Coryphomodes cephalicus, 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 : 102-104

Coryphomodes cephalicus sp. nov.

( Figs 44 , 81C , 99E , 100A )

Chinese common name: 焰ĦỀȁà甲

Type material (2 exx.). HOLOTYPE: CHINA: ♂ , ‘ China: nr. Mêdog County, alt. 1280 m, 29°18’48”N, 95°19’17”E; 18.iii.2017, X.-B. Song leg. [ƱẪẸṘ县]’ ( SNUC) . PARATYPE: CHINA: 1 ♀ , ‘ China: Mêdog County, 80K (ca. 29°39’22”N, 95°29’20”E), 2110 m, 11.viii.2016, Z.-L. Chen leg. [ƱẪẸṘ县 80K]’ ( SNUC) .

Diagnosis. Male. Body length 1.87 mm. Head rounded triangular, as broad as pronotum, tempus moderately long, vertex and frons modified, vertex with lateral impressed areas and large central cavity, frons with median projection covered with dense setae; antenna lacking modifications. Pronotum with laterally carinate median sulcus and lateral longitudinal sulci, with small antebasal and marginal spines. Elytron with inner two basal foveae close, discal stria broad and shallow, short, extending posteriorly from outer basal fovea to basal 1/4 of elytral length; disc with moderately sparse, large punctures. Fore legs simple, mesotrochanter with tiny ventral tubercle, metatrochanter with blunt triangular ventral spine. Aedeagus strongly asymmetric, stout; ventral stalk composed two plates apically, dorsal lobe plate-like, parameres reduced. Female genitalia as in Fig. 44G .

Description. Male. Body ( Fig. 44A ) length 1.87 mm; color reddish-brown, tarsi and mouthparts lighter. Dorsal surface of body covered with relatively dense pubescence.

Head ( Fig. 44B ) rounded triangular, as wide as long, length 0.42 mm, width across eyes 0.43 mm; vertex smooth, large mediobasal cavity with ridged posterior margin, small foveae at anterolateral margin of cavity, areas lateral to cavity with round impressions filled with short setae, anterior margin of cavity formed by thick, transverse ridge; frons anteriorly confluent with clypeus, with antero-lateral ridges, with large central tubercle covering with dense setae at middle, with short longitudinal ridge and tuft of setae lateral to tubercle; clypeus with smooth 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 transverse opening, with thin median carina extending from opening anteriorly to mouthparts. Compound eyes prominent, composed of approximately 45 ommatidia. Antenna lacking modification, length 0.93 mm, indistinct club formed by enlarged apical three antennomeres; antennomere 1 thick, subcylindrical, 2–8 each moniliform, 2 elongate, 3–8 short, each slightly elongate or as long as wide, 8 smallest, 9 much larger than 8, subconical, 10 slightly broader but shorter than 9, 11 largest, slightly shorter than 9 and 10 combined, subconical.

Pronotum ( Fig. 44B ) approximately as long as wide, length 0.43 mm, width 0.42 mm, widest posterior middle; lateral margins rounded at apical 1/2, basally evenly convergent; disc slightly convex, with sparse but distinct punctures, median longitudinal sulcus with carinate sides, with pair of shallow lateral longitudinal sulci; with small antebasal and marginal spines; lateral antebasal foveae small and asetose; with small outer and inner pair of basolateral foveae. Prosternum with anterior part slightly longer than coxal part, with small lateral procoxal foveae; thin hypomeral ridge extending from base to middle of anterior part, with punctiform lateral antebasal hypomeral pit; margin of coxal cavity weakly carinate.

Elytra wider than long, length 0.61 mm, width 0.77 mm; each elytron ( Fig. 44C ) with three large, asetose basal foveae, inner two close; discal stria broad and shallow, short, extending posteriorly from outer basal fovea to basal 1/4 of elytral length; humerus weakly and broadly prominent, lacking subhumeral fovea, carinate marginal stria extending from basal 1/4 to posterior margin of elytron.

Mesoventrite short, demarcated from metaventrite by transverse carinae; median mesoventral foveae narrowly separated, originating from shared oval opening, large lateral mesoventral foveae forked internally, with short mesoventral process. Metaventrite prominent admesally, inclined towards middle, with well-developed lateral mesocoxal and two lateral metaventral foveae, posterior margin with small and narrow split at middle. Marginal carina complete, extending from anterior margin of mesoventrite to posterior margin of metaventrite.

Legs more or less robust; protrochanter with exceptionally long seta on ventral margin, mesotrochanter with tiny tubercle on ventral margin; metatrochanter ( Fig. 44D ) with distinct rounded triangular spine on ventral margin.

Abdomen widest at lateral margins of tergite 1 (IV), length 0.50 mm, width 0.70 mm. Tergite 1 (IV) approximately twice as long as 2 (V), lacking mediobasal foveae or discal carinae, basal sulcus thin, with large basolateral foveae at lateral margins of sulcus, inner marginal carina slightly oblique, complete, outer one thicker, complete; tergite 2 (V) slightly longer than 3 (VI), 4 (VII) shorter than tergites 2 and 3 combined; tergites 2–4 (V–VII) each with one pair of basolateral foveae, tergite 5 (VIII) semicircular, transverse, posterior margin roundly emarginate at middle. Sternite 2 (IV) with one pair of small mediobasal and two 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 emarginate, sternite 7 (IX) entirely membranous, flattened.

Aedeagus ( Fig. 44E, F ) 0.23 mm long, strongly asymmetric, stout; median lobe with broad basal capsule and subtriangular foramen, basoventral projection short, ventral stalk apically expanded, short, truncate at apex; nonarticulated dorsal plate short and flattened, subtruncate; parameres reduced.

Female. Similar to male in external morphology; antenna slightly shorter; head and legs lacking modifications, vertex with reversed U-shaped sulcus connecting small foveae; each compound eye composed of approximately 28 ommatidia. Measurements (as for male): body length 1.83 mm; length/width of head 0.41/ 0.40 mm, pronotum 0.42/ 0.44 mm, elytra 0.60/ 0.75 mm; abdomen 0.49/ 0.70 mm; length of antenna 0.90 mm; genitalia ( Fig. 44G ) weakly sclerotized, transverse, maximum width 0.19 mm.

Comparative notes. This species is morphologically most similar to the Tibetan C. budda and C. chenzhilini , and can be readily separated from both species by the large punctures that cover the dorsal surface of the elytra, and the characteristic cephalic modifications and form of the aedeagus.

Distribution. Mêdog County, Tibet, SW China ( Figs 81C , 99E , 100A ).

Etymology. The specific epithet refers to the strong cephalic modification of the new species.

Figures

FIGURE 44. Morphology of Coryphomodes cephalicus sp. nov. (A–H. Male. G. Female). A. Dorsal habitus. B. Head and pronotum. C. Right elytron. D. Metatrochanter. E, F. Aedeagus, lateral (E) and ventral (F). G. Genitalia. Scale bars: 0.5 mm in A; 0.2 mm in B, C; 0.1 mm in D–G.

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 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.

FIGURE 100. Environment of and collecting sites at Nyingchi area (A–E) and Chamdo (ăƀ) (F). A. 80K. B. 96K. C–E. Xiachayu (T察ø). F. pass of Jueba Mountain (ẅ巴山口), Markam (Ẽ康). Photo Credit: A by Zhong Peng; B by Xiao-Bin Song; F by Wen-Xuan Bi.