Coryphomodes chenzhilini, 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 : 104-106

Coryphomodes chenzhilini sp. nov.

( Figs 45 , 81C , 100A )

Chinese common name: Ŀ氏Ềȁà甲

Type material ( 1 ex.). HOLOTYPE: CHINA: ♂, ‘ 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 2.20 mm. Head rounded triangular, approximately as broad as pronotum, tempus moderately long, vertex and frons lacking modifications, lacking distinct sulcus or carina, vertexal foveae asetose, relatively large, with thin, short mediobasal carina; 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 to apical 2/3 of elytral length; disc with moderately dense, large punctures. Fore legs simple, mesotrochanter with large ventral spine, metatrochanter with large, curved ventral projection.Aedeagus strongly asymmetric, stout; ventral stalk apically divided into ventral and dorsal sclerites, dorsal lobe large, parameres reduced.

Description. Male. Body ( Fig. 45A ) length 2.20 mm; color reddish-brown, tarsi and mouthparts lighter. Dorsal surface of body covered with relatively dense pubescence.

Head ( Fig. 45B ) rounded triangular, slightly wider than long, length 0.44 mm, width across eyes 0.49 mm; vertex smooth, lacking modifications, vertexal foveae (dorsal tentorial pits) asetose, relatively large, mediobasal carina thin, extending from head base for short distance anteriorly; frons anteriorly confluent with clypeus, with curved antero-lateral ridges; clypeus with smooth surface, its entire anterior margin carinate and moderately raised; ocular-mandibular carina complete, distinct. Venter with granulate surface; small gular foveae (posterior tentorial pits) originating from shared transverse slit, with thin median carina extending from opening anteriorly to mouthparts. Compound eyes prominent, composed of approximately 45 ommatidia. Antenna lacking modification, length 1.06 mm, distinct club formed by enlarged apical three antennomeres; antennomere 1 thick, subcylindrical, 2–8 each slightly elongate, 8 smallest, 9 much larger than 8, subconical, 10 broader and longer than 9, subconical, 11 largest, approximately as long as 9 and 10 combined, sub-fusiform.

Pronotum ( Fig. 45B ) approximately as long as wide, length 0.45 mm, width 0.46 mm, widest at middle; lateral margins rounded at apical 1/2, evenly convergent basally; disc slightly convex, with sparse but distinct punctures, median longitudinal sulcus with carinate sides, with pair of 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 0.67 mm, width 0.80 mm; each elytron ( Fig. 45C ) with three large, asetose basal foveae, inner two close; discal stria broad and shallow, short, extending posteriorly from outer basal fovea to apical 2/3 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, 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 elongate; foreleg simple, mesotrochanter ( Fig. 45D ) with large, triangular spine on ventral margin; metatrochanter ( Fig. 45E ) with large, apically curved ventral projection.

Abdomen widest at lateral margins of tergite 1 (IV), length 0.61 mm, width 0.75 mm. Tergite 1 (IV) more than 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) ( Fig. 45F ) membranous, weakly sclerotized laterally.

Aedeagus ( Fig. 45G, H ) 0.36 mm long, strongly asymmetric, stout; median lobe with broad basal capsule and rounded triangular foramen, basoventral projection short, ventral stalk apically expanded, with narrowed dorsal sclerite truncate at apex; non-articulated dorsal lobe long and flattened, apically membranous; parameres reduced.

Female. Unknown.

Comparative notes. This new species is morphologically similar to the two previously described species and shares with them a similar general form of the aedeagus. It can be readily separated from both species by the lack of modifications on the male head, markedly denser large punctures of the elytra, presence of a large ventral spine on the male mesotrochanter, as well as the characteristic form of the aedeagus.

Distribution. Mêdog County, Tibet, SW China ( Fig. 81C , 100A ).

Etymology. The new species is named after myrmecologist Zhi-Lin Chen, who collected the holotype and provided the material for study.

Figures

FIGURE 45. Morphology of Coryphomodes chenzhilini sp. nov., male. A. Dorsal habitus. B. Head and pronotum. C. Right elytron. D. Mesotrochanter. E. Metatrochanter. F. Sternite 7 (IX). G, H. Aedeagus, lateral (G) and ventral (H). Scale bars: 0.5 mm in A; 0.3 mm in B; 0.2 mm in C–E; 0.1 mm in F–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 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.