Gubernatoriana triangulus, 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 : 1295-1298

Gubernatoriana triangulus sp. nov.

( Figures 6A–C , 7A–H , and 8C )

Type specimens

Holotype: male (cw 12.52 mm, cl 10.60 mm, ch 6.28 mm, fw 5.22 mm), B.S. Lamba (ZSI, WRC-C.1134), Dhobi Waterfall, Mahabaleshwar, Satara district , Maharashtra, India, 17°56 ′ 8.484 ″ N, 73°38 ′ 49.311 ″ E, alt. 1207 m; paratypes: 1 male (cw 9.00 mm, cl 7.40 mm, ch 4.12 mm, fw 3.54 mm), S.K. Pati (ZSI, WRC-C.471), Bhaka Devi and vicinity, Bhimashankar Wildlife Sanctuary, Pune district, Maharashtra, India, 19°5 ′ 27.729 ″ N, 73°32 ′ 7.8246 ″ E, alt. 955 m and 1 female (cw 9.34 mm, cl 7.24 mm, ch 3.92 mm, fw 3.54 mm), S.K. Pati (ZSI, WRC-C.1087), Dongarwadi, Tahmini Ghat, Pune district, Maharashtra, India, 18°29 ′ 4.8948 ″ N, 73°24 ′ 53.8878 ″ E, alt. 593 m.

Diagnosis

Carapace squarish (cl/cw 0.76–0.78), highly arched anteriorly (ch/cl 0.59), less convex posteriorly; dorsal surface almost smooth; anterolateral margin short, smooth, cristiform; posterolateral margin with fine, oblique striations; frontal margin slightly concave medially; epigastric crests faint, flat, broad; postorbital crests indistinct; epibranchial tooth indistinct; branchial regions inflated; subhepatic region smooth; H-groove faint; frontal median triangle incomplete with only dorsal margin; epistomal median lobe broadly triangular, without median tooth ( Figure 6A,B ). Suture between thoracic sternites s2/s3 indistinct, suture between sternites s3/s4 absent except for two short lateral grooves ( Figures 6C , 7A ). Male abdomen short, almost Tshaped; fifth abdominal somite much broader than long; sixth abdominal somite slightly broader than long, equal in length to telson; telson short, broadly triangular ( Figure 7B ); male sternoabdominal cavity deep, long, extending beyond level of third maxilliped bases ( Figure 6C ). Exopods of first, second maxillipeds with long flagellum; exopod of third maxilliped lacking flagellum ( Figure 7D ). G1 short, stout with long terminal article (0.5 times length of subterminal segment); terminal article slimmer than subterminal segment, slightly curved outward, tip pointed; subterminal segment almost triangular, basal half broader than distal half ( Figure 7E–G ). G2 short, terminal article very short ( Figure 7H ).

Description

Carapace squarish, highly arched anteriorly (ch/cl 0.59), less convex posteriorly; dorsal surface almost smooth; anterolateral carapace inflated in frontal view; anterolateral margin short, smooth, cristiform; posterolateral margin with fine, oblique striations; front vertically deflexed, flat, square cut, wide (fw/cw 0.4); frontal margin slightly concave medially; epigastric crests faint, flat, broad; postorbital crests indistinct; external orbital angle poorly developed; epibranchial tooth indistinct; postorbital region flat; branchial regions inflated considerably; subhepatic region smooth; cervical grooves indistinct; mesogastric groove long, slightly extending into frontal region; H-groove faint; frontal median triangle incomplete with only dorsal margin; epistomal median lobe broadly triangular without median tooth ( Figure 6A,B ).

Chelipeds smooth, unequal; few small blunt teeth on anterior margin of major (left) chela; large gape between fingers of larger chela when tips in contact ( Figure 7C ); fingers slightly shorter than palm; teeth on fingers of smaller chela small, blunt; carpal spine poorly developed, blunt; outer surface of merus rugose.

Ambulatory legs (p2–p5) long with bristles on margins of carpus, propodus, and dactylus; dactylus (p4 and p5) equal in length to propodus; longest propodus (p3) almost three times as long as broad.

Suture between thoracic sternites s2/s3 indistinct, suture between sternites s3/s4 absent except for two short deep lateral grooves ( Figures 6C , 7A ).

Male abdomen short, almost T-shaped; fifth abdominal somite broader than long, lateral margins not parallel to each other; sixth abdominal somite broader than long, equal in length to telson, lateral margins convex; telson broadly triangular, length equal to proximal width ( Figure 7B ); male sternoabdominal cavity deep, long, extending beyond level of third maxilliped bases ( Figure 6C ).

Exopods of first, second maxillipeds with long flagellum; exopod of third maxilliped lacking flagellum, longer than ischium; ventral sulcus on ischium indistinct, anterior external angle of merus right angled, depression on merus towards inner sides ( Figure 7D ). Mandibular palp with two joints, terminal joint bilobed.

G1 short, stout with long terminal article (0.5 times length of subterminal segment); terminal article slimmer than subterminal segment, slightly curved outward, tip pointed; subterminal segment almost triangular, basal half distinctly broader than distal half ( Figure 7E–G ). G2 short with very short terminal article; proximal half of basal segment stout, broader than distal half ( Figure 7H ).

Colour

Live crabs have a brown carapace, and yellowish brown chelipeds and ambulatory legs ( Figure 8C ).

Etymology

In Latin triangulus means triangular, referring to the triangular shape of the G1 subterminal segment. Used as noun in apposition.

Remarks

Gubernatoriana triangulus sp. nov. is similar to both G. gubernatoris and G. pilosipes in carapace morphology. Differences between these three taxa include the carapace height, which in G. triangulus is more inflated in the branchial regions than in the other two species, a smooth subhepatic region in G. triangulus (vs a rugose subhepatic region), a male sternoabdominal cavity extending beyond the level of the third maxilliped bases in G. triangulus (vs a male sternoabdominal cavity not extending beyond the level of cheliped bases) ( Figure 6A,C ; Bott 1970: pl. 6, figs. 61, 62; pl. 34, figs. 33, 34). The G1 subterminal segment of G. triangulus is triangular in appearance i.e. basal half distinctly stouter than distal half (vs basal one-third slightly broader than distal two-thirds in G. gubernatoris and basal two-thirds slightly broader than distal one-third in G. pilosipes ) ( Figure 7E,F ; Bott 1970: pl. 27, fig. 27; pl. 34, fig. 36).

Ecological notes

Specimens were found in the Western Ghat Mountains, India, along the small stream banks, in small water bodies, and under small stones. This species is very active especially during the rainy season (from June to September) (Pati and Sharma, unpublished data).

Distribution

Northern Western Ghats (Satara and Pune).

Key to the species of Gubernatoriana

1. Branchial regions inflated (ch/cl 0.59); subhepatic region smooth. Male sternoabdominal cavity long, extending beyond level of third maxilliped bases. G1 subterminal segment stout, triangular ........................................... ................................................................. Gubernatoriana triangulus sp. nov. Branchial regions not inflated (ch/cl 0.48–0.58); subhepatic region rugose. Male sternoabdominal cavity short, extending to level of cheliped bases. G1 subterminal segment slim, not triangular ..................................................... 2

2. Suture between thoracic sternites 2 and 3 indistinct. Tips of fingers of major cheliped pointed. G1 terminal article long (0.45 times length of subterminal segment); basal third of subterminal segment broader than distal two-thirds .................................................. Gubernatoriana gubernatoris ( Alcock, 1909) Suture between thoracic sternites 2 and 3 visible, complete groove. Tips of fingers of major cheliped broadly rounded or spoon shaped. G1 terminal article short (0.35 times length of subterminal segment); basal two-thirds of subterminal segment broader than distal third .............................................. ......................................................... Gubernatoriana pilosipes ( Alcock, 1909)

Figures

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).

Figure 8. Newly described crabs from their natural habitats. (A) Ghatiana aurantiaca sp. nov., from laterite rocks in Phansad Wildlife Sanctuary, Raigad district; (B) Ghatiana hyacintha sp. nov., from bank of a stream in Radhanagari Wildlife Sanctuary, Kolhapur district; (C) Gubernatoriana triangulus sp. nov., from bank of a stream in Tahmini Ghat, Pune district.