Parastenocaris muvattupuzha, Reddy, Yenumula Ranga & Defaye, Danielle, 2009

Reddy, Yenumula Ranga & Defaye, Danielle, 2009, Two new Parastenocarididae (Copepoda, Harpacticoida) from India: Parastenocaris muvattupuzha n. sp. from a river and P. kotumsarensis n. sp. from a cave, Zootaxa 2077, pp. 31-55 : 32-51

publication ID	https://doi.org/ 10.5281/zenodo.187240
DOI	https://doi.org/10.5281/zenodo.6213777
persistent identifier	https://treatment.plazi.org/id/425E87E5-975D-FFEA-FF7B-FA4E46F1F966
treatment provided by	Plazi
scientific name	Parastenocaris muvattupuzha
status	sp. nov.

Treatment

Parastenocaris muvattupuzha View in CoL n. sp.

( Figs 2–8 View FIGURE 2 View FIGURE 3 View FIGURE 4 View FIGURE 5 View FIGURE 6 View FIGURE 7 View FIGURE 8 )

Material examined. Holotype Ƥ (intact on one slide: MNHN-Cp2343), allotype 3 (dissected on one slide: MNHN-Cp2485) and 27 paratypes (2 intact Ƥ on one slide each: MNHN-Cp2344, MNHN-Cp2490; 3 Ƥ dissected on one slide each: MNHN-Cp2345, MNHN-Cp2346, MNHN-Cp2491; 1 3 dissected on two slides, a, b: MNHN-Cp2486; 1 3 dissected on one slide: MNHN-Cp2487; 1 intact 3 on slide: MNHN-Cp2488; 2 intact Ƥ on one single slide: MNHN-Cp2489; 2 33 and 2 Ƥ on an SEM stub; 13 Ƥ in ethanol: MNHN- Cp2347), River Muvattupuzha at Muvattupuzha town (9°58'01"N, 76°34'59"E; altitude 15 m), India, leg. Y. Ranga Reddy, 29 October 2004.

Diagnosis. Body length about 400 µm. Male urosomites 2–5 and female urosomites 2–4 each with dorsal integumental window. Caudal rami of both sexes about 3.5 times as long as wide, slightly tapering distally, with inner corner of each ramus produced into small but distinct unguiform process; lateral setae inserted slightly distal to midlength of ramus. Male antennular segment 7 without apophysis; aesthetasc on segment 5 only slightly exceeding the combined length of segments 6–8. Apophysis of male leg 3 exopod longer than thumb. Male leg 4 basis with 1 large plate-like tooth and spinulose lobe; endopod characteristically clubshaped, with apical brush of spinules. Leg 5 similar in both sexes, represented by subquadrate plate armed with 4 setae and produced into smooth, slender, spiniform process at distal corner.

Description of adult female. Total body length of holotype, measured from base of rostrum to posterior margin of caudal rami (excluding caudal setae), 405 µm. Mean body length of paratypes 385 µm (335–425 µm; n = 19). Preserved specimens colourless. Naupliar eye absent. Body ( Figs 2 View FIGURE 2 A, 7A) cylindrical, very slender, without demarcation between prosome and urosome; prosome/urosome ratio 0.8; body length/width ratio 8.9. Integument moderately chitinised, without surface pits. Hyaline frills of somites smooth. Cephalothorax ( Figs 2 View FIGURE 2 A, 7D) subquadrate, 1.7 times as long as wide, comprising 19% of body length; double integumental window clearly delineated, roughly circular in outline; 2 pairs of cuticular pores present on dorsal surface ( Fig. 7 View FIGURE 7 D). Pedigerous somites 2 and 4 each with cuticular pore anterodorsally ( Fig. 7 View FIGURE 7 A). Urosomites 2–4 each with distinct dorsal integumental window; size and shape of windows as in Figs 2 View FIGURE 2 A–C, 7A. All somites, except preanal somite, with small sensilla ( Figs 2 View FIGURE 2 A–C, 7A).

Genital double-somite ( Figs 2 View FIGURE 2 B–D): slightly longer than wide, without any trace of subdivision, bears 6 sensilla. Genital field ( Fig. 2 View FIGURE 2 D) situated ventrally at proximal third of genital double-somite; composed of median copulatory pore, anterior pair of lobate seminal vesicles and paired distolateral lobes of unknown function. Urosomite 3 with short, transverse row of fine spinules posterodorsally; urosomite 4 with complete transverse row of spinules along posterodorsal margin. Anal somite 1.2 times as long as wide, with 2 small dorsal sensilla, 2 proximolateral cuticular pores and 2 diagonal rows of small proctodeal spinules; anal sinus spinulose ( Fig. 7 View FIGURE 7 B). Anal operculum representing 65% of anal somite width, generally not extending to posterior end of anal somite ( Fig. 2 View FIGURE 2 A), with smooth, straight posterior margin ( Figs 2 View FIGURE 2 A, C).

Caudal rami ( Fig. 2 View FIGURE 2 C): symmetrical, divergent, about 59% of anal somite length; each ramus 3.7 times as long as wide, slightly tapering distally, with inner distal corner produced into small dentate lobe, appearing as dentate projection in lateral view, and with cuticular pore near insertion of seta IV ( Figs 2 View FIGURE 2 B, 7B); outer distal corner ornamented with row of fine spinules. Dorsal seta (seta VII) inserted near inner margin at same level as 3 lateral setae (setae I–III), slightly longer than caudal ramus, bipinnate and basally biarticulate. Lateral setae thin, unequal, shorter than ramus and clustered together slightly beyond midlength of ramus. Inner apical seta (seta VI) inserted partly ventral to outer apical seta (seta V), 60% of ramus length. Outer apical seta (V) without fracture plane, sparsely bipinnate, over twice as long as outer subapical seta (IV) and slightly less than one-third of body length. Outer subapical seta without fracture plane, 14% longer than caudal ramus and with pinnate outer margin.

Rostrum ( Fig. 3 View FIGURE 3 A): small, triangular, weakly chitinised, reaching middle of first antennular segment and not defined at base; bears 2 dorsolateral sensilla.

Antennule ( Figs 3 View FIGURE 3 A, 7C): 7-segmented; segment 1 with ventral spinule row; segment 2 as long as next 3 segments combined. Setal formula: 0, 4 (1 unipinnate), 4, 2+aes, 1, 0 and 8+aes. Aesthetasc on segment 4 slender, nearly straight, constricted at about midlength and extending well beyond antennular tip; that on segment 7 more slender, about 75% longer than segment.

Antenna ( Fig. 3 View FIGURE 3 B): coxa ornamented with transverse row of spinules at inner distal corner. Allobasis 3.2 times as long as wide, with transverse spinule row on inner margin. Exopod 1-segmented, well-defined at base, 3.2 times as long as maximum width, with apical bipinnate seta, nearly twice as long as segment. Endopod 2.4 times as long as wide, 0.7 times as long as allobasis; inner margin with 1 naked and 1 unipinnate short spines, proximal spinule row and distomedial spinule; subdistally with surface frill; distally with 2 bipinnate spines, 2 unipinnate geniculate setae, 1 unipinnate transformed seta and spinule row at outer distal corner.

Mandible ( Fig. 3 View FIGURE 3 C): cutting edge with row of small teeth between smooth dorsal seta and 2 moderately large ventral teeth. Palp 1-segmented, somewhat enlarged apically, about thrice as long as wide, with 2 unequal apical setae.

Maxillule ( Fig. 3 View FIGURE 3 D): praecoxal arthrite with anterolateral articulate seta and 5 apical curved spines. Coxal endite small, with distal seta. Basis longer than coxal endite, armed with 3 apical setae.

Maxilla ( Fig. 3 View FIGURE 3 E): syncoxa with 2 endites; proximal endite shorter, with apical seta; distal endite with 1 smooth and 1 bipinnate seta. Allobasis prolonged into strong, distally spinulose claw. Endopod small, with 2 apical setae.

Maxilliped ( Fig. 3 View FIGURE 3 F): subchelate. Syncoxa small, unarmed. Basis slim and elongate, unarmed. Endopod 1- segmented, small, rounded, bears unipinnate claw.

Leg 1 ( Fig. 4 View FIGURE 4 A): coxa bare. Basis with small outer seta and spinule row along outer margin and between rami. Exopod only slightly longer than endopod; first segment with outer unipinnate spine, which is longer than second segment, and 3 spinule rows on outer margin; second segment half as long as preceding segment, unarmed, with spinule row on outer margin; third segment longer than second segment, with 2 outer setiform spines, 2 geniculate apical setae and 2 outer spinule rows. First endopodal segment shorter than first 2 exopodal segments combined, with 2 transverse spinule rows along outer margin, spinule row at about midlength of inner margin and terminal row of fine spinules; second segment about half as long as first segment, with apical spine, apical geniculate seta and outer and inner spinule rows. All armature elements on apical segments of rami unipinnate.

Leg 2 ( Fig. 4 View FIGURE 4 B): coxa bare. Basis unarmed, with spinule row on outer margin. First exopodal segment shorter than next 2 segments combined, with elongate outer bipinnate spine, 2 transverse spinule rows on outer margin, spinule row distally, spinules at base of spine and hyaline frill at inner distal corner. Second exopodal segment unarmed, with outer and apical spinule rows. Third exopodal segment as long as second segment, with outer spiniform seta, 2 unequal apical setae, outer spinule row and hyaline frill at inner distal corner; all armature elements bipinnate. Endopod 1-segmented, subcylindrical, about 4 times as long as wide and 68% as long as first exopodal segment; with slender apical seta and brush of spinules at apex.

Leg 3 ( Fig. 4 View FIGURE 4 C): coxa without ornamentation. Basis with long outer seta and spinule row at outer distal corner. Exopod 2-segmented; first segment 1.2 times as long as second, with outer bipinnate spine, 2 spinule rows on outer margin, spinule row distally and hyaline frill at inner distal margin; second segment with outer bipinnate spine, apical spiniform seta, spinule row on outer margin, spinules at base of outer spine and hyaline frill at inner distal margin. Endopod 1-segmented, naked, about 0.9 times as long as first exopodal segment, incurved and gradually tapering to acuminate point.

Leg 4 ( Fig. 4 View FIGURE 4 D): coxa bare. Basis with tiny outer seta, spinules on outer margin and oblique row of spinules on anterior surface. Exopod 3-segmented; first segment shorter than next 2 segments combined, with outer bipinnate spine, 2 spinule rows along outer margin, spinule row distally and hyaline frill at inner distal margin; second segment unarmed, with outer and terminal spinule rows; third segment longer than second segment, with outer bipinnate spine, apical seta, spinule row on outer distal margin, fine spinules at base of outer spine and hyaline frill at inner distal margin. Endopod lanceolate, nearly straight, longer than first exopodal segment, with 2 long spinules on inner margin and lateral margins of distal third spinulose.

Leg 5 ( Fig. 4 View FIGURE 4 E): without intercoxal sclerite; represented by subquadrate plate, with inner distal corner produced into smooth, slender spiniform process; free distal margin uneven, with 4 unequal setae; second innermost seta sharply reflexed laterally or anterolaterally; cuticular pore present near proximal outer corner.

Description of adult male. Total body length, excluding caudal setae, of allotype 395 µm. Mean body length of paratypes 380 µm (365–410 µm; n = 4). Habitus shape, ornamentation of prosomites and form of anal operculum similar to those of female. Dorsal integumental window present on cephalothorax and anterior surface of urosomites 2–5; each of these urosomites also ornamented with transverse row of fine spinules along posterodorsal margin ( Figs 5 View FIGURE 5 A–B, 7E). Large, longitudinally oriented spermatophore visible through cuticle of fifth pedigerous somite and genital somite ( Fig. 5 View FIGURE 5 B).

Rostrum as in Fig. 6 View FIGURE 6 A.

Caudal rami ( Figs 5 View FIGURE 5 A, 8A) as in female.

Antennule ( Figs 6 View FIGURE 6 B–C, 8B) 8-segmented, prehensile, strongly geniculate between segments 6 and 7; segment 1 ornamented with ventral spinule row. Segment 2 longest, segment 4 shortest and segments 3–5 moderately enlarged. Segment 7 without apophysis. Setal formula 0, 7 (1 unipinnate), 4, 0, 2+aes, 0, 0 and 8+aes. Aesthetasc on segment 5 more than twice as long as segments 6–8 combined, staff-like, constricted at about midlength. Aesthetasc on segment 8 about half as long as that on segment 5, slender, straight, constricted at midlength.

Other cephalic appendages ( Fig. 7 View FIGURE 7 F, I) and leg 2 (not illustrated) as in female.

Leg 1 ( Figs 6 View FIGURE 6 D, 7I): as in female, except basis with long inner seta.

Leg 3 ( Figs 6 View FIGURE 6 E–G, 7G, 8C): coxa bare. Basis with long lateral seta, lateral pore and oblique row of large spinules at outer distal angle. Exopod modified, with both segments partially fused. Proximal segment moderately strong, incurved, about 3.5 times longer than proximal width; in lateral view, spinule row situated on posterior surface at outer distal corner ( Figs 6 View FIGURE 6 F–G) and inner subdistal margin lined with narrow hyaline lamella ( Fig. 6 View FIGURE 6 G). Apophysis fused with proximal segment; proximal half somewhat swollen, distal half narrow as in Fig. 6 View FIGURE 6 E. Thumb shorter than apophysis, modified into smooth, incurved, pointed spine and inserted on proximal segment, close to base of apophysis.

Leg 4 ( Figs 6 View FIGURE 6 H–L, 7G, 8C): coxa without ornamentation. Basis with moderately long outer seta, spinule row at outer distal corner, 2 chitinous lobes on posterior surface and large conical spine and large spinulose lobe at inner distal corner. Exopod 3-segmented; first segment constricted at midlength, as long as next 2 segments combined, with outer bipinnate spine, 2 outer transverse spinule rows, distal spinule row and hyaline frill on inner distal margin; second segment unarmed, with outer and apical distal spinule rows; third segment as long as second segment, with outer bipinnate spine, apical bipinnate seta, fine spinules around insertion of outer spine and hyaline frill on inner distal margin. Endopod 1-segmented, shorter than first exopodal segment, club-shaped, apically with brush of spinules on medial surface.

Leg 5 ( Figs 5 View FIGURE 5 B, 6M, 7H): as in female, except second innermost seta posteriorly directed.

Leg 6 ( Fig. 5 View FIGURE 5 B): represented by bare, posterolaterally directed, pointed conical protrusion; extends close to posterior margin of second urosomite.

Variation. Anal operculum of one female paratype bilobed with medial concavity on posterior margin ( Fig. 7 View FIGURE 7 B); some female paratypes with anal operculum extending to posterior end of anal somite ( Fig. 2 View FIGURE 2 C). Caudal rami in either sex somewhat parallel to each other ( Fig. 7 View FIGURE 7 B). In one male paratype, 1 tiny seta discernible at inner distal corner of leg 3 basis, perhaps representing endopod. Ornamentation of endopod ( Fig. 6 View FIGURE 6 K–L) and spinulose pad on basis (i.e. appearing as fan-shaped structure in Fig. 6 View FIGURE 6 H) of male leg 4 may vary depending on angle of view. Spinules on male urosomites 2–4 sometimes reduced or absent ( Fig. 8 View FIGURE 8 A).

Etymology. The specific epithet, alluding to the River Muvattupuzha , the type locality of the new species, is proposed here as a noun in apposition to the generic name.

Ecology. The River Muvattupuzha is one of the 44 rivers in the State of Kerala, southwestern India ( Fig. 1 View FIGURE 1 ). The landmass of the State is wedged between the Arabian Sea to the west and the Western Ghats—identified as one of the world’s biodiversity hotspots—to the east (Water Resources of Kerala, 1958). The river, formed by the concourse of three small rivers, Thodupuzha, Kaliar and Kothamangalam, near Muvattupuzha town, empties into Vembanad Lake, which is connected to the Arabian Sea. The maximum length of the river is about 120 km. The drainage basin area is about 1528 km 2 and rich in crystalline rocks of igneous and metamorphic origin. The soils are generally deficient in nitrogen, phosphorus and lime in the basin, but loamy with a great admixture of humus from the hills. Mean annual temperatures range from 25.0 to 27.5o C, and the average rainfall in the basin varies from 254 cm in the coastal region to about 508 cm in the highlands. The riverbed at the sampling site has a deposit of fine sand and detritus particles, but with little or no clay, and is devoid of macrophytic vegetation.

The new species was found co-occurring with one congener, P. c u r v i s p i n u s, as well as a new parabathynellid species of the genus Habrobathynella Schminke, 1973 , nematodes, oligochaetes and insect larvae.

Parastenocaris kotumsarensis n. sp. ( Figs 9–14 View FIGURE 9 View FIGURE 10 View FIGURE 11 View FIGURE 12 View FIGURE 13 View FIGURE 14 )

Material examined. Holotype Ƥ (dissected on one slide: MNHN-Cp2482), allotype 3 (dissected on one slide: MNHN-Cp2484) and 5 paratypes (1 Ƥ intact on one slide: MNHN-Cp2483; 2 33 and 2 Ƥ on an SEM stub), Kotumsar Cave (18°52'09"N; 81°56'05"E; altitude 560 m) near Jagdalpur town, India, leg. Y. Ranga Reddy, 0 1 December, 2004.

Diagnosis. Male urosomites 4–5 and female urosomites 3–4 each with paired ventrolateral integumental windows. Caudal rami of both sexes slightly over three times as long as wide; lateral setae inserted slightly posterior to midlength of ramus. Male antennular segment 5 only moderately dilated, with small conical protrusion and aesthetasc over twice as long as segments 6–8 combined; segment 7 produced into short, blunt apophysis. Apophysis of male leg 3 exopod shorter than thumb. Male leg 4 endopodal complex consisting of at least 3 chitinous structures; endopod 1-segmented, with an apical spiniform process. Leg 5 similar in both sexes, represented by triangular plate, armed with 4 setae and produced into moderately strong, nearly straight spiniform process at inner distal corner; bears proximolateral cuticular pore.

Description of adult female. Total body length of holotype, measured from base of rostrum to posterior end of caudal rami (excluding caudal setae), 390 µm (2 paratypes 395 µm and 383 µm long). Preserved specimens colourless. Naupliar eye absent. Body ( Fig. 9 View FIGURE 9 A) vermiform, slender, without surface pits. Prosome/ urosome ratio 0.7; body length/width ratio 8.4. Hyaline frills of somites smooth. Cephalothorax subquadrate, 1.7 times as long as maximum width, comprising 20% of body length; double integumental window clearly delineated, subcircular in outline. Urosomites 3 and 4 each with paired ventrolateral integumental windows; windows on urosomite 3 smaller and spherical in lateral view; somites without spinular ornamentation ( Fig. 9 View FIGURE 9 A–B, E).

Genital double-somite ( Fig. 9 View FIGURE 9 A–B): about as long as wide, without any trace of subdivision, ornamented with 8 sensilla. Genital field ( Fig. 14 View FIGURE 14 E) situated ventrally at proximal third of genital-double somite; copulatory pore probably located in medial incision of crescentic plate, representing rudimentary P6, extending as linguiform expansion at each extremity; symmetrical slits near expansions probably representing location of gonopores; no internal structures identified precisely as seminal receptacles. All urosomites, except preanal somite, with small sensilla as in Fig. 9 View FIGURE 9 A. Fifth pedigerous somite with thick ventral sensillum lateral to leg 5 ( Fig. 14 View FIGURE 14 E). Anal somite slightly tapering distally, 1.2 times as long as maximum width and with 2 diagonal rows of small proctodeal spinules; anal sinus spinulose ( Fig. 9 View FIGURE 9 C). Anal operculum representing 66% of anal somite width, not reaching posterior end of anal somite, with straight posterior margin and fine spinules along posterior and lateral margins.

Caudal rami ( Figs 9 View FIGURE 9 C–D, 14C): symmetrical, divergent, 70% of anal somite length; each ramus 3.1 times as long as wide, distal 2/5 narrow; ornamented with transverse row of spinules at ventrodistal margin and cuticular pore near midlateral setae. Seta VII inserted close to inner margin at same level as setae I–III, slightly longer than caudal ramus and basally biarticulate. Setae I–III slender, unequal, shorter than ramus and clustered together slightly posterior to midlength of ramus. Seta VI half as long as caudal ramus and inserted partly ventral to seta V. Seta V without fracture plane, over thrice as long as outer apical seta and 43% of body length. Seta IV about 30% longer than caudal ramus and with pinnate outer margin.

Rostrum ( Fig. 10 View FIGURE 10 A): small, blunt, weakly chitinised projection, reaching midlength of first antennular segment; bears 2 dorsolateral sensilla.

Antennule ( Figs 10 View FIGURE 10 B, 14B): 7-segmented; segment 1 with ventral spinule row; segment 2 as long as next 2 segments combined. Setal formula: 0, 4 (1 unipinnate), 4, 2+aes, 1, 0 and 8+aes. Aesthetasc on segment 4 slender, nearly straight, constricted at midlength, extending beyond antennular tip; that on segment 7 more slender, over twice as long as segment.

Antenna ( Figs 10 View FIGURE 10 C, 14B): coxa without ornamentation. Allobasis 2.6 times as long as maximum width, with 2 transverse spinule rows on inner margin. Exopod 1-segmented, 2.7 times as long as wide; apical unipinnate seta nearly twice as long as segment. Endopod twice as long as maximum width, half as long as allobasis; 2 short unipinnate spines and 2 spinule rows on inner margin; subdistally with surface frill, distally with 2 unipinnate spines, 2 geniculate, distally serrate setae, transformed unipinnate, spiniform seta and spinule row at outer distal corner.

Mandible ( Fig. 10 View FIGURE 10 D): cutting edge with row of small teeth between 2 moderately large teeth. Palp 1- segmented, cylindrical, about thrice as long as wide, with 2 subequal apical setae.

Maxillule: not studied.

Maxilla ( Fig. 10 View FIGURE 10 E) and maxilliped ( Fig. 10 View FIGURE 10 F): as in P. muvattupuzha n. sp.

Leg 1 ( Fig. 11 View FIGURE 11 A): coxa unornamented. Basis with short outer seta and spinule row on outer margin and between rami. Exopod as long as endopod; outer unipinnate slender spine on first segment slightly longer than second segment; second segment 0.7 times as long as first segment; third segment 1.7 times as long as second segment. First endopodal segment as long as first two exopodal segments combined; second segment 0.7 times as long as first segment. Otherwise as in P. muvattupuzha n. sp.

Leg 2 ( Figs 11 View FIGURE 11 B, 14D): coxa with spinule row on outer distal margin. Basis unarmed, with cuticular pore and spinule row on outer margin and between rami. First exopodal segment with 2 transverse rows of spinules on outer margin, spinule row distally, hyaline frill at inner distal corner and outer bipinnate spine not extending to posterior end of second segment. Second exopodal segment unarmed, with spinule row on outer margin and distally. Third exopodal segment only slightly longer than second segment, with outer seta, 2 unequal apical setae, outer spinule row and hyaline frill at inner distal corner; all armature elements bipinnate. Endopod 1-segmented, cylindrical, 5 times as long as wide and 59% as long as first exopodal segment; with moderately long apical seta and group of tiny spinules at apex.

Leg 3 ( Figs 11 View FIGURE 11 C, 14F): coxa with spinule row on outer distal margin. Basis with long outer seta, pore on proximal anterior surface, transverse row of tiny spinules near insertion of endopod and row of somewhat long spinules on outer distal margin. Exopod 2-segmented; first segment about as long as second segment, with outer bipinnate spine, 2 spinule rows on outer margin, spinule row distally and hyaline frill at inner distal corner; second segment with spinule row on outer margin, hyaline frill at inner distal corner and short, bipinnate outer spine and elongate apical seta. Endopod 1-segmented, half as long as first exopodal segment, tapering to pointed tip, with distal half spinulose

Leg 4 ( Figs 11 View FIGURE 11 D, 14F): coxa bare. Basis with moderately long outer seta and spinule row between rami. Exopod 3-segmented, each segment somewhat slender and elongate. First exopodal segment longer than second segment, with outer bipinnate spine, 2 spinule rows on outer margin, spinule row distally and hyaline frill at inner distal corner. Second exopodal segment shorter than third segment, with spinule row on outer distal margin and distally; third segment as long as first segment, with outer bipinnate spine, apical seta, spinule row on outer margin and hyaline frill at inner distal corner. Endopod slender, nearly cylindrical, shorter than first exopodal segment, with distal third spinulose.

Leg 5 ( Figs 11 View FIGURE 11 E, 14E): without intercoxal sclerite; represented by triangular plate, with inner distal corner produced into smooth, moderately long, outwardly curved, acute process, extending to midlength of genital double-somite; free distal margin uneven, with 4 unequal setae; cuticular pore present near proximal outer corner.

Description of adult male. Total body length, excluding caudal setae, of allotype 425 µm, of paratypes 380 µm and 430 µm. Habitus shape and somitic ornamentation ( Fig. 14 View FIGURE 14 A, G) as in female. Dorsal double integumental window present on cephalothorax ( Fig. 14 View FIGURE 14 G); paired ventrolateral integumental windows of similar size on urosomites 4 and 5 ( Fig. 12 View FIGURE 12 A). Anal somite subrectangular, 1.5 times as long as wide. Anal operculum ( Fig. 12 View FIGURE 12 B) with slight concave posterior margin, reaching posterior end of anal somite and representing 79% of somite width; ornamentation of anal operculum and anal sinus as in female.

Rostrum ( Fig. 13 View FIGURE 13 A): anterior end triangular in dorsal view, with 2 moderately long dorsolateral sensilla.

Caudal rami ( Fig. 12 View FIGURE 12 A): each ramus 3.3 times as long as maximum width; seta V slightly dilated proximally, nearly 4 times as long as seta IV; otherwise as in female.

Antennule ( Figs 13 View FIGURE 13 B, 14G): 8-segmented, prehensile, strongly geniculate between segments 6 and 7; segment 1 ornamented with ventral row of spinules. Segment 2 longest; segment 4 shortest; segment 5 moderately dilated with short spiniform projection at about midlength of inner margin; segment 7 produced into short, blunt apophysis; segment 8 showing transverse cuticular fold distally. Setal formula: 0, 6 (1 unipinnate), 3, 0, 2+aes, 0, 0 and 8+aes. Aesthetasc on segment 5 slender, staff-like, constricted at about midlength and extending well beyond antennular tip. Aesthetasc on segment 8 shorter and slenderer than that on segment 5.

Other cephalic appendages, leg 1 ( Fig. 13 View FIGURE 13 C) and leg 5 as in female.

Leg 2 ( Fig. 13 View FIGURE 13 D): second exopodal segment slightly indented on inner margin. Endopod slightly dilated distally and 46% as long as first exopodal segment. Otherwise as in female.

Leg 3 ( Figs 13 View FIGURE 13 E, 14H): coxa with spinule row on distolateral margin. Basis with long outer seta and diagonal row of long spinules at outer distal corner. Exopod modified, apparently 2-segmented; proximal segment somewhat slender, about 3.3 times longer than proximal width, ornamented with transverse row of long spinules on outer proximal margin and row of tiny spinules at outer distal angle. Apophysis shorter than thumb, poorly sclerotised, distal end somewhat bifid. Thumb modified into strong spiniform structure, bent inwards and gradually tapering to acuminate tip. Endopod represented by small, bare seta.

Leg 4 ( Figs 13 View FIGURE 13 F, 14H): coxa without ornamentation. Basis with short outer seta and 3 large modified structures: (i) outcurved, sclerotised claw at proximal inner corner; (ii) conical, foliaceous sclerotised structure at outer corner, lying parallel to base of exopod; and (iii) somewhat oblong, obliquely directed, hyaline outgrowth at centre, with finely spinulose outer distal margin and additional rounded lobe on posterior surface. Exopod short, 3-segmented; first segment concave at midlength, 0.8 times as long as next two segments combined, with outer bipinnate spine, 2 spinule rows on outer margin and 1 spinule row distally; second segment unarmed, with outer and apical spinule rows; third segment slightly longer than second segment, with outer bipinnate, outcurved, spiniform seta, apical bipinnate seta, apical spinule row and hyaline frill at inner distal corner. Endopod subrectangular, 1-segmented, inserted on posterior surface, with longitudinal row of minute spinules at outer distal corner; inner distal corner produced into posteriorly directed spiniform structure, with finely spinulose inner margin.

Leg 6 ( Fig. 12 View FIGURE 12 A): bare, posteriorly directed conical protrusion, with acute tip.

Variation. Length-width ratio of caudal rami and size of anal operculum and its position relative to the posterior end of anal somite are subject to some variation.

Etymology. The specific name is an adjective for the type locality, derived from the Latin suffix “-ensis”.

Ecology. The Kotumsar Cave is one of the largest limestone caves in India. It lies on the bank of the River Kanger, which flows through Kanger Valley National Park. The cave entrance is a 15 m vertical and narrow, but twisted, fissure in the wall of a hill. The cave has several irregular chambers similar to those of a honeycomb. The cave tunnel is nearly 500 m long and has several lateral and perpendicular passages. The roofs and walls of the different chambers are lined with colourful dripstone formations, resulting from the precipitation of calcite-dissolved carbonate of lime. The chambers are floored with either rocks or pebbles of varying dimension or surface-derived soil/clay deposits.

According to Pati & Agrawal (2002), the general trends of some salient abiotic parameters of the cave, as observed during six months between May, 1987 and March, 1988, were as follows: the air and water temperatures remained relatively stable at an annual average of 28.25 ± 1.23°C (range 25.0–32.7°C) and 26.33 ± 0.96°C (range 22.9–29.3°C), respectively. The water pools were alkaline with pH around 8. Conductivity peaked during December, with an annual average of 0.27 ± 0.03 mMhos. The annual mean for dissolved oxygen and percentage saturation for oxygen in the cave water was 6.42 ± 0.52 ppm and 74.83 ± 5.91%, respectively. The cave is subject to frequent flooding when monsoon season begins around mid-June.

The new Parastenocaris species was found co-occurring with a parabathynellid, Chilibathynella kotumsarensis Ranga Reddy, 2007 , a crangonyctoid amphipod, Kotumsaria bastarensis Messouli, Holsinger & Ranga Reddy, 2007 and some unidentified cyclopoids, oligochaetes and nematodes.