Koponenius unicornis Golovatch & Vandenspiegel, 2014, sp. nov.

Koponenius unicornis sp. nov.

Figs 1–4

Material examined: Holotype male (ZMUM), India, West Bengal, Darjeeling District, Kalimpong (Gandhi Ashram), 27,06ºN, 88,45ºE, ca 880 m a.s.l., 5–15 November 2013, leg. K. Tomkovich. Paratypes: 7 males, 8 females (ZMUM), 1 male, 1 female (SMF), 2 males (SEM), same data, together with holotype.

Name: To emphasize the conspicuous central projection at the fore margin of the collum in both sexes; adjective.

Diagnosis: Differs clearly from the only other known congener, K. biramus sp. nov., in the presence of a highly conspicuous central process at the fore margin of the collum in both sexes, coupled with a uniramous gonopod telopodite.

Description: Length in both sexes ca 12–14 mm, width ca 1.3–1.5 and 1.8–2.0 mm on midbody pro- and metazonae, respectively. Holotype ca 13 mm long, 1.3 and 1.8 mm wide on midbody pro- and metazonae, respectively. Coloration in alcohol mostly brown to dark grey-brown, including vertigial region of head, as well as most of pleurosternal and midsternal regions, but pattern evident due to contrasting pale, whitish to light greyish clypeolabral and occipital regions of head, antennae, prozonae, porosteles, legs, epi-, hypo- and paraprocts (Fig. 1).

Body with 19 segments in both sexes, subcylindrical, not capable of volvation. Collum and following metaterga clothed with a dense, dull, microvillose cerategument crust (Fig. 2 M–P); vertigial region down to a well-expressed border with clypeolabral region clearly granular (Fig. 2 D). Clypeolabral region densely setose (Fig. 2 D, Q). Antennae short and clavate, in situ each placed inside a deep, transverse, nearly C-shaped groove (Fig. 2 D); in length, antennomere 6> 2> 1> 3=4=5; both antennomeres 5 and, especially, 6 with a tight dorso-apical group of bacilliform sensilla (Fig. 2 A, D, L). Ventral surface of cardo and gnathochilarium largely finely squamate (Fig. 2 L).

In width, head <collum = segment 3 = 4 <2 = 5=16, thereafter body gradually tapering towards telson (Fig. 2 H–J). Collum at fore margin dentate, with a highly conspicuous, central, tuberculate protuberance overhanging the head and concealing it from above (Fig. 2 A, D, H). Paraterga rather well developed, strongly declined, mostly wing-shaped, set low (at about lower ¼ of midbody height), starting from collum, laterally vaguely lobulate (Figs 1 & 2 A–J, M, P). Paraterga 2 clearly enlarged, subtending the head on both sides. Dorsum very convex (Fig. 2 M). Postcollum metaterga usually with 4, rarely 5, regular, transverse rows of rather flat, sometimes rather clearly obliterated, setigerous, isostictic (= regular in axial direction), mostly roundish bosses or tubercles (Figs 1 & 2 A–C, H–J); caudal row of particularly elongate bosses forming a faint waist (Fig. 2 I), a series of lobulations and ending up in a distinct crenulate limbus (Fig. 2 I, N); fore row likewise forming a row of similar lobulations (Figs 1 & 2 A–C, H–J, N, P). Caudolateral corner of postcollum paraterga mostly well rounded, nearly pointed only in segments 17 and 18 (Fig. 2 J, K). Ozopores borne on conspicuous dorsolateral porosteles, these lying close to caudolateral corners of paraterga; pore formula 5, 7–18 (Figs 1 & 2 A–C, I, M, O, P). Tergal setae filiform, rather long (Fig. 2 O, P). Epiproct strongly flattened dorsoventrally, lobulated laterally, subtruncate caudally, but tip ventral, invisible from above (Fig. 2 C, G, J, K). Hypoproct subtrapeziform (Fig. 2 G).

Sterna narrow, but evident, mostly slightly elevated due to small subtriangular lobules observed between both coxae (Fig. 2 D–F). Spiracles seem to be absent. Legs mostly tightly appressed to venter, densely setose, short and stout, about as long as body height and subequally incrassate in both sexes (Figs 1 & 2 B–F, M, Q, R), but only male coxae and, to a lesser degree, prefemora micropapillate (Fig. 4 A).

Gonopods (Figs 3 & 4 B) with large, subcylindrical, mediobasally fused coxae carrying a few long setae ventrally and a small, but evident, rounded, lateral lobe apically; cannulae long and slender. Telopodite strongly elongated, considerably longer than coxae, slender; prefemoral (= densely setose) portion suberect, about half as long as entire telopodite, set off from a subfalcate, rather gradually attenuating and narrowly truncate acropodite (= solenomere, sl) by a strong sulcus (s) on mesal face and by a ventral projection (p); seminal groove rapidly shifted laterad due to a twisted prefemoral portion, thereafter running only on lateral side all over sl extent. Neither an accessory seminal chamber nor a hairy pulvillus.