Brachysomus (Hippomias) rhinomioides Košťál, 1992

Yunakov, Nikolai, 2022, A review of the genus Brachysomus Schoenherr (Coleoptera: Curculionidae: Entiminae), Zootaxa 5193 (1), pp. 1-165 : 57-58

Brachysomus (Hippomias) rhinomioides Košťál, 1992

Figs. 62 , 128 , 212 , 239B

Brachysomus rhinomioides Košťál, 1992: 47 . Type locality: Turkey, Sinop; Yunakov, 1998: 39.

Redescription. Measurements: Body length 1.86–2.15 mm, width 1.10–1.31 mm. Colouration: Body, legs and antennae brown. Vestiture: Body densely covered with recumbent lanceolate or piliform scales and erect setae. Scales grey-brown, evenly covering dorsal surface of head, body, and external surface of femora. Length of erect setae uniform in length across elytra; setae at elytral interstriae forming one straight row; setae of pronotum suberect, evenly covering disc. Antennae, tibia, and tarsi with hairs and weakly widened setae. Abdomen with grey hairs and piliform scales.

Head: Rostrum conical, weakly narrowed from base to middle, as long as wide or weakly elongate (RL/RW = 1.00–1.10). Pterygia from above, well visible sharply projecting from outline of rostrum. Epifrons parallel-sided, distinctly convex longitudinally separated from vertex by sharp transverse depression. Frons weakly and evenly convex. Eyes in male large, in female small (VW/ELD in males = 1.75–1.90 in females = 2.3), oval, weakly convex; dorsal margin weakly lower than level of vertex. Dorsal margin of antennal scrobes reaching anterior margin of eye. Antennae: Scape weakly curved, evenly widened distally; funicular antennomeres: 1st and 2nd uniform, elongate; 1st distinctly wider than 2nd; 3rd as long as wide; 4 th –7th transverse; club egg-shaped.

Thorax: Pronotum transverse [PL/PW = 0.80–0.85 (0.83)], strongly convex at sides and disc, sharply constricted anteriorly; densely and moderately shallowly punctate; spaces between punctures very thin, shiny, weakly convex. Basal width of pronotum in male weakly narrower than width of elytra at base, in female distinctly narrower. Elytra: almost globose or cordate, strongly convex at sides and disc (EL/EW = 1.11–1.15). Basal margin weakly concave. Striae at disc 1.5x narrower than interstriae, at sides 2x narrower than interstriae; punctures well separated, spaces between punctures situated at level of flat interstriae. Legs: Femora weakly swollen at middle; tibiae thin, strongly elongate, straight, widened near apex, weakly sinuate internally. Hind tibiae in male not sinuate, weakly mucronate. Second tarsomere strongly transverse, 3rd tarsomere with broad lobes. Fifth fore tarsomere extending beyond apical lobes of 3rd by 0.86 length of the lobes.

Abdomen: Male 5th ventrite flat, without depression near apex, with apical margin straight, in female rounded. Male genitalia: Median lobe heavily sclerotized, acute apically; endophallus with two large sclerites; tegmen with well developed parameres. Spermatheca: collum thick and short, ramus thin and long.

Diagnosis. Brachysomus rhinomioides is easily distinguished from all known species of the genus Brachysomus by a sharp transverse depression before the frons. It is closely related to the B. transsylvanicus species group, differing in the following characters: rostrum sharply convex and strongly elongate; scales covering body, not excised apically; epifrons narrow; globose or cordate elytra; and structure of aedeagus.

Distribution. Ukraine (Crimea), Turkey (Sinop, Samsun).

Remarks. Brachysomus rhinomioides has all diagnostic features listed above and in Table 1 for the subgenus Hippomias ; however, the study of its male genitalia revealed two features strikingly different from other Hippomias . The parameres are strongly developed, and the endophallus bears a large sclerite in a subapical position. The latter is unique for this species and does exist in either Brachysomus nor in Rhinomias , nor in other similar genera. Complete parameres appear as plesiomorphic, and this might suggest that (if it is a true Hippomias ) it is sister to the rest of Hippomias . The sclerite could tentatively be interpreted as an apomorphic fusion of two groups of spicules. Such transformations occasionally occurs in other Coleoptera (see Kataev 1996 for Carabidae ). The presence of this sclerite is thus not in conflict with the placement of the species in Hippomias .

Type material. Holotype,♂ (MHNG): ‘Turquie, Sinop, Lala près Sinop, 20.v.1976 Besuchet, Löbl lgt.’ Paratypes: 2♂, 4♀ (MHNG): labeled as holotype.

Additional material examined. TURKEY: 2♀, ‘Turchia, Samsun Prov., Bafra, 19.v.1967, Besuchet leg.’ (OGc). UKRAINE: 1♀, ‘Crimea, Bolshoy Canyon, Chainyi Domik locality, Vilgiburun Mt., 900 m, pitfall trap, 19.VI–16.vii.1992, A.G. Koval leg.’ (ZIN).

Figures

FIGURE 212. Brachysomus rhinomioides: A: aedeagus; B: proximal endophallic sclerite; C: distal endophallic sclerite; D: tegmen; E: spermatheca; F: head; G: antenna; H: pronotum, lateral view; I: hind tibia of male.

FIGURE 239. Occurrence map of Brachysomus: A: Brachysomus s. str.; B: subgenus Hippomias.

FIGURES 57–62. Brachysomus, dorsal habitus: 57: B. albanicus. 58: B. commutatus. 59: B. mikati. 60: B. ponticus. 61: B. simulans. 62: B. rhinomioides.

FIGURES 124–130. Brachysomus, details: 124: B. albanicus, head dorsal view. 125: B. albanicus, head lateral view 126: B. simulans head dorsal view. 127: B. simulans, head lateral view. 128: B. rhinomioides, head dorsal view. 129: B. rhinomioides, head lateral view.