Gyrongita, Yin, 2022

Yin, Zi-Wei, 2022, The Batrisini of Tibet: unveiling an enigmatic ant-loving beetle diversity at Earth’s “ Third Pole ” (Coleoptera, Staphylinidae, Pselaphinae), Zootaxa 5111 (1), pp. 1-211 : 106-110

Gyrongita gen. nov.

( Figs 46–48 )

Chinese common name: 小吉Pà甲¤

Type species. Gyrongita uniformis sp. nov. (by present designation)

Diagnosis. Head subtriangular; vertex strongly convex, with reversed U-shaped sulcus connecting foveae, lacking distinct frontal rostrum, tempus angulate; eyes prominent. Pronotum with thin median and lateral longitudinal sulci and short discal carinae, small antebasal and marginal denticles present, with small, nude lateral antebasal and inner and outer pair of basolateral foveae. Elytra with three small basal foveae, lacking discal stria, subhumeral fovea and marginal stria present. Abdomen with tergite 1 (IV) longer than 2–3 (V–VI) combined, constricted near base and narrowing apically; tergite 1 with complete inner marginal carinae, lacking outer marginal carinae; sternites 3–5 (V–VII) lacking foveae. Aedeagus simple, flattened.

Description. Body small, length less than 1.7 mm; habitus ( Fig. 48A ) elongate; dorsal surface with dense, relatively long setae; antenna relatively short, surpassing pronotal base when extended posteriorly.

Head ( Fig. 46A–C ) subtriangular; lacking distinct frontal rostrum, antennal tubercles weakly raised; vertexal foveae ( Fig. 46A ; vf) relatively small, asetose, connected by reversed U-shaped sulcus, with short mediobasal and two pairs of lateral carinae; eyes prominent, ocular-mandibular carina ( Fig. 46B ; omc) complete, extending to posteroventral articulation of mandible. Venter with small gular foveae ( Fig. 46C ; gf) originating from shared opening, gular carina present for short distance behind mouthparts; antenna 11-segmented, club loosely formed by three apical antennomeres; maxillary palpus with small palpomere 1, 2 basally pedunculate and broad at apex, 3 subquadrate, 4 fusiform, with small apical cone.

Pronotum ( Fig. 46D–F ) moderately transverse, lateral margins rounded anterior to middle, convergent apically and constricted at basal 2/5, anterior margin slightly emarginate, posterior margin slightly curved; with thin median and lateral longitudinal sulci ( Fig. 46D ; mls, lls) and short mediobasal and discal carinae ( Fig. 46D ; mbc, dc), lateral antebasal foveae ( Fig. 46E ; laf) small and asetose, two pairs of basolateral foveae ( Fig. 46D ; blf) present, with small marginal and two pairs of antebasal tubercles, lacking antebasal sulcus; constricted basal portion with rough surface; hypomeral ridge ( Fig. 46E ; hr) complete; prosternum with small lateral procoxal foveae ( Fig. 46F ; lpf).

Elytra truncate at bases, each elytron with three widely separated basal foveae ( Fig. 46G ; bef), lacking subbasal fovea, discal stria ( Fig. 46G ; ds) presented but short, represented by indistinct impression, sutural stria complete, with subhumeral fovea and marginal sulcus ( Fig. 46G, H ; shf, ms).

Mesoventrite with median foveae ( Fig. 47A ; mmsf) moderately broadly separated in transverse opening, with large lateral mesoventral foveae deeply forked internally ( Fig. 47A ; lmsf); metaventrite with large, setose lateral coxal foveae ( Fig. 47A ; lmcf), lateral metaventral foveae ( Fig. 47A ; lmtf) separated, posterior margin with small, narrow split at middle; coxae broadly separated.

Abdomen constricted near base; tergite 1 (IV) slightly longer than 2–3 (V–VI) combined, with mediobasal and two pairs of basolateral foveae ( Fig. 47B ; mbf, blf), lacking discal carinae, tergites 2–4 (V–VII) each with one pair of tiny basolateral foveae and thin margin carinae; sternite 2 (IV) with one pair of mediobasal ( Fig. 47D ; mbf) and three pairs of basolateral foveae ( Fig. 47C, D ; blf), sternites 3–5 (V–VII) lacking foveae.

Legs moderately elongate, tarsomeres 2 and 3 subequal in length, with one major and one setiform claw.

Males lacking observable sexual characters; aedeagus ( Fig. 48E, F ) slightly asymmetric in dorsal view, flattened, with curved basoventral projection, median lobe with large basal capsule, dorsal lobe plate-like, embracing median lobe, parameres reduced to single membranous structure. Female unknown.

Comparative notes. Gyrongita is defined here by a unique combination of characters that occur in various genera rather than by a definitive synapomorphy. It belongs to a group including Tribasodites , Coryphomodes , and those genera that possess spinose pronotal lateral margins, lack a transverse antebasal sulcus of the pronotum, and have three basal foveae on each elytron (= Nomura & Idris (2003) ’s Tribasodes -group). Gyrongita differs from all known Asian genera of this group by the small body size, a subtriangular head with a strongly convex vertex, the angulate tempora and prominent eyes, the lack of a distinct gular carina, the pronotum with small marginal and antebasal tubercles, a roughened constricted base of the pronotum, the lack of foveae on sternites 3–5 (V–VII), as well as the lack of obvious sexual characters on the male.

Etymology. The new generic name is combined from ‘Gyirong (= Gyrong)’, the type locality of the type species, and the suffix ‘- ita (small, little)’. The gender is feminine.

Figures

FIGURE 46. Morphology of Gyrongita gen. nov. A–C. Head, in dorsal (A), lateral (B) and ventral (C). D–F. Prothorax, in dorsal (D), lateral (E) and ventral (F). G. Right elytron. H. Basal half of elytron, in lateral view. Abbreviations: bef—basolateral foveae, blf—basolateral fovea, dc—discal carina, ds—discal stria, gf—gular fovea, hr—hypomeral ridge, laf—lateral antebasal fovea, lls—lateral longitudinal sulcus, lpf—lateral procoxal fovea, mbc—mediobasal carina, mls—median longitudinal sulcus, ms—marginal stria, omc—ocular-mandibular carina, shf—subhumeral fovea, vf—vertexal fovea. Scale bars: 0.2 mm.

FIGURE 47. Morphology of Gyrongita gen. nov. A. Meso- and metaventrite. B–D. Abdomen, in dorsal (B), lateral (C) and ventral (D). Abbreviations: amsp—antero mesoventral projection, blf—basolateral fovea, lmcf—lateral mesocoxal fovea, lmsf—lateral mesoventral fovea, lmtf—lateral metaventral fovea, mbf—mediobasal fovea, mc—marginal carina, mmsf—median mesoventral fovea, s2–5—sternites 2–5 (IV–VII), t1–4—tergites 1–4 (IV–VII). Scale bars: 0.2 mm in A; 0.3 mm in B–D.

FIGURE 48. Morphology of Gyrongita uniformis sp. nov., male. A. Dorsal habitus. B. Head and pronotum. C. Antennomeres 9–11. D. Sternite 7 (IX). E–F. Aedeagus, lateral (E) and ventral (F). Scale bars: 0.5 mm in A; 0.2 mm in B; 0.1 mm in C–F.