Sathytes pengzhongi, 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 : 127-129

Sathytes pengzhongi sp. nov.

( Figs 55 , 84A , 93F, G )

Chinese common name: 彭氏ḛà甲

Type material (11 exx.). HOLOTYPE: CHINA: ♂ , ‘ China: Xizang, Dinggyê County, Zhêntang Town, Ganma Zangbo Valley , 27°51’50”N, 87°24’24”E, 2400 m, 28.vi.2021, Z. Peng leg., ƱẪŤĠ县ĿƋWH玛Ẫ布河ě ’ ( SNUC) . PARATYPES: CHINA: 2 ♂♂, 8 ♀♀, same data as that of holotype ( SNUC) .

Diagnosis. Male. Body length approximately 2.0 mm; ratio (length/width) of head 1.05–1.08, pronotum 1.09–1.11, elytra 0.75–0.78, length of eye/tempus 0.89. Antennomere 9 moderately transverse (length/width excluding apophysis 0.87), with hyaline apophysis at anterior 1/4 of mesal margin, antennomere 11 elongate (length/width 1.59), with single protuberance at base, apex of protuberance with tuft of curved setae. Aedeagus broadly rounded at base, narrowing apically. Female. Body length approximately 2.0 mm; antenna lacking modifications, genitalia as in Fig. 55G .

Description. Male. Body ( Fig. 55A ) length 1.94–1.95 mm; color reddish-brown, tarsi and mouthparts lighter. Dorsal surface of body covered with short, dense pubescence.

Head ( Fig. 55B ) sub-rectangular at base, slightly longer than wide, length 0.46–0.49 mm, width across eyes 0.44–0.45 mm, length/width 1.05–1.08; vertex moderately raised, with small asetose foveae (dorsal tentorial pits); frons anteriorly confluent with strongly declining clypeus, flat; clypeus with smooth surface, anterior margin carinate and moderately raised; ocular-mandibular carina short; postgenal region strongly projecting. Venter with small, broadly separated gular foveae (posterior tentorial pits), short median carina present posterior mouthpart. Compound eyes moderately prominent, composed of approximately 18 large ommatidia, length of eye/tempus 0.89. Antenna elongate, length 1.06–1.07 mm, distinct club ( Fig. 55C ) formed by enlarged apical three antennomeres; antennomere 1 thick, subcylindrical, 2–8 each transverse, 2 slightly wider, 3–8 subequal in width, 9 ( Fig. 55D ) strongly enlarged, moderately transverse, length/width excluding apophysis 0.87, mesal margin strongly expanded, hyaline apophysis located at apical fourth of mesal margin, 10 transverse, length/width 0.67, 11 largest, slightly longer than 9 and 10 combined, length/width 1.59, with small protuberance at base, apex of protuberance with curved tuft of golden setae.

Pronotum ( Fig. 55B ) slightly longer than wide, length 0.49–0.51 mm, width 0.45–0.46 mm, length/width 1.09– 1.11, widest at middle; lateral margins rounded, convergent apically and basally; disc weakly convex; asetose lateral antebasal foveae small. Prosternum with anterior part slightly longer than coxal part, with small lateral procoxal foveae; hypomeral ridge absent; margin of coxal cavity moderately carinate.

Elytra much wider than long, length 0.59–0.62 mm, width 0.79 mm, length/width 0.75–0.78; each elytron with four moderately large, asetose basal foveae; lacking discal stria; humerus moderately prominent, subhumeral fovea present, marginal stria extending from fovea to posterior margin of elytron.

Mesoventrite short, demarcated from metaventrite by strongly curved carinae; median mesoventral foveae contiguous, originating from shared opening, large lateral mesoventral foveae forked internally, mesoventral process short, with complete marginal stria. Metaventrite moderately prominent admesally, inclined towards middle, with well-developed lateral mesocoxal and two broadly separated lateral metaventral foveae, with large, round median pit shortly anterior to posterior margin, posterior margin narrowly and shortly emarginate at middle.

Legs elongate, simple.

Abdomen widest at lateral margins of tergite 1 (IV), length 0.51–0.53 mm, width 0.67–0.71 mm. Tergite 1 (IV) more than twice as long as 2 (V), lacking basal sulcus, with one pair of mediobasal and two pairs of basolateral foveae, lacking discal carinae, with indistinct, thin and short marginal carina; tergite 2 (V) slightly longer than 3 (VI), 4 (VII) longer than 3 but much shorter than 2 and 3 combined; tergites 2–3 (IV–VI) each with one pair of mediobasal and two pairs of basolateral foveae, 4 with one pair of basolateral foveae and marginal tubercles, tergite 5 (VIII) semicircular, transverse, posterior margin roundly emarginate at middle. Sternite 2 (IV) with one pair of mediobasal and three pairs of basolateral foveae, lateral carina absent; midlength of sternites 2–5 (IV–VII) gradually shorter, sternites 3–4 (IV–VI) each with three pairs and 5 (VII) with one pair of small basolateral foveae, sternite 6 (VIII) transverse, posterior margin broadly emarginate, sternite 7 (IX) ( Fig. 55E ) moderately sclerotized, elongate, apex with two long setae.

Aedeagus ( Fig. 55F ) 0.21 mm long, slightly asymmetric, plate-like; median lobe with large foramen, broad at base and narrowing from middle towards apex.

Female. Similar to male in external morphology; antenna slightly shorter, lacking modifications; each compound eye composed of approximately 12 ommatidia; humerus weakly prominent. Measurements (as for male): body length 1.98–2.02 mm; length/width of head 0.45–0.48/ 0.44–0.45 mm, pronotum 0.47–0.48/ 0.46–0.48 mm, elytra 0.53–0.58/ 0.76–0.83 mm; abdomen 0.63–0.65/ 0.76–0.78 mm; length of antenna 0.96–0.99 mm; maximum width of genitalia ( Fig. 55G ) 0.20 mm.

Comparative notes. The male of Sathytes pengzhongi can be easily separated from that of all congeners from the Himalayan region by the unique shape of antennomeres 9 and the anteriorly placed apophysis on them, combined with the small body size of 1.9–2.0 mm.

Distribution. Dinggyê County, Tibet, SW China ( Figs 84A , 93F, G ).

Etymology. The new species is named after Zhong Peng, the collector of this species.

Figures

FIGURE 55. Morphology of Sathytes pengzhongi sp. nov. (A–F. Male. G. Female). A. Dorsal habitus. B. Head and pronotum. C. Antennomeres 9–11. D. Antennomere 9. E. Sternite 7 (IX). F. Aedeagus, ventral. G. Genitalia. Scale bars: 0.5 mm in A; 0.3 mm in B; 0.2 mm in C; 0.05 mm in D, 0.1 mm in E–G.

FIGURE 84. Distribution of Tibetan Batrisini. A. Sathytes magnus Yin & Li (circle), S. panzhaohuii Yin & Shen (triangle) and S. pengzhongi sp. nov. (square). B. S. proclivis sp. nov. (circle), S. pseudograndis sp. nov. (triangle) and S. simplex Löbl (square). C. S. sympatricus sp. nov. (circle), S. transversus Yin & Shen (triangle) and S. virupaksa sp. nov. (square).

FIGURE 93. Environment of and collecting sites at Zhêntang Valley (ĿƋ沟). Slopes at altitudes of 3700 m (A), 4000 m (B), and 3050 m (C). D. Nadang Village (Ḅ当村). E. Road to Xiuxiongma Village (šŏ玛村). F, G. Environment of Ganma Zangbo Valley (HḼẪ布河ě). Photo Credit: F, G by Zhong Peng.