Tibetyrus Yin & Lin, 2020

Yin, Zi-Wei & Lin, Ye-Jie, 2020, Tibetyrus gen. nov., a new myrmecophilous Tyrini from Xizang, China (Coleoptera: Staphylinidae: Pselaphinae), Zootaxa 4786 (1), pp. 131-137 : 132-133

Tibetyrus Yin & Lin , gen. nov.

Type species. Tibetyrus formicarius sp. nov. (here designated).

Diagnosis. Head with relatively small vertexal and frontal foveae; maxillary palpi elongate and basally pedunculate, length of pedunculate portion successively shorter from palpomeres 2 to 4 ( Fig. 1B ). Pronotum with punctiform median- and small lateral antebasal foveae, with thin and shallow antebasal sulcus connecting foveae. Elytra short and strongly constricted at base, each with two small basal foveae. Visible tergites 1–4 (IV–VII) subequal at midlength. Legs with very short tarsomeres 1, and elongate tarsomeres 2 and 3.

Description. Relatively large-sized for pselaphines, body length 3.5–3.7 mm. Head with frontal rostrum moderately long, relatively narrow, formed largely by slightly prominent antennal tubercles; with setose frontal and vertexal foveae; with 11 antennomeres, clubs formed by three apical antennomeres; lacking postantennal notches at lateral margins; lacking lateral postantennal pits, at position where pits occur there are five short and thickened semi-transparent setae; maxillary palpi with small, subtriangular palpomeres 1, palpomeres 2 pedunculate for basal three-fifths, gradually widening and then narrowing again to apices, palpomeres 3 pedunculate for short distance at bases, widening to and truncate at apices, palpomeres 4 enlarged and elongate, suboval, constricted at bases and broadest at basal two-fifths, apices round, lacking apical palpal cones; gula moderately swollen, gular foveae close in shared transverse opening.

Pronotum elongate, broadest at apical third, with disc moderately convex; median antebasal fovea punctiform and nude, lateral antebasal foveae relatively small and setose; lateral procoxal foveae present, lacking paranotal carinae/sulci.

Elytra subtrapezoidal, each elytron with two small but distinct setose basal foveae; broad, shallow discal striae extending posteriorly from outer basal fovea to apical four-fifths.

Mesoventrite lacking median mesosventral fovea, with large lateral mesosventral foveae deeply forked internally, anterolateral mesosventral foveae absent; with large lateral mesocoxal foveae; single median metaventral fovea large and densely setose, posterior margin of metaventrite with looped notch at middle.

Legs noticeably elongate, lacking distinct cuticular features; femora moderately thickened, broadest at middle; pro- and mesotibiae slightly curved medially, metatibiae slightly sinuate, all tibiae narrowed at bases and thickened to apices; tarsomeres 1 very short, tarsomeres 2 and 3 elongate, 2 moderately to slightly shorter than 3; pretarsal claws paired and curved at apices.

Abdomen with tergites moderately convex, visible tergites 1–4 (IV–VII) subequal at mid-length, tergites 1–3 (IV–VI) each with transverse basal impression, 1–5 (IV–VIII) lacking mediobasal foveae, and each with pair of small basolateral foveae. Visible sternites 2–5 (IV–VII) each with deep basal sulcus, lacking mediobasal foveae, with two basolateral foveae.

Males with modified antennae and metaventrite. Aedeagus with apical half of median lobe strongly asymmetric; parameres reduced and symmetric; dorsal diaphragm opening oval.

Comparative notes. Among the Asian genera of Tyrini , Tibetyrus gen. nov. shares only with Megatyrus Hlaváč & Nomura the basally pedunculate maxillary palpi that lack apical cones on palpomeres 4. However, Tibetyrus gen. nov. differs from Megatyrus by numerous characters: 1) area between antennal tubercles much less impressed, not deeply sulcate, 2) much shorter pedunculate portion of maxillary palpomeres 3–4, 3) scapes longer than antennomeres 2–3 combined in male, subequal in length in female, 4) a different shape of the pronotum, 5) strongly reduced elytra and total loss of the hindwings, 6) tergites 1–4 (IV–VII) being subequal at their mid-length, 7) lack of a median carina on tergite 1 (IV), and 8) male sexual characters located on antennal clubs and metaventrite. In contrast, all Megatyrus species possess a deep to moderately deep median sulcus on the frons that separates the antennal tubercles, the pedunculate portions of maxillary palpomeres 3–4 are much longer, the scapes are shorter than the following two antennomeres combined in both sexes, the pronotum is broadest at the middle, the elytra have a very broad base, tergite 1 (IV) is as long as 2–3 (V–VI) combined, and with a median carina extends through the entire tergal length, and the male characters are located on the scapes and legs. Tibetyrus gen. nov. can be otherwise separated from all known Asian genera by the form of the maxillary palpi, together with the other external characters as well as the highly distinctive habitus.

Etymology. The new generic name is a combination of ‘Tibet’ and ‘ Tyrus Aubé’ (type genus of Tyrini ). The gender is masculine.

Figures

FIGURE 1. Tibetyrus formicarius (A–C. Male. D. Female). A. Habitus. B. Right maxillary palpus. C, D. Antennomeres 9–11. Scale bars: 1.0 mm in A; 0.2 mm in B; 0.5 mm in C, D.