Sahyadriana keshari, Pati & Thackeray, 2021

Pati, Sameer K. & Thackeray, Tejas, 2021, Five new species of freshwater crabs of the genera Ghatiana Pati & Sharma, 2014 and Sahyadriana Pati & Thackeray, 2018 from India (Decapoda: Brachyura: Gecarcinucidae), Zoosystema 43 (26), pp. 627-647 : 639-642

Sahyadriana keshari n. sp.

( Figs 3E ; 8 A-D; 9 A-H)

urn:lsid:zoobank.org:act:548CA624-C80A-48BF-86D0-19F9B835609E

TYPE MATERIAL. — Holotype. India • ♂ (CW 13.96 mm, CL 10.88 mm, CH 6.38 mm, FW 4.98 mm); Maharashtra: Nashik district: Bramhagiri, near Trimbak ; 19°54’46”N, 73°31’4”E; alt. 1048 m; 17.VIII.2017; Tejas Thackeray leg.; ZSI-WRC C.2007 .

Paratypes. India • ♂ ( CW 13.97 mm, CL 11.02 mm, CH 6.24 mm, FW 5.06 mm), ♀ ( CW 15.92 mm, CL 12.16 mm, CH 6.35 mm, FW 5.74 mm); same data as for holotype; ZSI-WRC C.2008 • 5 ♂ ( CW 12.44-14.18 mm, CL 9.55-11.01 mm, CH 5.58-7.16 mm, FW 4.46-4.94 mm), 5 ♀ ( CW 12.11-15.53 mm, CL 9.39-11.73 mm, CH 6.14-7.23 mm, FW 4.44-5.44 mm); same data as for holotype; ZSI-WRC C.2009 .

TYPE LOCALITY. — India: Maharashtra: Nashik district: Bramhagiri, near Trimbak; 19°54’46”N, 73°31’4”E; alt. 1048 m.

DIAGNOSIS. — Carapace in adult slightly broader than long (CW/ CL = 1.3), moderately to strongly deep ( CH /CL = 0.5-0.7); epibranchial tooth visible as relative distinct notch; branchial regions inflated; epistome posterior margin with gently concave lateral lobes ( Fig. 8 A-C). Third maxilliped lacking flagellum on exopod ( Fig. 9A ). Chelipeds with pointed fingertips ( Figs 8A, D ; 9B ). Ambulatory legs with densely setose dactylus and propodus ( Fig. 8A, D ). Male sternopleonal cavity long, extending beyond imaginary line joining bases of third maxillipeds ( Figs 8D ; 9C ). Male pleon relatively broad, T-shaped; pleonal somite 5 with concave lateral margins; pleonal somite 6 subquadrate, broader than long, subequal in length to telson, lateral margins strongly convex ( Figs 8D ; 9C ). Male telson short ( Figs 8D ; 9C ). G1 distinctly stout, almost straight; terminal segment relatively slender, subcylindrical, distally gently curved inwards, relatively short, c. 0.4 times length of subterminal segment; subterminal segment distinctly stout, triangular, distally relatively broad, with convex inner margin ( Fig. 9D, E ). G2 very short, with very short distal segment ( Fig. 9F ). Female pleon in adult broadly subtriangular ( Fig. 9G ). Vulvae in adult positioned apart from each other (VD/SW = c. 0.4), each suborbicular in shape, relatively large, occupying c. 0.5 times length of S6, positioned close to S5/S6 ( Fig. 9H ).

ETYMOLOGY. — The species name, derived from the Marathi language for orange coloured, refers to live colouration of the crab. The name is used as a Latin noun in apposition.

COLOUR IN LIFE. — Carapace, chelipeds, and ambulatory legs all are completely orange in colour ( Fig. 3E ). The orange colour on the ventral side of the carapace, however, is relatively faint.

ECOLOGICAL NOTES. — Sahyadriana keshari n. sp. dwells on the walls of high mountainous cliffs (1048 m above a.s.l.), which host ephemeral waterfalls. Crabs gather in large numbers during the daytime on these exposed walls between the downpour.

GEOGRAPHICAL DISTRIBUTION. — Sahyadriana keshari n. sp. is currently known only from Bramhagiri, an isolated high mountain of the Western Ghats in Nashik district of Maharashtra state, India. The new species is very likely to occur on the adjacent mountainous peak “Anjneri” of the same district because the second author (TT) once saw a dead crab of the species there.

REMARKS

The carapace of S. keshari n. sp. most resembles to that of S. waghi (Pati in Pati, Thackeray & Khaire, 2016) mainly due to the relatively distinct notch between the epibranchial tooth and the external orbital angle ( Fig. 8A, B ; see Pati et al. 2016: fig. 11A; Pati & Thackeray 2018: fig. 29A), the gently concave lateral lobes of the epistome posterior margin ( Fig. 8C ; see Pati et al. 2016: fig. 11B; Pati & Thackeray 2018: fig. 29B), and the pointed fingertips of the chelipeds ( Figs 8A, D ; 9B ; see Pati et al. 2016: fig. 11A, C, D; Pati & Thackeray 2018: fig. 29A, C). In the G1 structure, S. keshari n. sp. is most similar to S. waghi and S. triangulus because all have a distinctly stout G1, with the relatively slenderer, subcylindrical terminal segment ( Fig. 9D, E ; see Pati & Sharma 2014: fig. 7E-G; Pati et al. 2016: fig. 12A-C; Pati & Thackeray 2018: figs 28D, E, H; 29D-G, I-K).

Both S. keshari n. sp. and S. waghi can be differentiated from S. triangulus by the relatively distinct notch between the epibranchial tooth and the external orbital angle ( Fig. 8A, B ; see Pati et al. 2016: fig. 11A; Pati & Thackeray 2018: fig. 29A) (vs indistinct notch between the epibranchial tooth and the external orbital angle in S. triangulus ; see Pati & Sharma 2014: fig. 6A; Pati & Thackeray 2018: fig. 28A), the gently concave lateral lobes of the epistome posterior margin ( Fig. 8C ; see Pati et al. 2016: fig. 11B; Pati & Thackeray 2018: fig. 29B) (vs strongly concave lateral lobes of the epistome posterior margin in S. triangulus ; see Pati & Sharma 2014: fig. 6B; Pati & Thackeray 2018: fig. 28B), the relatively shorter G1 terminal segment, c. 0.4 times the length of the subterminal segment, with the gently inwardly curved distal portion ( Fig. 9D ; see Pati & Thackeray 2018: figs 29I-K) (vs relatively longer G1 terminal segment, c. 0.5 times the length of the subterminal segment, with the distinctly outwardly curved distal portion in S. triangulus ; see Pati & Sharma 2014: fig. 7E-G; Pati & Thackeray 2018: fig. 28D, E, H), and the convex inner margin of the G1 subterminal segment ( Fig. 9D, E ; see Pati et al. 2016: fig. 12A, B; Pati & Thackeray 2018: fig. 29D, F, I-K) (vs almost straight inner margin of the G1 subterminal segment in S. triangulus ; see Pati & Sharma 2014: fig. 7E, F; Pati & Thackeray 2018: fig. 28D, E, H). Sahyadriana keshari n. sp. can be further separated from S. waghi by the relatively stouter G1 terminal segment ( Fig. 9D ) (vs relatively slenderer G1 terminal segment; see Pati et al. 2016: fig. 12A; Pati & Thackeray 2018: fig. 29D, I-K), the relatively broader distal portion of the G1 subterminal segment ( Fig. 9D ) (vs relatively narrower distal portion of the G1 subterminal segment; see Pati et al. 2016: fig. 12A; Pati & Thackeray 2018: fig. 29D, I-K), and the relatively larger adult vulva that occupies c. 0.5 times the length of the S6 and is positioned close to S5/S6 ( Fig. 9H ) (vs relatively smaller adult vulva that occupies c. 0.4 times the length of the S6 and is positioned a clear distance from S5/S6; see Pati & Thackeray 2018: fig. 29M).

Figures

FIG. 3. — Colour in life: A, Ghatiana durrelli n. sp., ♀ from Amba; B, Ghatiana durrelli n. sp., ♂ from type locality; C, Ghatiana rouxi n. sp., ♂ from Chorla; D, Sahyadriana inopinata n. sp., ♂ from type locality; E, Sahyadriana keshari n. sp., ♂ from type locality; F-H, Sahyadriana tamhini n. sp., all ♂ from type locality and its vicinity. The photographed specimens could not be collected.

FIG. 8. — Sahyadriana keshari n. sp., holotype ♂ (13.96 × 10.88 mm), ZSI-WRC C.2007: A, overall dorsal view; B, dorsal view of cephalothorax; C, frontal view of cephalothorax; D, overall ventral view. Scale bars: A, D, 10 mm; B, C, 5 mm.

FIG. 9. — Sahyadriana keshari n. sp., holotype ♂ (13.96 × 10.88 mm), ZSI-WRC C.2007 (A-F); paratype ♀ (15.92 × 12.16 mm), ZSI-WRC C.2008 (G, H): A, left third maxilliped; B, major or right chela (outer view); C, S1-S7, pleonal somites 4-6, and telson; D, left G1 (dorsal view); E, left G1 (ventral view); F, left G2; G, pleonal somites 4-6 and telson; H, S1-S8 showing vulvae. Scale bars: A, 1 mm; B, C, G, H, 2 mm; D-F, 0.5 mm.