Epanerchodus telnovi Golovatch, 2022

Golovatch, S. I., 2022, A new species of the millipede genus Epanerchodus from western Nepal (Diplopoda: Polydesmida: Polydesmidae), Russian Entomological Journal 31 (4), pp. 432-435 : 433-435

Epanerchodus telnovi Golovatch sp.n.

Figs 1–5 . HOLOTYPE ♂ (somewhat macerated and broken into three pieces) ( ZMUM), Western Nepal, Karnali Prov., Humla Distr. , ca 12–13 km SE of Simikot, N 29°54´23´´ –29°54´00´´, E 81°55´7´´ – 81°55´11´´, 2990–3310 m, disturbed mixed forest, 17–18.VI.2022, D. Telnov leg.

NAME. Honours Dmitry Telnov, the collector.

DIAGNOSIS. Differs from congeners by the relatively small size (width ca 2.0 mm), coupled with the head being narrower than the collum, the absence of sphaerotrichomes, lateral bulges on ♂ prefemora, and an exomere, and the shapes of the endomere (en) and its single, basal, postfemoral process (pf). See also Remarks below.

DESCRIPTION. Length ca 14 mm, width of midbody pro- and metazonae 1.0 and 2.0 mm, respectively (♂). Colouration in alcohol uniformly brown with mostly lighter sterna and brown-yellow legs ( Figs 1–3 ). Body with 20 segments.

Tegument mostly dull, texture very delicately shagreened. Head pilose nearly throughout, with squarish genae. Antennae and most legs broken off. Interantennal isthmus about twice as large as diameter of antennal socket ( Figs 2–3 ).

In width, head <collum <segment 3=4 <2 <5=15, thereafter body gradually tapering towards telson ( Figs 1–3 ). Paraterga strongly developed, set high (at about upper ¼ of midbody height), starting with collum, dorsum very faintly convex; paraterga mostly weakly upturned above dorsum. Anterior shoulders and sides of paraterga mostly straight to only slightly rounded. Collum crescent-shaped, each side with only one lateral incision near midway ( Figs 1, 3 ). Caudolateral corner of paraterga spiniform and pointed, postcollum ones extending increasingly past rear tergal margin starting with paraterga 4, especially clearly so on rings 17 and 18. All poreless paraterga with three, all pore-bearing ones with four, minute incisions at lateral margin. Front margins of metaterga narrowly bordered and forming distinct shoulders. Pore formula normal, ozopores small, but evident, dorsal, located in front of posteriormost marginal indentation. Metatergal sculpture typical, starting with collum, poorly developed, but readily visible, with three transverse rows of typical (= polydesmid), setigerous, polygonal bosses ( Figs 1– 3 ), anterior row being the most obliterate and caudal row the most evident (up to rough wrinkles on ring 18). Tergal setae very short, simple, mostly obliterated. Stricture between pro- and metazona wide, shallow and nearly smooth. Limbus very thin, microdenticulate. Pleurosternal carinae absent. Epiproct rather short, conical, pre-apical lateral papillae inconspicuous. Hypoproct semi-circular; caudal, paramedian, setigerous papillae very prominent and well separated teeth ( Fig. 2 ). Sterna without modifications, nearly flat, densely setose. Legs (♂) generally rather long and slender, apparently slightly incrassate ( Figs 1–2 ), ca 1.7–1.8 times as long as midbody height, densely setose, almost all setae simple, very poorly branching setae with minute, distal, side branchlets being observed only on slender prefemora, the latter devoid of lateral bulges; sphaerotrichomes absent. In length, tarsus = femur> prefemur> coxa = postfemur = tibia ( Fig. 2 ).

Gonopods ( Figs 2 , 4–5 ) with large, subquadrate coxites (cx) strongly fused medially at base and carrying a few long setae ventrally; a long, simple and unciform cannula, as usual. Telopodite elongated, stout, subfalcate only distally, prefemorite (= densely setose part) more than half as long as entire telopodite; seminal groove running mesally over most of its extent, only distally moving frontally to recurve first laterad and then a little basad at base of a longer, subunciform and quite simple endomere (en); an exomere absent; a round accessory seminal chamber hidden inside at base of a single, stout and apically unequally bifid postfemoral process (pf).

REMARKS. The new species differs readily from all hitherto known Himalayan congeners primarily by the single, undivided postfemoral process of the gonopod [ Golovatch, 1986, 1987, 1990], in this respect rather resembling several species from China, e.g. E. coniger Liu et Golovatch, 2018 , E. parvus Liu et Golovatch, 2018 , E. gladiatus Liu et Golovatch, 2018 and some others, in which the single postfemoral process is relatively small, sometimes even barely discernible [ Liu, Golovatch, 2018].

Acknowledgements. I am most grateful to Dmitry Telnov (Natural History Museum, London, United Kingdom) for the provision of the holotype of the new species for study and the donation to the ZMUM collection. Special thanks go to Kirill Makarov (Moscow, Russia) who so skillfully took all pictures. The author was partly supported by the Presidium of the Russian Academy of Sciences , Programme No. 41 “Biodiversity of Natural Systems and Biological Resources of Russia ” .

Figures

Figs 1–3. Epanerchodus telnovi sp.n., ♂ holotype: 1–2 — habitus, dorsal and ventral views, respectively; 3 — anterior part of body, anterodorsal view. Pictures by K. Makarov, not taken to scale. Рис. 1–3. Epanerchodus telnovi sp.n., голотип ♂: 1–2 — обЩий вид, соответственно сверху и сниЗу; 3 — переднЯЯ часть головы, одновременно спереди и сверху. Фотографии К. Макарова, снЯты беЗ масШтаба.

Figs 4–5. Epanerchodus telnovi sp.n., ♂ holotype, right gonopod, mesal and lateral views, respectively. Scale bar: 0.2 mm. Abbreviations explained in text. Рис. 4–5. Epanerchodus telnovi sp.n., голотип ♂, правый гонопод, соответственно иЗнутри и сбоку. МасШтаб: 0,2 мм. ОбЪЯснение обоЗначений в тексте.