Ghatiana rouxi, 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 : 632

Ghatiana rouxi n. sp.

( Figs 3C ; 4 A-D; 5 A-H)

urn:lsid:zoobank.org:act:802C4E90-F54C-4060-A72D-23C1C42474C7

TYPE MATERIAL. — Holotype. India • ♂ (CW 13.38 mm, CL 10.95 mm, CH 7.28 mm, FW 6.13 mm); Karnataka: Uttara Kannada district: Shirley Waterfall ; 14°52’55”N, 74°39’46”E; alt. 168 m; 6.X.2016; Tejas Thackeray and Swapnil Pawar leg.; ZSI-WRC C.2002 . Paratypes. India • 2 ♂ ( CW 12.39-12.41 mm, CL 9.77-9.83 mm, CH 6.60-6.76 mm, FW 5.50-5.55 mm), ♀ ( CW 14.11 mm, CL 11.19 mm, CH 7.32 mm, FW 6.18 mm); same data as for holotype; ZSI-WRC C.2003 • 2 ♀ ( CW 12.87-13.16 mm, CL 10.44- 10.56 mm, CH 7.42-7.56 mm, FW 5.81-6.03 mm); Karnataka: Uttara Kannada district: Mavinagundi , near Jog Falls ; 14°15’18”N, 74°48’21”E; alt. 601 m; 7.X.2016; Tejas Thackeray and Swapnil Pawar leg.; ZSI-WRC C.2004 • ♂ ( CW 12.99 mm, CL 10.37 mm, CH 6.93 mm, FW 5.70 mm), ♀ ( CW 14.81 mm, CL 12.14 mm, CH 8.29 mm, FW 6.75 mm); Goa: North Goa district: Chorla ; 15°38’5”N, 74°7’12”E; alt. 423 m; 18.IX.2016; Tejas Thackeray and Swapnil Pawar leg.; ZSI-WRC C.2005 .

OTHER MATERIAL. — India • 4 ♂ ( CW 8.20-12.50 mm, CL 6.53- 9.62 mm, CH 4.06-6.45 mm, FW 3.81-5.50 mm), 6 ♀ ( CW 10.63-14.10 mm, CL 8.20-11.16 mm, CH 5.60-7.39 mm, FW 4.69-6.15 mm); Karnataka: Uttara Kannada district: Mavinagundi, near Jog Falls ; 14°15’18”N, 74°48’21”E; alt. 601 m; 7.X.2016; Tejas Thackeray and Swapnil Pawar leg.; ZSI-WRC C.2006 .

TYPE LOCALITY. — India: Karnataka: Uttara Kannada district: Shirley Waterfall; 14°52’55”N, 74°39’46”E; alt. 168 m.

DIAGNOSIS. — Carapace in adult proportionately narrow (CW/ CL = 1.2-1.3), moderately to strongly arched ( CH /CL = 0.6- 0.7); lateral margins gently convex; anterolateral margins relatively short, cristate; epibranchial tooth visible as distinct notch; branchial regions rugose; frontal margin very close to anterior margin of epistome, hiding antennular fossae ( Fig. 4 A-C). First, second maxillipeds with long flagellum on exopod; third maxilliped lacking flagellum on exopod ( Fig. 5A ). Major chela with pointed fingertips; palm in adult male relatively stout; ventral margin of fixed finger and distal half of palm in adult male strongly concave ( Figs 4A, D ; 5B ). Ambulatory legs relatively short (P3 length/CL = c. 2.0) ( Fig. 1A ). Male pleonal somite 6 subquadrate, slightly longer than broad ( Figs 4D ; 5C ). Male telson elongated ( Figs 4D ; 5C ). G1 relatively stout, medially gently curved outwards; terminal segment relatively slender, distally gently curved inwards, relatively long, c. 0.5 times length of subterminal segment; subterminal segment relatively stout ( Fig. 5D, E ). G2 very short, with very short distal segment ( Fig. 5F ). Female pleon in adult broadly subtriangular ( Fig. 5G ). Vulvae in adult relatively closely positioned (VD/SW = c. 0.2), each subovate in shape, relatively large, occupying c. 0.4 times length of S6, positioned some distance from S5/S6 ( Fig. 5H ).

ETYMOLOGY. — The species is named after the Swiss zoologist, Dr Jean Roux for his contributions on the study of crabs of the Western Ghats. The species name is conceived as a noun in the genitive singular.

COLOUR IN LIFE. — Carapace, chelipeds, and ambulatory legs all are deep purple dorsally ( Fig. 3C ). The carapace and pereiopods are relatively paler on the ventral surface.

ECOLOGICAL NOTES. — Ghatiana rouxi n. sp. was found under small boulders adjacent to waterfalls and along stream banks. They can be also seen underneath small boulders of forest trails clearly away from water bodies. On the basis of the collected material, the species occurs at both low and high elevations (168-601 m altitude).

GEOGRAPHICAL DISTRIBUTION. — Ghatiana rouxi n. sp. is currently known only from the Western Ghats of the Goa and Karnataka states, India.

REMARKS

Ghatiana rouxi n. sp. is a relatively smaller species (the largest known adult female with a fully developed pleon measures 14.81 mm in CW), which has a proportionately narrower adult carapace (CW/CL = 1.2-1.3) with the lateral margins gently convex ( Fig. 4A, B ). The gently convex lateral margins of the carapace is characteristic to G. rouxi n. sp. ( Fig. 4A, B ); the remaining species of the genus have a carapace with the lateral margins strongly convex ( Fig. 1A, B ; Pati & Sharma 2014: fig. 4A; Pati & Thackeray 2018: figs 3A; 4A; 5A; 6A; 7A; 8A; 9A; 10A).

Ghatiana rouxi n. sp. has an elongated male pleonal somite 6 ( Figs 4D ; 5C ), which is also characteristic to G. botti Pati & Thackeray, 2018 , G. rathbunae Pati & Thackeray, 2018 , and G. splendida Pati, Thackeray & Khaire, 2016 (see Pati et al. 2016: fig. 5C, G; Pati & Thackeray 2018: figs 6C, G; 9C, G; 10C). Ghatiana rouxi n. sp. is immediately distinguished from G. botti , G. rathbunae , and G. splendida by the basally broad subterminal segment of the G1 ( Fig. 5D, E ) (vs G1 subterminal segment basally narrow; see Pati et al. 2016: fig. 6A, B; Pati & Thackeray 2018: figs 6I, K; 9I, K; 10D, E) in addition to the gently convex lateral margins of its carapace ( Fig. 4A, B ) (vs carapace with strongly convex lateral margins; see Pati et al. 2016: fig. 5A; Pati & Thackeray 2018: figs 6A; 9A; 10A).

The stout, basally broad G1 subterminal segment of G. rouxi n. sp. is a character shared only with G. aurantiaca Pati & Sharma, 2014 ( Fig. 5D, E ; see Pati & Thackeray 2018: fig. 4D, E). In addition, their G1s are relatively slenderer, distally gently curved inwards, with the terminal segment relatively longer, c. 0.5 times the length of the subterminal segment ( Fig. 5D, E ; see Pati & Thackeray 2018: fig. 4D, E). The G1 is nevertheless gently curved outwards medially in G. rouxi n. sp. ( Fig. 5D, E ) as compared to the straight G1 of G. aurantiaca (see Pati & Thackeray 2018: fig. 4D, E). Moreover, the structure of the adult vulvae and most of the features of the carapace are similar in both. The antennular fossae, however, are being hidden by the closely located frontal margin and the anterior margin of the epistome in G. rouxi n. sp. ( Fig. 4C ) (vs exposed fossae due to the gap between the frontal margin and the anterior margin of the epistome in G. aurantiaca ; see Pati & Sharma 2014: fig. 2B; Pati & Thackeray 2018: fig. 4B). Again, their male pleonal somite 6 is different, being subquadrate, slightly longer than broad in G. rouxi n. sp. ( Figs 4D ; 5C ) and quadrate, as long as broad in G. aurantiaca (see Pati & Sharma 2014: figs 2C; 3B; Pati & Thackeray 2018: fig. 4C).

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. 4. — Ghatiana rouxi n. sp., holotype ♂ (13.38 × 10.95 mm), ZSI-WRC C.2002: A, overall dorsal view; B, dorsal view of cephalothorax; C, frontal view of cephalothorax; D, overall ventral view. Scale bars: A, B, D, 10 mm; C, 5 mm.

FIG. 5. — Ghatiana rouxi n. sp., holotype ♂ (13.38 × 10.95 mm), ZSI-WRC C.2002 (A-F); paratype ♀ (14.11 × 11.19 mm), ZSI-WRC C.2003 (G, H): A, left third maxilliped; B, major or right chela (outer view); C, S1-S7, pleonal somites 4-6, and telson; D, right G1 (dorsal view); E, right G1 (ventral view); F, right G2; G, pleonal somites 4-6 and telson; H, S1-S8 showing vulvae. Scale bars: A-C, G, H, 2 mm; D-F, 1 mm.

FIG. 1. — Ghatiana durrelli n. sp., holotype ♂ (19.53 × 13.19 mm), ZSI-WRC C.1999: 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.