merus and exopod with fringe of setae ( Figs. 1C View FIGURE 1 , 2C View FIGURE 2 , 5B View FIGURE 5 ).

Chelipeds equal, about 1.5 times length of carapace length, surface minutely granulated ( Figs. 1A View FIGURE 1 , 2A View FIGURE 2 ). Merus cylindrical, symmetrical along length, surfaces minutely granulate. Carpus smooth, unarmed. Chela stout, surfaces smooth ( Figs. 1A View FIGURE 1 , 2A View FIGURE 2 ); palm longer than broad, dorsoventrally compressed; fingers almost as long as palm, terminating in sharp tooth, outer margins with scattered setae, dactylus inner surface with single longitudinal groove, pollex with 2 longitudinal ridges on inner surface, cutting edges of fingers with blunt denticles with scattered setae ( Figs. 1A View FIGURE 1 , 2A View FIGURE 2 ).

P2–P5 subcylindrical ( Figs. 1A View FIGURE 1 , 2A View FIGURE 2 ); total lengths decreasing from first to last pair, merus and carpus glabrous, unarmed; merus longest as compared to carpus, propodus and dactylus, upper and lower margins of propodus and dactylus covered with setae ( Figs. 1A, F View FIGURE 1 2A, F View FIGURE 2 ).

Thoracic sternum transversely broad, surface punctate; sternites 1–3 completely fused without trace of sutures ( Figs. 1E View FIGURE 1 , 2E View FIGURE 2 , 4A, C View FIGURE 4 ); sternite 3 separated from sternite 4 by shallow groove; sternites 4–7 progressively narrow; outer lateral margin of sternite 4 swollen forming longitudinal ridge on either side in adults, sternite 5 with large tubercle near inner lateral margin on either side opposite to base of first ambulatory leg; sternite 8 visible when pleon closed, between margins of pleonal somites 2 and 3; penis arising under constriction between sternites 7 and 8 ( Figs. 1E View FIGURE 1 , 2E View FIGURE 2 , 4A, C View FIGURE 4 ). Sternopleonal cavity deep; reaching to mid distance between fused thoracic sternites 1–3 ( Figs. 1E View FIGURE 1 , 2E View FIGURE 2 , 4A, C View FIGURE 4 ).

Pleon narrow, long ( Figs. 4A, C View FIGURE 4 , 5A View FIGURE 5 ); somite 1 longitudinally narrow, wide ( Figs. 4A, C View FIGURE 4 , 5A View FIGURE 5 ); somite 2 yokelike, reaching coxae of fourth ambulatory leg ( Figs. 4A, C View FIGURE 4 , 5A View FIGURE 5 ); somite 3–5 fused, forming elongated trapezoidal plate, shallow suture just visible between somite 3 and 4, surface sparsely punctate ( Figs. 4A, C View FIGURE 4 , 5A View FIGURE 5 ); somite 6 longitudinally rectangular, free, surface unarmed, broad base with rounded posterolateral corners, posterior margin slightly concave medially ( Figs. 4A, C View FIGURE 4 , 5A View FIGURE 5 ); telson nearly twice longer than broad, triangular, with curved apex ( Figs. 4A, C View FIGURE 4 , 5A View FIGURE 5 ).

G1 long, slender, tip with short setae, apical process spatuliform ( Figs. 5C–F View FIGURE 5 ). G2 short, slender ( Fig. 5G View FIGURE 5 )

Females: The female carapace is similar to that of males in appearance except for the straight posterior margin ( Figs. 3A, D View FIGURE 3 ) and the adult chelipeds are proportionately shorter ( Figs. 3A, D View FIGURE 3 ).The pleon is longitudinally ovate, with somites 1 and 2 free and somites 3–6 completely fused to form a domed plate that completely covers the thoracic sternum ( Fig. 3B, E View FIGURE 3 ). The telson is triangular and mobile ( Fig. 3B, E View FIGURE 3 ). The vulvae are large, obliquely ovate and positioned on the anterior part of sternite 6, without any sign of a sternal vulvar cover ( Fig. 3C, F View FIGURE 3 ).

Colour. The coloration of fresh specimen slightly varies from that given by Kemp (1915). The carapace is pale brown (pale French grey according to Kemp 1915) with irregular patches of purple red. The chelipeds are dark purple with fingers pale brown; the ambulatory legs are pale brown in colour, and the ventral surface of the cephalothorax is whitish.

Distribution. So far, the species is only known from its type locality Chilika Lake located in Odisha state of India ( Kemp 1915; Deb 1995; Mohapatra et al. 2007; Dev Roy and Nandi 2008; Sahoo et al. 2008; Mahapatro et al. 2015; Dev Roy 2017; Dev Roy and Rath 2017; Trivedi et al. 2018).

Ecology. The type and fresh specimens were collected from the depth ranging from 5 to 10 feet with muddy or sandy bottom in Chilika Lake located in Odisha state of India .

Remarks. Kemp (1915: 215) noted that he had a total of 16 specimens collected from various parts of Odisha state in India: Rambha to Barkul and Nalbano at Chilika Lake, and that “the type specimens are registered under no. 8944/10” ( Kemp 1915: 216). No holotype was identified. In the ZSI, there are two specimens catalogued under this number, a male and a female, and as such, both are here regarded as syntypes. The whereabouts of the other 14 specimens is not known, but they should not be regarded as syntypes as they were not identified as such in the original paper. For taxonomic stability, the male syntype is here designated the lectotype of P. alcocki Kemp, 1915 .

The fresh specimens obtained in the present study agree well with the description and figures of Kemp (1915). They differ only slightly from the types in terms of having faint two tuberculated ridges present on the branchial region which are more prominent in types. With regards to the male pleon, Kemp (1915: 214) commented that “The first segment is acutely produced on either side and, though it appears distinct, is in reality fused to the succeeding piece.” We have examined the lectotype male and we confirm that the two somites are actually mobile and not fused, as in the fresh material.