Lesticus bii , Zhu, Pingzhou, Shi, Hongliang & Liang, Hongbin, 2018
treatment provided by
Lesticus bii sp. n. Figs 5-9
China, Xizang: Mêdog (ca. 29.32°N, 95.34°E), altitude 1500-1900 m.
Holotype: male (IZAS), body length = 17.8 mm, board mounted, genitalia dissected and glued on plastic film pinned under specimen, "Xizang, Mêdog, / 1500-1900m, 2013. / VIII.20, Bi Wenxuan"; "HOLOTYPE ♂ / Lesticus bii sp.n. / des. ZHU & SHI 2018" [red label]. Paratypes (one male and three females): one male (IZAS), "Xizang, Nyingchi, Mêdog Pari village / 1807m / 2014-VIII-9 / along road during day, Yang Xiaodong Leg. / 14Y0437 CCCC"; "PARATYPE ♂ / Lesticus bii sp.n. / des. ZHU & SHI 2018" [red label]. Two females (CCCC), "Xizang, Nyingchi, Mêdog / 1559m / 2016-VIII-5 / along road during night, Yang Xiaodong Leg. / 16Y CCCC"; "PARATYPE ♂ / Lesticus bii sp.n. / des. ZHU & SHI 2018" [red label]. One female (IZAS), "China Xizang Mêdog / Phomshen village 1850m / 2016-VII-10 / light trap, Lu Yanquan Leg. / CCCC"; "PARATYPE ♂ / Lesticus bii sp.n. / des. ZHU & SHI 2018" [red label].
Odd intervals prominently raised but not carinate, much wider than depressed even ones; third interval without setigerous pore; pronotal lateral margins crenulate through full length; basal fovea very deep; metepisternum short and wide, length subequal to its basal width; apical lamella of aedeagus truncated, shorter than basal width, without hook.
This new species can be readily distinguished from all the other Chinese species of the genus by the prominently raised odd elytral intervals. There are three other species ( L. tricostatus Chaudoir, L. wittmeri Morvan, and L. cupricollis Pouillaude) from the Himalayan region with similar elytral characters, but they are different from the new species by: pronotal lateral margins not crenulated; odd intervals carinate, of about the same width as the even ones; apical lamella hooked or much longer than its basal width. Among these three, the new species is most similar to L. wittmeri from Bhutan for they both have pronotal basal fovea markedly prolonged anteriorly, elytral first interval not carinate, and apical lamella unhooked.
Body length 17.8-20.0 mm, elytra’s greatest width 6.2-7.3 mm, both sexes with similar body form. Head, pronotum, elytra and appendages black, polished but without metallic lustre; basal antennomere, maxillae, labial and maxillary palpi, lateral sides of labrum, pro- and mesotarsomeres reddish brown; apical half of terminal labial and maxillary palpomeres yellow; ventral side black. Head, pronotum and elytra with isodiametric microsculpture and minute punctures.
Head with dense and fine punctures on vertex and occiput; vertex densely rugose, deeper and longitudinal near eyes, shallower and reticular at middle; labrum with anterior margin nearly straight; temporae slightly tumid behind eyes; antennal apex reaching elytra basal sixth.
Pronotum wider than head, PW/HW = 1.38-1.44; width a little greater than median length, PW/PL = 1.13-1.21; pronotum widest near anterior third; lateral margins crenulate along full length, curved near middle, distinctly sinuate before posterior angles; posterior angles rectangular, not pointed outwards; posterior margin a little narrower than anterior margin, barely extended backward on each side, middle portion gradually concave; median line fine but a little deep, not reaching posterior margin; disc with dense transverse wrinkles alongside median line; basal fovea strongly incised, inner and outer grooves indistinct, completely fused together forming large and deep depression, extending forward beyond midpoint of pronotum, and gradually fused to widened lateral channel; basal fovea finely and densely punctated and rugose, wrinkles present on middle region of pronotal base between basal fovea.
Elytra oviform, EL/EW = 1.52-1.66, gradually widened to apex, widest near posterior third; basal ridge complete, forming indistinct obtuse angle with lateral margin, humeral teeth not pointed. Intervals with shallow transverse wrinkles; odd intervals strongly raised but not carinate, much more convex and wider, about twice width of the even ones; third interval without setigerous pore; striae deeply incised, with fine and sparse punctures alongside; scutellar stria very short, apex free; parascutellar pore on base of second interval, sometimes one additional parascutellar pore present; umbilicular series on ninth interval composed of 15-20 pores almost evenly arranged. Hind wings very small.
Ventral side: propleuron and mesopleuron with dense, fine punctures; metepisternum short and wide, length a little less than its basal width (Fig. 7), with dense, fine punctures; abdominal sterna glabrous medially, finely rugose laterally, lateral sides of sternum II and sometimes sternum III as well, finely and sparsely punctate.
Legs: basal three meso- and metatarsomeres prominently carinate along full length of outer surface, fourth tarsomeres barely carinate only near base; fifth tarsomeres with 3-4 pairs of spines ventrally.
Male genitalia: median lobe of aedeagus with apical orifice opened dorsally; in lateral view, ventral margin distinctly expanded in middle, apical portion straight, turned neither ventrally nor dorsally, basal portion a little narrowed; in dorsal view, apical lamella short, length about half basal width, apex truncated; apical portion straight, oriented to neither left nor right. Endophallus (Fig. 8) short and straight, extending to dorsum, the inscribed angle between axes of aedeagus and endophallus about 90°; main portion of endophallus on dorsal side of aedeagus when everted; gonopore (gp, gonopore lobe folded in Fig. 8) located at a little before apical lamella, oriented to dorsal side of aedeagus. Basal tubercle (bt) much larger than in other species, very densely and heavily spined; basal band (bb) absent. Five distinct lobes recognized: dorsal lobe (dl) small, nearly rounded, almost touching bt; right basal lobe (rb) divided into two separate lobes; right basal lobe I (rb-1) elongated, bent to dorsal direction of endophallus, placed at right-dorsal surface, decorated with dense and fine scales; right basal lobe II (rb-2) close to rl-1, bent to apical direction of endophallus, apex pointing out to dorsal direction, without scales; right apical lobe (ra) small, on right side of gp, bent to dorsal direction of endophallus, apex curved; left basal lobe (lb) absent; left apical lobe (la) close to dl, on left side of gp, bent to apical direction of endophallus, apex a little bifid.
This species is known only in a few localities of Xizang, Mêdog (Map 2).
The new species is named for our friend Mr. BI Wenxuan, an excellent beetle collector, who was first to collect this rare and peculiar new species.
Lesticus bii sp. n. was presumed to be close to L. tricostatus , L. wittmeri , and L. cupricollis for the following similarities: elytral odd intervals prominently raised; third interval without setigerous pore; pronotal lateral margins distinctly sinuate before posterior angles; and all from the Himalayan region. Among them, the new species has more plesiomorphies than the others, such as: all odd elytral intervals not carinate, apical lamella unhooked. Moreover, L. bii sp. n. was considered to be associated with two other Himalayan species ( L. harmandi Tschitschérine, and L. holzschuhi Straneo) for their similarities in: pronotal lateral margins crenulate and distinctly sinuate before posterior angles; large, deep basal fovea; elytral third interval without setigerous pore; short metepisternum. Another species from Northern Myanmar, L. nigroviolaceus Dubault, Lassalle & Roux was similar to the new species in external and male genitalia characters, although pronotal lateral margins are not crenulate and odd intervals not raised.. Thus, all seven species are assumed to be associated with and forming one species group defined by: (1) short metepisternum, length less than or subequal to its basal width; (2) elytra third interval without setigerous pore; (3) pronotal lateral margins distinctly sinuate before posterior angles, large, deep basal fovea; (4) relatively small body size, generally less than 24 mm.
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