Ghatiana dvirupa, Pati & Bajantri & Hegde, 2024

Pati, Sameer Kumar, Bajantri, Parashuram Prabhu & Hegde, Gopalkrishna Dattatraya, 2024, The “ Mr. and Mrs. Ghat crab ”, Ghatiana dvirupa sp. nov. (Decapoda: Brachyura: Gecarcinucidae) from the Central Western Ghats of India, Zootaxa 5443 (1), pp. 116-126 : 118-125

Ghatiana dvirupa sp. nov.

[Mr. and Mrs. Ghat Crab]

( Figs. 2A–C , 3A–H , 4A–F , 5A–D, F )

Material examined. HOLOTYPE: INDIA – Karnataka State: male adult ( CW 26.11 mm, CL 17.52 mm, CH 13.06 mm, FW 9.90 mm), Atle, Castlerock Range, Kali Tiger Reserve , Uttara Kannada District (15.419° N, 74.288° E), alt. 746 m, 3 Aug. 2023, Md. Jafer Palot et al. leg. ( ZSI-WRC C.2443) . PARATYPES: male adult ( CW 29.99 mm, CL 20.05 mm, CH 14.60 mm, FW 10.72 mm), female adult ( CW 28.67 mm, CL 19.07 mm, CH 13.97 mm, FW 10.66 mm), same collection data as for holotype ( ZSI-WRC C.2444); male adult ( CW 26.06 mm, CL 17.59 mm, CH 12.36 mm, FW 9.87 mm), female adult ( CW 27.25 mm, CL 18.54 mm, CH 12.78 mm, FW 10.14 mm), same collection data as for holotype ( ZSI-WRC C.2445); male adult ( CW 23.96 mm, CL 15.66 mm, CH 11.27 mm, FW 9.29 mm), female adult ( CW 23.12 mm, CL 15.81 mm, CH 11.15 mm, FW 8.93 mm), same collection data as for holotype ( ZSI-WRC C.2446) . ADDITIONAL MATERIAL: 13 males ( CW 16.10–23.76 mm, CL 10.15–15.08 mm, CH 6.84–10.60 mm, FW 6.08–8.78 mm), same collection data as for holotype ( ZSI-WRC C.2447) ; 8 females ( CW 13.98–24.80 mm, CL 9.17–15.73 mm, CH 6.12–11.45 mm, FW 5.31–8.92 mm), same data as for holotype ( ZSI-WRC C.2448) .

Diagnosis. Carapace in adult proportionately broad (CW/CL = 1.5–1.6), strongly arched ( CH /CL = 0.7); lateral margins strongly convex; frontal margin some distance from anterior margin of epistome, exposing antennular fossae ( Figs. 2A, B , 4A, D ). Eyes relatively small as compared to orbital space; each eye with relatively stouter eyestalk ( Fig. 2B ). Maxillipeds 1, 2 each with long flagellum on exopod ( Fig. 3A ). Major chela in adult male with palm relatively stouter; ventral margin of fixed finger and distal half of palm strongly concave ( Figs. 2A, C , 3C , 4A, D ). Ambulatory legs relatively short (P3 length/CL = ca. 2.0–2.2) ( Figs. 2A , 4A, D ). Male pleonal somite 6 subquadrate, slightly longer than broad ( Figs. 2C , 3D , 4B ). G1 relatively slender, medially gently curved outwards; ultimate article relatively slender, distally gently curved inwards, relatively long, ca. 0.4 times length of penultimate article; penultimate article relatively slender ( Figs. 3E–G , 4C ). Vulvae in adult relatively closely positioned (VD/ SW = ca. 0.2), relatively large (occupying ca. 0.5 times length of s6), positioned close to s5/s6 ( Fig. 4F ).

Description of male holotype. Carapace transversely ovate, distinctly broad (CW/CL = 1.5), conspicuously arched ( CH /CL = 0.7); dorsal surface smooth, glabrous, strongly convex in frontal view; lateral margins strongly convex; anterolateral margins entire; front broad (FW/CW = 0.4), strongly deflexed anteriorly, trapezoidal; frontal margin smooth, cristate, some distance from anterior margin of epistome, exposing antennular fossae; frontal medial triangle incomplete, with dorsal margin only, lateral margins indiscernible; epigastric cristae low, only visible as 2 broad, rugose protuberances; postorbital cristae indiscernible; external orbital angle indistinct, low; epibranchial tooth indiscernible; postorbital region shallow; branchial regions inflated, smooth; cervical grooves shallow, narrow, interrupted; mesogastric groove shallow, narrow, long, bifurcated posteriorly; H-shaped groove visible; subhepatic region rugose; suborbital region generally smooth; pterygostomial region anteriorly with distinct tubercles; supraorbital margin almost straight, cristate, smooth; suborbital margin concave, subcristate, almost smooth, continuous with supraorbital margin; epistome posterior margin with well-developed, broadly triangular medial tooth and gently concave lateral parts ( Fig. 2A–C ). Eyes small as compared to orbital space; eyestalk short, stout; cornea moderately large, pigmented ( Fig. 2B ).

Antennules short, folded in longitudinally broad fossae; antennae conspicuously short ( Fig. 2B ). Mandibular palp with 2 articles; terminal article bilobed, anterior lobe stout, short, ca. 0.5 times length of posterior lobe ( Fig. 3A ). Maxillipeds 1, 2 each with long flagellum on exopod ( Fig. 3A ). Maxilliped 3 cover most of buccal cavity when closed; ischium subrectangular, longer than broad, longitudinal groove indiscernible; merus subquadrate, slightly broader than long, sunken; exopod stout, distally narrow, reaching beyond anterolateral corner of ischium, completely lacking flagellum ( Figs. 2B , 3B ).

Chelipeds smooth, glabrous, unequal, right chela conspicuously larger ( Fig. 2A, C ). Major chela with 3 or 4 low, blunt teeth on each finger, remaining teeth inconspicuous, fingertips pointed, distinct gape when fingers closed; dactylus curved, stout, longer than upper margin of palm; palm stout, as long as high, smooth, distal half of palm and ventral margin of fixed finger strongly concave; carpus smooth, gently inflated, with low, blunt inner distal tooth; merus smooth except for low tubercles on margins, lacking subterminal spine ( Figs. 2A, C , 3C ).

Ambulatory legs slender, shorter than major cheliped, P3 length/CL = ca. 2.2, margins with tuft of 2–6 short brown setae with yellowish tips; merus (P2–P5) elongated, lacking subdistal spine; propodus (P2–P5) with distinct, sharp chitinous spines on lower margins; dactylus (P2–P5) gently recurved, subequal in length to propodus, with distinct, sharp chitinous spines on upper and lower margins ( Fig. 2A, C ).

Thoracic sternites smooth, generally glabrous ( Fig. 2C ); s1–s4 completely fused forming single structure, lacking suture or groove ( Fig. 2C ); s4/s5 shallow, narrow, medially interrupted; s5/s6 shallow, narrow, medially interrupted, each half extending anteriorly to join s4/s5; s6/s7 shallow, narrow, medially joining with longitudinal groove on s6; s7/s8 shallow, narrow, medially interrupted by longitudinal groove on s7, lacking transverse ridge; s8 almost covered by pleon ( Fig. 2C ), narrowed medially, longitudinal medial groove indiscernible. Pleonal locking mechanism with prominent tubercle on distal quarter of s5. Sternopleonal cavity deep, conspicuously long, reaching beyond imaginary line joining bases of ischium of maxilliped 3 ( Figs. 2C , 3B ).

Pleon narrow, T-shaped, with strongly concave lateral margins; pleonal somites 1–6 progressively longer; pleonal somites 1, 2 subrectangular, broadest; pleonal somites 3, 4 trapezoidal, with straight lateral margins; pleonal somite 5 subtrapezoidal, with concave lateral margins; pleonal somite 6 subquadrate, slightly longer than broad, medial length ca. 1.1 times proximal width, longest among pleonal somites, distinctly shorter than telson, with sinuous lateral margins ( Figs. 2C , 3D ). Telson elongated, medial length ca. 1.3 times proximal width, with gently concave lateral margins, apex narrow ( Figs. 2C , 3D ).

G1 slender, medially gently curved outwards, short, tip reaching half-length of s 5 in situ; ultimate article slender, conical, long, ca. 0.4 times length of penultimate article, distally gently curved inwards, tip blunt; penultimate article stouter than ultimate article, broad proximally, relatively narrow distally, outer margin sinuous, inner margin weakly sinuous; groove for G2 ventral in position ( Fig. 3E–G ). G2 distinctly shorter than G1, ca. 0.6 times G1 length; ultimate article conspicuously short, ca. 0.1 times length of penultimate article ( Fig. 3H ).

Colour in life. Male crabs have pink carapace, ambulatory legs and chelipeds with blanched fingers ( Fig. 5A, B ). Female crabs are dark purplish brown ( Fig. 5C, D ).

Etymology. The species name is derived from the Sanskrit meaning ‘having two forms’, alluding to the difference in colour between male and female crabs in life. The name is to be treated as a Latin noun in apposition.

The common name of the new species is proposed herein as “Mr. and Mrs. Ghat Crab” as males and females possess different colours in life.

Ecological notes. Ghatiana dvirupa sp. nov. is found on a high mountain laterite plateau (approximately 3 km 2) of the Central Western Ghats of India ( Fig. 1 ). The mountain plateau ( Fig. 5E ) is almost devoid of vegetation but surrounded by the dense forest of a protected area, i.e., the Kali Tiger Reserve. Crabs of this new species are most active during the monsoon (June-September) and are often seen during the daytime when rain halts momentarily. These semiterrestrial crabs inhabit the holes and crevices of the laterite boulders ( Fig. 5F ) clearly away from the streams. Crabs of the new species can also be seen underneath stones and small laterite boulders. Although the new species is currently restricted to a small area with specific habitat requirements, the population of the species appears to be high within the area. Ghatiana rouxi Pati & Thackeray, 2021 , is also found on the same laterite plateau but generally dwells under the stones and small boulders adjacent to the streams.

Remarks. The paratype males (ZSI-WRC C.2444–2446) of G. dvirupa sp. nov. are adults and similar to the holotype in most of the diagnostic features, including the gently inwardly curved distal portion of the G1 ultimate article ( Fig. 4A–C ). The subadult males, however, have the cristate anterolateral margins of the carapace (versus entire anterolateral margins of the carapace in adult males), the visible epibranchial tooth (versus indistinct epibranchial tooth in adult males) and the rugose branchial regions (versus generally smooth branchial regions in adult males).

The female paratypes (C.2444–2446) of G. dvirupa sp. nov. are adults and share most of the non-sexual diagnostic character states, including the proportionately broader carapace ( Fig. 4D ), the noticeable distance between the frontal margin and the anterior margin of the epistome exposing the antennular fossae, the relatively small eyes, and the long flagellum on the exopod of each of the maxillipeds 1, 2. As in subadult males, adult and subadult females of the new species possess a relatively rugose carapace on the branchial regions, with the cristate anterolateral margins and the visible but low epibranchial tooth ( Fig. 4D ). The heterochely is less pronounced in adult females ( Fig. 4D ) than in adult males ( Figs. 2A, C , 4D ). More importantly, female crabs of the new species have a darker colour in life (purplish brown) ( Fig. 5C, D ) in contrast to the pink colouration of live male crabs ( Fig. 5A, B ). While live colouration of crabs may help identify a species of Ghatiana [e.g., G. sanguinolenta Pati, Thackeray & Pawar, 2023 (see Pati et al. 2023a)], it should not be considered a key character. In a species of Ghatiana , the colour of live crabs may vary between males and females [e.g., G. botti Pati & Thackeray, 2018 (see Pati & Thackeray 2018: fig. 2A, B)]. As in the present new species, the contrasting colour in life between males and females may lead to wrong identification. The colour of the crabs may also vary between wet and dry seasons [e.g., G. aurantiaca Pati & Sharma, 2014 ( Fig. 5G, H )]. Irrespective of gender and season, the difference in live colouration is also observed among the individuals of G. rouxi , which varies from deep purple to purplish brown ( Fig. 5I, J ).

In the adult females of G. dvirupa sp. nov., the pleon and telson together form a broadly subtriangular structure that completely covers the sternopleonal cavity when closed, the remaining portion of the thoracic sternum being exposed ( Fig. 4E ). The pleonal somite 1 of adult females of the new species is the shortest; pleonal somites 2–5 are progressively longer; and pleonal somite 6 is the longest, distinctly broader than long, shorter than the telson, with the convex lateral margins ( Fig. 4E ). The female telson in adults of G. dvirupa sp. nov. is triangular, broader than long, with the strongly concave lateral margins and a broad apex ( Fig. 4E ). The vulvae in adult females of G. dvirupa sp. nov. are located close to each other (VD/SW = ca. 0.2) on s6; each vulva is subovate, large (occupying ca. 0.5 times the length of s6), positioned close to s5/s6 (not touching s5/s6), covered with a soft membranous operculum, and surrounded by a low, broad rim ( Fig. 4F ).

Ghatiana dvirupa sp. nov. most closely resembles G. sanguinolenta from Karnataka in having a broader carapace ( Figs. 2A , 4A, D ; see Pati et al. 2023a: figs. 2A, 3A, C); the relatively smaller eyes ( Figs. 2B , 4A, D ; see Pati et al. 2023a: fig. 2B); relatively stouter palm of the major chela in adult males, with the ventral margin of the distal half of the palm and the fixed finger strongly concave ( Fig. 3C ; see Pati et al. 2023a: fig. 2F); the medially gently outwardly curved G1, with the relatively slenderer and longer ultimate article, ca. 0.4 times the length of the penultimate article ( Figs. 3E–G , 4C ; see Pati et al. 2023a: fig. 2H, I); and the strongly concave lateral margins of the female telson ( Fig. 4E ; see Pati et al. 2023a: fig. 3D). The G1 ultimate article, however, is gently curved inwards distally in G. dvirupa sp. nov. ( Figs. 3E–G , 4C ) (versus G1 ultimate article distally gently curved outwards in G. sanguinolenta ; see Pati et al. 2023a: fig. 2H, I). Other features also differentiate them: the frontal margin is located some distance from the anterior margin of the epistome, exposing the antennular fossae in G. dvirupa sp. nov. ( Fig. 2B ) (versus frontal margin relatively close to the anterior margin of the epistome, almost hiding the antennular fossae in G. sanguinolenta ; see Pati et al. 2023a: fig. 2B); maxillipeds 1, 2 each with a long flagellum on the exopod in G. dvirupa sp. nov. ( Fig. 3A ) (versus each of the maxillipeds 1, 2 with a short flagellum on the exopod in G. sanguinolenta ; see Pati et al. 2023a: fig. 2D).

Ghatiana rouxi was also collected from the type locality of G. dvirupa sp. nov. The new species, G. dvirupa sp. nov., can easily be differentiated from G. rouxi mainly by its proportionately broader carapace, CW/CL = 1.5–1.6 ( Figs. 2A , 4A, D ) (versus carapace proportionately narrower, CW/CL = 1.2–1.3; see Pati & Thackeray 2021: fig. 4A, B); the strongly convex lateral margins of the carapace ( Figs. 2A , 4A, D ) (versus carapace with gently convex lateral margins; see Pati & Thackeray 2021: fig. 4A, B); the relatively small eyes ( Fig. 2B ) (versus eyes relatively larger; see Pati & Thackeray 2021: fig. 4C); the relatively shorter ultimate article of the G1, ca. 0.4 times the length of the penultimate article ( Figs. 3E , 4C ) (versus G1 ultimate article relatively longer, ca. 0.5 times the length of the penultimate article; see Pati & Thackeray 2021: fig. 5D); the relatively slenderer penultimate article of the G1 ( Figs. 3E, G , 4C ) (versus G1 penultimate article relatively stouter; see Pati & Thackeray 2021: fig. 5D, E); and the vulvae being located close to the s5/s6 ( Fig. 4F ) (versus vulvae located some distance from the s5/s6; see Pati & Thackeray 2021: fig. 5H).

Concerning other species of Ghatiana occurring in Karnataka [ G. atropurpurea Pati, Thackeray & Khaire, 2016 , G. basalticola Klaus, Fernandez & Yeo, 2014 , and G. dvivarna Pati, Thackeray, Bajantri & Hegde, 2022 (cf. Pati et al. 2023a)], G. dvirupa sp. nov. differs from them by the relatively stouter palm of the major chela in adult males, with the ventral margin of the distal half of the palm and the fixed finger strongly concave ( Fig. 3C ) (versus palm of the major chela in adult males relatively slenderer, with the ventral margin of the distal half of the palm and the fixed finger gently concave; see Klaus et al. 2014: fig. 3C; Pati et al. 2016: fig. 3D; 2022a: fig. 4B) in addition to the relatively elongated male pleonal somite 6 ( Figs. 2C , 3D , 4B ) (versus male pleonal somite 6 subquadrate or slightly broader than long; see Klaus et al. 2014: fig. 3C; Pati et al. 2016: fig. 3G; 2022a: fig. 4C).

Among these Ghatiana species of Karnataka, G. basalticola is known from an area that is located some 15 km north of the type locality of G. dvirupa sp. nov. (see Klaus et al. 2014; Pati & Thackeray 2018). As such it is possible that one may encounter both species in the same locality. In G. dvirupa sp. nov., the carapace, however, is relatively less broad, CW/CL = 1.5–1.6 ( Figs. 2A , 4A, D ) (versus carapace distinctly broader, CW/CL = 1.6–1.9 in G. basalticola ; see Klaus et al. 2014: fig. 3B); the eyes are relatively small as compared to the orbit ( Fig. 2B ) (versus eyes relatively large in relation to the orbit in G. basalticola ; see Klaus et al. 2014: fig. 3A); the G1 is medially gently curved outwards, with the relatively slenderer, distally gently curved inwards and relatively longer ultimate article, ca. 0.4 times the length of the penultimate article ( Figs. 3E–G , 4C ) (versus G1 medially distinctly curved outwards, with the relatively stouter, straight and relatively shorter ultimate article, ca. 0.3 times the length of the penultimate article in G. basalticola ; see Klaus et al. 2014: fig. 3D, E); and the female telson has strongly concave lateral margins ( Fig. 4E ) (versus female telson with almost straight lateral margins in G. basalticola ; see Pati & Thackeray 2018: fig. 5G). The additional differences in the major chela and pleonal somite 6 of adult males are already mentioned in the preceding paragraph.

The strongly convex lateral margins of the carapace ( Figs. 2A , 4A, D ), the long flagellum on the exopod of each of the maxillipeds 1, 2 ( Fig. 3A ), the elongated male pleonal somite 6 ( Figs. 2C , 3D , 4B ), the distally gently inwardly curved G1 ultimate article ( Figs. 3E–G , 4C ), the basally narrow G1 penultimate article ( Figs. 3E, G , 4C ), and the relatively closely positioned vulvae, VD/SW = ca. 0.2 ( Fig. 4F ) of G. dvirupa sp. nov. resemble those of G. botti and G. splendida Pati, Thackeray & Khaire, 2016 (see Pati & Thackeray 2018: figs. 6A, G, I–K, N, 10A, C–E, H). Both G. botti and G. splendida are found in the Sindhudurg district of the neighbouring Maharashtra state, approximately 50 to 100 km away from the type locality of the present new species (see Pati et al. 2016; Pati & Thackeray 2018). Ghatiana dvirupa sp. nov. is nevertheless differentiated from G. botti and G. splendida mainly by the proportionately broader carapace, CW/CL = 1.5–1.6 ( Figs. 2A , 4A, D ) (versus carapace proportionately narrower, CW/CL = 1.3–1.4; see Pati & Thackeray 2018: figs. 6A, 10A); the relatively small eyes as compared to the orbits ( Fig. 2B ) (versus eyes relatively large; see Pati & Thackeray 2018: figs. 6B, 10B); the medially gently outwardly curved G1 ( Figs. 3E, G , 4C ) (versus G1 almost straight; see Pati & Thackeray 2018: figs. 6I, K, 10D, E); and the strongly concave lateral margins of the female telson ( Fig. 4E ) (versus female telson with almost straight to gently concave lateral margins; see Pati & Thackeray 2018: figs. 6M, 10G). The relatively slenderer G1 ultimate article ( Figs. 3E, G , 4C ) and the relatively large vulvae (occupying ca. 0.5 times the length of the s6) ( Fig. 4F ) of G. dvirupa sp. nov. further distinguish the new species from G. botti , in which, the G1 ultimate article is relatively stouter (see Pati & Thackeray 2018: fig. 6I–K) and the vulvae are relatively smaller (occupying ca. 0.3 times the length of the s6) (see Pati & Thackeray 2018: fig. 6N). Moreover, the vulva is much closer to the s5/s 6 in G. dvirupa sp. nov. ( Fig. 4F ), while the said structure is located some distance from the s5/s 6 in G. botti (see Pati & Thackeray 2018: fig. 6N). Additional difference in the G1 structure separates the new species from G. splendida , i.e., the ultimate article is relatively shorter, ca. 0.4 times the length of the penultimate article in G. dvirupa sp. nov. ( Figs. 3E , 4C ); whereas G. splendida has a relatively longer ultimate article, ca. 0.5 times the length of the penultimate article (see Pati & Thackeray 2018: fig. 10D).

Geographical distribution. Ghatiana dvirupa sp. nov. is presently known only from Atle (type locality) of the Uttara Kannada district of Karnataka state, India ( Fig. 1 ). The type locality is situated in the Castlerock Range of the Kali Tiger Reserve, which is in the Central Western Ghats ( Fig. 1 ).

Figures

FIGURE 1. Map showing the distribution of Ghatiana dvirupa sp. nov. A, Western Ghats; B, Kali Tiger Reserve; C, Atle (type locality). This figure is available in colour at Zootaxa online.

FIGURE 2. Ghatiana dvirupa sp. nov., holotype male (26.11 × 17.52 mm), ZSI-WRC C.2443. A, habitus, dorsal view; B, frontal view of cephalothorax; C, habitus, ventral view. Scale bars = 10 mm.

FIGURE 3. Ghatiana dvirupa sp. nov., holotype male (26.11 × 17.52 mm), ZSI-WRC C.2443. A, mouth parts exposed; B, left maxilliped 3; C, outer view of major or right chela; D, pleon; E, dorsal view of left G1; F, dorsal view of left G1 ultimate article; G, ventral view of left G1; H, left G2. Scale bars = 5 mm (C, D), 2 mm (A, B), 1 mm (E, G, H), 0.5 mm (F).

FIGURE 4. Ghatiana dvirupa sp. nov.: A–C, paratype male (29.99 × 20.05 mm), ZSI-WRC C.2444; D–F, paratype female (28.67 × 19.07 mm), ZSI-WRC C.2444. A, D, habitus, dorsal view; B, pleonal somites 3–6 and telson; C, dorsal view of left G1; E, pleonal somites 4–6 and telson; F, thoracic sternites showing vulvae. Scale bars = 10 mm (A, D), 5 mm (B, E, F), 1 mm (C).

FIGURE 5. Ghatiana dvirupa sp. nov., colour in life:A, holotype male, ZSI-WRC C.2443; B, male, ZSI-WRC C.2447; C, paratype female, ZSI-WRC C.2444; D, paratype female, ZSI-WRC C.2446. Habitats of Ghatiana dvirupa sp. nov.: E, general habitat at type locality; F, male, ZSI-WRC C.2447, in crevice of laterite boulder. Ghatiana aurantiaca Pati & Sharma, 2014, colour in life: G, crab in its natural habitat during wet season (31 August 2013); H, crab outside of its habitat during dry season (28 November 2011). Ghatiana rouxi Pati & Thackeray, 2021, colour in life. I, male, ZSI-WRC C.2177; J, male, ZSI-WRC C.2176. Figure G is credited to Satyen Mehta, which is modified from https://www.inaturalist.org/observations/51882255. This figure is available in colour at Zootaxa online.