Batrisocenus shantouensis, Feng & Yin, 2025

Feng, Ting & Yin, Zi-Wei, 2025, A new species of Batrisocenus Raffray (Coleoptera: Staphylinidae: Pselaphinae) from coastal Guangdong, South China, Zootaxa 5659 (3), pp. 439-443 : 440-442

Batrisocenus shantouensis sp. nov.

( Figs 1 , 2 )

Type material (3 exx.). HOLOTYPE: CHINA: ♂ , ‘ China: Guangdong, Shantou, Tieling Temple, Foguangyan , 23°24'58"N, 116°38'25"E, 57 m, 23.vi.2024, sifted, T. Feng leg., Ḿ头 Ḧėēŵ 佛光ǟ封ḆNJ ’ ( SNUC) . PARATYPES: CHINA: 2 ♂♂ , China: Guangdong, Shantou, Nan’ao Is., Huanghua For. Pk. , Dajian Mt. , 23°25'56"N, 116°58'10"E, 560 m, 23.vi.2024, T. Feng, Ḿ头南êã大尖Ɯ封ḆNJ ’ ( SNUC) .

Diagnosis. Male. Body length approximately 1.4–1.6 mm. Head distinctly transverse; with short mediobasal carina; antenna simple, lacking modifications. Pronotum with pair of small pits on anterior portion of disc. Elytra coarsely punctate, with discal striae extending posteriorly to approximately apical 3/5 of elytral length. Tergite 1 (IV) with narrow cavity on posterior part, with greatly raised ridge posterior to and setose patches lateral to cavity. Aedeagus with constricted, dorsoventrally transverse basal capsule; ventral stalk of median lobe reduced to short lobe; dorsal lobe broad and with rounded apex. Female. Unknown.

Description. Male. Body ( Fig. 1A ) length 1.43–1.56 mm; color red brown, with yellow-brown tarsi and mouthparts. Dorsal surface with relatively long and sparse pubescence.

Head ( Fig. 1B ) distinctly transverse, broadly truncate at base, much wider than long, length 0.31 mm, width 0.37–0.39 mm; vertex unmodified, finely punctate, with widely separated foveae (dorsal tentorial pits) at level of middle of eyes, anterior margin with short transverse sulcus at middle; tempora much shorter than eyes; antennal tubercles moderately raised, lacking postantennal foveae; frons broadly impressed between antennal tubercles, finely punctate, anteriorly fused with clypeus; clypeus with smooth surface, anterior margin carinate and moderately raised; ocular-clypeal carinae complete. Venter with two small gular foveae (posterior tentorial pits) in single transverse pit, with thin median carina extending from pit anteriorly to mouthpart. Eyes greatly prominent, each composed of 28–30 ommatidia. Maxillary palpus with palpomere 1 minute; 2 elongate, curved, pedunculate basally and enlarged apically; 3 short, sub-triangular; 4 fusiform, widest near middle. Antenna moderately long, lacking modifications, length 0.77–0.79 mm; club formed by markedly enlarged apical three antennomeres; antennomere 1 thick, subcylindrical, 2 larger than 3, 3–8 each submoniliform, with 7 slightly larger than 6 and 8, 9 and 10 each submoniliform, 11 largest, slightly shorter than 9 and 10 combined (16:18), sub-conical.

Pronotum ( Fig. 1B ) slightly wider than long, length 0.35–0.37 mm, width 0.39–0.42 mm, widest anterior to middle; disc moderately convex, finely punctate; lateral margins rounded; median longitudinal sulcus much longer than lateral sulci, posteriorly confluent to median antebasal impression; lateral antebasal foveae connected by transverse antebasal sulcus; small antebasal tubercles and inner and outer pair of basolateral foveae present. Prosternum with basisternal (precoxal) portion slightly longer than procoxal rests (which constitute composite structures that unite posterior basisternal region with furcasternum, the latter being positioned posterior to profurcal invagination sites); with small lateral procoxal foveae; oblique hypomeral grooves present at basal halves of hypomera, lacking lateral antebasal impressions; hypomeral ridges close to coxal cavities.

Elytra wider than long, length 0.51–0.55 mm, width 0.59–0.64 mm, roundly quadrate, truncate at bases; disc with sparse, large punctures and sparse, long pubescence; each elytron with two distinct, asetose basal foveae; discal striae slightly curved, extending from outer basal foveae posteriorly to approximately 3/5 of elytral length; humeri with small but distinct denticles; small subhumeral foveae present, sulcate marginal striae extending from foveae to posterior margins of elytra. Metathoracic wings reduced (brachypterous, indicating flightlessness).

Mesoventrite short, laterally fully demarcated from metaventrite by oblique ridges; median mesoventral foveae broadly separated, originating from shared setose, transverse opening, lateral mesoventral foveae large and setose, forked internally; prepectus broadened, collar-shaped; mesoventral intercoxal process short, apically acute. Metaventrite slightly and broadly impressed at middle, with pair of large, setose lateral mesocoxal foveae and lateral metaventral foveae, metaventral intercoxal process broad, slightly prominent at middle.

Legs moderately elongate; protrochanter ( Fig. 1C ) with small ventral denticle, protibia ( Fig. 1D ) with thin, pencil-like setose brush at apex of mesal margin.

Abdomen slightly narrower than elytra, widest at lateral margins of tergite 1 (IV), length 0.36–0.39 mm, width 0.54–0.58 mm. Tergite 1 (IV) ( Fig. 1E ) much longer than 2–4 (V–VII) combined, basal sulcus present between inner pair of basolateral foveae, outer pair of foveae larger than inner ones; discal carinae long and distinct; posterior part of disc with narrow cavity, with short median ridge and lateral small, setose tubercles inside cavity, with large, greatly raised projection posterior to cavity; areas lateral to cavity with patches composed of short and dense setae; shallow marginal carinae present; tergites 2 (V)–4 (VII) each short and with one pair of small basolateral foveae, tergite 5 (VIII) transverse, posterior margin roundly emarginate at middle. Sternite 2 (IV) densely setose at base, with one pair of mediobasal and three pairs of basolateral foveae, lacking basal impression, with moderately long lateral carinae extending for approximately 2/3 of sternal length; midlength of sternite 2 longer than 3–5 (V–VII) combined, 3–5 each short at middle, lacking foveae, sternite 6 (VIII) short, greatly transverse, posterior margin slightly roundly convex at middle, sternite 7 (IX) ( Fig. 1F ) composed of weakly sclerotized median plate and pair of lateral membranous structures.

Aedeagus ( Fig. 1G, H ) 0.17 mm long, moderately sclerotized, greatly asymmetric; median lobe with constricted, dorsoventrally transverse basal capsule and foramen, ventral stalk on right side of median lobe (orientation according to Fig. 1H ), composed of single elongate projection gradually narrowing apically; dorsal lobe much broader and moderately longer than ventral stalk, rounded at apex; parameres lacking.

Female. Unknown.

Comparative notes. The diversity of Batrisocenus in South China is generally insufficiently documented, and the species described herein constitutes the first record of the subfamily Pselaphinae from Shantou City. Among its geographically proximate congeners are B. sinensis Raffray, 1904 from Hong Kong and B. sauteri Raffray, 1912 distributed in Taiwan. Batrisocenus sinensis is distinguished by a more elongate habitus, a notably larger body size (1.7 mm) ( Raffray 1904), and antennae that are also comparatively more elongate. The generic placement of Batrisocenus sauteri is questionable, given that its scape, described by Raffray (1912) as possessing the “ angulo spicali (apicali?) externo fasciculato et lamella minuta translucida praedito (external apical angle tufted and provided with a minute, translucent lamella), is characteristic of several genera allied with Batrisiella Raffray. Examination of the type material will be necessary to clarify the status of this species. Furthermore, the new species is readily distinguished from both B. sinensis and B. sauteri by its coarsely punctate elytra, whereas the latter two species possess finely punctate elytral discs.

Distribution. South China: Guangdong ( Fig. 2 ).

Etymology. The name is a Latin adjective in nominative singular derived from the type locality, Shantou City, with the suffix “- ensis ” meaning “originating from” or “belonging to”.

Figures

FIGURE 1. Batrisocenus shantouensis sp. nov. male. A. Dorsal habitus. B. Head and pronotum. C. Protrochanter and profemur. D. Protibia. E. Tergite 1 (IV). F. Sternite 7 (IX). G, H. Aedeagus, lateral (G) and ventral (H). Scale bars: 0.5 mm in A; 0.2 mm in B–E; 0.1 mm in G–H.

FIGURE 2. Distribution and habitats of Batrisocenus shantouensis sp. nov. in Shantou. A. Map showing the collection localities. B, C. Habitat at Tieling Zen Temple (B), and Dajian Mountain on Qi’ao Island (C).