Brachysomus (s. str.) styriacus Formánek, 1905

Yunakov, Nikolai, 2022, A review of the genus Brachysomus Schoenherr (Coleoptera: Curculionidae: Entiminae), Zootaxa 5193 (1), pp. 1-165 : 35

Brachysomus (s. str.) styriacus Formánek, 1905

Figs. 71, 72 , 191 , 238A

Brachysomus styriacus Formánek, 1905: 183 . Type locality: Austria, Styria; Dalla Torre et al. 1937: 175; Caldara 1974: 214; Košťál 1991a: 108.

Redescription. Measurements: Body length 1.80–2.15 mm, width 1.10–1.30 mm. Vestiture sparse, body covered with small slender grey scales and weakly erected spatulate setae. Setae as long as 0.5x width of interstriae.

Colouration: Body and appendages light-brown to reddish- or yellowish brown.

Head: Rostrum as long as wide, strongly narrowed apically, lateral margins in line with lateral margins of temples.Antennal sockets distinctly visible in dorsal view. Pterygia not projecting from outline of rostrum. Antennal scrobes sharply developed and deep, directed to ventral margin of eye, reaching ventral side of rostrum. Epistome with indistinct U-shaped carina. Epifrons parallel-sided, flat, without carina, with distinct median longitudinal sulcus, without transverse depression. Vertex flat, finely striate and longitudinally punctate. Eyes oval [VW/ELD = 2.5], weakly convex, highest posteriorly. Antennaе: Scape gently curved, evenly widened distally; funicular antennomeres: 1st weakly elongate 1.5x longer than wide, 2x longer than 2nd, 2nd and 3rd as long as wide; 4 th –7th transverse; club broad, spindle-shaped.

Thorax: Pronotum transverse [PL/PW = 0.70–0.73 (0.71)], widest at middle, gently and evenly convex at disc and at sides, distinctly constricted anteriorly. Elytra: oval, strongly convex at disc and sides. Elytral interstriae weakly convex, 2x wider than striae. Punctures broadly separated; spaces between punctures very weakly concave, somewhat narrower than diameter of puncture. Legs: Fore tibiae straight. Second tarsomere as long as wide. Fifth fore tarsomere extending beyond apical lobes of 3rd by length of the lobes.

Abdomen: First ventrite with posterior margin weakly sinuate. 5th ventrite of both sexes flat, in male truncate and with scattered pale hairs, in female apical margin widely rounded. Male genitalia: Aedeagus slightly and evenly sclerotized, median lobe as long as apodemes, parallel-sided along most length, evenly narrowed only along apical 1/4, apex narrowly rounded. Endophallus with granuliform spicules. Ventral membranes triangular, transparent. Parameres as long as width of tegmenal ring, posterior margin of basal piece sinuate. Spermatheca: ramus and collum connate at base, collum 2x longer than ramus.

Diagnosis. Brachysomus styriacus is very similar to B. subnudus , differing in the following characters: epifrons with deep and broad median longitudinal sulcus, hind tibiae in male weakly mucronate and apex of median lobe weakly elongate.

Distribution. Austria (Steiermark: Graz), Slovenia (Maribor), Italy (Veneto, Udine) ( Caldara 1974; Košťál 1991a).

Type material. Lectotype ♂ (HNHM), (designation: Košťál 1991a) ‘Styria, Penecke St. Marburg’, ‘Paratypus Brachysomus styriacus Formánek 1905 ’, ‘ Brachysomus styriacus Penecke typi m.’, ‘coll. Reitter’, ‘Lectotypus Brachysomus styriacus Form., M. Košťál design.’. Paralectotypes 2ex. (HNHM), as lectotype, ‘Paralectotypus Brachysomus styriacus Form., M. Košťál design.’.

Additional material examined. AUSTRIA: 2♂, ‘Styria, Reitter’ (NMPC, HNHM). SLOVENIA: 3♂, 1♀, ‘Marburg an der Drau [= Maribor]’ (NHMUK, ZMUH, MTD); 1♂, 1♀, ‘Felber Insel’ (NMPC).

Figures

FIGURE 191. Brachysomus styriacus: A: aedeagus, dorsal and lateral view; B: tegmen; C: spermatheca; D: tergite VIII; E: antenna; F: head.

FIGURE 238. Occurrence map of Brachysomus s. str.

FIGURES 71–78. Brachysomus, details: 71, 72: B. styriacus. 73, 74: B. frivaldszkyi. 75, 76: B. subnudus. 77, 78: B. dispar.