Batrisiella ordinaria, 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 : 141-144

Batrisiella ordinaria sp. nov.

Chinese common name: 普ª小ƭdzü甲 urn:lsid:zoobank.org:act:9C4B90AB-55C1-489C-BB43-E710F28C0AC8 Fig. 3

Diagnosis

Male

Body elongate, length approximately 2.1 mm. Head subrectangular; vertex with shallow, slightly curved transverse sulcus between antennal tubercles and moderately long mediobasal carina, vertexal foveae relatively small and asetose. Antenna elongate, antennomeres submoniliform, lacking modifications; antennomere 11 longer than 9 and 10 combined. Discal striae of elytra extending to approximately apical ¾ of elytral length. Mesotrochanter with small tubercle on ventral margin, mesotibia with small apical spur. Abdomen with large tergite 1 (IV) longer than tergites 2–4 (V–VII) combined in dorsal view, unmodified. Aedeagus strongly asymmetric, median lobe with greatly enlarged basal capsule and roundly triangular foramen, both ventral stalk of median lobe and dorsal lobe elongate, recumbent, parameres reduced and forming single membranous structure.

Female

Unknown.

Etymology

The specific epithet is derived from the Latin adjective ‘ ōrdinārius ’, meaning ‘usual’, ‘regular’, ‘ordinary’, reflecting that the male of this species lacks prominent secondary sexual characteristics. The name is an adjective in the feminine singular nominative form.

Type material

Holotype

CHINA • ♂; Yunnan, Zhaotong City, Wumengshan Conservation Area, Miaoshan , Xiaocaoba ; 27°29′33″ N, 104°10′19″ E; 1709–1800 m a.s.l.; 20 Jul. 2022; Wei leg.; Ǖ南昭ª市乌®山小ẽữ, 魏 ǡ豪*; SNUC.

Description

Male

BODY ( Fig. 3A ). Length 2.06 mm; colour reddish-brown, tarsi and mouthparts slightly lighter. Dorsal surface of body covered with short pubescence.

HEAD ( Fig. 3B ). Subrectangular, truncate at base, as long as wide, length and width 0.41 mm; vertex finely punctate, with relatively small, asetose vertexal foveae (dorsal tentorial pits), with shallow, slightly curved transverse sulcus between antennal tubercles, thin mediobasal carina extending from near head base anteriorly to transverse, slightly curved sulcus, antennal tubercles moderately raised, surrounding area coarsely punctate; tempora slightly shorter than eyes, convergent posteriorly; frons slightly impressed medially, confluent with clypeus; clypeus smooth, anterior margin carinate and moderately raised; ocular-mandibular carinae complete, distinct. Venter with small gular foveae (posterior tentorial pits) in single pit, with distinct median carina extending from pit anteriorly to mouthparts. Compound eyes prominent, composed of approximately 35 ommatidia. Maxillary palpus with palpomere 1 minute, 2 elongate, curved, pedunculate basally and enlarged apically, 3 short, subtrapezoidal, 4 fusiform, widest near middle. Antenna moderately elongate, length 0.96 mm; club ( Fig. 3C ) loosely formed by enlarged apical three antennomeres; antennomere 1 thick, subcylindrical, anterolateral margin with tuft of setae, 2–7 each elongate, 8 shortest, 9 longer and broader than 8, 10 shorter than 9, 11 longest, longer than 9 and 10 combined (21:17), subfusiform.

PRONOTUM ( Fig. 3B ). As long as wide, length and width 0.43 mm, widest at middle; lateral margins rounded; disc moderately convex, finely punctate, with median longitudinal sulcus slightly longer than semicircular lateral sulci in dorsal view; lacking median antebasal fovea, with complete, deep transverse antebasal sulcus connecting lateral antebasal foveae; lacking outer and inner pair of basolateral foveae. 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, lacking lateral antebasal pits, hypomeral carinae short, close to margins of coxal cavities.

ELYTRA. Slightly wider than long, length 0.64 mm, width 0.77 mm; truncate at bases; each elytron with two large, asetose basal foveae; discal striae long, curved, extending from outer basal foveae posteriorly to ¾ of elytral length; humeri prominent, small subhumeral foveae present, thin marginal striae extending posteriorly from foveae to posterior margins of elytra. Metathoracic wings fully developed.

MESOVENTRITE. Short, laterally fully demarcated from metaventrite by oblique ridges; 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 acute; marginal striae complete. Metaventrite broadly and slightly impressed at middle and densely setose at lateral portions of impression, with large, setose lateral mesocoxal foveae and pair of smaller, setose lateral metaventral foveae, metaventral intercoxal process with small and narrow split at middle.

LEGS. Moderately elongate; mesotrochanter ( Fig. 3D ) with small tubercle on ventral margin, mesotibia ( Fig. 3E ) with small apical spur.

ABDOMEN. Slightly narrower than elytra, widest at lateral margins of tergite 1 (IV), length 0.63 mm, width 0.67 mm; lacking modifications. Tergite 1 (IV) slightly longer than 2–4 (V–VII) combined, setose basal sulcus separated by mediobasal and two pairs of basolateral foveae, with pair of short discal carinae; 2–3 (V–VII) lacking foveae; 4 (VII) slightly shorter than 2 and 3 combined along middle, with one pair of basolateral foveae; 5 (VIII) semicircular, posterior margin roundly emarginate at middle. Sternite 2 (IV) with small mediobasal and broad, setose basolateral foveae, with pair of long lateral carinae, slightly shorter than 3–5 (V–VII) combined; 3–5 each lacking basolateral foveae; 6 (VIII) transverse, posterior margin sinuate; sternite 7 (IX) ( Fig. 3F ) suboval, weakly sclerotized, with scattered long setae along apical margin.

AEDEAGUS ( Fig. 3G–I ). 0.30 mm in length, dorso-ventrally strongly asymmetric; median lobe with large, extended basal capsule and roundly triangular foramen, ventral stalk broadened at base, strongly curved rightwards (orientation according to Fig. 3I ) in ventral view, with pointed apex; dorsal lobe recumbent and curved ventrally, narrowing at apex; parameres reduced to single broad membranous structure.

Female

Unknown.

Remarks

This species is characterized by the absence of distinct male sexual characters, which contrasts with most species in the genus that typically exhibit modified abdomens, and, less frequently, modified legs or antennae. The unique form of the aedeagus, along with its distribution, leads to reliable identification of this species. The recumbent dorsal lobe of the aedeagus is a typical character state for members of the genus Batrisiella Raffray, 1904 (e.g., Yin & Zeng 2023; Yin 2024).

Distribution

Southwest China: Yunnan.

Figures

Fig. 3. Batrisiella ordinaria sp. nov., holotype, ♂ (SNUC). A. Dorsal habitus. B. Head and pronotum. C. Antennal club. D. Mesotrochanter. E. Mesotibia. F. Sternite 7 (IX). G. Aedeagus, anterior view. H. Aedeagus, lateral view. I. Aedeagus, ventral view. Scale bars: A = 0.5 mm; B, D = 0.3 mm; C, E = 0.2 mm; F = 0.05 mm; G–I = 0.1 mm.