Ghatiana hyacintha, 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 : 1292-1294

Ghatiana hyacintha sp. nov.

( Figures 4A–C , 5A–H , 8B )

Type specimens

Holotype: male (cw 13.58 mm, cl 10.54 mm, ch 6.62 mm, fw 5.60 mm), coll. S.S. Jadhav and party (ZSI, WRC-C.1130), Mahadeb Mandir, Radhanagari Wildlife Sanctuary, Kolhapur district , Maharashtra, India, 16°25 ′ 24.2796 ″ N, 73°54 ′ 7.1964 ″ E, alt. 883 m; paratypes: 3 males (cw 12.36–13.42 mm, cl 9.56–10.24 mm, ch 6.06– 6.54 mm, fw 5.16–5.66 mm) and 2 females (cw 12.02–13.80 mm, cl 9.20–10.50 mm, ch 6.22–6.64 mm, fw 5.04–5.84 mm) (ZSI, WRC-C.825), same data as holotype.

Diagnosis

Carapace broader than long (cl/cw 0.76–0.78); anterolateral margin curved with finely serrated crest curving into branchial regions, short, oblique, distinct striations on lateral sides; epigastric crests distinct, low, broad, blunt; postorbital crests indistinct; epibranchial tooth indistinct; mesogastric groove long, deep, wide, extending into frontal region; frontal median triangle incomplete with only dorsal margin; epistomal median lobe broadly triangular with slightly acute apex, lacking median tooth ( Figure 4A,B ). Suture between thoracic sternites s2/s3 indistinct, suture between s3/s4 incomplete except for short lateral grooves; s1–s4 with setae spreading uniformly ( Figures 4C , 5A ). Male abdomen elongated T-shape; fifth abdominal somite broader than long; sixth abdominal somite longer than broad; telson longer than sixth abdominal somite ( Figures 4C , 5B ). G1 short, slightly curved outward with long terminal article (0.55 times length of subterminal segment); tip pointed; subterminal segment comparatively much broader than terminal article, basal half much broader than distal half ( Figure 5E–G ). G2 short with very short or vestigial terminal article ( Figure 5H ). Living specimens with violet carapace and legs ( Figure 8B ).

Description

Carapace slightly broader than long (cw/cl 1.3), narrow posteriorly, highly arched (ch/cl 0.63), anterolateral carapace inflated in frontal view; anterolateral margin curved with a very finely serrated crest curving into branchial regions, short, oblique, distinct striations on lateral sides; posterolateral margin with short, distinct, oblique striations; front slightly depressed in middle, vertically deflexed, broad, fw/cw 0.4; frontal margin nearly straight; epigastric crests distinct, low, broad, blunt; postorbital crests indistinct; external orbital angle poorly developed; epibranchial tooth indistinct, very close to level of supraorbital margin; postorbital region shallow; branchial regions inflated, rugose; subhepatic region with fine striations; cervical grooves poorly developed, interrupted; mesogastric groove long, deep, wide, extending into frontal region, bifurcate posteriorly; H-groove visible; frontal median triangle incomplete with only dorsal margin; epistomal median lobe broadly triangular with slightly acute apex, lacking distinct median tooth ( Figure 4A,B ).

Chelipeds unequal; right chela larger; smooth; fingers of major cheliped with two or three larger teeth, fingers meeting only at tip; dactylus of major cheliped shorter than palm ( Figure 5C ); carpus with large blunt tooth; carpus almost devoid of bristles; outer surface of merus rugose.

Ambulatory legs (p2–p5) long with very fine, small, tuft of two or three brownish bristles with yellowish tips mostly on margins; dactylus (p4 and p5) longer than propodus; longest propodus (p4) three times as long as broad.

Suture between thoracic sternites s2/s3 indistinct, suture between s3/s4 missing except for two lateral grooves; s1–s4 with setae spreading uniformly ( Figures 4C , 5A ).

Male abdomen elongated, T-shaped; fifth abdominal somite broader than long with concave lateral margins, distal width shorter than proximal width; sixth abdominal somite longer than broad, shorter than telson with convex lateral margins, proximal width equal to distal width; telson elongated, broadly rounded at apex ( Figures 4C , 5B ); male sternoabdominal cavity deep, very long, extending much beyond level of third maxilliped bases ( Figure 4C ).

Exopod of first and second maxillipeds with long flagellum; exopod of third maxilliped lacking flagellum, longer than ischium; ventral sulcus on ischium shallow, towards centre; merus quadrangular, anterior external angle of merus right angled, slightly depressed ( Figure 5D ). Mandibular palp with two joints, terminal joint bilobed.

G1 short, slightly curved outward with long terminal article (0.55 times length of subterminal segment); terminal article narrower than subterminal segment, tip pointed; subterminal segment broader than terminal article, basal half broader than distal half ( Figure 5E–G ). G2 short with very short or vestigial terminal article; proximal half of basal segment distinctly broader than distal half ( Figure 5H ).

Colour

Live animals have a violet carapace and chelipeds ( Figure 8B ); specimens preserved in ethanol have a dark brown carapace and faint violet chelipeds.

Etymology

The specific epithet, hyacintha alludes to the violet colour of the species with reference to the colour of the flowers of water hyacinth.

Remarks

Ghatiana hyacintha is similar to G. aurantiaca in overall carapace morphology and G1 structure. Nevertheless, the species can be distinguished by the colouration of the carapace, relative width of the carapace, appearance of the apex of the epistomal median lobe, pattern of the setae on thoracic sternites, and relative length of G1 terminal article and relative broadness of G1subterminal segment. For differences see Remarks for G. aurantiaca .

Ecological notes

Specimens were collected from burrows of the banks of small streams, and from under small stones. These crabs are generally more active during the rainy season (from June to September) (Pati and Sharma, unpublished data).

Distribution

Known only from the type locality.

Key to the species of Ghatiana

1. Carapace of living specimens orange-red; wide (cl/cw 0.71–0.73); epistomal median lobe semicircular; thoracic sternites 3 and 4 smooth, lacking setae. G1 terminal article 0.45 times length of subterminal segment; basal twothirds of subterminal segment much broader than distal third ...................... .......................................................................... Ghatiana aurantiaca sp. nov. Carapace of living specimens violet; not widened (cl/cw 0.76–0.78); epistomal median lobe broadly triangular; thoracic sternites 3 and 4 setose. G1 terminal article 0.55 times length of subterminal segment; basal half of subterminal segment much broader than distal half .............. Ghatiana hyacintha sp. nov.

Figures

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 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.