Dazzling rove beetle (Apecholinus speciosus) from Mangshan, Hunan, has similarity to Apecholinus imitator

NEWS - Dazzling rove beetle (Apecholinus speciosus Sun & Liu, sp. nov.) from Mangshan, Hunan, China, has similarity to Apecholinus imitator Smetana & Hu 2019 and phylogenetic analysis based on mitochondrial genome showed the two species form a sister clade to Ocypus and Dinothenarus, all belonging to the Ocypus lineage.

Apecholinus Bernhauer 1933 was established with Apecholinus kaiseri Bernhauer 1933 as the type species established by monotypy. So far, 7 species have been described and are found only in East Asia. Of these, 6 species are in mainland China and Taiwan, only one species is native to North Korea.

They are A. aglaosemanticus (He & Zhou, 2017), A. canifer Smetana & Hu 2019, A. fraternus (Fairmaire, 1891), A. imitator Smetana & Hu 2019, A. kaiseri Bernhauer 1933, A. liui (He & Zhou, 2017) and A. septentrionalis Senda & Han 2023.

Apecholinus is recognized by mandibles each having one simple tooth on the medial edge, no subdental mandibular notch; last segment of maxillary palpi short, anteriad broad, broadly truncated apically, acetose; last segment of labial palpi anteriad broad, broadly truncated apically, setose.

Recently, researchers found a specimen collected in Mangshan that has a new description. Mangshan, the northern foot of the Nanling Mountains, has dense, extensive forests and has a reputation as the 'largest biological gene bank' in Hunan.

A. speciosus gets its specific name from 'speciosus' (dazzling) in Latin. Chinese common name: 炫丽背眼隐翅虫. Males are BL 19.05 mm; FL 10.75 mm; hL 3.70 mm; hW 3.90 mm; PL 3.57 mm; PW 3.85 mm; EL 4.00 mm; EW 4.33 mm.

Body black, slightly shining; body pubescence black to brown, each elytron with more or less triangular patch of luminous golden-yellow tomentose pubescence below humerus; and abdominal tergites 6 and 7 each with two almost separated patches comprised of golden-yellow tomentose pubescence.

Maxillary and labial palpi reddish brown; antennae with three basal segments reddish black, following segments gradually becoming paler, 8–11 segments yellowish brown; legs piceous to piceous black, with paler brown tarsi, tarsi and proximal tibiae covered with yellowish brown pubescence.

Head rounded quadrangular, with rounded posterior angles, slightly wider than long; eyes small, moderately convex, slightly shifted dorsad, tempo much longer than length of eyes seen from above (ratio 1.76); disc of head finely and densely punctate; linear impunctate midline apparent; interspaces between punctures without microsculpture.

Antenna moderately long, hardly thickened toward the apex, segment 3 longer than segment 2, segments 4–10 longer than wide, gradually becoming shorter, segment 11 small, asymmetrically emarginated, along lateral margin longer than penultimate segment.

Pronotum sub-scutellate, slightly wider than long (ratio 1.07), moderately convex, moderately narrowed anteriad; narrow marginal groove disappearing downwards at about anterior third of pronotal length; punctation on disc slightly finer than that on disc of the head, interspaces between punctures without microsculpture; impunctate midline distinct. Scutellum densely punctate-setose, with granulose microsculpture.

Elytra short, vaguely dilated posteriad, at suture shorter than pronotum at midline (ratio 0.55), at sides shorter than pronotum at midline; punctation very fine and very dense, interspaces between punctures with fine microscopic irregularities.

Abdomen with the fifth visible tergite without pale apical seam of palisade setae; tergite 2 (in front of first fully visible tergite) moderately densely punctate-setose, surface with extremely fine, superficial microsculpture of mostly oblique striae.

Punctation of all tergites finer and denser than that on elytra, punctation becoming gradually somewhat sparser toward apex of abdomen, interspaces with extremely fine, granular microsculpture.

Sternite 8 with shallow, obtuse medioapical emargination. Sternite 9 with minutes, narrow basal portion, apical portion with deep and wide medioapical u-shaped emargination. Tergite 10 narrow, markedly, and evenly narrowed toward narrowly arcuate apex, apical portion with moderately long setae at apex, rest of tergite moderately densely setose.

Aedeagus distinctly sclerotized; median lobe almost parallel-sided, apex subtruncate, slightly asymmetrical, left side extending a bit further distad than right side in ventral view; parameter (partially broken at the middle in holotype) situated on median lobe quite asymmetrically toward left margin of median lobe, with obliquely sinuate apex.

The left apparently higher than the right from ventral view, markedly not reaching the apex of median lobe; with several unequally short apical setae (more than 20); underside with numerous, closely set sensory peg setae (more than 30) arranged in two rows, merged apically.

The new species is similar to A. imitator in general appearance. They share a more or less triangular patch with golden yellow tomentose pubescence behind humerus on each elytron and a golden yellow tomentose pubescent basal patch on abdominal tergites 6 and 7.

However, the new species has two nearly separate patches on tergites 6 and 7, whereas A. imitator has one large continuous patch at the base. They clearly have a different aedeagus structure, with peg setae in a different pattern and differently shaped paramere apices and median lobes.

Original research

Wan-Wan Sun, Fei-Yan Jiang, Gang Chen, Lin He & Zhi-Ping Liu (2024). A new species of Apecholinus Bernhauer, 1933 (Coleoptera: Staphylinidae: Staphylininae) from Mangshan, China. Zootaxa 5528 (1): 357–364, DOI:10.11646/zootaxa.5528.1.25

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