Platystethus vicinior, Lü, Liang & Zhou, Hong-Zhang, 2015

Lü, Liang & Zhou, Hong-Zhang, 2015, Review of the Genus Platystethus Mannerheim (Coleoptera: Staphylinidae: Oxytelinae) in China, Zootaxa 3915 (2), pp. 151-205 : 193-201

publication ID	https://doi.org/ 10.11646/zootaxa.3915.2.1
publication LSID	lsid:zoobank.org:pub:BEAD42C0-1031-4C82-A71A-15A670C3467A
DOI	https://doi.org/10.5281/zenodo.6114352
persistent identifier	https://treatment.plazi.org/id/03CE8795-FFF8-A474-FF11-A7EAFCA1F8CD
treatment provided by	Plazi
scientific name	Platystethus vicinior
status	sp. nov.

Treatment

12. Platystethus vicinior View in CoL sp. nov.

( Figs. 28 View FIGURE 28 ; 29; 30; 31A–H; 32M)

Type material examined. Holotype: ♂, CHINA: Xinjiang, Manasi Co. [=Manas Co.], Wangjiacun Village [44.28ºN 86.27ºE], from a grass heap in potato field, 444 m, 2010. VII.3, Y.-C. Li leg. (IZ-CAS). Paratype: 1♂, Xinjiang, valley of Yining River [= Yili River], 540–630 m, 1957. VIII.5, C.-P. Hong leg., Platystethus degener Rey , det. P.M.Hammond, 1980 (IZ-CAS).

Description (holotype). Body ( Fig. 30 View FIGURE 30 A) black to dark brown; mandibles, maxillary palpi, antennae, and legs reddish; elytra with paler pattern in center and posteromedial area. Length [average]: ♂, 2.9 mm.

Male. Head ( Figs. 28 View FIGURE 28 A; 30B) broadest at temples. Disc coriaceous, nearly glabrous, with punctures dense and coarse. Clypeus transverse and protruding beyond anterior border of supra-antennal ridges, with anterior margin shallowly emarginate in middle, furnished a pair of sharp and slender spines. Epistomal suture with middle portion absent, lateral portions short but obvious and posteromedially directed. Supra-antennal ridges elevated. Vertex depressed in anterior part, convex in center; mid-longitudinal suture short, posteriorly reaching occipital suture. Eyes slightly convex, shorter than temples, with fine facets; orbital sulcus feeble. Long and deep longitudinal groove sculptured throughout mesial side of eye and temple. Temple not dilated laterally. Neck not constricted. Occipital suture curved, present only in middle, with large setal fovea and feeble paralateral suture lying behind and at each 1/4 of head width. Mandible stout, incurved at apex.

Pronotum ( Figs. 28 View FIGURE 28 A; 30B) slightly wider than head, widest at near anterior margin, with mid-longitudinal sulcus present whole length, with punctures dense but smaller than in head, surface coriaceous but not microstriate; anterior margin bi-emarginate, anterior lateral angles prominent, no posterior angles; lateral and posterior margins integrated and evenly rounded, without crenulation. Scutellar impression ( Fig. 30 View FIGURE 30 B) bi-reniform in anterior part, anterior margins crescent. Elytra ( Fig. 30 View FIGURE 30 B) with posterior margin truncate, elytral suture dehiscent or partly overlapping.

Abdomen coriaceous. Sternite VII ( Figs. 28 View FIGURE 28 B; 30C) with two reduced teeth on posterior margin, between which not emarginate. Sternite VIII ( Figs. 28 View FIGURE 28 C; 30D) tri-partitioned by 2 curved narrow sutures, middle part truncate on posterior margin, without mid-longitudinal internal ridge, lateral parts separated by middle part but touched at anterior margin, each with two teeth at mesial side of posterior margin: one sharp, one dull; basal ridge interrupted in middle and subbasal ridge with only lateral portions present but short.

Aedeagus ( Figs. 28 View FIGURE 28 D–F; 31A–D) with median lobe slightly inflated at base and gradually narrowed apically; apical orifice fissured to middle of ventral surface, edges of ventral fissure sharply protruding into a pair of long spines which upcurved at apex and constricted at near base; internal sac membranous and rolling into watchspring-shape at base. Paramere arm-like, basal arm with furrow on ventral surface; apical arm explanate and furnished with small seta at apex, another seta at near apical 1/4, and with pits scattered.

Paratype. Body smaller and color lighter. Clypeal spines shorter ( Figs. 29 View FIGURE 29 A; 30E). Abdominal sternites VII–VIII ( Figs. 29 View FIGURE 29 B, C; 30F, G) similar to holotype but smaller. Aedeagal parameres a little asymmetric ( Figs. 29 View FIGURE 29 D–F; 31E–H).

Female. Unknown.

Distribution. China (Xinjiang).

Etymology. The specific epithet is comparative of the Latin adjective “ vicinus ”.

Remarks. The paratype is not completely consistent with the holotype, but we suppose it is an aberrant form or premature adult, because the paratype is much lightly colored both in exocuticle and in aedeagus, and it is located not very far from holotype locality. The new species is allied to P. degener , but different in coloration, sternite VII and aedeagus: the elytral pale pattern is smaller than that in P. degener ; the two teeth on posterior margin of sternite VII are more reduced and farther placed (as in P. alutaceus ); the spines of aedeagal median lobe look obviously different from P. degener or P. alutaceus in lateral view, and the emargination on apex of paramere is larger in the new species (cf. Figs. 31–32 View FIGURE 31 View FIGURE 32 ). Platystethus akkumus Kashcheev is another species alike P. vicinior , but the aedeagal medianlobe of P. akkumus without the two spines as long as that appear on P. vicinior (cf. Fig. 1 View FIGURE 1 (14) in Kashcheev, 1999a: 145). The new species can be distinguished by coloration from P. praetermissus Eppelsheim (cf. Fig. 34 View FIGURE 34 A–B), P. rugifrons Bernhauer , (cf. Fig. 34 View FIGURE 34 F–J), P. rufospinus Hochhuth (cf. Hochhuth, 1851: 51-53 [ P. rufospinus is “mostly black”]), and P. spinicornis Luze (cf. Fig. 34 View FIGURE 34 C–E). Platystethus vicinior can also be separated from the following species: P. depravatus Eppelsheim whose posterior margin of male sternite VII with emargination between teeth (cf. Eppelsheim, 1892: 342); P. spinosus Erichson which with “sutural striae not continued on to the posterior margins of elytra” (cf. Hammond, 1971: 94); P. zaisanicus Kashcheev who has the “vertex tubercles”, which are absent from P. vicinior , and whose posterior margin of sternite VII is emarginated between teeth (cf. Kashcheev, 1999b [1996]: 13–14, Figs. 1–3 View FIGURE 1 View FIGURE 2 View FIGURE 3 ).