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

A new genus of freshwater crab, Ghatiana, with two new species, Ghatiana aurantiaca and Ghatiana hyacintha, and a new species of Gubernatoriana Bott, 1970, are described from the Western Ghat Mountains in Maharashtra State, India. Ghatiana is most similar to Gubernatoriana by its wide, highly arched carapace and by the shape of the male abdomen. Nevertheless, the new genus can be distinguished from Gubernatoriana by the broadness of carapace, length of male abdomen, shape of sixth abdominal somite, length of telson and length of G1 terminal article. Ghatiana aurantiaca sp. nov. and G. hyacintha sp. nov. are distinguished by differences in body colour, carapace width, and G1 morphology, whereas Gubernatoriana triangulus sp. nov. is distinguished from two other known species [Gubernatoriana gubernatoris (Alcock, 1909) and Gubernatoriana pilosipes (Alcock, 1909)] by its triangular G1 subterminal segment and by its carapace morphology. Keys to the species of both the genera are provided. http://www.zoobank.org/urn:lsid:zoobank.org:pub:36BAA1EA-DC15-4B06-BA09-7BD26C63FF54

Type species Ghatiana aurantiaca sp. nov, by present designation.

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.    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) ( 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).
Chelipeds unequal; right chela much larger; smooth; teeth on fingers blunt, almost of equal size; dactylus shorter than palm; fingers of larger chela meet only at tip ( Figure 3C); carpal spine distinct, blunt; carpus devoid of bristles; outer surface of merus rugose. Ambulatory legs (p2-p5) long with very fine, small tuft of brownish bristles with yellowish tips mostly on margins; dactylus (p4 and p5) longer than propodus; longest propodus (p3) three times as long as broad.
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 slightly convex lateral margins, proximal width equal to distal width; telson elongated, broadly rounded at apex (Figures 2C, 3B); male sternoabdominal cavity deep, very long, extending much beyond level of bases of third maxillipeds ( Figure 2C).
G1 short, slightly curved outward with long terminal article (0.45 times length of subterminal segment); terminal article narrower than subterminal segment, tip pointed; subterminal segment broader than terminal article, basal two-thirds broader than distal third ( Figure 3E-G). G2 short with very short or vestigial terminal article; proximal half of basal segment distinctly broader than distal half ( Figure 3H).

Colour
Live animals have an orange-red carapace and chelipeds ( Figure 8A); specimens preserved in ethanol have a yellow-brown carapace and chelipeds.

Etymology
The specific epithet derived from the Latin word aurantiacus meaning 'orange-red', refers to the orange-red colour of the live crab.

Remarks
Ghatiana aurantiaca sp. nov. is similar to G. hyacintha sp. nov. in general carapace morphology and G1 structure. However, these two species are clearly differentiated by the following characters: orange-red colour when alive (vs violet when alive); carapace more transversely elongate in appearance, cw/cl 1.4 (vs carapace less transverse and more squarish in appearance, cw/cl 1.3); epistomal median lobe broadly triangular with rounded apex (vs epistomal median lobe broadly triangular with slightly acute apex); thoracic sternites s3/s4 smooth, lacking setae (vs sternites s3/s4 highly setose); short G1 terminal article 0.45 times length of subterminal segment (vs long terminal article 0.55 times length of subterminal segment); basal two-thirds of G1 subterminal segment broader than distal one-third (vs basal half of G1 subterminal segment broader than distal half) (Figures 2A,B, 3A,E, 4A,B, 5A,E, 8A,B).

Ecological notes
Ghatiana aurantiaca lives on land inside cavities of laterite boulders, and inside holes in tree trunks (present study). This crab species is active during the night in the rainy season when it is often seen walking on the ground, on laterite boulders, or climbing up tree trunks (Pati and Sharma, unpublished data).

Distribution
Known only from the type locality.
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.
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.
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).