Sarmatium crassum Dana, 1851

Sarmatium crassum Dana, 1851 View in CoL

( Fig. 1 View Figure 1 )

Sarmatium crassum Dana, 1851: 251 View in CoL ; H. Milne Edwards, 1853: 189; De Man, 1887: 660; Barnard, 1955: 28, fig. 9; Crosnier, 1965: 74, figs. 121–124, pl. 5, fig. 1; Serène and Soh, 1970: 397, 405 (list); Fishelson, 1971: 128, 130 (list); Davie, 1992: 81, figs. 1A, 2A–C; Ng et al., 2008: 223 (list).

Sarmatium crassum View in CoL [doubtful identification, not confirmed]: Nobili, 1899: 505 (list); Alcock, 1900: 426; Tesch, 1917: 215; Dev Roy and Nandi, 2012: 216 (list); Trivedi et al., 2018: 73 (list).

not Sarmatium crassum View in CoL : Serène and Soh, 1970: pl.

4C, D; 1971; 237, fig. 2, pl. 2 [= S. striaticarpus ]

Material Examined. One male, CL 9.6 mm; CW: 10.6 mm, LFSc. ZRC –155, India, Goa State , Chapora estuary (15º37.953’N 73º45.765’E), mangrove habitat, 12 July 2016, coll. M. Bhat. GoogleMaps

Diagnosis (modified from Davie, 1992). Carapace ( Fig. 1a View Figure 1 ) slightly broader than long, glabrous, deeply vaulted, punctate with setae arranged sparsely on branchial lines. Regions moderately defined with mesogastric distinct. Anterolateral margins regularly convex with 2 blunt teeth behind exorbital angle. Front bilobed.Branchial ridges prominent forming series of short broken granular striations. Inner orbital tooth well developed; ocular peduncle swollen basally, cornea constricted and reduced. Chelipeds ( Fig. 1a View Figure 1 ) subequal, large, robust. Merus posterior border with minutely granular striations; distinct subdistal spine; carpus with small spine at inner angle. Palm upper surface with series of transverse grooves separating swollen ridges ( Fig. 1d View Figure 1 ), distal margin of ridges granular with row of 8 pectinated comb-like teeth. Dactylus ( Fig. 1c View Figure 1 ) dorsal surface of males bearing 4 large, broad, chitinous tubercles proximally; first proximal tooth placed distally from articulation. Male pleon relatively narrow, third somite widest, telson subequal to the sixth somite in length, longer than wide. G1 ( Fig. 1e View Figure 1 ) moderately stout; slightly curved, dorsal surface of shaft flattened with poorly developed protuberance on the distal end; apical process ( Fig. 1f View Figure 1 ) corneous; strongly produced; straight.

Remarks. The specimen examined in the present study agrees with the description given by Dana(1851) and Davie (1992) viz., the cheliped carpus upper surface having a large patch of tiny,flattened,squamous granules situated distally behind articulation with the palm ( Fig. 1d View Figure 1 ); Palm upper surface with subparallel ridges and grooves. Cheliped dactylus with first proximal tooth placed distally from articulation.

Sarmatium crassum View in CoL resembles S. striaticarpus View in CoL in having the carapace broader than long (1.1 times), deeply vaulted; surface smooth, shiny, punctuate, chelipeds subequal, large and robust, ambulatory legs of medium size and compressed, G1 stout and slightly curved, dorsal surface of shaft f lattened and completely calcified. However, S. crassum View in CoL can be differentiated from S. striaticarpus View in CoL based on the following characters: all the ridges on the upper surface of the palm subparallel ( Fig. 1d View Figure 1 ) (versus the proximal-most corrugated ridge is separated from the next broad groove by a triangular space in S. striaticarpus View in CoL , cf. Davie, 1992: fig. 4C), the first proximal tooth on the dactyl of the cheliped placed somewhat distally from the articulation ( Fig. 1c View Figure 1 ) (versus the first proximal tooth on the dactyl of the cheliped placed almost on the very edge of the proximal end in S. striaticarpus View in CoL , cf. Davie, 1992: fig. 4B) and G1 with poorly developed protuberance located at the distal end of the shaft ( Fig. 1e, f View Figure 1 ) (versus G1 with well developed protuberance in S. striaticarpus View in CoL , cf. Davie, 1992: fig. 3E).

Sarmatium crassum View in CoL has thus far been reported from the type locality, Samoa ( Dana, 1851; 1852); South Africa ( Barnard, 1955); Madagascar ( Crosnier, 1965); Tanzania ( Hartnoll, 1975); Eritrean coast of the Red Sea ( Fishelson, 1971; Holthuis, 1977); India (present study); Philippines ( Davie, 1992); Australia ( McNeill, 1968; Davie, 1992); New Caledonia ( Serène, 1973), and Tahiti ( Davie, 1992). The records of S. crassum View in CoL by Nobili (1899) and Tesch (1917) are questionable due to the following reasons: Nobili(1899) did not provide the diagnostic characters of the specimen which was collected from Sumatra and hence it could be attributable to S. striaticarpus View in CoL . Tesch (1917) reported the species from the ‘Pacific’ only on the basis of a single female specimen lacking diagnostic characters and hence the record becomes questionable ( Davie, 1992). In India, this species was recorded from the Nicobar Islands by Alcock (1900) on the basis of a single female specimen (CL 8 mm, CW 9 mm) (the specimen is not traceable in the Zoological Survey of India, Kolkata where it was deposited). This record made by Alcock (1900) also appeared in the brachyuran crab list of the Andaman and Nicobar Islands and India prepared by Dev Roy and Nandi (2012) and Trivedi et al. (2018), respectively.But according to Davie (1992), the record of S. crassum View in CoL from Nicobar Islands is doubtful because the main diagnostic character of the species, such as the presence of distinct ridges and grooves on the upper surface of the palm of chelipeds, are only present in males and not in females and therefore cannot consider it as a confirmed record. In the present study, one male specimen was collected and examined, and the distinct taxonomic characters are illustrated and described to elucidate the first confirmed report of S. crassum View in CoL from India.