Ghatiana atropurpurea, Pati & Thackeray & Khaire, 2016

Pati, S. K., Thackeray, T. & Khaire, A., 2016, Five new species of freshwater crabs of the genera Ghatiana Pati & Sharma, 2014, and Gubernatoriana Bott, 1970 (Crustacea, Decapoda, Brachyura: Gecarcinucidae Rathbun, 1904) from the Western Ghats, India, Zootaxa 4083 (4), pp. 569-586 : 572-574

Ghatiana atropurpurea n. sp.

( Figs. 3 , 4 )

Type material. INDIA: adult male, holotype (cw 20.70 mm, cl 13.80 mm, ch 9.10 mm, fw 7.80 mm), Near Whistling Woods Hotel, Amboli, Sawantwadi taluk, Sindhudurg district, Maharashtra (15.959° N and 73.997° E), altitude 736 m, 6 July 2015, coll. Tejas Thackeray (ZSI, WRC-C.1507); paratypes, two females (cw 21.14–25.10 mm, cl 14.32–16.42 mm, ch 10.58–11.94 mm, fw 8.38–8.96 mm), same collection data as holotype (ZSI, WRC- C.1508); paratypes, two males (cw 21.40–31.02 mm, cl 14.22–20.38 mm, ch 10.36–15.20 mm, fw 7.72–10.40 mm) (ZSI, WRC-C.1509) and three females (cw 14.10–31.94 mm, cl 11.22–20.90 mm, ch 8.08–15.44 mm, fw 6.18– 11.24 mm) (ZSI, WRC-C.1510), Hathipal, ca. 6.5 km north east of Poinguinim, Canacona taluk, South Goa district, Goa (14.994° N and 74.151° E), altitude 54 m, 10 July 2015, coll. Tejas Thackeray.

Diagnosis. Carapace slightly broad to broader than long (cw/cl = 1.3–1.5), highly arched (cw/cl = 0.66–0.75), narrow posteriorly; dorsal surface almost smooth, dark purple coloured; anterolateral margin short, curved with finely serrated, short, oblique striations; posterolateral margin with long, distinct, oblique striations; front vertically deflexed, broad (fw/cw = 0.34–0.40); epigastric cristae low, broad, blunt; postorbital cristae indistinct; exorbital angle triangular, distinct; epibranchial tooth distinct; frontal median triangle incomplete; epistomal median lobe with acute apex, lacking median tooth ( Figs. 3A, B ). Suture between male thoracic sternites s2/s3 indistinct, suture between sternites s3/s4 missing except for two short lateral grooves ( Figs. 3C, F ). Male abdomen long, T-shaped; sixth abdominal somite longer than broad; telson long ( Figs. 3C, G ). G1 slightly sigmoid-shaped; terminal article distinctly curved inwards, cylindrical, long, ca. 0.55 times length of subterminal segment ( Figs. 4A–C ). G2 terminal article very short or vestigial ( Fig. 4D ).

Description of holotype. Carapace broader than long (cw/cl = 1.5), highly arched (cw/cl = 0.66), narrow posteriorly; dorsal surface almost smooth except rugose lateral sides; anterolateral carapace inflated in frontal view; anterolateral margin short, curved with finely serrated, short, oblique striations; posterolateral margin with long, distinct, oblique striations; front slightly depressed at middle, vertically deflexed, broad (fw/cw = 0.4); frontal margin almost straight; epigastric cristae distinct, low, broad, blunt; postorbital cristae indistinct; exorbital angle triangular, distinct, outer margin ca. 1 time length of inner margin; epibranchial tooth distinct, at level of supraorbital margin; postorbital region slightly deep; branchial regions inflated, rugose; subhepatic region with striations; cervical grooves poorly developed, interrupted; mesogastric groove long, deep, wide, bifurcate posteriorly; H-groove visible; frontal median triangle incomplete with only dorsal margin; epistomal median lobe broadly triangular with slightly acute apex, lacking median tooth ( Figs. 3A, B ).

Chelipeds almost smooth, unequal; right chela larger; fingers of major cheliped with four or five larger teeth, small gape when their tips in contact; dactylus of major cheliped equal in length to palm, upper surface with many small tubercles; palm longer than high; carpal spine distinct, blunt; carpus devoid of bristles; outer surface of merus rugose ( Figs. 3D, I ). Ambulatory legs (p2–p5) long, slender, with fine, small tuft of two or three brownish bristles with yellowish tips mostly on margins; dactylus (p2–p5) longer than propodus; longest propodus (p4) three times as long as broad ( Fig. 3E ).

Suture between male thoracic sternites s2/s3 indistinct, suture between sternites s3/s4 missing except for two short lateral grooves; s1–s4 with setae spreading uniformly ( Figs. 3C, F ).

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, with lateral margins gently diverging distally, proximal width equal to distal width; telson elongated, broadly rounded at apex; male sternoabdominal cavity deep, conspicuously long, extending much beyond level of bases of third maxillipeds ( Figs. 3C, G ).

Mandibular palp with two joints, terminal joint bilobed; exopods of first, second maxillipeds with long flagellum; exopod of third maxilliped lacking flagellum, longer than ischium; ventral sulcus on ischium shallow, towards centre; merus quadrangular, slightly depressed, anterior external angle of merus right angled ( Fig. 3H ).

G1 short, slightly sigmoid-shaped; terminal article distinctly curved inwards, cylindrical, long, ca. 0.55 times length of subterminal segment, tip pointed; subterminal segment broader than terminal article, basal half broader than distal half ( Figs. 4A–C ). G2 short with very short or vestigial terminal article; proximal half of basal segment distinctly broader than distal half ( Fig. 4D ).

Live colour. Individuals have a deep purple carapace (resembling the fruit of the Indian blackberry, or jamun) and indigo or deep purple ambulatory legs ( Figs. 2A , 3A, C ). Chelipeds: outer surface of merus and carpus, outer and inner upper half surface of palm, and proximal upper half surface of dactylus are light indigo (resembling the colour of blueberries); surface of remaining portions is light pink ( Figs. 2A , 3A, C, D, I ).

Paratypes. Paratypes are similar to the holotype in morphology except for these differences: the smallest female paratype from Hathipal (ZSI, WRC- C.1510) has a less broad carapace (cw/cl = 1.3), distinctly rugose dorsolateral carapace, anterolateral margin with crest curving into branchial regions and cheliped carpus with few bristles; the larger male from Hathipal (ZSI, WRC- C.1509) with indistinct epibranchial tooth and a large gape between fingers of the major cheliped when their tips are in contact; the larger female from Amboli (ZSI, WRC- C.1508) and the larger male from Hathipal (ZSI, WRC- C.1509) are with bigger left chela.

Etymology. The specific epithet is derived from the Latin atropurpureus meaning ‘dark purple’, refers to the deep purple colour of the live crab resembling the Indian blackberry, or jamun.

Type Locality. Amboli, Sawantwadi taluk, Sindhudurg district, Maharashtra (15.959° N and 73.997° E) (altitude 736 m).

Remarks. Ghatiana atropurpurea n. sp. is immediately distinguished from its congeners by the striking deep purple colour of its carapace ( Figs. 2A , 3A ). Normally, G. atropurpurea n. sp. has a relatively broad carapace (cw/ cl = 1.5) than any other species of Ghatiana . Other unique morphological features of the species are distinct exorbital angle, distinct epibranchial tooth, upper surface of dactylus of the major cheliped with many small tubercles, and slightly sigmoid-shaped G1 with terminal article distinctly curved inwards ( Figs. 3A, I , 4A–C ).

Ghatiana atropurpurea n. sp. and G. hyacintha have an epistomal median lobe with acute apex and a long G1 terminal article, ca. 0.55 times the length of the subterminal segment ( Figs. 3B , 4A ; see Pati & Sharma 2014a: figs. 4B, 5E for G. hyacintha ) whereas G. splendida n. sp. and G. aurantiaca have an epistomal median lobe with rounded apex and a short G1 terminal article, ca. 0.45 times the length of the subterminal segment ( Figs. 5B , 6A ; see Pati & Sharma 2014a: figs. 2B, 3E for G. aurantiaca ).

Ghatiana atropurpurea n. sp. is more similar to G. hyacintha among its congeners in many morphological features of the carapace and gonopods. It can be easily differentiated from G. hyacintha , however, by its deep purple and broader carapace (cw/cl = 1.5), and inwardly curved G1 terminal article ( Figs. 3A , 4A, C ) [vs. violet and less broad carapace (cw/cl = 1.3), and straight G1 terminal article (see Pati & Sharma 2014a: figs. 4A, 5E, G, 8B)].

Ecological notes. Ghatiana atropurpurea n. sp. is an arboreal crab found in association mainly with the Indian blackberry plant. Crabs were observed in tree holes containing rain water at Amboli, and none of them were observed foraging on open ground or leaf litters or barks (T. Thackeray, unpublished data). Adult and sub-adult crabs of the Hathipal area were found in tree holes near ground level whereas many juveniles gathered under small boulders or foraging on leaf litters. An adult female crab was also seen in a burrow under the crown of a large boulder. One freshly recruit crab was noticed adjacent to an ephemeral stream, which had left its trail. True phytotelmy is therefore not achieved by G. atropurpurea n. sp..

Individuals of this species were mainly seen during heavy or frequent rainfall with or without fog and all day long with a 24°C–32°C atmospheric temperature range. The feeding habits of G. atropurpurea n. sp. are not precisely known. Local people of the Hathipal area mentioned about feeding on roadkills of snails and millipedes. During a night field visit, an adult crab was observed in a small pond filled with tadpoles, which could also be a possible source of prey. Population size of this species appeared to be higher at Hathipal than at Amboli.

Geographical distribution. Ghatiana atropurpurea n. sp. is only found in the Western Ghats. The species is so far recorded from two localities viz. Amboli (type locality) in Sindhudurg district of Maharashtra, and Hathipal in South Goa district of Goa, which is approximately 110 km south of the type locality. There is also one sighting of the species from Amba Ghat in Kolhapur district, about 115 km north of Amboli (A. Sayyed, personal communication).

Figures

FIGURE 2. Live crabs of new species of Ghatiana and Gubernatoriana. A, Ghatiana aurantiaca n. sp. from Amboli; B, Ghatiana splendida n. sp. from Chaukul; C, Gubernatoriana alcocki n. sp. from Vankusawade; D, Gubernatoriana thackerayi n. sp. from Raghuvir Ghat; C, Gubernatoriana waghi n. sp. from Malshej Ghat. Photo credits: A, B, Arjun Kamdar; C, B. V. Jadhav; D, Shailesh Bhosale; E, Rachit Shah.

FIGURE 3. Ghatiana atropurpurea n. sp., holotype male (ZSI, WRC—C. 1507). A, dorsal view; B, frontal view; C, ventral view; D, right or major cheliped; E, right ambulatory leg (p 4); F, anterior male thoracic sternites; G, male abdomen; H, left third maxilliped; I, dorsal view of dactylus of major cheliped. Scale bars = 5 mm (A, C), 2 mm (B, D – G, I), 1 mm (H).

FIGURE 4. Ghatiana atropurpurea n. sp., holotype male (ZSI, WRC—C. 1507). A, dorsal view of right G 1; B, ventral view of right G 1; C, dorsal view of right G 1 terminal article; D, right G 2. Scale bar = 0.5 mm.

FIGURE 5. Ghatiana splendida n. sp., holotype male (ZSI, WRC—C. 1511). A, dorsal view; B, frontal view; C, ventral view; D, left or major cheliped; E, right ambulatory leg (p 3); F, anterior male thoracic sternites; G, male abdomen; H, left third maxilliped. Scale bars = 5 mm (A, C), 2 mm (B, D – G), 1 mm (H).

FIGURE 6. Ghatiana splendida n. sp., holotype male (ZSI, WRC—C. 1511). A, dorsal view of right G 1; B, ventral view of right G 1; C, dorsal view of right G 1 terminal article; D, right G 2. Scale bar = 0.5 mm.