Batrisodes hanmi, 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 : 92-94

Batrisodes hanmi sp. nov.

( Figs 39 , 81A , 98C, D )

Chinese common name: 汗ṁqà甲

Type material (4 exx.). HOLOTYPE: CHINA: ♂ , ‘ China: Xizang, Mêdog County, Hanmi (ca. 29°21’53”N, 95°07’46”E), alt. 2200 m; 19.viii.2005, Liang Tang leg. [ƱẪẸṘ汗ṁ]’ ( SNUC) . PARATYPE: CHINA: 2 ♂♂, 1 ♀, same data as that of holotype ( SNUC) .

Diagnosis. Male. Body length 2.50–2.58 mm. Head sub-rectangular at base, approximately as broad as pronotum; head and antenna lacking modifications. Pronotum with five dorsally visible longitudinal sulci, discal sulci slightly curved at middle, one pair of marginal sulci present ventral to lateral expansion. Elytron with short discal stria. Protibia with tiny apical denticle, mesotrochanter with distinct ventral spine, metatrochanter with small ventral tooth, metatibia with blunt apical projection and long bunch of setae at apex. Aedeagus strongly asymmetric; median lobe with large basal capsule and foramen, dorsal lobe well-developed, with apex deeply forked, split to two lobes. Female. Body length approximately 2.5 mm; legs lacking spine or projection, genitalia as in Fig. 39I .

Description. Male. Body ( Fig. 39A ) length 2.50–2.58 mm; color reddish-brown, tarsi and mouthparts lighter. Dorsal surface of body covered with relatively dense pubescence.

Head ( Fig. 39B ) sub-rectangular at base, slight wider than long, length 0.50–0.51 mm, width across eyes 0.55– 0.57 mm; vertex roughly punctate, with large, asetose vertexal foveae (dorsal tentorial pits), with U-shaped sulcus connecting foveae, lateral vertexal carina faint, extending from occipital constriction to level of anterior margin of eyes, mediobasal carina short, extending anteriorly to level of middle of eyes; antennal tubercles moderately raised; frons impressed at middle, confluent with clypeus; clypeus with rough surface, its entire anterior margin carinate and raised; ocular-mandibular carina complete, distinct. Venter with granulate surface; small gular foveae (posterior tentorial pits) originating from shared opening, with distinct median carina extending from opening anteriorly to mouthparts. Compound eyes prominent, composed of approximately 35 ommatidia. Antenna lacking distinct club and modification, length 1.16–1.27 mm; antennomere 1 thick, subcylindrical, 2–7 each elongate, 8 smallest, 9 much larger than 8, 10 slightly broader but shorter than 9, 11 largest, longer than 9 and 10 combined, subconical.

Pronotum ( Fig. 39B ) approximately as long as wide, length 0.57 mm, width 0.58 mm, widest at middle; lateral margins rounded; disc slightly convex, finely punctate, antebasal tubercles small, lacking discal spines, with one median, one pair of discal and one pair of lateral longitudinal sulci, discal sulci curved at middle; with one pair of marginal sulci beneath lateral expansions; with small asetose median pit and large, setose lateral antebasal foveae; outer and inner pair of basolateral foveae distinct. Prosternum with anterior part slightly longer than coxal part, well-demarcated from hypomera by pair of lateral carinae, which extend posterolaterally to form complete hypomeral ridges; lateral procoxal foveae distinct; anterior and lateral margin of coxal cavity carinate.

Elytra wider than long, length 0.77–0.78 mm, width 0.89–0.96 mm; each elytron with three large, asetose basal foveae, inner two close; discal stria only broadly and shallowly present for short distance posterior to outer basal fovea; small subhumeral fovea present, with carinate marginal stria extending from fovea to posterior margin of elytron.

Mesoventrite short, demarcated from metaventrite by thin carinae; median mesoventral foveae narrowly separated, lateral mesoventral foveae deeply forked internally. Metaventrite moderately impressed at middle, with welldeveloped lateral mesocoxal and two lateral metaventral foveae, posterior margin with small and narrow split at middle.

Legs more or less robust. Protrochanter simple, protibia with tiny apical spur; mesotrochanter with distinct, slightly curved ventral spine ( Fig. 39C ); metatrochanter with tiny ventral tooth ( Fig. 39D ; note: the male paratype has ventral margin smooth and lacks this tooth, which was treated as an intraspecific variation), metatibia ( Fig. 39E ) with dense golden setae along mesal margin of apical 1/2, apex with small, blunt projection and elongate bunch of long setae.

Abdomen widest at lateral margins of tergite 1 (IV), length 0.63–0.67 mm, width 0.85–0.89 mm. Tergite 1 (IV) approximately twice as long as 2 (V), with pair of short, triangular discal carinae, basal sulcus separated by one pair of mediobasal and two pairs of basolateral foveae, with thick marginal carinae; tergite 2 (V) slightly longer than 3 (VI), 4 (VII) as long as tergites 2 and 3 combined, with pair of small tubercles at lateral margins; tergites 2–4 (V–VII) each with one pair of basolateral foveae, tergite 5 (VIII) semicircular. Sternite 2 (IV) with one pair of small mediobasal and three pairs of basolateral foveae; midlength of sternites 2–5 (IV–VII) gradually shorter, 3–5 each with one pair of small basolateral foveae, sternite 6 (VIII) transverse, posterior margin broadly impressed, sternite 7 (IX) ( Fig. 39F ) with asymmetric, membranous basal part and semicircular, well-sclerotized apical part.

Aedeagus ( Fig. 39G, H ) 0.67 mm long, strongly asymmetric; median lobe with large basal capsule and foramen, basoventral projection relatively long, middle and apical portion of ventral stalk each with one long seta; dorsal lobe well-developed, apically narrowed and deeply forked, split into two lobes.

Female. Similar to male in external morphology; antenna approximately as long as that of male; legs lacking spines or projections; each compound eye composed of approximately 12 ommatidia. Measurements (as for male): body length 2.47 mm; length/width of head 0.51/ 0.59 mm, pronotum 0.56/ 0.56 mm, elytra 0.77/ 0.93 mm; abdomen 0.74/ 0.87 mm; length of antenna 1.19 mm; genitalia ( Fig. 39I ) moderately sclerotized, rounded triangular, maximum width 0.38 mm.

Comparative notes. The new species is morphologically similar to B. guoguotang by sharing most external characters and may be separated from the latter by the following characters: 1) slightly curved discal longitudinal sulci of the pronotum (strongly curved in B. guoguotang ), 2) a large ventral spine of mesotrochanter (with small ventral denticle in B. guoguotang ), 3) a small ventral tooth of the metatrochanter (large ventral projection in B. guoguotang ), and 4) the apical portion of aedeagal dorsal lobe split into two lobes (split into three lobes in B. guoguotang ).

Distribution. Mêdog County, Tibet, SW China ( Figs 81A , 98C, D ).

Etymology. The specific name refers to the type locality of the new species, i. e., Hanmi.

Figures

FIGURE 39. Morphology of Batrisodes hanmi sp. nov. (A–H. Male. I. Female). A. Dorsal habitus. B. Head and pronotum. C. Mesotrochanter. D. Metatrochanter. E. Metatibia. F. Sternite 7 (IX). G, H. Aedeagus, lateral (G) and ventral (H). I. Genitalia. Scale bars: 0.5 mm in A; 0.3 mm in B, E; 0.1 mm in C, D, F, I; 0.2 mm in G. H.

FIGURE 81. Distribution of Tibetan Batrisini. A. Batrisodes guoguotang sp. nov. (circle) and B. hanmi sp. nov. (triangle). B. Coryphomimus levigatus sp. nov. C. Coryphomodes budda sp. nov. (circle), C. cephalicus sp. nov. (triangle) and C. chenzhilini sp. nov. (square).

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.