Volker Assing rove beetle (Sinlathrobium assingi) and Zhi-Lin Chen rove beetle (Sinlathrobium chenzhilini) similar to Sinlathrobium lobrathioides

NEWS - Volker Assing rove beetle (Sinlathrobium assingi Chen & Peng, sp. nov.) from Chongqing and Zhi-Lin Chen rove beetle (Sinlathrobium chenzhilini Chen & Peng, sp. nov.) from Guangxi in shrub habitats have a very close relationship with Sinlathrobium lobrathioides (Assing, 2012).

The small genus Sinlathrobium Assing 2013 contains 4 species distributed in southern China: Sinlathrobium densitypunctatum Assing 2013 from Sichuan, Sinlathrobium iniquum Assing 2013 from Yunnan, Sinlathrobium lobrathiforme (Assing, 2012) from Yunnan and Sinlathrobium lobrathioides (Assing, 2012) from Chonqing.

Researchers now present taxonomic and faunal data for three Chinese species, including two new species (S. assingi and S. chenzhilini), and detailed bionomic data for previously unknown females of S. lobrathioides.

S. assingi was described from the type locality west of Chengkou, northern Chongqing, China. The specimens were sieved from leaf litter, moss and grass roots in a scrub habitat at 1830 m elevation. The epithet is dedicated to the prematurely deceased Volker Assing. He was a specialist primarily in Palaearctic Staphylinidae.

The male sexual characteristics are very similar, in particular the shape of sternites VII–VIII of males and the similarly derived aedeagus morphology, suggesting that S. assingi is closely related to S. chenzhilini and S. lobrathioides.

This species differs from S. chenzhilini and S. lobrathioides by its yellowish legs, particularly the more compact and coarse pronotal protuberance, the slightly asymmetric ventral processes of the aedeagus and the differently shaped female tergites IX–X.

S. chenzhilini was described from the type locality in the Maoer Mountains north of Guilin, northern Guangxi, China. The specimens were collected from leaf litter and dead wood in a mixed deciduous forest at an elevation of about 1940–2030 m. The epithet is dedicated to Zhi-Lin Chen who supported the researchers on the field trip.

The male sexual characters are very similar, particularly the shape of male sternites VII–VIII and the similarly derived aedeagus morphology, suggesting that S. chenzhilini is closely related to S. assingi and S. lobrathioides.

This species differs from S. assingi in the coloration of the legs, in particular in the less frequent and finer pronotal processes, and in the different form of the ventral processes of the aedeagus. S. chenzhilini differs from S. lobrathioides in that the elytra are somewhat longer, in particular in that the head and pronotal processes are less frequent, and the dorsal plate of the aedeagus is longer.

DESCRIPTION

Sinlathrobium assingi measurements (mm) and ratios: BL 7.67–7.73, FL 3.61–3.67, HL 0.85–0.92, HW 1.02–1.04, PL 1.05–1.11, PW 0.96–0.98, EL 1.04–1.05, AL 1.94–2.04, AeL 1.02, HL/HW 0.83–0.88, HW/PW 1.06, HL/PL 0.81–0.83, PL/PW 1.09–1.13, EL/PL 0.95–0.99.

Body black, elytra with moderately large, transverse yellowish spot posteriorly reaching lateral and posterior margins; legs yellowish with darker femora; antennae dark brown to brown.

Head transverse, widest across eyes; punctation coarse and very dense, in median dorsal portion and on frons somewhat sparser; interstices with shallow microsculpture. Eyes large and bulging, 0.80–0.83 times as long as postocular region in dorsal view. Antennae not particularly slender.

Pronotum nearly parallel-sided; punctation sparser and distinctly coarser than that of head; interstices without microsculpture and glossy. Elytra broader than pronotum; humeral angles weakly pronounced; punctation coarse and rather dense; interstices without microsculpture and glossy. Hind wings presumably fully developed.

Abdomen somewhat narrower than elytra; punctation conspicuously dense and fine on all tergites; interstices with distinct microsculpture and subdued gloss; posterior margin of tergite VII with palisade fringe.

Male: Sternites III–VI unmodified; sternite VII strongly transverse, with shallow median impression without modified pubescence, posterior margin broadly and shallowly concave; sternite VIII weakly transverse, with shallow median impression posteriorly, this impression without modified setae, posterior excision V-shaped and moderately deep; aedeagus ventral process somewhat asymmetric, dorsal plate lamellate and weakly sclerotized.

Female: Tergite VIII with strongly convex posterior margin; sternite VIII weakly oblong, and with strongly convex posterior margin; tergite IX with slender posterior processes; tergite X flat, nearly reaching anterior margin of tergite IX.

Sinlathrobium chenzhilini measurements (mm) and ratios: BL 6.12–7.78, FL 3.67–3.89, HL 0.89–0.94, HW 1.04–1.09, PL 1.11–1.20, PW 0.96–1.05, EL 1.07–1.15, AL 1.81–1.91, AeL 1.04–1.14, HL/HW 0.85–0.87, HW/PW 1.03–1.08, HL/PL 0.78–0.80, PL/PW 1.14–1.16, EL/PL 0.95–0.96.

Body black, elytra with extensive orange spot in postero-lateral angles, this spot reaching posterior and lateral margins, near suture; legs with the femora blackish, tibiae dark brown and tarsi brown; antennae dark brown to brown.

Head transverse, widest across eyes; punctation coarse and very dense, in median dorsal portion and on frons distinctly sparser; interstices with shallow microsculpture. Eyes large and bulging, 0.90–0.92 times as long as postocular region in dorsal view. Antennae not particularly slender.

Pronotum nearly parallel-sided; punctation distinctly sparser and distinctly coarser than that of head; interstices without microsculpture and glossy. Elytra broader than pronotum; humeral angles pronounced; punctation coarse and rather dense; interstices without microsculpture and glossy. Hind wings fully developed.

Abdomen somewhat narrower than elytra; tergites III–VI with very fine and dense punctation, tergites VII–VIII with distinctly sparser punctation; posterior margin of tergite VII with palisade fringe.

Male: Sternites III–VI unmodified; sternite VII strongly transverse, with shallow median impression without modified pubescence, posterior margin broadly concave; sternite VIII transverse, with shallow median impression posteriorly, this impression without modified setae, posterior excision V-shaped and moderately deep; aedeagus ventral process symmetric, dorsal plate long and strongly sclerotized.

Female: Tergite VIII with broadly convex posterior margin; sternite VIII weakly oblong, and with strongly convex posterior margin; anterior portion of tergite IX divided in middle, tergite X approximately twice as long as tergite IX in the middle.

Original research

Chen X, Ye J-P, Peng Z (2024). Two new species and additional records of Sinlathrobium Assing (Coleoptera, Staphylinidae, Paederinae) from southern China. ZooKeys 1218: 25-33, DOI:10.3897/zookeys.1218.128973

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