Karkata ghanarakta, Pati & Rajesh & Raj & Sheeja & Kumar & Sureshan, 2017

Pati, S. K., Rajesh, L., Raj, Smrithy, Sheeja, V. U., Kumar, A. Biju & Sureshan, P. M., 2017, Karkata, a new genus of gecarcinucid freshwater crab with two new species, and four new species of Pilarta Bahir and Yeo, 2007 and Cylindrotelphusa Alcock, 1909 (Decapoda: Brachyura) from Kerala, India, Journal of Natural History (J. Nat. Hist.) 51 (23 - 24), pp. 1295-1330 : 1301-1305

publication ID

https://doi.org/ 10.1080/00222933.2017.1324054

publication LSID

lsid:zoobank.org:pub:AB9B01DA-B23F-4AC2-9349-75ADDBBBF707

persistent identifier

https://treatment.plazi.org/id/6B110E66-FC42-4B68-969E-26EB082FA2C7

taxon LSID

lsid:zoobank.org:act:6B110E66-FC42-4B68-969E-26EB082FA2C7

treatment provided by

Felipe

scientific name

Karkata ghanarakta
status

sp. nov.

Karkata ghanarakta View in CoL sp. nov.

( Figures 2 View Figure 2 (a–i), 3(a–d) and 6(a,b))

Type specimens

Holotype: male (cw 27.94 mm, cl 21.06 mm, ch 13.12 mm, fw 8.39 mm), Kolumba , Thattekkad Bird Sanctuary, Ernakulam district, Kerala, India (10.115°N, 76.709°E; altitude 58 m), 18 June 2016, coll. P.M. Sureshan (ZSI, WRC-C.1523). GoogleMaps

Paratypes: 1 male (cw 28.41 mm, cl 21.14 mm, ch 12.79 mm, fw 8.53 mm), Kallippara, near Sathrappadi, Thattekkad Bird Sanctuary , Ernakulam district, Kerala, India (10.136°N, 76.726°E; altitude 85 m), 22 April 2015, coll GoogleMaps . P GoogleMaps .M . Sureshan (ZSI, WRC-C.1524); 1 male (cw 23.91 mm, cl 18.17 mm, ch 11.73 mm, fw 7.74 mm), Urulanthanni , Thattekkad Bird Sanctuary, Ernakulam district, Kerala, India (10.131°N, 76.750°E; altitude 120 m), 25 February 2014, coll GoogleMaps . Md GoogleMaps . Jafer Palot (ZSI, WRC-C.1525); 1 female (cw 38.20 mm, cl 28.51 mm, ch 17.98 mm, fw 11.06 mm), Knachery , Thattekkad Bird Sanctuary, Ernakulam district, Kerala, India (10.123°N, 76.749°E; altitude 256 m), 29 October 2015, coll GoogleMaps . K GoogleMaps .G. Emiliyamma (ZSI, WRC-C.1526).

Diagnosis

Carapace slightly broader than long (cw/cl = ca. 1.3), deep (ch/cl = ca. 0.6), maroon coloured; dorsal surface smooth except epigastric and postorbital cristae, frontal region and lateral margins; anterolateral margin with short, oblique striae; posterolateral margin with long, transverse striae; front slightly broad, granular; epigastric and postorbital cristae well developed; external orbital angle acutely triangular; epibranchial tooth small, blunt; cervical grooves distinct; H-shaped groove deep ( Figure 2 View Figure 2 (a,b)). Sutures between male thoracic sternites s2/s3 and s3/s4 prominent as deep grooves ( Figure 2 View Figure 2 (c,g)). Male abdomen T-shaped; sixth abdominal somite nearly as long as broad, longer than telson ( Figure 2 View Figure 2 (c,h)). G1 almost straight; terminal segment cone-shaped, very short, ca. 0.2 times length of subterminal segment; basal half of subterminal segment with almost straight outer margin ( Figure 3 View Figure 3 (a–c)). G2 with short distal segment, ca. 0.3 times length of basal segment ( Figure 3 View Figure 3 (d)).

Description of male holotype

Carapace slightly broader than long (cw/cl = 1.3), deep (ch/cl = 0.6); dorsal surface slightly convex in frontal view, smooth except epigastric and postorbital cristae, frontal region and lateral margins; anterolateral surface slightly inflated in frontal view; anterolateral margin short, with distinct, short, oblique striae; posterolateral margin with distinct, long, transverse striae; front distinctly granular; frontal margin almost straight, slightly broad (fw/cw = 0.3); epigastric cristae distinct; postorbital cristae distinct, sharp, reaching rugose epigastric cristae; external orbital angle acutely triangular, outer margin short, ca. 2 times length of inner margin; epibranchial tooth small, blunt, separated from external orbital angle by distinct cleft; postorbital region strongly concave; branchial regions slightly inflated, with distinct striae adjacent to lateral margins; subhepatic region rugose; cervical grooves distinct, shallow, broad, discontinuous, not reaching up to postorbital cristae; mesogastric groove deep, long, narrow, bifurcated posteriorly; H-shaped groove distinct, deep; frontal median triangle incomplete, with cristate dorsal margin only, lateral margins not developed; epistome posterior margin with prominent, triangular median lobe, almost straight lateral lobes ( Figure 2 View Figure 2 (a,b)).

Chelipeds unequal, right chela slightly larger; fingers of major cheliped with 9 or 10 large, blunt teeth, small gape when their tips in contact; outer surface of carpus rugose; major tooth of carpus long, sharp; outer surface of merus rugose ( Figure 2 View Figure 2 (c–e)).

Ambulatory legs long, slender, with only scattered setae; dactylus (p2–p5) longer than propodus; longest propodus (p3) 2.5 times as long as broad ( Figure 2 View Figure 2 (a,f)).

Suture between thoracic sternites s2/s3 prominent, deep, not reaching lateral margins, suture between sternites s3/s4 prominent, deep, reaching lateral margins ( Figure 2 View Figure 2 (c,g)).

Abdomen T-shaped; fifth abdominal somite distinctly broader than long; sixth abdominal somite nearly as long as broad, longer than telson, with almost straight lateral margins; telson broadly triangular, as long as broad, with straight lateral margins, apex round; sternoabdominal cavity deep, long, extending up to imaginary line joining median part of cheliped coxae ( Figure 2 View Figure 2 (c,h)).

Mandibular palp with 2 segments, terminal segment bilobed. First, second maxillipeds each with long flagellum on exopod. Third maxillipeds cover most of buccal cavity when closed; ischium subrectangular, longer than broad, with distinct oblique, median sulcus; merus subrectangular, broader than long; exopod longer than ischium, not reaching lower third of merus, lacking flagellum ( Figure 2 View Figure 2 (i)).

G1 almost straight; terminal segment cone-shaped, very short, ca. 0.2 times length of subterminal segment; subterminal segment with almost straight inner and outer margins ( Figure 3 View Figure 3 (a–c)). G2 with short distal segment, ca. 0.3 times length of basal segment ( Figure 3 View Figure 3 (d)).

Live colour

The carapace is with dark maroon dorsal surface and light maroon ventral surface. Chelipeds and ambulatory legs are maroon.

Paratypes

The male paratypes (ZSI, WRC-C.1524, 1525) are similar to the holotype in carapace morphology and gonopod structure except for some minor differences: slightly inflated anterolateral surface of carapace (vs less inflated), comparatively more inflated branchial regions (vs slightly inflated), and larger left chela in the bigger male paratype (ZSI, WRC- C.1524) (vs larger right chela).

The female paratype (ZSI, WRC-C.1526) is an adult and resembles the holotype in most non-sexual characters except for its slightly inflated anterolateral surface of carapace (vs less inflated), slightly granular front (vs distinctly granular), larger left chela (vs larger right chela), and indistinct median sulcus on the third maxilliped ischium (vs distinct). The abdomen of the female paratype is broadly ovate, covering most of the sternum except for the thoracic sternite 2 when closed ( Figure 6 View Figure 6 (a)). The vulvae are orbicular, large, occupying nearly half the length of thoracic sternite 6, situated slightly away from the margin with thoracic sternite 5, surrounded by a low rim and completely covered by a soft operculum ( Figure 6 View Figure 6 (b)).

Etymology

The species epithet, ghanarakta , is derived from the Sanskrit for ‘maroon’, referring to the maroon colouration of the live crabs. Used as a noun in apposition.

Type locality

Kolumba , Thattekkad Bird Sanctuary, Ernakulam district, Kerala, India (10.115°N, 76.709°E; altitude 58 m) GoogleMaps .

Remarks

Karkata ghanarakta sp. nov. is most similar to K. kusumbha sp. nov. in general carapace morphology and gonopod structure. Nevertheless, K. ghanarakta is easily differentiated from K. kusumbha by its maroon live colouration ( Figure 2 View Figure 2 (a)) as against the orange-red live colouration of the latter species ( Figure 4 View Figure 4 (a)). The basal half of the G1 subterminal segment has an almost straight outer margin in K. ghanarakta ( Figure 3 View Figure 3 (a,c)) whereas that of K. kusumbha is distinctly concave ( Figure 5 View Figure 5 (a,c)).

Ecological notes

Karkata ghanarakta was found inside a degraded semi-evergreen forest patch in rocky terrain with numerous boulders and almost no undergrowth or water flow. Specimens were collected from the crevices underneath the boulders. The species is very common in Thattekkad Bird Sanctuary.

Geographic distribution

Karkata ghanarakta sp. nov. is known only from the Thattekkad Bird Sanctuary, which is within the limits of the Western Ghats in Ernakulam district of Kerala.

Kingdom

Animalia

Phylum

Arthropoda

Class

Malacostraca

Order

Decapoda

Family

Gecarcinucidae

Genus

Karkata

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