Arthromelodes punctiventris, Zhang & Yin, 2025

Zhang, Yong-Qin & Yin, Zi-Wei, 2025, The ant-like litter beetle fauna from the Wumenshan National Nature Reserve, China, with description of eight new species (Staphylinidae: Pselaphinae), European Journal of Taxonomy 1007, pp. 133-162 : 134-138

Arthromelodes punctiventris sp. nov.

urn:lsid:zoobank.org:act:F9381946-124D-49AA-A82A-DD00BE8A03F6

Fig. 1

Chinese common name

糙ª丽º甲.

Diagnosis

Male

Body length approximately 2.0– 2.2 mm. Dorsal surface of head, pronotum, and tergite IV coarsely punctate. Head roundly rectangular; vertex with complete reversed U-shaped sulcus connecting large, asetose vertexal foveae; antenna elongate, lacking modifications; antennomeres each more or less elongate, 4 and 8 smallest, 11 as long as 9 and 10 combined. Dorsal surface with scattered long, thickened, erect setae and normal setae. Discal striae of elytra extending posteriorly to approximately ¾ of elytral length. Protibia with distinct apical trichome. Tergite 1 (IV) modified, with dense and coarse punctures as well as dense and markedly long setae oriented anteriorly. Aedeagus asymmetric, with markedly elongate ventral and dorsal lobes.

Female

Body length approximately 2.0– 2.2 mm; legs and abdomen simple; genitalia as in Fig. 1H .

Etymology

The specific epithet ‘ punctiventris ’ refers to the coarsely punctures occupying most surface of male tergite 1 (IV) of the new species. The name is an adjective in the masculine singular nominative form.

Type material

Holotype

CHINA • ♂; Yunnan, Zhaotong City, Wumengshan Conservation Area, Miaoshan , Xiaocaoba ; 27°30′7″ N, 104°10′56″ E; 1427–1650 m a.s.l.; 22 Jul. 2022; Wei leg.; Ǖ南昭ª市乌®山小ẽữ, 魏 ǡ豪*; SNUC.

Paratypes

CHINA • 1 ♂; same data as for holotype; SNUC • 3 ♂♂, 2 ♀♀; same data as for holotype; 27°29′33″ N, 104°10′19″ E; 1709–1800 m a.s.l.; 20 Jul. 2022; SNUC .

Description

Male

BODY ( Fig. 1A ). Length 2.04–2.15 mm; colour dark brown, elytra reddish-brown, tarsi and mouthparts lighter in colour. Dorsal surface of body covered with scattered long thickened, erect setae and normal ones.

HEAD ( Fig. 1B ). Roundly rectangular, truncate at base, much wider than long, length 0.40–0.42 mm, width 0.55–0.57 mm; dorsal surface coarsely punctate, with large punctures; centre of vertex smooth, with large, asetose vertexal foveae (dorsal tentorial pits), with complete, broad reversed U-shaped broad impression connecting foveae; antennal tubercles moderately raised, postantennal area and frons coarsely punctate; frons broadly impressed medially, anteriorly fused with clypeus; clypeus with coarse surface, its anterior margin carinate and moderately raised; ocular-mandibular carinae complete, distinct. Venter with small gular foveae (posterior tentorial pits) in shared small opening, with distinct median carina extending from opening anteriorly to mouthparts. Compound eyes prominent, each composed of approximately 20 ommatidia. Antenna 1.17–1.18 mm long, lacking modifications; antennomere 1 thick, subcylindrical, anterolateral margin slightly impressed and filled with short setae (but not to form prominent trichome), antennomere 2 elongate, 3–8 each submoniliform, 4 and 8 smallest, 9–11 moderately enlarged, loosely forming club, 10 as long as 9, 11 largest, as long as 9 and 10 combined (23:23), subfusiform.

PRONOTUM ( Fig. 1B ). Approximately as long as wide, length and width 0.50–0.51 mm, widest at middle, lateral margins rounded, with few long thickened, erect setae pointed anteriorly; disc moderately convex, coarsely punctate, with one median and one pair of semicircular lateral longitudinal sulci; lacking median antebasal fovea, with complete transverse antebasal sulcus connecting distinct lateral antebasal foveae; outer and inner pair of basolateral foveae small. Prosternum with basisternal (precoxal) portion longer than procoxal rests; with small lateral procoxal foveae; hypomeral grooves obliquely extending from base anteriorly to half-length of hypomera, with lateral antebasal hypomeral impression, hypomeral carinae short, close to margins of coxal cavities.

ELYTRA. Much wider than long, length 0.59–0.64 mm, width 0.76–0.79 mm; each elytron with two large, widely separated basal foveae; discal striae long, slightly curved, extending from outer basal foveae to approximately apical ¾ of elytral length; humeri roundly prominent; subhumeral foveae small, carinate marginal striae extending posteriorly from foveae to apices of elytra. Metathoracic wings remnant.

MESOVENTRITE. Short, demarcated from metaventrite by oblique ridges; setose median mesoventral foveae moderately separated, originating from shared setose, transverse opening, lateral mesoventral foveae large and setose, forked internally; prepectus massive, collar-shaped; mesoventral intercoxal process short, apically blunt, marginal striae complete. Metaventrite weakly convex admesally, with setose lateral mesocoxal and two lateral metaventral foveae, metaventral intercoxal process with small and narrow split at middle.

LEGS. Elongate; protibia ( Fig. 1C ) with small apical trichome.

ABDOMEN. Distinctly narrower than elytra, widest at basolateral margins of tergite 1 (IV), length 0.60– 0.62 mm, width 0.68–0.70 mm. Tergite 1 (IV) ( Fig. 1D ) in dorsal view longer than tergites 2–4 (V–VII) combined, basal sulcus separated by mediobasal and one pair of basolateral foveae, with pair of relatively long discal carinae, dense and coarsely punctures occupying most surface of tergite, markedly long setae oriented anteriorly, posterior margin moderately protruding at middle; tergites 2 and 3 (V and VI) each short, 4 (VII) approximately as long as 2 and 3 combined along middle, 2–4 (V–VII) each with one pair of small basolateral foveae, 5 (VIII) semicircular, posterior margin broadly and roundly emarginate at middle. Sternite 2 (IV) with large mediobasal and two pairs of basolateral foveae in setose basal impression; midlength of sternite 2 (IV) approximately as long as 3 and 4 (V and VI) combined, 3 as long as 4 (VI), 5 (VII) slightly longer than 4, lacking fovea, 6 (VIII) greatly transverse, posterior margin evenly roundly curved, sternite 7 (IX) ( Fig. 1E ) suboval, weakly sclerotized, apex rounded and with few long setae along apical margin.

AEDEAGUS ( Fig. 1F–G ). 0.35 mm long, greatly asymmetric; median lobe with large, elongate basal capsule and small foramen, basoventral projection short, ventral stalk at middle with one branch on right side (orientation according to Fig. 1G ), obliquely erect; dorsal lobe broad and protruding, in lateral view narrowing toward apex; parameres reduced to broad membranous structure.

Female

Similar to male in external morphology; antenna slightly shorter, abdomen simple, protibia lacking trichome; each compound eye composed of approximately 15 ommatidia; humeri of elytra weakly raised; metathoracic wings absent. Measurements (as for male): body length 2.05–2.15 mm; length/width of head 0.40–0.45/ 0.53–0.56 mm, pronotum 0.46–0.49/ 0.49 mm, elytra 0.58–0.61/ 0.74–0.76 mm; abdomen 0.62–0.63/ 0.70 mm; length of antenna 1.03–1.08 mm; genitalia ( Fig. 1H ) moderately sclerotized, broad, maximum width 0.24 mm.

Remarks

The scape of Batriscenellus pengzhongi Jiang & Yin, 2017 from Guizhou lacks glandular structures on the anterolateral margin; whereas the presence of such structures is diagnostic for the genera Batriscenellus and Batrisiella Raffray, 1904 . Consequently, Batriscenellus pengzhongi is transferred to Arthromelodes Jeannel, 1954 , resulting in A. pengzhongi comb. nov. This species exhibits close affinities with A. punctiventris sp. nov., based on several shared morphological features: the presence of robust, dispersed setae on the dorsal body surface; a trichome at the protibial apex; a similarly modified male tergite 1 (IV); and a comparable aedeagus (cf. Fig. 1F–G with Jiang & Yin 2017: fig. 7d–e). Nevertheless, these two species are readily distinguishable: A. punctiventris is characterized by a coarsely punctate head and pronotum ( Fig. 1B ), while A. pengzhongi possesses a finely punctate head and pronotum ( Jiang & Yin 2017: fig. 7b). Furthermore, disparities are evident in the conformation of the abdominal modifications (cf. Fig. 1D with Jiang & Yin 2017: fig. 7c) and in the structure of the aedeagus.

Distribution

Southwest China: Yunnan.

Figures

Fig. 1. Arthromelodes punctiventris sp. nov. A–G. Holotype, ♂ (SNUC). H. Paratype, ♀ (SNUC). A. Dorsal habitus. B. Head and pronotum. C. Protibia. D. Tergite 1 (IV). E. Sternite 7 (IX). F. Aedeagus, lateral view. G. Aedeagus, ventral view. H. Genitalia, ventral view. Scale bars: A = 0.5 mm; B = 0.3 mm; C–D = 0.2 mm; E = 0.05 mm; F–H = 0.1 mm.