Holotype male: China, Sichuan, Jinchuan, 31°29'N, 102°05'E, 2647 m, 31 Jul. 2012, Y. C. Li and Y. P. Lai leg. (MCWNU). Paratypes: 9 males and 5 females, same data as the holotype (MCWNU).

This new species can be distinguished from other Itagonia species by the following differences: each elytron with traces of two longitudinal carinae; inner surface of male protibiae with arcuate prominence near base. Itagonia tibialis sp. n. belongs to the group including also Itagonia bisetosa Medvedev, 1998, Itagonia tuberculata Shi et al., 2010 and Itagonia trisetosa Medvedev, 1998. Representatives of this group differ from other Itagonia species in having apicale of aedeagus flat, smoothly tapering from base to apex, forming no sharp narrowing in apical part (Figs 9, 11, 13, 22). Occurring together with Itagonia bisetosa, Itagonia tuberculata and Itagonia trisetosa, the new species can be distinguished by upper edge of inner surface of profemur forming in apical part rectangular tooth. Also, the described species sharply differs from Itagonia bisetosa and Itagonia trisetosa in having less than anterior 1/2 of outer margin of epipleura visible from above, and from Itagonia tuberculata in having the pronotum widest before middle.

Named after the protibiae of male, inner surface of which has an arcuate prominence near base. This sharply differs from those of other species of Itagonia.

Body black, elytra dull, other parts of body weakly shining.

Male (Figs 16, 18–26). Anterior margin of clypeus weakly sinuate. Lateral margin of head almost without incision above antennal base. Genal margin parallel before eyes. Eyes not protruding beyond contour of head. Vertex slightly convex or flat, with moderately dense punctures. Frontoclypeal suture very shallow or invisible. Antennae (Fig. 16) reaching or nearly reaching pronotal base. Length (width) ratio of antennomeres 2 to 11 as follows: 18(17): 67(18): 25(16): 27(17): 31(18): 31(18): 23(22): 22(24): 21(25): 31(23).

Pronotum (Fig. 18) 1.15–1.24 (1.19 on average, n=10) times as wide as long, maximum width before middle, 1.63–1.77 (1.68 on average, n=10) times as wide as head. Ratio of pronotal width at anterior margin to its maximum width and width at base (n=10) 0.55: 1.00: 0.94 on average. Lateral margins of pronotum sharply arcuately converging to anterior margin in anterior 1/3, slightly narrowing to base in basal half or nearly parallel in basal 1/4, entirely bordered. Anterior margin of pronotum weakly sinuate, bordered laterally; base straight, not bordered. Anterior angles of pronotum weakly obtuse, rounded apically; posterior ones weakly obtuse or nearly rectangular. Pronotal surface between lateral margins weakly convex, with shallow median depression at disc; punctures as large as those on head, fine at disc center and larger laterally. Propleura concave in basal half, with wrinkles and very sparse granules. Prosternum in front of procoxae gently sloping; intercoxal process with shallow median depression, steeply sloping behind procoxae.

Elytra elongate-oval, 1.56–1.65 (1.60 on average, n=10) times as long as wide, maximum width in anterior 1/3, 1.35–1.44 (1.41 on average, n=10) times as wide as pronotum. Less than anterior 1/2 of outer margin of epipleura visible from above. Elytral surface between epipleura and sutural margin convex. Each elytron with traces of 2 longitudinal carinae, dense granules and sparse irregular prominences. Epipleural surface smooth, with sparse wrinkles and very sparse granules. Abdominal ventrites with punctures and short brown setae, abdominal ventrites 1 to 3 with longitudinal wrinkles, basal two abdominal ventrites with concave impression in middle.

Legs (Figs 19–21) moderately robust, length (width) ratio of pro-, meso- and metafemora 74(26): 74(19): 100(21); tibiae: 70(11): 63(13): 95(14). Upper edge of inner surface of profemur with rectangular tooth in apical part. Inner surface of protibiae with arcuate prominence near base. Upper spur of protibiae not very massive, shorter than protarsomere 1, lower spur fine and pointed. Plantar surface of protarsomeres 1 and 2 and mesotarsomere 1 with hair brushes. Metatibiae weakly incurved, regularly widening apicad. Length (width) ratio of metatarsomeres 1 to 4 as follows: 25(6.4): 12(6.0): 12(5.7): 22(6.4).

Aedeagus (Figs 22–24): length 3.83 mm, width 0.79 mm. Apicale 1.33 mm long and 0.70 mm wide, with outer margins arcuately narrowing to apex. Spiculum gastrale as in Fig. 25. Apical margin of abdominal ventrite 8 sinuate (Fig. 26).

Female (Figs 17, 27–29). Body wider. Antennae (Fig. 17) shorter than in male. Pronotum 1.24–1.33 (1.28 on average, n=5) times as wide as long. Elytra 1.41–1.48 (1.44 on average, n=5) times as long as wide. Less than anterior 1/3 of outer margin of epipleura visible from above. Protibiae nearly straight. Upper spur of protibiae massive and rounded apically; lower spur fine. Metatibiae straight. Plantar surface of protarsomeres and mesotarsomeres without brush. Ovipositor as in Figs 27–28. Spiculum ventrale as in Fig. 29.

Male body length 13.4–15.1 mm, width 5.4–6.3 mm; female body length 13.8–15.6 mm, width 6.7–7.2 mm.

Holotype male: China, Sichuan, Litang, 30°18'N, 100°16'E, 3410 m, 2 Aug. 2012, A. M. Shi leg. (MCWNU). Paratypes: 5 males and 4 females, same data as the holotype (MCWNU).

The new species resembles Itagonia medvedevi Shi et al., 2010 and Itagonia cordiformis Shi & Ren, 2007 by less than anterior 1/2 of outer margin of epipleura visible from above and apicale of aedeagus with outer margins sinuate, apical part rather sharply narrowing apicad (Figs 12, 15, 36). Itagonia litangensis sp. n. differs from Itagonia medvedevi and Itagonia cordiformis in having the prosternum in front of procoxae steeply sloping; upper spur of protibiae not massive, shorter than protarsomere 1; plantar surface of mesotarsomeres 1 to 2 with hair brushes; apical margin of abdominal sternite 8 weakly sinuate. Also, the new species can be distinguished from Itagonia medvedevi by apical part of outer margin of epipleura invisible from above, and from Itagonia cordiformis by lateral margins of pronotum weakly arcuately protruding.

Named after the type locality, Litang.

Body black, weakly shining.

Male (Figs 30, 32–40). Anterior margin of clypeus nearly straight. Lateral margin of head with obtuse-angled shallow incision above antennal base. Genal margin arcuately converging to clypeal base. Eyes not protruding beyond contour of head. Vertex slightly convex, with moderately dense punctures. Frontoclypeal suture shallow. Antennae (Fig. 30) reaching posterior 1/4 of pronotum. Length (width) ratio of antennomeres 2 to 11 as follows: 16(13): 33(14): 18(14): 18(14): 18(14): 20(14): 18(17): 18(19): 18(20): 25(19).

Pronotum (Fig. 32) transverse, 1.25–1.35 (1.28 on average, n=6) times as wide as long, maximum width before middle, 1.77–1.86 (1.84 on average, n=6) times as wide as head. Ratio of pronotal width at anterior margin to its maximum width and width at base (n=6) 0.67: 1.00: 0.91 on average. Lateral margins of pronotum more sharply arcuately narrowing to anterior margin than to base, entirely bordered. Anterior margin of pronotum nearly straight; base straight, both bordered laterally. Anterior angles of pronotum obtuse, rounded apically; posterior ones weakly obtuse. Pronotal surface between lateral margins convex, with short median depression at disc; punctures as large as those on head, fine at disc center and larger laterally. Propleura slightly concave, with wrinkles and very sparse granules. Prosternum in front of procoxae steeply sloping; intercoxal process with shallow median depression, steeply sloping behind procoxae.

Elytra elongate-oval, 1.35–1.42 (1.39 on average, n=6) times as long as wide, maximum width before middle, 1.21–1.31 (1.25 on average, n=6) times as wide as pronotum. Less than anterior 1/2 of outer margin of epipleura visible from above. Elytral surface between outer margin of epipleura and sutural margin convex, sparsely covered with irregular fine wrinkles and fine punctures. Epipleural surface with sparse wrinkles. Abdominal ventrites with punctures and brown setae, abdominal ventrites 1 to 3 with longitudinal wrinkles.

Legs (Figs 33–35) robust, length (width) ratio of pro-, meso- and metafemora 78(22): 82(20): 100(21); tibiae: 74(11): 71(12): 94(16). Upper spur of protibiae not massive, shorter than protarsomere 1, lower spur fine and pointed. Plantar surface of protarsomeres 1 to 3 and mesotarsomeres 1 to 2 with hair brushes. Metatibiae weakly incurved. Length (width) ratio of metatarsomeres 1 to 4 as follows: 24(8.0): 13(7.5): 12(6.7): 25(6.7).

Aedeagus (Figs 36–38): length 2.24 mm, width 0.71 mm. Apicale 0.69 mm long and 0.48 mm wide, with outer margins slightly sinuate in basal 1/3. Spiculum gastrale as in Fig. 39. Apical margin of abdominal ventrite 8 weakly sinuate (Fig. 40).

Female (Figs 31, 41–43). Body wider. Antennae (Fig. 31) shorter than in male. Pronotum 1.27–1.35 (1.32 on average, n=4) times as wide as long. Elytra 1.27–1.35 (1.31 on average, n=4) times as long as wide. Less than anterior 1/3 of outer margin of epipleura visible from above. Upper spur of protibiae massive and rounded apically; lower spur missing. Plantar surface of protarsomeres and mesotarsomeres without brush. Ovipositor as in Figs 41–42. Spiculum ventrale as in Fig. 43.

Male body length 11.0–12.2 mm, width 5.2–5.8 mm; female body length 11.4–12.1 mm, width 5.6–6.1 mm.