Nanosesarma minutum ( De Man, 1887 )

Nanosesarma minutum ( De Man, 1887) View in CoL

( Figs. 1C View Figure 1 , 4 View Figure 4 , 7E View Figure 7 , F)

Sesarma minuta De Man, 1887: 650 View in CoL .

Sesarma barbimana View in CoL — Cano, 1889 (nec De Man, 1888): 245.

Sesarma (Sesarma) minutum — Rathbun, 1910: 327.

Sesarma (Sesarma) minuta View in CoL — Tesch, 1917: 174. — Tweedie, 1936: 52. — Chhapgar, 1957: 522, pl. 16, figs. k–m.

Sesarma (Sesarma) gordoni View in CoL — Shen, 1935: 27, figs. 7A–D.

Nanosesarma minuta View in CoL — Tweedie, 1950: 311.

Nanosesarma cf. minutum View in CoL — Crosnier, 1965: 70, textfigs. 89, 109–115, pl. 6, fig. 1.

Nanosesarma minutum View in CoL — Serène and Soh,1970: 393.

Material examined. 10 males (CL: 2.4–4.6 mm, CW: 3.1–5.9 mm), 7 females (CL: 2.6–4.9 mm, CW: 3.3–6.2 mm), LFSC.ZRC-186, India, Goa , Chapora Estuary (15°37’21”N 73°44’45”E), coll. Mithila Bhat, 13 May 2016 GoogleMaps .

Diagnosis. Carapace quadrangular, 1.26 wider than long; lateral margins almost straight, gradually diverging posteriorly; dorsal surface, strongly rugose, slightly convex, covered with scattered pits and sparsely placed setae only on front, protogastric, mesogastric and branchial regions delimited by conspicuous depressions. External orbital tooth truncate and triangular, followed by sharp epibranchial tooth. Several oblique, low, setose granulated striations extending across branchial regions ( Figs. 1C View Figure 1 , 4A View Figure 4 ). Frontal margin bilobed, strongly declivous, thickly setose, at level of eyes, frontal lobes separated by shallow depression; 4 inconspicuous postfrontal lobes covered with setose patches, separated by longitudinal grooves. Ocular peduncle well-developed, slightly setose, cornea terminal ( Fig. 4A View Figure 4 ).

Third maxillipeds with distinct rhomboidal gap when closed; ischium subrectangular,1.38 ± 0.19times longer than wide, 1.18 ± 0.10 times longer than merus, with oblique setose ridge; merus 1.01 ± 0.11 times longer than wide, with oblique setose ridge. Exopod slender, f lattened, with long f lagellum ( Fig. 4B View Figure 4 ).

Male chelipeds subequal, massive, longer than carapace; palm massive,surfaces rugose, dorsal surface without oblique pectinated crest, 3 inconspicuous oblique granulated ridges; outer surface with densely setose patch extending anteriorly to proximal portion of fingers, pitted, prominent granular ridge on lower half commencing on pollex and extending posteriorly up to carpal junction, 4 rows of closely spaced granules above granular ridge; inner surface sparsely granulated. Fingers massive, curved, with rounded spatulate tips, gaping when closed. Cheliped dactylus of male short with proximal setose granular patch on dorsal surface, transverse ridges absent; inner and outer surfaces with proximal setose granular patch. Cutting edge of dactylus with large subdistal tooth, followed by 2 small median and 2 large proximal teeth, that of pollex with large subdistal tooth, followed by 2 small teeth, large median tooth and 3 or 4 small teeth ( Fig. 4C View Figure 4 ).

Pereopods compressed, shorter than chelipeds. P2 and P5 short, P3 and P4 subequal. P4 and P5 meri f lattened, anterior margin terminating in blunt angle followed by subdistal spine; postero-distal margin with minute distal tooth-shaped granules followed by one spinule. P2–P5 propodi and carpi with long bristles on anterior margins. Propodi about twice as long as wide, posterior margins with 2 distal spines and few long bristles. Dactyli smooth, tip corneous, slightly curved, with 4 slender subdistal spines ( Fig. 4D View Figure 4 ).

Male pleon narrow ( PW /CW = 0.40 ± 0.04), bluntly triangular, surface pitted; lateral margins finely granulated, densely setose; telson 1.17 times as long as wide, 2.00 times as long as pleomere 6 ( Fig. 4E View Figure 4 ). Female pleon wide ( AW /CW = 0.72 ± 0.10), rounded, pleomere6withroundeddistalmargin,marginsdensely setose; telson wider than long, almost completely sunken into distal margin of pleomere 6 ( Fig. 4F View Figure 4 ).

G1 long, straight, corneous distal part curved, long scoop-shaped, flanked by stiff bristles, groove at base of tip extends along ventral surface to G1 base ( Fig. 7E, F View Figure 7 ).

Remarks. The morphology of the present specimens agree with that reported by De Man (1887), Rathbun (1910), Tweedie (1950),and Crosnier(1965).However, it differs in having the presence of stiff distal setae on the G1 tip, which was probably omitted in the earlier reports.Morphological comparison with other Indian congeneric species is provided in Tab. 1.

Distribution. Nanosesarma minutum was originally described from Edam Island near Jakarta, Indonesia and later reported from Malaysia, Singapore, Gulf of Thailand, South China Sea ( Tweedie, 1936, 1950), Madagascar ( Crosnier, 1965), Tanzania ( Hartnoll, 1975), and India ( Trivedi et al., 2018). In India, it is known from Gujarat ( Saravanakumar et al., 2007), Maharashtra ( Pati et al., 2012), Goa (present study), and Tamil Nadu ( Kathirvel and Gokul, 2010).