Nanosesarma batavicum ( Moreira, 1903 )

Trivedi, Vinay P. Padate Krupal J Patel Chandrashekher U. Rivonker Jigneshkumar N., 2022, On Indian species of Nanosesarma Tweedie, 1950 (Decapoda: Brachyura: Sesarmidae), Nauplius (e 2022031) 30, pp. 1-18 : 5-7

Nanosesarma batavicum ( Moreira, 1903)

( Figs. 1B , 3 , 7C, D )

Sesarma barbimana — De Man,1890:104,pl. 6, fig.13. Sesarma batavica Moreira, 1903: 117 (nom. nov.). —

Tweedie, 1940: 90, fig. 1.

Sesarma batavicum — Kemp, 1915: 238, pl. 12, fig. 7.

Sesarma (Parasesarma) batavica — Tweedie, 1936: 62.

Nanosesarma batavica — Tweedie, 1950: 311.

Nanosesarma (Beanium) batavicum — Serène and

Soh, 1970: 394.

Material examined. 1 male (CL: 4.8 mm, CW: 6.6 mm), GUMSIS1, India, Goa , Verem (15°29’74”N 73°48’20”E), coll. Mithila Bhat, 9 April 2014 .

Description. Carapace quadrangular, 1.35 times wider than long, with slightly concave, converging lateral margins; dorsal surface covered with scattered pits, prominent setal tufts on postfrontal lobes, protogastric and anterior branchial regions, and sparsely placed setae on posterior half of carapace. External orbital tooth triangular. Several oblique, low, setose granulated striations extending across branchial regions ( Figs. 1B , 3A ). Frontal lobes separated by shallow depression; 4 inconspicuous post-frontal lobes covered with setose patches, separated by longitudinal grooves ( Fig. 3A ).

Third maxillipeds with distinct rhomboidal gap when closed; ischium subrectangular, 1.17 times longer than wide, 1.59 times longer than merus, with oblique setose ridge; merus subovate, 0.89 times longer than wide, with oblique setose ridge. Exopod slender, flattened, with long flagellum ( Fig. 3B ).

Right cheliped massive, longer than carapace; palm massive ( Fig.3C ), surfaces rugose, dorsal surface with 2 oblique pectinate crests and 5 or 6 oblique granular ridges ( Fig. 3D ); outer surface smooth, slightly pitted, thin granular line on lower half commencing on pollex and extending posteriorly to carpal junction; inner surface sparsely granulated. Fingers massive, curved, with rounded spatulate tips, gaping when closed, outer surface with dense setose patch. Male dactylus with row of 12 prominent transverse ridges, proximal granules and scattered setae on dorsal surface; inner surface with proximal granular, setose patch. Cutting edges of dactylus and pollex with 4 subequal blunt teeth each ( Fig. 3C ).

P2–5, compressed, shorter than chelipeds. P2 and P5 short, P3 and P4 subequal. P2 and P3 propodi and carpi densely setose on anterior surface, P4– P5 propodi and carpi without dense setae. P2–P5 propodi posterior margins with one distal spine, ventral surface with inconspicuous oblique groove. P5 dactylus smooth, tip corneous, slightly curved, dorsal margin with six spines, ventral margin with three pairs of spines ( Fig. 3E ).

Male pleon bluntly triangular (AW/CW = 0.38), surface pitted, sutures with sparsely setose patches; lateral margins finely granulated, densely setose; telson 1.04 times as long as wide, 1.88 times as long as pleomere 6 ( Fig. 3F ).

G1 long, straight, distal part corneous, slender, f lattened, slightly bent,lined by thick bristles, groove at base of tip extends along ventral surface to proximal portion of G1 ( Fig. 7C, D ).

Remarks. The specimen examined in the present study agrees with the description by De Man (1890) but differs in having 6 oblique granular ridges on dorsal surface of male cheliped propodus (vs. 7 or 8 in the holotype), and 4 occlusal teeth on pollex (vs. 3 in the holotype). Morphological comparison with other Indian species is provided in Tab. 1.

Geographical distribution. Nanosesarma batavicum was originally described from Batavia, Indonesia and later reported from Java, Malaysia, Singapore, ( Tweedie, 1950) and India ( Trivedi et al., 2018). In India, it is known from Goa (present study), Kerala ( Devi et al., 2015), Tamil Nadu ( Varadharajan and Soundarapandian, 2014), and Odisha ( Dev Roy and Rath, 2017).

Figures

Figure 1. Dorsal habitus of Nanosesarma species. (A) N. andersoni (De Man, 1888), male (LFSC.ZRC-185) CL: 6.2 mm; CW: 8.4 mm; (B) N. batavicum (Moreira, 1903), male (GUMSIS1), CL: 4.8 mm; CW: 6.6 mm; (C) N. minutum (de Man, 1887), male (LFSC.ZRC-186), CL: 4.8 mm; CW:5.9 mm; (D) N. sarii Naderlooand Türkay, 2009, male (LFSC.ZRC-188), CL: 5.6 mm; CW: 6.6 mm; (E) N. jousseaumei (Nobili, 1906), male (LFSC.ZRC-187), CL: 4.8 mm; CW: 5.5 mm.

Figure 3.Nanosesarma batavicum (Moreira,1903).Male,(GUMSIS1) (CL:4.8 mm;CW:6.6 mm), Verem, Goa, India.(A) Carapace; (B) right third maxilliped; (C) palm of left cheliped (outer face); (D) dorsal view of left cheliped palm; (E) left P5 (dorsal view); (F) male pleon.

Figure 7.Nanosesarma G1 ventral view.(A, B) N.andersoni (De Man, 1888), male (CL: 4.8 mm; CW:6.5 mm), (LFSC.ZRC-185); (C, D) N. batavicum (Moreira, 1903), male (CL: 4.8 mm; CW: 6.6 mm) (GUMSIS1); (E, F) N. minutum (De Man, 1887), male (CL: 4.8 mm; CW: 5.9 mm) (LFSC.ZRC-186); (G, H) N. sarii Naderloo and Türkay, 2009, male (CL: 5.6 mm; CW: 6.6 mm) (LFSC.ZRC-188); (I, J) N.jousseaumei (Nobili, 1906), male (CL: 4.8 mm; CW: 5.5 mm) (LFSC.ZRC-187); (A, C, E, G, I) ventral view of left G1; (B, D, F, H, J) ventral view of distal part of left G1 (setae removed). Scale bars = 1 mm.