Kotumsaridae

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, Zootaxa 1589, pp. 33-46 : 34-35

Kotumsaridae new family

Diagnosis. Slender, blind and unpigmented, of troglomorphic (subterranean) facies; head small, rostrum lacking. Antenna 1 longer than antenna 2, accessory flagellum absent. Upper lip symmetrical, apical margin bluntly rounded and entire. Mandibles well developed, with strong incisor, lacinia mobilis, spine row and triturative molar; palp 3-segmented but bearing E setae only. Lower lip lacking inner lobes. Maxilla 1: small inner plate, bearing single distal seta, outer plate with 6 apical, serrated spines, palp 1-segmented and poorly setose. Inner and outer plates of maxilla 2 sparsely setose. Outer plate of maxilliped without row of blade spines medially. Gnathopods strong: first larger than second, carpi triangular and more than half length of corresponding propodi; palmar margins of propodi armed with simple setae, defining angles with pair of long, notched spines; posterior margins of propodi much shorter than palmar margins; nails of gnathopod dactyls well developed and elongate.

Coxal plates of gnathopods and pereopods very short, wider than deep, not lobate or contiguous. Coxal gills and simple median sternal gills (processes) on pereonites 2–6. Basis of pereopods 5–7 narrow, with subparallel margins. Pereopod 7 little longer than pereopod 6, which is longer than pereopod 5. Distoposterior corners of pleonal plates not produced. Rami of pleopods greatly reduced, with 1–2 segments. Urosomites: 1 bearing 2 dorsal spine-like setae and 2 small, ventral (ecdysial) spines; 2 with a short dorsoposterior spine; 3 with small posteroventral spine at base of insertion of uropod 3. Uropods 1 and 2 short (shorter than uropod 3), peduncles with long distal seta, peduncle of 2 without basoventral/basofacial spine; rami styliform, each with single distal spine. Uropod 3 parviramus/dispariramus, with 1-segmented rami; inner ramus (endopodite) scale-like, outer ramus (exopodite) proportionately elongate, tapering distally, about 2.8 times longer than peduncle. Telson about half length of uropod 3, narrowing slightly distally, about 1.2 times longer than wide, with weakly convex apical margin and bearing 2 prominent spines subapically.

Type genus. Kotumsaria Messouli, Holsinger and Ranga Reddy , new genus. At present this family is known only from the type genus.

Relationships. The new family Kotumsaridae can easily be distinguished by a combination of characters that includes: absence of accessory flagellum on antenna 1; reduction of several mouthparts, including especially 1-segmented palp of maxillae 1 and absence of all but few E setae on mandibular palp; lack of spines on palms of gnathopod propodi except for 2 prominent spines at defining angles; long, prominent dactyl nails of gnathopods 1 and 2 and pereopods 3 and 4; reduced, non-contiguous coxae of gnathopods and pereopods; single medial sternal gills on pereonites 2–6; rami of pleopod flagellae reduced to only 1 or 2 articles; rami of uropods 1 and 2 spiniform and having only single, long, deeply implanted apical spine each; ramus of uropod 3 greatly reduced to small plate bearing 2 weak, apical notches; and small, sparsely armed telson with weakly convex lateral and apical margins.

In addition to this suite of unique characters, the new family possesses a rather interesting mix of plesiomorphic and apomorphic characters as well. Moreover, several potentially troglomorphic characters, including absence of calceoli, elongate dactyl nails of the gnathopods, elongate, plumose setae of the pleopod flagellae, and reduced, non-contiguous coxae of pereopods 5–7, obscure its potential relationship with other crangonyctoid groups and are difficult to interpret at this juncture. Consequently, the phylogenetic relationship of Kotumsaria with other freshwater amphipod taxa remains unclear, pending collection of additional material and rigorous phylogenetic analyses, both morphological and molecular, of taxa currently assigned to the Crangonyctoidea from the Southern Hemisphere.