Cylindrotelphusa longiphallus, 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 : 1325-1328

Cylindrotelphusa longiphallus sp. nov.

( Figures 6 (i,j), 13(a–i) and 14(a–d))

Type specimens

Holotype: male (cw 24.12 mm, cl 18.84 mm, ch 15.53 mm, fw 6.25 mm), Kuzhikattusseri , ca. 8 km south west of Chalakudi , Mukundapuram taluk, Thrissur district, Kerala, India (10.289°N, 76.278°E; altitude 14 m), 10 May 2015, coll. V. U. Sheeja (ZSI, WRC-C.1536).

Paratypes: 2 males (cw 19.98–22.70 mm, cl 15.86–18.00 mm, ch 12.71–15.29 mm, fw 5.14–5.86 mm), 1 female (cw 30.43 mm, cl 24.19 mm, ch 20.41 mm, fw 7.54 mm), same data as holotype (ZSI, WRC-C.1537).

Diagnosis

Carapace slightly broader than long (cw/cl = ca. 1.3), deep (ch/cl = ca. 0.8–0.9); dorsal surface strongly convex; anterolateral margin distinctly serrated; frontal margin narrow (fw/cw = ca. 0.25), smooth, bilobed; epigastric cristae represented by 2 low, broad protuberances; postorbital cristae indistinct except for two short lateral ridges; external orbital angle triangular, outer margin same length as inner margin; epibranchial tooth indistinct or small, blunt; postorbital region gently concave; cervical grooves shallow, narrow, almost continuous, not reaching up to postorbital cristae; mesogastric groove shallow, long, bifurcated posteriorly; epistome posterior margin with gently sinuous lateral lobes ( Figure 13 (a,b)). Ambulatory legs long, slender ( Figure 13 (a,f)). Anterior male thoracic sternites (s1–s4) sparsely setose; suture between thoracic sternites s2/s3 visible as shallow depression, suture between sternites s3/s4 visible as deep, broad groove, reaching lateral margins ( Figure 13 (c,g)). Male abdomen narrowly triangular; sixth abdominal somite with straight lateral margins; telson as long as broad ( Figure 13 (c,h)). G1 long, slender; terminal segment slightly curved outwards, slender, very long, ca. 0.6 times length of subterminal segment, with pointed tip ( Figure 14 (a–c)). G2 short, with short distal segment, ca. 0.3 times length of basal segment; proximal third of basal segment distinctly broader than distal two-thirds ( Figure 14 (d)).

Description of male holotype

Carapace slightly broader than long (cw/cl = 1.3), deep (ch/cl = 0.8); 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 represented by 2 low, broad protuberances; postorbital cristae indistinct except for two short lateral ridges; external orbital angle triangular, outer margin same length as inner margin; epibranchial tooth small, blunt; postorbital region gently concave; branchial regions highly inflated, slightly rugose; subhepatic region rugose; cervical grooves shallow, narrow, almost continuous, not reaching up to postorbital cristae; mesogastric groove shallow, long, bifurcated posteriorly; H-shaped groove visible; frontal median triangle with dorsal margin only; epistome posterior margin with prominent, triangular median lobe, gently sinuous lateral lobes ( Figure 13 (a,b)).

Chelipeds rugose, unequal; right chela larger; cheliped fingers with blunt and/or conical teeth; inner surface of palm nearly smooth; carpal spine prominent, pointed ( Figure 13 (a,c–e)).

Ambulatory legs long, slender; dactylus (p2–p5) longer than propodus; longest propodus (p3) 2.5 times as long as broad ( Figure 13 (a,f)).

Anterior thoracic sternites (s1–s4) sparsely setose; suture between thoracic sternites s2/s3 visible as shallow depression, suture between sternites s3/s4 visible as deep, broad groove, reaching lateral margins ( Figure 13 (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 median part of cheliped coxae ( Figure 13 (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, reaching lower third of merus, with well developed flagellum ( Figure 13 (i)).

G1 long, slender; terminal segment slightly curved outwards, slender, very long, ca. 0.6 times length of subterminal segment, with pointed tip ( Figure 14 (a–c)). G2 short, with short distal segment, ca. 0.3 times length of basal segment; proximal third of basal segment distinctly broader than distal two-thirds ( Figure 14 (d)).

Live colour

Carapace is dark brown, with brown chelipeds and ambulatory legs.

Paratypes

The male paratypes (ZSI, WRC-C.1537) have the same characteristics of carapace and gonopods as the holotype. The epibranchial teeth of the smaller male paratype, however, are indistinct. Also, the left chela is larger than the right chela in the male paratypes.

The female paratype (ZSI, WRC-C.1537) is an adult and looks like the holotype in nonsexual characters. Its abdomen is ovate, expanded, covering the sternum except for the anterior thoracic sternites when closed ( Figure 6 (i)). The vulvae are suborbicular, large, occupying nearly half the length of thoracic sternite 6, situated adjacent to the margin with thoracic sternite 5, surrounded by a raised rim and completely covered by a soft operculum ( Figure 6 (j)).

Etymology

The species name is derived from the Latin ‘longi’ for long, and the Greek ‘phallus’ for the penis, used as per the general convention in brachyuran names, alluding to the long 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

Kuzhikattusseri , Thrissur district, Kerala, India (10.289°N, 76.278°E; altitude 14 m) .

Remarks

Cylindrotelphusa longiphallus sp. nov. is easily distinguished from all congeners due to its shallow, narrow cervical grooves and relatively slender ambulatory legs ( Figure 13 (a)).

In addition, C. longiphallus sp. nov. is differentiated from C. breviphallus sp. nov. and C. steniops by the indistinct epigastric and postorbital cristae (vs distinct epigastric and postorbital cristae), slightly curved G1 terminal segment (vs distinctly curved G1 terminal segment), and comparatively long G2 distal segment, ca. 0.3 times the length of the basal segment (vs comparatively short G2 distal segment, ca. 0.2 times the length of the basal segment) ( Figures 11 (a) and 12(a–d) for C. breviphallus ; Figures 13 (a) and 14(a–d) for C. longiphallus ; see Bahir and Yeo 2007, figs 4(a–d) and 5(a) for C. steniops ).

Besides the differences in appearance of the cervical grooves and ambulatory legs, C. longiphallus is separated from C. granulata by the smooth, bilobed frontal margin (vs finely granular, nearly straight frontal margin), triangular, distinct external orbital angle (vs low, indistinct external orbital angle), and cervical grooves not 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 13 (a,b) for C. longiphallus ; see Pillai 1951, fig. 3 for C. granulata ).

Ecological notes

Specimens were collected from deep burrows along the paddy field embankments near to a pond from either shaded or open areas. Their burrows were interconnected and filled with water at the base. They were common at the collection site.

Geographic distribution

The new species is known only from the type locality, Kuzhikattusseri of Thrissur district in Kerala .

Key to the species of Cylindrotelphusa

1. Frontal margin finely granular, nearly straight; external orbital angle low, indistinct; cervical grooves long, extending beyond postorbital cristae up to external orbital angle........................................ ........................................ Cylindrotelphusa granulata ( Pillai, 1951)

- Frontal margin smooth, bilobed; external orbital angle triangular, distinct; cervical grooves relatively short, not extending beyond postorbital cristae.................................. 2

2. Epigastric and postorbital cristae indistinct; cervical grooves shallow, narrow; ambulatory legs relatively slender; G1 terminal segment slightly curved; G2 distal segment relatively long, ca. 0.3 times length of basal segment................................................................. ................................................................................................ Cylindrotelphusa longiphallus sp. nov.

- Epigastric and postorbital cristae distinct; cervical grooves deep, broad; ambulatory legs relatively stout; G1 terminal segment distinctly curved; G2 distal segment relatively short, ca. 0.2 times length of basal segment .................................................................. 3

3. Epistome posterior margin with gently sinuous lateral lobes; sixth male abdominal somite with straight lateral margins; male telson as long as broad; G1 stout, with stout, short terminal segment, ca. 0.4 times length of subterminal segment; G2 with slimmer basal segment, proximal third distinctly broader than distal two-thirds........... ................................................................................................ Cylindrotelphusa breviphallus sp. nov.

- Epistome posterior margin with distinctly sinuous lateral lobes; sixth male abdominal somite with slightly convex lateral margins; male telson slightly longer than broad; G1 slender, with slender, long terminal segment, ca. 0.6 times length of subterminal segment; G2 with stouter basal segment, proximal half distinctly broader than distal half.................................................................................... Cylindrotelphusa steniops ( Alcock, 1909)

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 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.