Lisubatrus, Yin, 2017

Yin, Zi-Wei, 2017, Lisubatrus dongzhiweii gen. et sp. nov. from the Gaoligong Mountains, China (Coleoptera: Staphylinidae: Pselaphinae), Acta Entomologica Musei Nationalis Pragae (Acta. Ent. Mus. Natl. Pragae) 57 (2), pp. 593-601 : 594-597

Lisubatrus gen. nov.

( Figs 1–3 )

Type species. Lisubatrus dongzhiweii sp. nov., here designated.

Diagnosis. Head rectangular; lacking frontal rostrum; with punctiform vertexal foveae; posterolateral margins of head with row of dense setae; ocular-mandibular carinae distinct; antennomeres elongate, antennal club formed by apical three antennomeres. Pronotum slightly elongate, lacking foveae, with one pair of antebasal spines. Elytra lacking basal foveae and discal striae, strongly constricted at base and apex. Abdomen with thick triangular discal carinae on tergite IV (first visible tergite), lacking marginal carinae; tergite IV longest, much longer than tergites V–VIII combined.

Description. Body ( Fig. 1 ) elongate, strongly constricted between pronotum and elytra, and between elytra and abdomen. Body length less than 2 mm. Head ( Figs 2B–C ) rectangular; lacking frontal rostrum, antennal tubercles indistinct; vertexal foveae small and punctiform, lacking sulcus connecting foveae; posterolateral margins of head with row of gold, thick setae; antennae ( Fig. 2A ) with 11 antennomeres, clubs formed by apical three antennomeres, antennomeres XI largest, elongate and conical; ocular-mandibular carinae distinct; eyes nearly oval; maxillary palpi with short and triangular palpomeres III, palpomeres IV fusiform, widest at middle; gular region with single fovea just anterior of occipital constriction. Pronotum ( Figs 2B–C ) slightly elongate, rounded at lateral margins, constricted and parallel-sided at basal fourth, lacking any foveae or carinae, antebasal spines present, antebasal sulcus distinct at sides, faint in middle; disc slightly convex; lacking paranotal carinae; prosternum with small procoxal foveae. Elytra ( Fig. 2D ) constricted at base and at apex; lacking basal foveae, lacking discal striae, with complete sutural striae; lacking marginal striae; weak humeri present. Posterior margin of metaventrite ( Fig. 2E ) with small split. Abdomen ( Fig. 2F ) constricted at base; tergite V largest, much longer than remaining tergites combined, lacking lateral carinae, with thick, triangular discal carinae; tergites V–VI short, subequal in length, VII as long as V and VI combined. Legs with tarsomeres II slightly longer than tarsomeres III. Males with head, and meso- and metatrochanters modified. Aedeagus ( Figs 3C–E ) with parameres fused with median lobe to form elongate ventral lobe.

Relationships. The new genus is placed in the group of genera related to Dendrolasiophilus ( Fig. 4A ), which also includes the genera Songius ( Fig. 4B ) and Tangius ( Fig. 4C ). These taxa form a small myrmecophilous lineage within the Asian Batrisitae, sharing a usually glabrous body, presence of a setose tuft at the basolateral margins of the head, and aedeagus with a large basal capsule, and a well-developed dorsal lobe. Lisubatrus can be readily separated from these genera by the elongate antennomeres, a sub-cylindrical pronotum rounded at the lateral margins, elytra strongly constricted apically, and predominantly enlarged abdominal tergite IV. The genera Maajappia Nomura, 2010 ( Fig. 4D ) from Japan, and Myrmicophila Yin & Li, 2011 from China may also belong to this group based on the general body form and aedeagal structures, but both these genera lack the cephalic setose tufts ( NOMURA 2008, 2010; YIN et al. 2011). Maajappia have a distinct U-shaped sulcus connecting vertexal foveae, and were collected from leaf litter samples, whereas Myrmicophila have modified antennomeres V in the male, and are hosted by Myrmica ants. The key given below serves to a quick separation of Lisubatrus from all these likely allied genera.

Etymology. The new generic name is derived from ‘ Lisu ’, the name of the local minority ethnic group, and combined with ‘ batrus ’, an arbitrary abbreviation of Batrisus . The gender is masculine.

Figures

Fig. 1. Habitus of Lisubatrus dongzhiweii gen. & sp. nov., male in dorsal (A) and dorsolateral (B) views. Scale bars: 0.5 mm.

Fig. 2. Morphological details of Lisubatrus dongzhiweii gen. & sp. nov., male. A – left antenna. B–C – head and pronotum, in dorsal (B), and lateral (C) views. D – right elytron. E – meso- and metaventrite. F – abdomen in dorsal view, showing tergites IV–VII. Scale bars: 0.3 mm in A, F; 0.2 mm in B–E.

Fig. 3. Morphological details of Lisubatrus dongzhiweii gen. & sp. nov., male. A – tergite VIII. B – sternite VIII. C–E – aedeagus, in dorsal (C), lateral (D), and ventral (E) views. Scale bars: 0.2 mm.

Fig. 4. Representatives of the Dendrolasiophilus group of genera.A – Dendrolasiophilus wenhsini Yin & Li, 2013, female. B – Songius hlavaci Zhao, Yin & Li, 2010, male. C – Tangius indicus Yin & Li, 2013, male. D – Maajappia omotonis Nomura, 2010, male. E – Myrmicophila tangliangi Yin & Li, 2011, male (Figs 4A–C reproduced from YIN & LI 2013a,b, 2015, respectively). Scale bars: 0.5 mm.