Brachyllus dongzhiweii Zhao, 2023

Zhao, Ming-Zhi, Qi, Zhi-Hao, Su, Rong-Xiang & Liao, Tao-Kun, 2023, New and poorly known species of the genus Brachyllus Brenske, 1896 (Coleoptera Scarabaeidae: Melolonthinae) from China, Zootaxa 5256 (4), pp. 358-370 : 361-364

Brachyllus dongzhiweii Zhao , new species

( Figs. 3A–B , 4A, 4C, 4E , 7I–J )

Type material. Holotype ♁ ( SCAU), “ CHINA: Xizang Autonomous Region / Nyingchi City , Motuo County / Beibeng Township , Jiangxincun Village [ ḢfflLj ] / 15 – 17.VII.2017, Zhi-Wei Dong leg.”

Description of the holotype ( Figs. 3A–B , 4A, 4C, 4E , 7I–J ). Elongated ovoid, subcylindrical, somewhat broadened behind.

Colour. Generally reddish brown, with head, pronotum, and irregularly raised reliefs on elytra dark brown. Head and pronotum with weak metallic green sheen. Setae yellowish brown.

Head. Clypeus strongly emarginated, anterior margin reflexed, strongly swollen but weakly reflexed at middle, lateral corner rounded, lateral margin strongly converging posteriad. Frontoclypeal suture distinct, weakly raised at middle. Inner margin of eyes weakly raised. Surface of clypeus and frons with dense and coarse punctures, vertex with dense and small punctures, posterior part of vertex only punctured medially. Each puncture with a minute seta; frons and outer surface of clypeus with scattered, moderately long and erect setae. Antenna 9-segemented, antennal club 3-segmented, length of antennal club equals to the combined length of antennomeres 3–4, antennomere 2 glabrous.

Pronotum. Wider than long. Lateral margin generally parabolic, with rather strong scalloped modification. Anterior angle strongly protruding and acute at apex, posterior angle weakly protruding, and surface depressed on all margins except before the scutellum. Disc with scattered and large punctures, punctures smaller and more aggregated near lateral and depressed portions. Each puncture with a minute seta; lateral margin of pronotum along with several rather short setae.

Scutellum. Ogival. With several irregularly-distributed punctures, somewhat smaller than those on pronotal disc. Each puncture with a minute seta.

Elytra. Surface uneven, with somewhat reticulated raised reliefs, the sutural interval well-defined, other intervals are interrupted by the depressed portions and hardly recognizable; humeral umbone prominent, subapical umbone indistinct. Raised portions rarely punctured, except for the sutural interval; unraised portions with moderately dense and large punctures, the sutural interval with scattered punctures, punctures slightly smaller than those on scutellum. Each puncture with a minute, scaly seta, some rather short to short setae emerge sparsely, being slightly denser near apex; epipleura with a row of several rather short setae at basal fourth.

Ventral thoracic surface. Ventral prothoracic surface with moderately dense and large punctures, ventral mesoand metathoracic surfaces with smaller but very dense punctures. Ventral prothoracic surface with moderately dense and long setae, mesoventrite sparsely setose, metaventrite with dense and rather long setae. Prosternal process small and conical, not extending beyond procoxa.

Abdomen. Abdominal ventrites I–V weakly carinate laterally. Abdominal ventrites with moderately dense punctures, becoming somewhat denser laterally, the punctures as large as those on metaventrite; ventrite VI with punctures on margins only. Each puncture on ventrites with a minute seta, each puncture on posterior half of lateral portions of each ventrite with a short and recumbent seta; very dense, short and oblong setae aggregated along the lateral carinae of ventrites I–IV, ventrite VI with a row of moderately dense and moderately long setae along posterior margin. Pygidium weakly convex, surface with dense and large punctures; posterior margin a row of moderately long setae, which becoming long near apex.

Legs. Slender. Protibia tridentate, apical and second teeth prominent, proximal tooth small, equally spaced; without protibial spur. Each tarsal claw with a strong medial tooth. Femora with moderately dense and large punctures, somewhat aggregated on profemora. Meso- and metafemora each with a transverse row of sparse and moderately long setae behind middle, anterior portions of femora with scattered and moderately long setae; tibiae with scattered and short to moderately long setae.

Male genitalia. As in Fig. 7I–J .

Female. Unknown.

Measurements. Body length (measured from anterior margin of clypeus to apex of elytron): 15.3 mm, body width (measured across humeri): 6.6 mm.

Differential diagnosis. Brachyllus dongzhiweii Zhao , new species is most similar to B. frontalis Brenske, 1896 ( Fig. 3C–D ). The new species can be easily separated from B. frontalis by the shorter antennal club, which is equal to the combined length of antennomeres 3–4 but of antennomeres 3–6 in the latter species ( Fig. 4A–B ). The setae on lateral portions of abdominal ventrites are stouter ( Fig. 4C–D ). The elytra of the new species bear some short setae, while short setae are almost imperceptible on elytra of B. frontalis ( Fig. 4E–F ). Moreover, the shape of parameres differs a lot in lateral view: in B. dongzhiweii new species, the dorsal concavity is much shallower and the upper lobe is rounded ventrally, the lower lobe distinctly protruding. B. frontalis has deep dorsal concavity, ventrally protruding upper lobe and weakly protruding lower lobe ( Fig. 7I–L ).

Other two Himalayan congeners, B. ulcerosus Brenske, 1896 and B. bhutanensis Keith, 2005 are also similar. But the two have a distinctly opaque and uneven pronotum, in contrast to the shiny and less uneven in B. dongzhiweii new species and B. frontalis .

Etymology. This species is dedicated to Zhi-Wei Dong, who collected and donated the holotype of this new species.

Figures

FIGURE 3. Habitus and labels of Brachyllus spp. A–B, B. dongzhiweii new species, holotype; C–D, B. frontalis; E–F, B. rougeriei langeri; G–I, B. rougeriei rougeriei, holotype. A, C, E, G, dorsal view; B, D, F, H, ventral view.

FIGURE 4. Detailed characters of Brachyllus species, arrows indicate the moderately long setae. A, C, E, B. dongzhiweii new species, holotype; B, D, F, B. frontalis; G, B. rougeriei rougeriei, holotype; H, B. rougeriei langeri. A–B, antennae; C–D, abdominal ventrites; E–F, elytra; G–H, pronotum.

FIGURE 7. Male genitalia of Brachyllus species. A–B, B. songhaitiani new species, holotype; C–D, B. deuveianus, holotype; E–F, B. rougeriei rougeriei, holotype; G–H, B. rougeriei langeri; I–J, B. dongzhiweii new species, holotype; K–L, B. frontalis; M–N, B. itohi mantilleri, holotype; O–P, B. tangzhaoyangi new species, holotype. Upper row, parameres in dorsal view; lower row, aedeagus in lateral view.