Habrobathynella savitri, Reddy, Yenumula Ranga & Totakura, Venkateswara Rao, 2010

Reddy, Yenumula Ranga & Totakura, Venkateswara Rao, 2010, A taxonomic revision of the genus Habrobathynella Schminke, 1973, with the description of four new species from southeastern India (Crustacea, Malacostraca, Bathynellacea), Zootaxa 2532, pp. 1-54 : 20-23

Habrobathynella savitri n. sp.

( Figs 15–21)

Type material. Holotype 3 (dissected on 4 slides) (C5842/2, C5843/2, C5844/2, C5845/2), allotype Ƥ (dissected on 3 slides) [MNHN-Sy33 (1–3)] and 5 paratypes: 1 Ƥ (dissected on 3 slides) [MNHN-Sy34(1–3); 2 33 (dissected on 3 slides each) [MNHN-Sy36(1–3), MNHN-Sy37(1–3)]; 1 3 (whole-mounted) (MNHN- Sy39), 1 3 in alcohol ((MNHN-Sy47); also, 1 adult 3 and 1 juvenile 3 (in junior’s collection), River Godavari at Sundarapalli village (16o47ʹ20ʹ N 82 o0 3 ΄25΄ E; elevation 14 m; water 30°C; pH 7.5) in East Godavari District, Andhra Pradesh, India, leg. V.R. Totakura, 18 May 2008.

Other material examined. 1 Ƥ, 1 3 (dissected on 3 slides each) [MNHN-Sy35(1-3), [MNHN-Sy38(1– 3)]; 2 33, 1 Ƥ in alcohol (MNHN-Sy48), River Godavari at Dhawaleswaram town (16o48ʹ0 9ʹ N 80 o0 4 ʹ18ʹ E; elevation 27 m) in East Godavari District, Andhra Pradesh, India, leg. V.R. Totakura, 13 October 2008. 1 adult 3 (in junior’s collection), River Godavari at Kapileswarapuram (16o41ʹ26ʹ N 82 o0 2 ΄24΄ E; elevation 23 m), India, leg. V.R. Totakura, 3 March 2008.

Diagnosis. On male thoracopod VIII, outer lobe conical, longer than basipod and smooth apically; dentate and inner lobes only moderately produced, extending but little beyond exopod; exopod claw-like, incurved in lateral views but somewhat rectangular, with denticulate apical margin in anterior, posterior and ventral views. Female thoracopod VIII as thin elliptical lobe. Uropodal sympod with inhomonomous row of 4 spines; ultimate spine modified into barbed seta; penultimate spine thicker and longer than proximal 2 spines. Setae on pleotelson longer than caudal furca. Maxilla with 1 tiny seta on segment 1 and long but slender prehensile claw-like seta on segment 2. Apophysis on antennular segment 4 nearly as long as segment 5.

Description of adult male. Total body length of holotype 0.67 mm, of paratypes 0.66–0.73 mm, mean 0.69 mm (n = 3). Body ( Fig. 15) elongate, perforated, 9.2 times as long as wide. Abdominal segments as in H. krishna . Head 1.3 times as long as wide and 11.5% longer than first three thoracic segments combined.

Antennule ( Fig. 16 a): 6-segmented; 23% longer than head. First segment with 1 plumose seta on subdistal outer margin, 1 simple seta and 1 plumose seta at outer distal corner, and 2 simple setae on dorsal surface. Second segment with 1 ventral and 2 dorsal plumose setae near inner distal corner, 1 plumose seta and 1 tiny seta near distal margin. Third segment with 2 ventral plumose setae and 1 simple seta near inner distal corner; 1 simple seta at inner distal corner. Inner flagellum square, with 3 unequal apical setae. Fourth segment with 2 plumose unequal setae on apophysis and 1 plumose seta on small protrusion near inner distal corner; stub seta absent. Apophysis almost reaching distal end of fifth segment. Fifth segment with 3 nearly equal aesthetascs, as long as next segment, and 4 setae. Sixth segment with 3 aesthetascs and 4 unequal setae.

Antenna ( Fig. 16 b): 2-segmented, proximal segment unarmed, 0.4 times as long as distal segment; second segment 2.4 times as long as wide, with 1 tiny proximal seta, 2 unequal terminal setae, of which inner one plumose and 1.4 times as long as segment, and 1 tiny subterminal dorsal seta.

Labrum ( Fig. 16 c): dentate margin moderately vaulted on either side, bearing 12 main nearly uniform, pointed, curved teeth and 1 small tooth on either side. Also, 4 rows of fine spinules (ctenidia) and 3 teats on ventral surface.

Mandible ( Fig. 16 e): distal part of pars incisiva with 4 unequal teeth. Tooth of ventral edge large. Pars molaris developed into subpyriform outgrowth, 0.8 times as long as wide, carrying 2 smooth, curved teeth on inner margin and 3 straight slender pointed teeth in a group at distal end, all teeth articulate and apparently without ornamentation; also, 1 unarticulate tooth at distal outer corner. Palp completely absent.

Paragnath ( Fig. 16 f): represented by hemispherical plate with nipple-like median protuberance; proximal margin ornamented with very tiny denticles, as in preceding species.

Maxillule ( Fig. 16 g–h): with 2 endites; proximal endite oval, carrying 4 unequal claw-like unipinnate spines on inner distal margin; distalmost claw sturdy and falcate. Distal endite subcylindrical, 3.6 times as long as wide and armed with 4 terminal claws, distalmost claw large, bent inwards; 2 unequal claws on inner margin and 3 subterminal setae on outer distal margin.

Maxilla ( Fig. 16 i–j): 3-segmented, somewhat bent inwards; basal segment 1.9 times as long as wide, with 1 tiny seta on small protuberance at inner distal corner. Second segment 1.3 times as long as basal segment and armed with 14 simple setae including 1 seta at midlength of inner margin and 1 long but slender prehensile claw-like seta at inner distal corner. Third segment completely fused with terminal sickle-shaped claw; claw with finely serrulate inner margin.

Thoracopods I–VII ( Figs 17 a–e, 18a–b): as in H. krishna except for proportions of exo- and endopodal segments.

Thoracopod VIII ( Figs 18 c–d, 19a–c): somewhat globular and 1.1 times as long as wide. Protopod large and dilated in lateral views. Outer lobe fused with protopod, conical, longer than basipod and smooth apically. Dentate and inner lobes only moderately produced, extending but little beyond exopod. Dentate lobe stronger and longer than inner lobe and ornamented with 3 rows of denticles. Inner lobe thumb-like. Basipod welldefined at base, armed with thick seta at outer subdistal corner and without any ornamentation at inner distal angle. Exopod claw-like, incurved in lateral views ( Fig. 18 c–d), somewhat rectangular, with denticulate apical margin in anterior, posterior and ventral views ( Fig. 19 a–c) and distinct from basipod. Endopod represented by 1 seta, inserted close to exopod.

Pleopod 1: absent.

Uropod ( Fig. 20 a): sympod 3.7 times as long as maximum width, bearing inhomonomous row of 4 spines: proximal 2 spines almost equal in size; penultimate spine longer and thicker than other spines; ultimate spine modified into slender barbed seta. Exopod slightly incurved, 31% of sympod length and with 1 long apical and 1 short subapical plumose setae. Endopod falcate, 61% of sympod length, with 2 equal, barbed setae at proximal quarter of outer margin; disto-lateral margins ornamented with spinules.

Pleotelson ( Fig. 20 a): with 1 seta on either side at base of caudal furca; seta as long as caudal furca.

Anal operculum: somewhat protruded in lateral view ( Figs 20 a–c), medially concave (not illustrated).

Caudal furca ( Fig. 20 a): slightly longer than maximum width, with 1 terminal and 3 inner serrulate spines and 2 unequal dorsal plumose setae; spines without spinules at base; furcal organ small, ventral.

Description of adult female. Total body length 0.72 mm, of paratypes length 0.67–0.76 mm, mean 0.71 mm (n = 3). Body and all appendages except Th. VIII as in male.

Thoracopod VIII ( Fig. 20 d): thin, elliptical lobe, lying obliquely to anterior margin of eighth thoracic segment.

Variation. Vau l ti ng condition of labrum shows inter-population variation ( Fig. 16 c–d). No variation in the number of spines on uropodal sympod.

Description of juvenile male ( Fig. 21 a–e): total length 0.62 mm. Body form as in adult, 7.3 times longer than maximum width. Head 1.4 times as long as wide. Body segmentation and various details of cephalic appendages also as in adult, but differing in the following respects: Th. I–V adult-like; Th. V–VII ( Fig. 21 a–c) rudimentary; epipod present but not well defined at base; basis without seta; exo- and endopod unsegmented; exopod slightly shorter than endopod and with 2 simple apical setae; endopod unarmed. Th. VIII ( Fig. 21 e) rudimentary; protopod large; outer lobe distinct; dentate lobe with smooth margin. Basipod with well-defined base and without setae. Pleotelson seta as in adult ( Fig. 21 d). Sympod 4.2 times as long as maximum width. Exopod straight, 29% of sympod length; endopod 45.8% of sympod length; armature as in adult. Caudal furca 1.3 times as long as maximum width, with 1 terminal and 3 inner serrulate spines and 2 unequal dorsal plumose setae; proximal 2 spines distinctly smaller than others.

Etymology. The specific epithet is derived from Sri Aurobindo’s epic “ Savitri ”, meaning “a ray of light”; proposed here as a noun in apposition to the generic name.

Figures

FIGURE 16. Habrobathynella savitri n. sp., holotype male (c, f – j), allotype female (d) and paratype male (a, b, e). (a) antennule, dorso-lateral; (b) antenna, dorsal; (c) labrum, dorsal; (d) same, ventral; (e) mandible, ventral; (f) paragnath, ventral; (g) maxillule, lateral; (h) same, ventral; (i) maxilla, lateral (j) same, inner distal corner of segment 1 enlarged.

FIGURE 17. Habrobathynella savitri n. sp., holotype male. (a – e) Th. I – V.

FIGURE 18. Habrobathynella savitri n. sp., holotype male (a – c) and paratype male (d). (a – b) Th. VI – VII; (c) Th. VIII.,

FIGURE 19. Habrobathynella savitri n. sp., paratype male. (a) Th. VIII, anterior; (b) Th. VIII, posterior; (c) Th. VIII,

FIGURE 20. Habrobathynella savitri n. sp., holotype male (a), allotype female (d) and paratype female (b – c). (a) pleotelson, lateral (arrow pointing to dilated inner margin of sympod); (b – c) anal operculum, lateral; (d) Th. VIII, lateral.

FIGURE 21. Habrobathynella savitri n. sp., male juvenile. (a – c) Th. V – VII; (d) pleotelson, ventral; (e) Th. VIII, latero – internal.