Cylindrotelphusa breviphallus, 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 : 1322-1325

Cylindrotelphusa breviphallus sp. nov.

( Figures 6 (g,h), 11(a–i) and 12(a–d))

Type specimens

Holotype: male (cw 27.58 mm, cl 21.60 mm, ch 15.63 mm, fw 7.50 mm), Ponmudi , Thiruvananthapuram district, Kerala, India (8.766°N, 77.110°E; altitude 945 m), 11 August 2014, coll. V. U. Sheeja (ZSI, WRC-C.1533).

Paratypes: 1 male (cw 35.36 mm, cl 27.12 mm, ch 19.60 mm, fw 8.85 mm), 1 female (cw 28.70 mm, cl 21.67 mm, ch 15.80 mm, fw 7.44 mm), same data as holotype (ZSI, WRC-C.1534); 1 male (cw 32.22 mm, cl 24.99 mm, ch 17.02 mm, fw 8.55 mm), 1 female (cw 30.29 mm, cl 23.15 mm, ch 16.73 mm, fw 7.90 mm), same locality and collector as holotype, 10 October 2014 (ZSI, WRC-C.1535).

Diagnosis

Carapace slightly broader than long (cw/cl = ca. 1.3), deep (ch/cl = ca. 0.7); dorsal surface strongly convex; anterolateral margin distinctly serrated; frontal margin narrow (fw/cw = ca. 0.25), smooth, bilobed; epigastric cristae distinct, low, broad; postorbital cristae well developed; external orbital angle triangular, outer margin same length as inner margin; epibranchial tooth small, blunt; postorbital region strongly concave; cervical grooves deep, broad, almost continuous, reaching up to postorbital cristae; mesogastric groove deep, long, bifurcated posteriorly; epistome posterior margin with gently sinuous lateral lobes ( Figure 11 (a,b)). Ambulatory legs long, moderately stout ( Figure 11 (a,f)). Anterior male thoracic sternites (s1–s4) glabrous; suture between thoracic sternites s2/s3 visible as shallow depression, suture between sternites s3/s4 visible as shallow, broad groove, reaching lateral margins ( Figure 11 (c,g)). Male abdomen narrowly triangular; sixth abdominal somite with straight lateral margins; telson as long as broad ( Figure 11 (c,h)). G1 long, stout; terminal segment distinctly curved outwards, stout, short, ca. 0.4 times length of subterminal segment, with narrow, blunt tip ( Figure 12 (a–c)). G2 short, with short distal segment, ca. 0.2 times length of basal segment; proximal third of basal segment distinctly broader than distal twothirds ( Figure 12 (d)).

Description of male holotype

Carapace slightly broader than long (cw/cl = 1.3), deep (ch/cl = 0.7); dorsal surface strongly convex; anterolateral surface inflated in frontal view; anterolateral margin distinctly serrated; posterolateral margin with distinct, long, transverse striae; frontal margin narrow (fw/cw = 0.25), smooth, bilobed; epigastric cristae distinct, low, broad; postorbital cristae well developed; external orbital angle triangular, outer margin same length as inner margin; epibranchial tooth small, blunt; postorbital region strongly concave; branchial regions highly inflated, rugose; subhepatic region rugose; cervical grooves deep, broad, almost continuous, reaching up to postorbital cristae; mesogastric groove deep, long, bifurcated posteriorly; H-shaped groove faintly visible; frontal median triangle with dorsal margin only; epistome posterior margin with prominent, triangular median lobe, gently sinuous lateral lobes ( Figure 11 (a,b)).

Chelipeds highly rugose, unequal; left chela larger; fingers of both chelipeds with large, blunt teeth; inner surface of palm with distinct tubercles; carpus with prominent, pointed inner distal major tooth and small sub-basal granule ( Figure 11 (a,c–e)).

Ambulatory legs long, moderately stout, p3 longest ( Figure 11 (a,f)).

Anterior thoracic sternites (s1–s4) glabrous; suture between thoracic sternites s2/s3 visible as shallow depression, suture between sternites s3/s4 visible as broad, shallow groove, reaching lateral margins ( Figure 11 (c,g)).

Abdomen narrowly triangular; fifth abdominal somite distinctly broader than long, with straight lateral margins; sixth abdominal somite broader than long, as long as telson, with straight lateral margins; telson narrowly triangular, as long as broad, with distinctly concave lateral margins, apex round; sternoabdominal cavity deep, long, extending up to imaginary line joining posterior part of cheliped coxae ( Figure 11 (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 deep, oblique, median sulcus; merus subquadrate, slightly broader than long, not as broad as ischium; exopod longer than ischium, almost reaching lower half of merus, with well developed flagellum ( Figure 11 (i)).

G1 long, stout; terminal segment distinctly curved outwards, stout, short, ca. 0.4 times length of subterminal segment, with narrow, blunt tip ( Figure 12 (a–c)). G2 short, with short distal segment, ca. 0.2 times length of basal segment; proximal third of basal segment distinctly broader than distal two-thirds ( Figure 12 (d)).

Live colour

Carapace, chelipeds and ambulatory legs are all dark brown.

Paratypes

The male paratypes (ZSI, WRC-C.1534, 1535), despite their size differences, are indistinguishable from the holotype in general physiognomy and gonopod structure.

The female paratypes (ZSI, WRC-C.1534, 1535) are adults and identical to the holotype in most non-sexual characters, except that the larger female (ZSI, WRC-C.1535) has a larger right chela. The abdomen of the female paratypes is narrowly ovate, expanded but barely conceals the anterior thoracic sternites ( Figure 6 (g)). The vulvae are suborbicular, 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 (h)).

Etymology

The species name is derived from the Latin ‘brevi’ for short, and the Greek ‘phallus’ for the penis, used as per the general convention in brachyuran names, referring to the short male gonopods (intromittent organs that are not analogous to a penis) of the crab. The name is used as a noun in apposition.

Type locality

Ponmudi , Thiruvananthapuram district, Kerala, India (8.766°N, 77.110°E; altitude 945 m) .

Remarks

Cylindrotelphusa breviphallus sp. nov. is distinguished from C. longiphallus sp. nov. and C. steniops by the stout G1 with stout, short terminal segment, ca. 0.4 times the length of the subterminal segment ( Figure 12 (a–c)) (vs slender G1 with slender, very long terminal segment, ca. 0.6 times the length of the subterminal segment, Figure 14 (a–c) for C. longiphallus ; see Bahir and Yeo 2007, fig. 4(a–c) for C. steniops ).

The new species, C. breviphallus , can be separated from C. granulata by the smooth, bilobed frontal margin (vs finely granular, nearly straight frontal margin), distinct epigastric cristae (vs almost indistinct epigastric cristae), well developed postorbital cristae (vs indistinct postorbital cristae), triangular, distinct external orbital angle (vs low, indistinct external orbital angle), small, blunt epibranchial tooth (indistinct epibranchial tooth), and cervical grooves reaching up to the level of postorbital cristae (vs cervical grooves extending beyond the level of postorbital cristae up to the external orbital angle) ( Figure 11 (a,b) for C. breviphallus ; see Pillai 1951, fig. 3 for C. granulata ).

In the general structure of the carapace and gonopods, C. breviphallus sp. nov. is more similar to C. steniops than to C. longiphallus sp. nov. because both C. breviphallus sp. nov. and C. steniops have distinct epigastric and postorbital cristae, deep, broad cervical grooves, moderately stout ambulatory legs, distinctly curved G1 terminal segment, and comparatively short G2 distal segment, ca. 0.2 times the length of the basal segment ( Figures 11 (a), 12(a–d) for C. breviphallus ; see Bahir and Yeo 2007, figs 4(a–d) and 5(a) for C. steniops ) as compared to the indistinct epigastric and postorbital cristae, shallow, narrow cervical grooves, slenderer ambulatory legs, slightly curved G1 terminal segment, and comparatively long G2 distal segment, ca. 0.3 times the length of the basal segment of C. longiphallus sp. nov. ( Figures 13 (a) and 14(a–d)). Besides the structure of G1, C. breviphallus is separated from C. steniops by the epistome posterior margin with gently sinuous lateral lobes (vs epistome posterior margin with distinctly sinuous lateral lobes), straight lateral margins of the sixth male abdominal somite (vs slightly convex lateral margins of the sixth male abdominal somite), male telson as long as broad (vs male telson slightly longer than broad), and slimmer G2 basal segment, the proximal third distinctly broader than the distal two-thirds (vs stouter G2 basal segment, the proximal half distinctly broader than the distal half) ( Figures 11 (b,c,h) and 12(d) for C. breviphallus ; see Bahir and Yeo 2007, figs 4(d) and 5(b,c) for C. steniops ).

Cylindrotelphusa breviphallus can be further distinguished from C. longiphallus by the absence of setae on the anterior male thoracic sternites ( Figure 11 (c,g)) (vs sparsely setose anterior male thoracic sternites, Figure 13 (c,g)) and blunt tip of the G1 terminal segment ( Figure 12 (b)) (vs pointed tip of the G1 terminal segment, Figure 14 (b)).

Ecological notes

Crabs were collected under the stones of steep hill streams. In addition, the new species is found in shallow burrows in wet soil adjoining the shaded areas of streams. Individuals were also gathered from the tea gardens at Ponmudi. Crabs were generally active during the daylight.

Geographic distribution

Cylindrotelphusa breviphallus is known only from the Western Ghats in Ponmudi (type locality) of Thiruvananthapuram district of Kerala .

Figures

Figure 6. Abdomen and thoracic sternites of female paratypes. (a, b) Adult female paratype of Karkata ghanarakta gen. et sp. nov. (ZSI, WRC-C.1526); (c, d) juvenile female paratype of Karkata kusumbha sp. nov. (ZSI, WRC-C.1528); (e, f) sub-adult female paratype of Pilarta punctatissima sp. nov. (ZSI, WRC-C.1532); (g, h) adult female paratype of Cylindrotelphusa breviphallus sp. nov. (ZSI, WRC-C.1535); (i, j) adult female paratype of Cylindrotelphusa longiphallus sp. nov. (ZSI, WRC-C.1537). (a, c, e, g, i) abdomen; (b, d, f, h, j) thoracic sternites. Scale bars: a, b, g–j = 5 mm; c–f = 2 mm.

Figure 11. Cylindrotelphusa breviphallus sp. nov., holotype male (ZSI, WRC-C.1533). (a) Dorsal view; (b) frontal view; (c) ventral view; (d) left or major cheliped; (e) carpus of major cheliped; (f) right ambulatory leg (p3); (g) anterior thoracic sternites (s1–s4); (h) abdominal somites 4–6 and telson; (i) left third maxilliped. Scale bars: a–c = 10 mm; d, f = 5 mm; e, g–i = 2 mm.

Figure 12. Cylindrotelphusa breviphallus sp. nov., holotype male (ZSI, WRC-C.1533). (a) Dorsal view of left G1; (b) dorsal view of left G1 terminal segment; (c) ventral view of left G1; (d) left G2. Scale bars: a, c, d = 1 mm; b = 0.5 mm.

Figure 13. Cylindrotelphusa longiphallus sp. nov., holotype male (ZSI, WRC-C.1536). (a) Dorsal view; (b) frontal view; (c) ventral view; (d) right or major cheliped; (e) carpus of major cheliped; (f) right ambulatory leg (p3); (g) anterior thoracic sternites (s1–s4); (h) abdominal somites 4–6 and telson; (i) left third maxilliped. Scale bars: a–c = 10 mm; d, f = 5 mm; e, g–i = 2 mm.

Figure 14. Cylindrotelphusa longiphallus sp. nov., holotype male (ZSI, WRC-C.1536). (a) Dorsal view of left G1; (b) dorsal view of left G1 terminal segment; (c) ventral view of left G1; (d) left G2. Scale bars: a, c, d = 1 mm; b = 0.5 mm.