Trisiniotus taoismus Feng & Yin, 2022

Feng, Ting & Yin, Zi-Wei, 2022, A new species of Trisiniotus Jeannel from Mao-shan, East China (Coleoptera, Staphylinidae, Pselaphinae), ZooKeys 1095, pp. 75-81 : 75

Trisiniotus taoismus Feng & Yin sp. nov.

Chinese common name: 道隐沟蚁甲 Figs 1 , 2

Type material

(15 exx.). Holotype: China: ♂, 'China: Jiangsu, Jurong City, Mao Shan, 31°47'41.99"N, 119°18'43.38"E, leaf litter, sifted, 140 m, 24.viii.2020, Ting Feng leg., 江苏句容市茅山风景区’ (SNUC). Paratypes: China: 6 ♂♂, 3 ♀♀, same data as that of holotype; 1 ♂♂, 2 ♀♀, 'China: Jiangsu, Jurong City, Yaji-shan, 31°39'24.06"N, 119°17'253.71"E, leaf litter, sifted, 100 m, 23.viii.2020, Zi-Wei Yin leg., 江苏句容市丫髻山脚; 2 ♀♀, China: Jiangsu, Jurong City, nr. Wawu-shan, 31°39'6.28"N, 119°16'20.99"E, leaf litter, sifted, 100 m, 22.viii.2020, Ting Feng leg., 江苏句容市瓦屋山上杆湖农庄 (all SNUC).

Diagnosis.

Male. Body length approximately 1.9 mm. Head sub-rectangular at base; vertex with large and setose foveae, with transverse sulcus at anterior portion; antenna elongate; antennomeres more or less elongate, lacking modifications. Pronotum lacking a median longitudinal sulcus. Discal stria of elytron long, extending posteriorly to approximately apical 3/4 of elytral length. Mesotibia with small apical spine. Metaventrite with setose admesal longitudinal ridges. Tergite 1 (IV) predominantly large, dorsally longer than 2-4 (V-VII) combined, lacking modifications. Aedeagus strongly asymmetrical; median lobe with restricted basal capsule and triangular foramen, ventral stalk erect, narrowing towards apex in lateral view; dorsal lobe narrowed at base, broadened towards apex. Female. Body length approximately 1.8 mm, legs and metaventrite lacking modifications, genitalia as in Fig. 1F .

Description.

Male. Body (Fig. 1A ) length 1.88-1.92 mm; color reddish-brown, tarsi and mouthparts lighter. Dorsal surface of body covered with short pubescence.

Head (Fig. 1B ) roundly triangular, sub-rectangular at base, much wider than long, length 0.37-0.39 mm, width across eyes 0.44 mm; vertex finely punctate, with large, setose vertexal foveae (dorsal tentorial pits), with transverse sulcus at apical portion of vertex, mediobasal carina thin and faint; antennal tubercles weakly raised; frons slightly impressed medially, confluent with clypeus; clypeus smooth, its anterior margin carinate and moderately raised; ocular-mandibular carina complete, distinct, carina branched below eye, extended ventrally and then anteriorly to posteroventral articulation of mandible. Venter with single, small gular fovea (posterior tentorial pit), with distinct median carina extending from fovea anteriorly to mouthparts. Eyes greatly prominent, each composed of approximately 35 large ommatidia. Antenna moderately elongate, length 0.94-0.97 mm, simple, club loosely formed by moderately enlarged apical three antennomeres; antennomere 1 thick, subcylindrical, 2-7 each elongate, 8 shortest, 9 much longer and broader than 8, 10 as long as and slightly wider than 9, 11 longest, shorter than 9 and 10 combined, sub-conical.

Pronotum (Fig. 1B ) approximately as long as broad, length 0.45-0.46 mm, width 0.46-0.47 mm, widest at middle; sides rounded; disc slightly convex, finely punctate, median longitudinal sulcus absent, semi-circular lateral sulci extending from dorsal surface laterally and posteriorly and then fused with lateral ends of antebasal sulcus; lacking median antebasal fovea, with short mediobasal impression, antebasal tubercles small, lateral antebasal foveae connected by transverse antebasal sulcus; outer and inner pairs of basolateral foveae distinct. Prosternum with anterior part as long as coxal part, with small lateral procoxal foveae; hypomeral ridge short, present only at base, with a lateral antebasal hypomeral impression; margin of coxal cavity weakly carinate.

Elytra much wider than long, length 0.62-0.63 mm, width 0.69-0.70 mm; each elytron with two large, asetose basal foveae, lacking a subbasal fovea; discal stria long, carinate, extending from outer basal fovea to approximately apical 3/4 of elytral length; humerus rounded, weakly prominent, subhumeral fovea absent, with sulcate marginal stria from below middle to posterior margin of elytron. Metathoracic wings fully developed.

Mesoventrite short, demarcated from metaventrite by ridged anterior edges of impressed areas where lateral mesocoxal foveae situated at mesal ends of impressions, with pair of thin admesal carinae; setose median mesoventral foveae widely separated, lateral mesoventral foveae large and setose, broadly forked internally; intercoxal process short. Metaventrite (Fig. 1C ) broadly impressed at middle, with setose admesal longitudinal ridges; with large, setose lateral mesocoxal foveae and a pair of smaller, setose lateral metaventral foveae, posterior margin broadly emarginate, with narrow split at middle.

Legs moderately elongate; mesotibia with small spine at apex.

Abdomen compressed, widest at lateral margins of tergite 1 (IV), length 0.47-0.50 mm, width 0.64-0.68 mm. Tergite 1 (IV) in dorsal view longer than 2-4 (V-VII) combined, lacking basal sulcus, with one pair of basolateral foveae and a short discal carina; tergites 2-4 each with one pair of small basolateral foveae, 4 as long as 2 and 3 combined along middle, 5 (VIII) semicircular, posterior margin roundly emarginate at middle. Sternite 2 (IV) with mediobasal and two basolateral foveae, with a pair of short lateral carinae; midlength of sternite 2 as long as 3-5 (V-VII) combined, 3-5 each short at middle, lacking fovea, 6 (VIII) transverse, posterior margin emarginate at middle, 7 (IX) membranous or absent.

Aedeagus (Fig. 1D, E ) 0.30 mm long, strongly asymmetrical; median lobe with constricted basal capsule and small, roundly triangular foramen, ventral stalk erect, in lateral view broadest anterior to middle and then narrowing towards apex; dorsal lobe approximately as long as ventral stalk, narrowed at base and broadening towards apex; parameres reduced to single broad membranous structure.

Female. Similar to male in external morphology; antenna shorter; each compound eye composed of approximately 30 ommatidia; elytra constricted at bases, humerus not prominent; metathoracic wings absent; mesotibia lacking apical spine, metaventrite lacking admesal ridges. Measurements (as for male): body length 1.79-1.83 mm; length/width of head 0.37/0.42-0.43 mm, pronotum 0.41-0.43/0.45 mm, elytra 0.56-0.57/0.69 mm; abdomen 0.52-0.53/0.65 mm; length of antenna 0.85-0.87 mm; maximum width of genitalia (Fig. 1F ) 0.23 mm.

Comparative notes.

Trisiniotus taoismus sp. nov. shares with its two congeners the lack of a median longitudinal sulcus on the pronotum, as well as a similar aedeagus. This species can be readily separated by the simple male antennomere 10, which is swollen in both species from India and Myanmar.

Distribution.

East China: Jiangsu (Fig. 2A, B ).

Bionomics.

All individuals were collected by sifting the leaf litter layer in broad-leaved forests (Fig. 2C, D ).

Etymology.

The specific epithet reflects that Mao-shan is a Taoist sacred mountain in eastern China.

Figures

Figure 1. Morphological characters of Trisiniotus taoismus sp. nov. A dorsal habitus B head dorsum and pronotum C central part of metaventrite D, E aedeagus, lateral (D) and ventral (E) F female genitalia. Scale bars: 0.5 mm (A); 0.3 mm (B); 0.2 mm (D-F).

Figure 2. Distribution (A, B) and habitat (C, D) of Trisiniotus. A distribution of T. taoismus sp. nov. (circle), T. nitidulus (triangle), and T. nodicornis (square) B distribution of T. taoismus sp. nov. in the Mao-shan mountains C environment of Mao-shan D habitat of T. taoismus sp. nov.