Laemostenus (Pristonychus) zhentangensis, Zhu & Shi & Liang, 2021

Zhu, Pingzhou, Shi, Hongliang & Liang, Hongbin, 2021, The first record of the genus Laemostenus from China, with descriptions of two new species from the Himalaya (Carabidae, Sphodrini, Sphodrina), ZooKeys 1017, pp. 77-88 : 77

publication ID	https://dx.doi.org/10.3897/zookeys.1017.61383
publication LSID	lsid:zoobank.org:pub:09CCA8F4-5E25-4DD6-B37F-FEF66B0E809D
persistent identifier	https://treatment.plazi.org/id/DDFF30AE-D552-44F4-9B82-3F7E4DDDDC5D
taxon LSID	lsid:zoobank.org:act:DDFF30AE-D552-44F4-9B82-3F7E4DDDDC5D
treatment provided by	ZooKeys by Pensoft
scientific name	Laemostenus (Pristonychus) zhentangensis
status	sp. nov.

Treatment

Laemostenus (Pristonychus) zhentangensis View in CoL sp. nov. Figs 1 View Figures 1, 2 , 3-5 View Figures 3–8 , 9-11 View Figures 9–14

Type locality.

China, Xizang: Dinggyê (27.9161°N, 87.4607°E), altitude 3151 m.

Type material.

Holotype: male (IZAS), body length 15.6 mm, pin mounted, with genitalia dissected and glued on cardboard pinned under the specimen; labeled: "CHINA: Xizang, Xigazê Prefecture, Dinggyê County, Zhêntang Town, Zangqiong, 27.9161°N 87.4607°E, 3151 m"; "2019.VII.4, pitfall trap, Shi HL, Yan WF & Zhu PZ lgt. Expedition of BJFU 2019. 定结县陈塘镇藏琼云雾林”; "Holotype ♂ Laemostenus (Pristonychus) zhentangensis sp. n. des. ZHU, SHI & LIANG 2020" [red label].

Diagnosis.

Body dark brown. Head slightly narrow. Eyes small, slightly prominent laterally; tempora oblique, as long as eyes. Elytra with lateral margins straight near sutural angles; sutural angles acute. Parascutellar pores present. Ventral side of profemora smooth, with one seta on posterior margin, without tooth on anterior margin. Mesotibiae faintly curved in male. Meso- and metatibiae with a dense brush of reddish-yellow setae in apical half. Metatrochanters reniform, not elongate. Apical lamella of median lobe short, length half its basal width, apex slightly truncate. Right paramere strongly curved (the angle between basal and apical portions near 90°), distinctly widened at middle, strongly narrowed to apex, apex very thin.

Comparison.

This new species belongs to the Laemostenus brunneus species group sensu Casale (1988) for (1) reniform metatrochanters, not elongate in shape; (2) the ventral side of profemora smooth or at most with a small tooth on anterior margin; (3) eyes small, not very prominent; (4) body dark brown, without metallic luster; and (5) metatibiae usually curved in males at least.

Among this species group, the new species is most similar to Laemostenus (Pristonychus) arthuri (Morvan, 1982) and L. (P.) migliaccioi (Casale, 1982), both from Nepal, sharing the ventral side of profemora with one or two setae on posterior margin and the subcordate pronotum. The new species differs from them by the narrower head, the slightly larger eyes, and the slightly truncate apical lamella of the aedeagus. The apical lamella of the aedeagus is rounded in L. (P.) arthuri and emarginate in L. (P.) migliaccioi , and both species have a more globular head with smaller eyes.

Description

(male). BL = 15.6 mm, BW = 5.9 mm. Body (Fig. 1 View Figures 1, 2 ) dark brown, without metallic luster; antennomeres 4-11, labial and maxillary palpi, and apex of mouthparts brown to light brown; venter reddish brown. Head, base of pronotum, and elytra with strong isodiametric microsculpture; disc of pronotum with slightly transverse microsculpture.

Head (Fig. 3 View Figures 3–8 ) medium in width. Vertex smooth; frontal impressions reduced to two small pits in front of eyes, shallow but distinct; anterior margin of labrum emarginate, with four setae; eyes small, slightly prominent laterally; tempora oblique, as long as eyes; two pairs of supraorbital setae present; antennae long and slender, extended to half of elytra.

Pronotum (Fig. 4 View Figures 3–8 ) subcordate, wider than long, PW/PL = 1.16, widest near anterior quarter; apical margin weakly concave, its width subequal to basal margin; sides distinctly converged to base (PW/PBW = 1.32), faintly sinuate before posterior angles, with two pairs of setae, at widest points of pronotum and at posterior angles, respectively; basal margin nearly straight; anterior angles rounded, clearly projecting forwards; posterior angles forming distinct obtuse angles; disc gently convex, with some shallow transverse wrinkles; median line fine but clearly defined, reaching anterior and posterior borders; basal foveae shallow and wide, extending beyond middle of pronotum, without punctures or wrinkles.

Elytra elongate, EL/EW = 1.61, slightly dilated towards apex, widest at posterior third; lateral margins straight before sutural angles, sutural angles acute (Fig. 5 View Figures 3–8 ); basal margins straight; shoulders moderately oblique; shoulder angles between basal ridges and lateral margins forming obtuse angles; humeral teeth very small, not pointed; striae shallow, impunctate; parascutellar striae well developed, short, located between suture and stria 1; parascutellar pores present; intervals feebly convex, interval 3 without setigerous pores, interval 7 with two setigerous pores near apex; umbilicate series composed of 20 or 21 setigerous pores, sparser in middle. Hind wings reduced.

Venter. Propleuron, mesepisternum, and metepisternum smooth. Mesosternum not denticulate in front of mesocoxae. Metepisternum long and narrow. All abdominal sternites with a few shallow wrinkles laterally, without ambulatory setae.

Legs long and slender; ventral side of profemora smooth, with one seta on posterior margin, without tooth on anterior margin; protibiae with sparse pubescence on apices; mesotibiae faintly curved (in male); meso- and metatibiae inner sides with a dense brush of reddish-yellow setae in apical half; metatrochanters reniform; tarsi elongate and narrow; metatarsomere 1 sparsely pubescent dorsally; claws smooth on internal margin. Protarsomeres 1-3 distinctly dilated and with ventral adhesive vestiture in male.

Male genitalia. Median lobe (Fig. 9 View Figures 9–14 ) short and stout, distinctly bent ventrally; apical orifice very long, stretching from basal bulb to apical lamella, slightly narrowed in middle; in dorsal view, left and right margins of median lobe both straightly converged to apex and rounded to base; apical lamella short, length half its basal width, apex slightly truncate; in lateral view, ventral margin straight, not expanded in the middle; apex slightly thickened; left paramere (Fig. 11 View Figures 9–14 ) large and rounded, apical membranous filament small; right paramere (Fig. 10 View Figures 9–14 ) markedly styloid, strongly curved (the angle between basal and apical portions near 90°), distinctly widened at middle and strongly narrowed to apex, apex very thin.

Female unknown.

Distribution and habitat.

This species is only known from Zhêntang Town, Dinggyê County, Xizang, China (Fig. 15 View Figure 15 ). The only specimen was caught by pitfall trap in a cloudy forest at 3151 m a.s.l. (Fig. 16 View Figures 16, 17 ).

Etymology.

The new species is named for its type locality, Zhêntang Town.

Remarks.

There is an unusual character in this new species: only four setae are present on the anterior margin of labrum instead of six, but they are irregularly arranged (Fig. 3 View Figures 3–8 ), leaving gaps for the 2nd and 6th (from the left to right) of the normally six setae presenting in the genus. Among all Sphodrina of the world, only Miquihuana rhadiniformis Barr, 1982, a cavernicolous ground beetle from Mexico, has four setae present on the anterior margin of labrum, and these are evenly arranged ( Barr 1982; Casale 1988). Considering the other characters and geographical distance, it is obvious that these two species have no close relationship. It is presumed that the absence of the two setae on the anterior margin of labrum is probably an individual variation rather than a specific character.