Cosmocerca asansolensis, Banerjee & Sou, 2020

Banerjee, Siddharthasankar & Sou, Sujan Kumar, 2020, Description of a new species of Cosmocerca Diesing, 1861 (Nematoda Cosmocercidae) in Hoplobatrachus crassus (Jerdon, 1853) (Anura: Dicroglossidae from Asansol coal-field area, West Bengal, India, Zootaxa 4859 (2), pp. 293-299 : 294

Cosmocerca asansolensis sp. nov.

( Fig. 1 a–1i; Fig. 2 a–2f)

General morphology: Adult worms whitish in colour and filiform in shape with transversely striated cuticle. Lateral alae large, extending from the posterior to the head to the level of second pair of plectanes posterior from cloaca in males and at the base of the tail in females. Somatic papillae in four submedian rows which extend at the level of nerve ring to the tail end. Triangular mouth with three lips; dorsal lip with two submedian cephalic papillae and each ventrolateral lip with one submedian cephalic papilla and one amphid. Oesophagus divided into a short pharynx, a long corpus and an oesophageal bulb followed by a long intestine. Nerve ring situated at the middle of the corpus. Cervical papillae situated above the nerve ring. Excretory pore anterior to the oesophageal bulb.

Male: (Based on holotype and three paratypes): Body length 3.063±0.908 (2.09–3.89) [3.80], maximum width 0.283±0.030 (0.25–0.31) [0.30]. Total length of oesophagus 0.320±0.010 (0.31–0.33) [0.32], of pharynx 0.256±0.025 (0.023–0.028) [0.02] long and 0.022±0.0002 (0.0224–0.0229) [0.02] wide, of cylindrical part of oesophagus 0.021±0.001 (0.21–0.23) [0.23] long and 0.026±0.002 (0.024–0.028) [0.02] wide, of oesophageal bulb 0.70±0.001 (0.07–0.072) [0.07] long and 0.586±0.005 (0.058–0.059) [0.051] wide. Distance of nerve ring 0.176±0.015 (0.16– 0.19) [0.18], of excretory pore 0.323±0.005 (0.32–0.33) [0.32], of cervical papillae 0.142±0.001 (0.14–0.143) [0.14] from anterior end. Tail 0.34±0.020 (0.32–0.36) [0.35] long, conical, ending in a small spike. Five pairs of preanal plectanes consisting of 10–12 sclerotized segments present in two rows. Each plectane supports a central rosette papilla with 7–8 posterior tubercles. Caudal region provided with numerous subventral and lateral small papillae indistinguishable from the somatic papillae by their size and continuation with the rows of somatic papillae of the pre-caudal region. Larger caudal papillae consisting of one pair large postanal papillae situated slightly posterior to the cloaca, one unpaired median papilla on the upper lip of cloaca, one papilla on the lower lip of cloaca and one pair adanal papillae on lateral fields of cloaca. Plectane region provided with oblique, paired subventral muscle bands. Phasmids 0.243±0.005 (0.24–0.25) [0.24] from posterior end. Spicules equal, 0.136±0.015 (0.12–0.15) [0.15] long and 0.063±0.005 (0.06–0.07) [0.07] wide, moderately sclerotized, knobbed and wide proximal end gradually tapering to a fine point distally. Gubernaculum well sclerotized, Y-shaped, 0.101±0.001 (0.10–0.102) [0.10] in length and 0.065±0.004 (0.06–0.069) [0.06] in width .

Female: (Based on allotype and five paratypes): Body length 5.376±0.253 (5.10–5.76) [5.55], maximum width 0.418±0.021 (0.39–0.45) [0.43]. Total length of oesophagus 0.520±0.015 (0.50–0.54) [0.52], of pharynx 0.041±0.001 (0.04–0.042) [0.04] long and 0.048±0.0008 (0.047 –0.049) [0.04] wide, of cylindrical part of oesophagus 0.40±0.012 (0.39–0.42) [0.41] long and 0.064±0.005 (0.06–0.07) [0.07] wide, of oesophageal bulb 0.766±0.047 (0.071 –0.082) [0.08] long and 0.424±0.462 (0.08–0.10) [0.09] wide. Distance of nerve ring 0.186±0.008 (0.18–0.20) [0.19], of cervical papillae 0.158±0.001 (0.157 –0.159) [0.15], of excretory pore 0.50±0.048 (0.45–0.56) [0.54] from anterior end. Tail, 0.434±0.005 (0.43–0.44) [0.42] long, conical at the base then narrows rapidly to form a terminal filament. Phasmids 0.352±0.019 (0.33–0.38) [0.37] from posterior end. One pair of postanal papillae present at the base of the tail filament. Vulva equatorial, 2.804±0.101 (2.68–2.91) [2.89] from posterior end. Ovaries two, uteri prodelphic. Eggs 0.051–0.08 x 0.03–0.052, embryonated when laid.

Figures

FIGURE 1 (a–i): Cosmocerca asansolensis sp. nov. 1a. Anterior end of male, lateral view. 1b. Anterior end of female, dorsal view. 1c. Enlarged view of anterior end of female, dorsal view. 1d. Posterior end of male, ventral view. 1e. Enlarged view of cloacal region of male, ventral view. 1f. Enlarged view of plectane with rosette papilla, ventral view. 1g. Vulvar region, lateral view, arrow points indicate towards the cephalic end. 1h. Posterior end of female, ventral view. 1i. Embryonated egg.

FIGURE 2 (a–f), SEM micrographs: Cosmocerca asansolensis sp. nov. 2a. Head, en face view. 2b. Posterior region of male, ventro-lateral view. 2c. Ventral region of male showing arrangement of plectanes. 2d. Plectanes of male, ventral view. 2e. Posterior region of male showing rosette papillae, ventral view. 2f. Posterior region of female showing tail filament. (Abbreviations used: a—anus, adp—adanal papillae, al—lateral alae, am—amphid, cla—cloaca, cp—cephalic papillae, cr—cuticular rim, m—mouth, plc—papillae on lower lip of cloaca, pap—postanal papillae, pl—plectane, puc—papillae on upper lip of cloaca, rsp—rosette papillae, sp—somatic papillae, tt—tail tip).