Kotumsaria bastarensis Messouli, Holsinger & Reddy, 2007, new species

Abstract

Kotumsaria bastarensis new species (Figs. 2 –7) Material examined. Jagadalpur, Bastar District, Chhattisgarh State, INDIA: Kotumsar cave, Kanger Valley National Park (see Type locality). HOLOTYPE: disarticulated (sex unknown), 2.23 mm, in 70 % ethanol [MHNM reg. no. Amph-061MHR]. PARATYPES: 3 specimens (2 of them disarticulated) in 70 % ethanol deposited in the collection of the MHN Marrakesh. Leg. Y. Ranga Reddy, 1 December 2004. In freshwater. Accompanying fauna: parabathynellid Chilibathynella kotumsarensis Ranga Reddy, 2006, and a new harpacticoid copepod of the genus Parastenocaris Kessler, 1913. Description. Sex unknown. Body length of 4 specimens: 2.23, 2.15, 2.12, and 2.05mm. Without eyes and pigment, of subterranean facies. Tergites of body somites with sparsely set, long setules (Figs. 2 A, B). Head lacking rostrum; lateral lobes (interantennal lobes) of head rounded, well developed, extending beyond anterior margin of head (Fig. 3 A). Antenna 1 relatively short, about 33 % length of body (Figs 2 A, 3 B); peduncular segments proportionately elongate, slender, first longer than combined length of following two, second about half length of preceding segment, third shorter than second. First segment with 2 short spines and longer pedicellate seta on ventral margin; other armature details on segments as shown in Fig. 3 B. Primary flagellum composed of 6 segments, each bearing 1 long aesthetasc except proximal segment. Accessory flagellum lacking. Antenna 2 (Figs 2 A, 3 C) rather short, 65 to 75 % length of antenna 1, first and second peduncular segments incompletely separated, short; gland cone not reaching beyond distal margin of third peduncle segment. Fourth and fifth peduncular segments much longer, fifth as long as combined length of 3 proximal segments of peduncle, fourth somewhat longer; flagellum (Fig. 3 D) 4 -segmented, shorter than combined length of 2 distal peduncular segments, each segment, except penultimate, bearing a characteristic thick “seta” which is probably a ribbon-shaped aesthetasc; each flagellar segment also bearing several rather long, slender setae. Upper lip (Fig. 4 A) globose, with defined epistome; 2 patches of sparsely set, short setules on posterodistal surface. Left mandible (Fig. 4 B): incisor 4 -cuspidate, lacinia mobilis 5 -cuspidate; cusps rounded; spine row composed of 3 multi-denticulate elements along medial surface spines; parallel row of 2 slender plumose setae lying lateral to spine row; molar triturative, bearing long seta; palp strong, 3 -segmented, segment 1 short, unarmed, segment 2 subtriangular, well developed, with ventral margin longer than dorsal and bearing single long seta, segment 3 narrow and slightly longer than segment 2, bearing 3 long E-setae; A–D setae absent. Right mandible (Fig. 4 C) similar to left counterpart except for multi-cuspidate lacinia and shape of proximal element of spine row. Lower lip (Fig. 4 D) asymmetrical, inner lobes absent, outer lobes covered distally with densely set, stout spinules directed inwards. Maxilla 1 (Fig. 4 E): inner plate tapered distally, with single, apical plumose seta; outer plate broader than inner plate, bearing 6 stout, distally serrate spines on apex; palp short, 1 -segmented, about as long as outer plate and bearing 2 rather long, distally plumose on apex. Maxilla 2 (Fig. 4 F): outer plate slightly longer than inner plate, with 3 distal setae, inner plate only about one-half size of outer plate, bearing 1 distal and 1 subdistal plumose setae. Maxilliped (Figs. 4 G, H, I) inserted on naked fused coxae, inner plate (Fig. 4 G) finger-shaped, with 2 small, bifid spines distally and 1 short seta subdistally; outer plate (Fig. 4 H) elongate, tip slightly overextending basis of second palp segment, armature feeble, consisting of 1 plumose seta distally and 2 naked setae subdistally; palp 4 -segmented (Fig. 4 I), segments 2 and 3 with row of rather long setae on inner margin; dactyl nail long and curved. Gnathopod 1 (Fig. 5 A): basis slightly expanded distally, about 1.8 times longer than wide, with single long seta on anterior margin, and 2 setae of unequal length near posterior margin; ischium subtrapezoidal, short, about as long as wide; merus rhomboid, about 1.3 times longer than wide, with 3 distal setae; carpus triangular, short, about as long as wide, lacking prominent posterior lobe; propodus sub-ovoid, more than 2 times longer than carpus, palm strongly oblique, convex, more than 2 times longer than posterior margin, defining angle bearing 2 similar, long bifid spines, palmar margin microspinulate, with submarginal row of 5 smooth setae, 2 of them long, with expanded tip, and distal part bearing 2 curved spines; dactylus when closed not extending beyond defining angle of palm, with one spine fused at base to segment, 1 tiny, smooth seta and 1 flattened seta with rounded tip near insertion of nail on posterior margin of segment; posterior margin of dactyl finely pectinate along distal half and bearing long seta on anterior margin; nail of dactyl long, stout, nearly one-half length of entire dactylus. Gnathopod 2 (Fig. 5 B) smaller than gnathopod 1, basis similar but less expanded distally and lacking long seta on anterior margin; propodus ovoid and smaller than that of gnathopod 1; palm strongly oblique, about twice length of convex posterior margin; defining angle with 2 long, similar bifid spines; dactylus not extending beyond defining angle of palm, with tooth-like spine and 2 tiny, smooth setae on posterior margin of segment near insertion of nail; dactyl nail long and slender, about onehalf length of entire dactylus. Pereopods 3 and 4 (Fig. 6) subequal, bases slender with parallel margins, about 3.3 times longer than wide; propodi elongate, longer than carpi; dactyls slender, with smooth seta on posterior margin of segment near insertion of nail; dactyl nail slightly curved, about half as long as dactylus. Pereopod 5 (Fig. 6 C) shorter than pereopods 6 and 7, bases slender with parallel margins, distoposterior lobes indistinct. Pereopods 6 and 7 (Figs. 6 D, E) subequal in length, about 35 percent as long as body; propodi of pereopods 5–7 longer than corresponding segments, nails rather long, slender, and not curved. Coxal plates very short, 2 to 3 times wider than deep, not contiguous ( Fig. 2 A). Coxal gills subovate and stalked, present on gnathopod 2 and pereopods 3–6. Median sternal processes present on pereonites 2–6 (Figs. 6 A, B, C). Oöstegites and genital papillae not observed and apparently absent in specimens examined. Pleonal (epimeral) plates 1–3 (Figs. 2 A, 7 A, B) subequal; posterior corners rounded and poorly marked by single seta; ventral margins unarmed except plate 3 with single submarginal spine. Pleopods 1–3 (Figs. 7 A, B) similar, consisting of subrectangular peduncles 2.3 times longer than wide and inserted on short pedestal; rami of equal length, greatly reduced, shorter than corresponding peduncles; pleopods 1 and 2 with 2 -segmented rami, ramus of 3 with single segment; peduncles with 2 club-shaped, denticulated retinacles (coupling spines) inserted subdistally on medial margin; terminal segments of each ramus bearing long plumose seta distally on both sides. Uropod 1 (Figs. 2 B; 7 C): inner ramus longer than outer ramus, subequal in length to peduncle, armed with single, implanted, apical spine; outer ramus with single, implanted apical spine and seta near apex; peduncle approximately equal in length to urosomite 2, with 3 dorsal spines and 1 long apical seta, without basofacial spine. Uropod 2 (Figs. 2 B, 7 D) subequal to uropod 1 but little shorter, peduncle little shorter than rami, approximately equal in length to urosomite 3. Uropod 3 (Figs. 2 B, 7 E, F) rather long, slender, tapered distally, with 1 -segmented rami; inner ramus (endopodite) subquadrate, about 2 / 3 width of peduncle, but only about 50 % as long, distal margin of inner ramus with three small lobes, the anterior lobe bearing minute spinule; outer ramus more than twice length of peduncle, tapering distally, bearing few slender spines on lateral and medial margins and 3 slender spines of unequal length near sharply pointed apex; peduncle subrectangular, slightly longer than broad, bearing set of two distal spine-like setae, and one smaller seta subdistally near base of inner ramus. Telson (Fig. 7 G) about 1.2 times longer than wide, narrowing slightly distally, apical margin weakly rounded and bearing 2 prominent flanker spines and accompanying penicellate setae, upper (dorsal) side with 2 pairs of relatively long penicellate setae inserted toward lateral margins. Etymology. The epithet bastarenis refers to the occurrence of this species in the Bastar District in the Indian state of Chhattisgarh. Variability. Individuals did not vary significantly. The only variation discerned, in one specimen, was the absence of the pre-peduncular ecdysial spine on the third urosomite. Remarks. The absence of oöstegites, pene, and very small size of the specimens may indicate immaturity but this is not certain and cannot be determined without collection of additional material. However, despite the tiny size of the specimens, most of the structural characters appear to be adult, although some are modified. FIGURE 6. Kotumsaria bastarensis new species, sex (?), 2.23 mm, Kotumsar Cave (India). A, Pereopod 3 with attached coxal and median sternal gills, and detail of dactylus; B, sagital view of 4 th somite showing attached right pereopod and coxal and mediosternal gills; C, lateral view of right pereopod 5, with attached coxal and mediosternal gills; D, right pereopod 6 (coxal and mediosternal gills omitted); E, right pereopod 7, lateral. FIGURE 7. Kotumsaria bastarensis new species, sex (?), 2.23 mm, Kotumsar Cave (India). A, right 1 st epimeral plate with pleopod; B, right 3 rd epimeral plate with pleopod; C, uropod 1 with detail of distal part of outer ramus; D, uropod 2; E, uropod 3; F, detail of peduncle and inner ramus of uropod 3; G, telson. Type locality. Kotumsar Cave, the type-locality and only known locality, is situated on the bank of the River Kanger, which flows through the Kanger Valley National Park (KVNP) (18 º 52´09˝ N; 81 º 56´05˝ E) at an altitude of 560 m. (Fig. 1). It is one of the largest caves in India and one of several caves (both explored and unexplored) in KVNP. The entrance to the cave is a vertical fissure in the wall of a hill and is a narrow but twisted opening, measuring about 15 m in length. The cave has several irregular chambers similar to that of a honeycomb. The main tunnel of the cave is nearly 500 m long and has several lateral and perpendicular passages. The roofs and walls of the different chambers are lined with colorful dripstone formations, resulting from the precipitation of calcite-dissolved carbonate of lime. The chambers are floored with either rocks or pebbles of varying dimensions 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 different 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 ºC and 26.33 ± 0.96 ºC, respectively (range = 25.0– 32.7 ºC for air; 22.9–29.3 ºC for water). The water pools were alkaline with pH hovering around 8. Conductivity peaked during December, with an annual average of 0.27 ± 0.03 m Mhos. 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 the middle of June.Published as part of Messouli, Mohammed, Holsinger, John R. & Reddy, Ranga, 2007, Kotumsaridae, a new family of subterranean amphipod crustaceans from India, with description of Kotumsaria bastarensis, new genus, new species, pp. 33-46 in Zootaxa 1589 on pages 36-44, DOI: 10.5281/zenodo.17852