Batrisiella concisa, 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 : 78-80

Batrisiella concisa sp. nov.

( Figs 33 , 80B , 99B )

Chinese common name: Ṋú小毛唇à甲

Type material (3 exx.). HOLOTYPE: CHINA: ♂ , ‘ China: Xizang, Mêdog County, Beibeng , road to Gelin Vill., 29°14’49.15”N, 95°11’2.86”E, 1060 m, 2019.vii.23, leaf litter, Z.-W. Yin leg., [ƱẪÜ崩乡格ff村]’ ( SNUC) . PARATYPES: CHINA: 1 ♂, 1 ♀, same data as that of holotype ( SNUC) .

Diagnosis. Male. Body length 1.76–1.78 mm. Head sub-rectangular at base; vertexal foveae small and asetose, lacking sulcus connecting them; antenna long, antennomeres each elongate, lacking modifications. Discal stria of elytron extending to apical 1/10 of elytral length. Legs almost simple, only mesotibia with tiny apical spur. Abdomen with large tergite 1 (IV) and vertical tergites 2–5 (V–VIII); tergite 1 with large posteromedial cavity and setose lateral patches. Aedeagus strongly asymmetric; ventral stalk narrowing apically and with truncate apex; dorsal lobe composed of one broad and one long, thin and curved structures; parameres reduced and forming single membranous structure. Female. Body length 1.65 mm; mesotibia lacking apical spur, tergite 1 lacking modifications, genitalia as in Fig. 4H .

Description. Male. Body ( Fig. 33A ) length 1.76–1.78 mm; color reddish-brown, tarsi and mouthparts lighter. Dorsal surface of body covered with moderately long pubescence.

Head ( Fig. 33B ) sub-rectangular at base, approximately as long as wide, length 0.37–0.38 mm, width across eyes 0.39 mm; vertex finely punctate, sparsely pubescent, with small, asetose vertexal foveae (dorsal tentorial pits), lacking U-shaped sulcus connecting foveae or mediobasal carina, with T-shaped sulcus at middle and few large punctures anterior and lateral to anterior margin of sulcus; antennal tubercles slightly raised; frons slightly impressed between antennal tubercles, anterolateral margins carinate and with small tufts of setae; clypeus with smooth surface, its anterior margin weakly carinate; ocular-mandibular carina present. Venter with two small gular foveae (posterior tentorial pits) originating from shared transverse slit, with distinct median carina extending from foveae anteriorly to mouthparts. Compound eyes prominent, composed of approximately 25 large ommatidia. Antenna elongate, length 0.93 mm, apical three antennomeres forming moderately distinct club; antennomere 1 thick, subcylindrical, apicolateral portion with small inner glandular structure ( Fig. 33C ), lacking trichome, 2–7 each elongate, 8 moniliform, 9 much larger than 8, 10 slightly broader than and as long as 9, 11 largest, as long as 9 and 10 combined, sub-fusiform.

Pronotum ( Fig. 33B ) approximately as long as broad, length 0.40–0.43 mm, width 0.41 mm, widest at middle; lateral margins rounded; disc slightly convex, finely punctate and sparsely pubescent; median longitudinal sulcus as long as semicircular lateral sulci in dorsal view, the latter extending from dorsal surface laterally and posteriorly and then fusing with lateral ends of antebasal sulcus; lacking median antebasal fovea, lateral antebasal foveae connected by thin antebasal sulcus; outer and inner pair of basolateral foveae distinct. Prosternum with anterior part as long as coxal part, with large lateral procoxal foveae; hypomeral ridge extending from base to middle of anterior part, with punctiform lateral antebasal hypomeral pit; margin of coxal cavity weakly carinate.

Elytra much wider than long, length 0.58 mm, width 0.73–0.74 mm; each elytron with two large, asetose basal foveae, lacking subbasal fovea; discal stria carinate, extending from outer basal fovea to apical 1/10 of elytral length; humerus moderately prominent, with small subhumeral fovea, with marginal stria extending from fovea to posterior margin of elytron.

Mesoventrite short, demarcated from metaventrite by ridged anterior edges of impressed areas where lateral mesocoxal foveae situated at mesal margins, with pair of thin admesal carinae; setose median mesoventral foveae widely separated, lateral mesoventral foveae large and setose, not forked internally; intercoxal process short. Metaventrite broadly impressed at middle, with large, setose lateral mesocoxal foveae and pair of smaller, setose lateral metaventral foveae, posterior margin with small and narrow split at middle.

Legs moderately elongate, lacking distinct modifications; mesotibia with tiny apical spur.

Abdomen widest at lateral margins of tergite 1 (IV), length 0.46–0.47 mm, width 0.65 mm. Tergite 1 (IV) ( Fig. 33D ) much longer than tergites 2–4 (V–VII) combined, setose basal sulcus separated by mediobasal and one pair of basolateral foveae, with short discal and outer marginal carinae; with large posteromedial cavity, anterior margin of cavity carinate, inside cavity there is one small anteromedial process and row of dense median setae, area lateral to cavity with large setose patches covered with dense, short setae; tergites 2–5 (V–VIII) tightly compressed, vertical, 2–4 each with one pair of basolateral foveae, tergite 4 (VII) longer than 2 and 3 combined along middle, tergite 5 (VIII) broad and slightly transverse, posterior margin roundly emarginate at middle. Sternite 2 (IV) with large mediobasal and two pairs of basolateral foveae in broad setose basal impression; midlength of sternite 2 (IV) approximately as long as 3–4 (V–VI) combined, sternites 3–5 (V–VII) each with one pair of small basolateral foveae, sternite 6 (IX) ( Fig. 33E ) rounded, apical 1/3 moderately sclerotized and with a few setae along anterior margin, basal 2/3 membranous.

Aedeagus ( Fig. 33F–H ) 0.33 mm long, strongly asymmetric; median lobe with large basal capsule and sub-triangular foramen, ventral stalk narrowing apically and with truncate apex in dorso-ventral view; dorsal lobe transversely protruding and then strongly curved towards apex, with one thin, long and curved sclerite; parameres reduced and forming single membranous structure.

Female. Similar to male in external morphology; antenna shorter; frons and tergite 1 (IV) lacking modifications; each compound eye composed of approximately 20 ommatidia; humeral angle rounded; mesotibia lacking apical spur. Measurements (as for male): body length 1.65 mm; length/width of head 0.36/ 0.37 mm, pronotum 0.40/ 0.38 mm, elytra 0.46/ 0.64 mm; abdomen 0.47/ 0.58 mm; length of antenna 0.84 mm; maximum width of genitalia ( Fig. 33I ) 0.21 mm.

Comparative notes. The new species is close to B. ganma by sharing the similar placement and form of the male tergal modification and the aedeagus. Batrisiella concisa can be readily separated from B. ganma by the presence of a broad, deep median longitudinal sulcus on the vertex of the head (sulcus absent in B. ganma ).

Distribution ( Fig. 98 ). Mêdog County, Tibet, SW China ( Figs 80B , 99B ).

Etymology. The specific epithet ‘ concîsus, - um, - a ’ is a Latin adjective meaning ‘cut, broken up’, referring to the vertical plane of tergites 2–5 (V–VIII) of the new species.

Figures

FIGURE 4. Morphology of Arthromelodes aniqiao sp. nov., male. A. Dorsal habitus. B. Head and pronotum. C. Mesotrochanter and mesofemur. D. Tergite 1 (IV). E. Sternite 7 (IX). F, G. Aedeagus, lateral (F) and ventral (G). Scale bars: 0.5 mm in A; 0.3 mm in B; 0.2 mm in D, F, G; 0.1 mm in E.

FIGURE 33. Morphology of Batrisiella concisa sp. nov. (A–H. Male. I. Female). A. Dorsal habitus. B. Head and pronotum. C. Antennomere 1. D. Tergite 1 (IV). E. Sternite 7 (IX). F–H. Aedeagus, dorsal (F), lateral (G) and ventral (H). I. Genitalia. Scale bars: 0.5 mm in A; 0.2 mm in B, D; 0.05 mm in C; 0.1 mm in E–I.

FIGURE 80. Distribution of Tibetan Batrisini. A. Batriscenaulax campestris sp. nov. B. Batrisiella acclivis sp. nov. (circle), B. beibeng sp. nov. (triangle), B. bomea sp. nov. (square) and B. concisa sp. nov. (cross). C. B. curvitibialis sp. nov. (circle), B. ganma sp. nov. (triangle), B. guttata sp. nov. (square) and B. zhujianqingi (diamond).

FIGURE 98. Environment of and collecting sites at Nyingchi area. A, B. Lage (Ń格). C, D. Hanmi (汗ṁ). E, F. Aniqiao (Nj 尼桥). Photo Credit: A, B by Chao Wu; C, D by Wen-Xuan Bi; E, F by Hao Huang.

FIGURE 99. Environment of and collecting sites at Nyingchi area. A. Beibeng Township (Ü崩乡). B. Road near Gelin Village (格ff村). C. A bridge at Yarang (亚ü). D. A village near Guoguotang Great Bend (果果Ƌkm弯). E. Environment near Mêdog County (ẸṘ县). F. Path to Renqingbeng Temple (仁ů崩寺). G. An overall view of Guoguotang Great Bend. Photo Credit: E, F by Xiao-Bin Song.