Brachysomus (Brachysomus) fremuthi Košťál, 1991

Yunakov, Nikolai, 2022, A review of the genus Brachysomus Schoenherr (Coleoptera: Curculionidae: Entiminae), Zootaxa 5193 (1), pp. 1-165 : 28

Brachysomus (Brachysomus) fremuthi Košťál, 1991

Figs. 93, 94 , 184F, G , 235B

Brachysomus fremuthi Košťál, 1991b: 84 . T ype locality: Hungary, Vizslás; Białooki 2007: 164.

Redescription. Measurements: Body length 2.0–2.3 mm, width 1.2–1.5 mm. Vestiture: Body, head and legs (excepting tarsi) densely covered with small, round, overlapping scales. Sides and median line of pronotum with denser vestiture, surface between median line and sides without rounded scales. Setae strongly erect (almost vertical), weakly spatulate, obtuse, as long as setae on the elytra, evenly covering dorsal surface of head and pronotum. Interstriae of elytra with 1–2 rows of short setae (0.5x as long as width of interstiae). Antennal scape setose, funicle and club with thin pale hairs. Tarsi setose and pilose. Abdomen covered with hairs and piliform scales. Colouration: Integument of body and appendages brown to dark-brown. Scales and erect setae uniformly pale, with distinct pearly shine; spotted pattern well developed.

Head: Rostrum weakly transverse [RL/RW = 0.85–0.96 (0,905)] weakly narrowed apically, lateral margins in line with lateral margins of temples. Antennal sockets partly visible in dorsal view. Pterygia not projecting from outline of rostrum. Antennal scrobes sharply developed, deep, directed to ventral margin of eye, reaching ventral side of rostrum. Epistome flat, delimited from epifrons by weakly developed and thin V-shaped carina. Epifrons narrowed from base to midlength and parallel-sided from midlength to apex, flat, with very thin median carina, without median longitudinal sulcus nor transverse depression. Vertex flat, finely punctate. Eyes oval, strongly convex, highest at middle; dorsal margin of eye in lateral view situated nearly to level of vertex [VW/ELD = 2.0–2.3 (2.12)]. Antennae: Scape almost straight, strongly widened along apical 1/3. funicular antennomeres: 1st and 2nd elongate, 1st 1.75x longer than wide; 2nd 1.66x as long as wide; 3rd–6th as long as wide; 7th weakly transverse (L/W = 0.75); club broad, spindle-shaped or oblong and egg-shaped (L/W in males = 2.25; in females = 2.7).

Thorax: Pronotum transverse [PL/PW = 0.6–0.7 (0.65)], widest at middle, constricted anteriorly and posteriorly, densely shallowly punctate. Disc without lateral depressions. Elytra: broadly-oval [EL/EW = 1.17–1.3], strongly convex at disc and sides. Elytral interstiae weakly convex, shiny, 2x wider than striae. Punctures narrowly separated; spaces between punctures very weakly concave, somewhat narrower than diameter of puncture. Legs: Fore tibiae straight, with apical external angle not protruding. Hind tibiae in male without mucro. Second tarsomere transverse. Fifth fore tarsomere extending beyond apical lobes of 3rd by length of the lobes.

Abdomen: First ventrite with posterior margin weakly sinuate. Male 5th ventrite transversally convex, obtuse; in female flat and rounded. Male genitalia: Aedeagus heavily sclerotized through entire length. Median lobe 0.75x as long as apodemes, attenuate apically; apex truncate, not dentate (in lateral view). Endophallus with two spiculate fields, with large, oblong endophallic sclerite. Parameres free, well developed, as long as width of tegmenal ring. Tegminal ring sinuate at base. Ventral membranes oblong, weakly sclerotized. Spermatheca: ramus and collum connate, ramus large.

Diagnosis. Brachysomus fremuthi very similar to B. turpificatus from Romania, and may be differentiated from the latter by the acute shape of the median lobe ( Fig. 184G ); B. turpificatus has an attenuate median lobe ( Fig. 184A ). Brachysomus fremuthi is also similar to B. lituratus and B. frivaldszkyi . From B. lituratus it differs by the uniform vestiture, without brown spots on elytra and pronotum; by the curved antennal scape and lack of lanceolate scales on the pronotum and elytra, as well in the long and erect setae along the elytral interstriae. From B. frivaldszkyi it differs by the straight medial margin of the hind tibiae, the convex 5th ventrite of the male, the lack of prominences on the head before the eyes, and the slender scales.

Distribution. Hungary.

Bionomics. This species inhabits xerothermic grasslands of the Tisza River valley.

Remarks. This little-known species has been described based on two specimens from northern Hungary. I was not able to study these specimens, the holotype deposited in the private collections of Michael Košťál and a paratype female, deposited in the collection of Jan Fremuth (now in University of Torino, Italy).

Material examined. HUNGARY: 3♂, 11♀, Tiszavasvári, Fehér-szik, 17.vi.1997 G. Hegyessy leg. (HNHM); 1♂, 3♀, Tiszavasvári, Fehér-szik, Várostelki-legelő, 4.vii.1997 G. Hegyessy leg. (HNHM); 5♀, Hortobágyi N. P., Újszentmargita, Margitai erdő fűhálózva, 13.vi.1974 Kaszab leg. (HNHM); 3♀, Újszentmargita, Margitai erdő fűhálózva, 2–5.vi.1975 Vásárhelyi & Papp leg. (HNHM); 1♀, Berettyóújfalu—Berettyó, 27.v.1995 P. Moravec leg. (HNHM); 1♂, 2♀, Kalocsa, Speiser leg. (HNHM); 1♂, 1♀, Jászberény, 1938 Móczár leg. (HNHM); 2♂, Tiszaug, Tiszaugm Kőrtvélyes (fáslegelő).v.2002 B. Tallósi leg. (HNHM); 1♀, Rákóczifalva, Felsővarsány 2, 06.vii.2004 G. Hegyessy leg. (HNHM).

Figures

FIGURE 184. Brachysomus turpificatus: A: aedeagus, dorsal and lateral view; B: tegmen; C: tergite VIII; D: scales of elytra; E: eye. B. fremuthi: F: aedeagus, dorsal and lateral view; G: spermatheca.

FIGURE 235. Occurrence map of Brachysomus: A: B. echinatus; B: Brachysomus s. str.

FIGURES 87–94. Brachysomus, details: 87, 88: B. echinatus. 89, 90: B. ornatus. 91, 92: B. strawinskii. 93, 94: B. fremuthi.