Ghatiana, Pati & Sharma, 2014

Pati, S. K. & Sharma, R. M., 2014, Description of Ghatiana, a new genus of freshwater crab, with two new species and a new species of Gubernatoriana (Crustacea: Decapoda: Brachyura: Gecarcinucidae) from the Western Ghat Mountains, India, Journal of Natural History 48 (21), pp. 1279-1298 : 1281-1286

Ghatiana gen. nov.

Type species

Ghatiana aurantiaca sp. nov, by present designation.

Diagnosis

Carapace slightly broader than long (cl/cw 0.71–0.78) (cw 1.3–1.4 times cl), highly arched (ch/cw 0.45–0.52), narrow posteriorly, ch more than 0.6 times cl; anterolateral margin short, slightly curved; front vertically deflexed, depressed, broad, nearly 0.4 times cw; epigastric crests distinct, low, broad, blunt; postorbital crests indistinct; external orbital angle poorly developed; epibranchial tooth indistinct, very close to level of supraorbital margin; cervical grooves poorly developed, interrupted; mesogastric groove long, deep, wide, extending into frontal region, bifurcate posteriorly; frontal median triangle incomplete with only dorsal margin; lacking epistomal median tooth ( Figures 2A,B , 4A,B ). Chelipeds unequal, carpal spine distinct, blunt, outer surface of merus rugose. Ambulatory legs with tuft of fine bristles. Suture between thoracic sternites s2/s3 indistinct and between s3/s4 incomplete visible as short grooves on sides only; s1, s2 with setae ( Figures 2C , 3A , 4C , 5A ). Male abdomen elongated, T-shaped; fifth abdominal somite broader than long; sixth abdominal somite longer than broad, but shorter than telson; telson long ( Figures 3B , 5B ); male sternoabdominal cavity deep, very long, extending beyond level of bases of third maxillipeds ( Figures 2C , 4C ). Exopods of first, second maxillipeds each with long flagellum; exopod of third maxilliped lacking flagellum, exopod longer than ischium ( Figures 3D , 5D ). G1 short with long terminal article (0.45–0.55 times length of subterminal segment); subterminal segment much broader than the terminal article ( Figures 3E,F , 5E,F ). G2 short with very short terminal article ( Figures 3H , 5H ).

Etymology

The genus name is derived from the word ‘Ghat’ because all the species in this genus are endemic to the Western Ghats. Gender feminine.

Remarks

Ghatiana , new genus, can be distinguished from other Indian gecarcinucid genera by the absence of a flagellum on the exopod of the third maxilliped ( Figures 3D , 5D ) (except Pilarta , Snaha , Globitelphusa, Inglethelphusa and Gubernatoriana , which possess a flagellum on this maxilliped).

The new genus is distinguished from Pilarta and Snaha by the G2 terminal article, which is very short ( Figures 3H , 5H ) (whereas Pilarta and Snaha have a flagellum-like G2 distal article) ( Bahir and Yeo 2007: figs. 25H, 27G, 29E).

Ghatiana can be distinguished from Globitelphusa by the distal part of the subterminal segment of the G1: this is narrow, with an inner margin that gradually tapers without angulation in Ghatiana ( Figures 3E,G , 5E,G ) but broad with an inner margin that tapers sharply at an angle in Globitelphusa ( Bott 1970: pl. 33, fig. 15). In addition, Globitelphusa is restricted to northeast India whereas Ghatiana is only found in the Western Ghats.

The new genus has some affinities with the monotypic genus Inglethelphusa in carapace morphology: both genera have a slightly curved anterolateral margin; very low, broad and blunt epigastric crests; a long mesogastric groove bifurcating posteriorly and extending into the frontal region; both lack an epistomal median tooth; both have an elongated and T-shaped male abdomen; both have a long sixth male abdominal somite and long telson; both have a very long male sternoabdominal cavity extending beyond the level of the third maxilliped base, and a short G2 with a short terminal article. However, Ghatiana can easily be distinguished from Inglethelphusa by its broad carapace (cw/cl 1.3–1.4 vs 1.1), narrow frontal margin (fw/cw 0.38–0.41 vs 0.46), long third maxilliped exopod that is longer than the ischium (vs a short third maxilliped exopod), and a short, slightly curved and stout G1 with a short terminal article ( Figures 2A,B , 3D–F , 4A,B , 5D–F ) (vs a long, almost straight, narrow G1 with a very long terminal article) ( Bott 1970: pl. 34, figs. 25–28).

The G1s of Ghatiana and Gubernatoriana appear superficially similar but the terminal article of the former is longer than that of the latter ( Figures 3E , 5E , 7E ; Bott 1970: pl. 27, fig. 27; pl. 34, fig. 36). Further, Ghatiana can be differentiated from Gubernatoriana by its broad and highly arched carapace (vs squarish and comparatively less arched carapace), elongated T-shaped male abdomen with sixth male abdominal somite longer than broad and a long telson (vs short T-shaped male abdomen with sixth male abdominal somite slightly broader than long and a short telson) ( Figures 2A,C , 3B , 4A,C , 5B , 6 A,C , 7 B ; Bott 1970: pl. 6, figs. 61, 62; pl. 34, figs. 33, 34).

Ecological notes

Specimens were found in burrows dug into the banks of small streams, or under small stones, or inside cavities of laterite boulders on land or in holes in tree trunks. These crabs were especially active during the night in the rainy season where they were found either walking on the ground or on laterite boulders or climbing up tree trunks (Pati and Sharma, unpublished data).

Distribution

Northern Western Ghat Mountains , India. The type species was found in laterite regions of Konkan (244 m above sea level) whereas the other species was recorded from elevated Ghat areas (883 m above sea level).

Two species are included in Ghatiana gen. nov.: Ghatiana aurantiaca sp. nov. (type species) and Ghatiana hyacintha sp. nov.

Figures

Figure 2. Ghatiana aurantiaca sp. nov., holotype male (ZSI, WRC-C.1129). (A) Dorsal view; (B) frontal view; (C) ventral view. Scale bars: 10 mm.

Figure 3. Ghatiana aurantiaca sp. nov., holotype male (ZSI, WRC-C.1129). (A) Anterior thoracic sternites; (B) abdomen; (C) right cheliped; (D) left third maxilliped; (E) dorsal view of right G1; (F) ventral view of right G1; (G) dorsal view of terminal article of right G1; (H) right G2. Scale bars: 5 mm (A, B); 10 mm (C); 2.5 mm (D) and 1 mm (E–H).

Figure 4. Ghatiana hyacintha sp. nov., holotype male (ZSI, WRC-C.1130). (A) Dorsal view; (B) frontal view; (C) ventral view. Scale bars: 10 mm.

Figure 5. Ghatiana hyacintha sp. nov., holotype male (ZSI, WRC-C.1130). (A) Anterior thoracic sternites; (B) abdomen; (C) right cheliped; (D) left third maxilliped; (E) dorsal view of right G1; (F) ventral view of right G1; (G) dorsal view of terminal article of right G1; (H) right G2. Scale bars: 5 mm (A, B); 10 mm (C); 2.5 mm (D) and 1 mm (E–H).

Figure 6. Gubernatoriana triangulus sp. nov., holotype male (ZSI, WRC-C.1134). (A) Dorsal view; (B) frontal view; (C) ventral view. Scale bars: 10 mm.

Figure 7. Gubernatoriana triangulus sp. nov., holotype male (ZSI, WRC-C.1134). (A) Anterior thoracic sternites; (B) abdomen; (C) left cheliped; (D) left third maxilliped; (E) dorsal view of right G1; (F) ventral view of right G1; (G) dorsal view of terminal article of right G1; (H) right G2. Scale bars: 5 mm (A, B); 10 mm (C); 2.5 mm (D) and 1 mm (E–H).