Awas helii Yin, 2017

Yin, Zi-Wei, 2017, New species and records of Awas Löbl (Coleoptera: Staphylinidae: Pselaphinae) from China, with notes on the biology of the genus, Zootaxa 4338 (2) : -

Awas helii Yin , new species

( Figs 1–3 )

Type material (2 exs). Holotype: CHINA: ♂, ‘ China: Sichuan, Chengdu (成 都), Dujiangyan (都江 堰市), Zipingpu Town (紫坪铺镇), Ling-yan-guan-yin-shan Park (灵岩观音山景区), 31.03N, 103.61E, alt. 1160 m, 03.iv.2017, mixed forest, under stone with Ectomomyrmex ants, L. He & C. Zhou leg.’ (in SNUC). Paratype: CHINA: ♀, also from Ling-yan-guan-yin-shan Park, with same host ants and collector, except ‘ 31.02656N, 103.61816E, alt. 1075 m, 23.iv.2017 ’ (in SNUC).

Diagnosis. Body medium-sized, length around 3.5–3.55 mm; head with greatly elongate postocular region, lacking dense setae at posterolateral corners; pronotum widest at middle, anteriorly narrowed, basolateral margins shallowly incised at level of broad antebasal sulcus, posterolateral corners with setal tufts; each elytron with one basal fovea. Female has slightly larger abdomen than male.

Description. Male ( Fig. 1A ). BL 3.51 mm; body reddish-brown, mouth parts and tarsi lighter. Head ( Fig. 2B– C ) strongly elongate, HL 0.91 mm, HW 0.45 mm, dorsal surface densely punctate and roughly sculptured; most pubescence directed anteriorly; anterior frontal margin roundly protruding medially; postocular margins gradually narrowed toward occipital constriction; gula slightly depressed, with elongate median slit; eyes prominent, situated anterior to head length midpoint, each eye composed of about 70 facets; maxillary palpi with palpomeres I short, II elongate, slightly expanded apically, III nearly triangular, IV oval, with distinct membranous apical palpal cone; antennae ( Fig. 2A ) with subquadrate antennomeres, gradually broadened apically, antennomeres XI largest, narrowed apically. Pronotum ( Fig. 2D ) longer than wide, PL 0.7 mm, PW 0.58 mm; finely and sparsely punctate, with T-shaped antebasal sulcus followed with small round median pit; posterior margin with two small admesal foveae. Prosternum with dense admesal pubescence, pubescence on lateral margins sparser. Elytra slightly longer than wide, EL 1.22 mm, EW 1.08 mm, widest at basal two-fifths, rounded laterally, narrowed basally and apically; each elytron with one basal fovea ( Fig. 2E ), sutural striae complete. Mesoventrite with broad median ridge demarcated by pair of lateral carinae; metaventrite with distinctly raised median rostrum, laterally and posteriorly with row of long, dense setae. Legs slender, profemora with thin band of projection at apical third. Abdomen much broader than long, AL 0.68 mm, AW 0.95 mm; tergite IV predominantly largest, base largely covered under elytra; tergites V–VIII not visible in dorsal view. Aedeagus ( Fig. 2F–H ) symmetric, length 0.51 mm; anterior margin of median lobe broadly emarginate; endophallus with numerous hair-like structures; with ventrally curved hook-like parameres.

Female ( Fig. 1B ). Similar to male in external morphology, size slightly larger; with relatively larger abdomen and smaller eyes, each eye comprises about 60 facets. Measurements: BL 3.55 mm, HL 0.96 mm, HW 0.44 mm, PL 0.68 mm, PW 0.55 mm, EL 1.2 mm, EW 1.08 mm, AL 0.71 mm, AW 0.98 mm.

Comparative notes. Awas helii is morphologically most similar to A. kayan Yin & Li from Hunan, central China ( Yin & Li 2012, detailed description and figures). These two species share similar body sizes, relative lengths and proportions of the antennomeres, and presence of admesal foveae at the pronotal base and single basal fovea on the elytra. However, A. kayan possesses a relatively narrower (in relation to head width across eyes) and longer postocular region, the pronotum from the broadest point is more strongly narrowed toward the apex, the elytra are more constricted posteriorly from their broadest point, the mesotibiae are more densely setose at the apices, and the aedeagal endophallus has the apical pair of sclerites much thinner than in the new species.

Host ant. Ectomomyrmex sp. ( Fig. 3 ).

Distribution. Southwestern China: Sichuan.

Etymology. The species name is dedicated to Li He (Chengdu, China), who collected both specimens of the new species, and kindly provided us the material for study.

Figures

FIGURE 1. Dorsal habitus of Awas helii. A. Male. B. Female. Scale bars: 0.5 mm

FIGURE 2. Morphological details of Awas helii male. A. Antenna. B – C. Head, in dorsal (B), and lateral (C) views. D. Pronotum. E. Elytral base. F – H. Aedeagus, in dorsal (F), lateral (G), and ventral (H) views. Scale bars: 0.5 mm in A – D, 0.2 mm in E – H.

FIGURE 3. Habitat and living Awas helii with host ant. A. Habitat of Awas helii, image in box shows the original state of the beetle (male holotype) when the stone was turned over. B. A living Awas helii female with host in the field. C – F. A living Awas helii female with host in laboratory sample, showing rest pose (C) and lack of recognition of the beetle by the hosts (D – F).