Bryaxis issensis ( J. Müller, 1909 ), J. Muller, 1909

Bekchiev, Rostislav & Hlaváč, Peter, 2016, New and interesting species of the genus Bryaxis Kugelann, 1794 (Coleoptera, Staphylinidae, Pselaphinae) from Croatia, Zootaxa 4144 (1), pp. 109-116 : 111-112

Bryaxis issensis ( J. Müller, 1909)

( Fig. 1 )

Bythinus issensis J. Müller, 1909: 279 .

Literature data. Vis Island in cave ( Müller 1909); Vora Špilja ( Nonveiller et al. 2000); Kraljičina špila, island Vis, vicinity of Oključna (Hlaváč et al. 2008).

New records. 3 ƋƋ (forme gracilipes): Croatia, Vis isl., Kostirna , Špilja kod Vlore; 1 ♂: 19.10. 2007, leg. H. Cvitanović ; 1♂ (forme inflatipes): 29.4. 2013, leg. B. Jalžić; 1 ♂ (forme gracilipes): 27.4. 2015, leg. B. Jalžić. (PCPH).

Redescription. Body reddish-brown, antennae, maxillary palpi and legs slightly lighter, length 1.67–1.80 mm, max width 0.54–0.59 mm. Pubescence on head, pronotum and elytra gold, long, sparse and recumbent. Head 1.15– 1.25 times as long as wide. Frons with deep, frontal triangular impression between antennal tubercles; rostrum triangular anteriorly, with sharp median projection. Vertex flat, with well-defined median longitudinal carina reaching frontal triangular impression; frontal fovea absent, vertexal foveae large, their diameter equal to distance between them. Eyes completely atrophied. Maxillary palpi normally developed, with small, sparse tubercles on external part of apex of palpomeres II and III, terminal palpomere 0.23 mm long, about 0.33 times as long as wide. Gular region with shallow impression, anterior third with transverse elevated carina. Antennae about 0.73–0.75 mm long, scape long, simple without any modification, slightly extended to apex, 2.40–2.80 times as long as pedicel; pedicel simple, 1.75 times as long as wide; antennomeres III–VII elongate, III 1.3 times as long as IV, IV– V subequal in length, slightly longer than subequal antennomeres VI and VII, VIII smallest, quadrate, IX quadrate, about 1.4 times as wide as VIII, X 1.2 times as long as wide and 1.4 0–1.50 times as long as IX, terminal antennomere largest, fusiform, about twice as long as wide. Pronotum 1.05–1.15 as long as wide and 1.20–1.40 times as long as head, widest in anterior third, with well-defined antebasal sulcus connecting large lateral foveae, median fovea absent. Elytra 1.10–1.20 times as wide as long, slightly convex, with two basal foveae and sutural entire striae, discal striae absent. Legs robust, anterior tibiae with deep preapical indentation on inner margin, II and III simple, hind femora very thick (forme inflatipes) or slender (forme gracilipes). Aedeagus ( Fig. 1 ) elongate, 0.40 mm long, 2.85 times as long as wide, narrowed to apex of apical lobe, with three short preapical setae, basal bulb 1.20 times as long as apical lobe, ventrolateral foramen slightly projecting, phallobase diaphragm oval, large about 1.6 of length of median lobe, endophallus bifurcate, sharply pointed at apex.

Sexual dimorphism. Females unknown to the authors.

Differential diagnosis. Bryaxis issensis differs from all other anophthalmous Bryaxis by its simple, Tychobythinus -like shaped scape, simple elongate pedicel, and shape of the aedeagus.

Biology. All specimens were found in deep areas of the cave.

Distribution. The species is endemic to the island Vis, and so far all specimens have been collected in the cave Špilja kod Vlore near Kostirna village.

Figures

FIGURE 1. Bryaxis issensis: aedeagus, ventral (a) and lateral (b) view (scale bar— 0.1 mm).