Brachysomus (Hippomias)

Yunakov, Nikolai, 2022, A review of the genus Brachysomus Schoenherr (Coleoptera: Curculionidae: Entiminae), Zootaxa 5193 (1), pp. 1-165 : 20-21

Hippomias : B. kubanensis group

1. Male 5th ventrite emarginate at posterior margin, distinctly depressed in posterior third. Medial margin of hind tibiae straight, in male sharp. Sides of median lobe heavily sclerotized, ventral wall partly membranous. Ventral membranes of aedeagus elongate, moderately sclerotized; endophallus with distinctly U-shaped sclerite, sometimes sclerite divided longitudinally in two halves.......................................................................... B. kubanensis (Reitter)

- Male 5th ventrite with posterior margin not emarginate, posterior third weakly depressed or flat. Medial margin of of hind tibiae moderately sinuate, obtuse. Sides of median lobe weakly sclerotized, ventral wall entirely membranous. Ventral membranes of aedeagus as long as wide, membranous; endophallus without U-shaped sclerite.................................... 2

2. Elytra in male broad-ovate (EL/EW = 1.17–1.32). Erect setae on elytra long (as long as 1/2 interstrial width), narrow, parallelsided, obtuse, arranged in one straight row. Eyes large, strongly convex. Apodemes almost 2x longer than median lobe........................................................................................... B. kovali Yunakov

- Elytra in male ovate or oblong-ovate (EL/EW = 1.36–1.38). Erect setae on elytra short (as long as 1/3 interstrial width), spatulate, apically rounded, arranged in 1–2 confused rows. Eyes small, weakly convex. Apodemes as long as median lobe..................................................................................... B. ellipticus Yunakov

Taxonomy

Genus Brachysomus Schoenherr, 1823

Schoenherr, 1823: 1144. Type species: Curculio hirsutulus Fabricius, 1792 = Curculio echinatus Bonsdorff, 1785

= Pavrosomus Fischer de Waldheim, 1829: 94 .

= Platytarsus Schoenherr, 1840: 919 .

= Thricolepoides O’Brien, 1979: 71 .

Diagnosis. Body length 1.5–4.3 mm, width 1.5–1.7 mm. Vestiture and colour. Body sparsely or densely covered with scales, or almost glabrous. Scales with or without obliterate metallic shine, normally grey to brown. Integument brown to dark-brown; legs and antennae brown, light-brown or yellow. Head: including the eyes not wider than the pronotum at its anterior margin, and without a constriction behind the eyes. Eyes well developed, with 10 or more ommatidia along ELD. Rostrum on average as long as wide. Pterygia only slightly projecting from outline of rostrum. Antennal scrobes lateral, slightly/not visible in dorsal aspect, directed obliquely ventrally, either with well pronounced and parallel dorsal and ventral margins, or with dorsal margin obliterate. Epifrons not separated by transverse sulcus from vertex. Vertex flat, without fovea. Antennae: Scape extending behind posterior margin of eye, does not reach anterior margin of pronotum. 2nd funicular antennomere not longer than 1st. Club compact, antennomeres appearing fused. Legs: Femora edentate. Metatibial apex simple, without proximal fringe and flange ( Thompson 1992). Ventroterminal lobes of 3rd tarsomere not or weakly separated, with well developed bridge between lobes. Claws connate in basal half, divergent in distal half. Thorax: Prothorax with straight anterior margin in lateral view, without prosternal excision and postocular lobes and vibrissae. Hindwings absent. Elytra (longto broad-) ovate to globose, without prominent humeral nor posterior tubercles; elytra with abrupt basal margin. Scutellar shield small, not projecting beyond basal margin of elytra. Abdomen: Posterior margin of ventrite 1 deeply emarginate, that of ventrite 2 straight. Male genitalia: Apex of median lobe acutely or widely rounded, without lateral prominences. Base of endophallus with paired ventral membranes, which are moderately sclerotized, oblong or round or triangular; mesal endopallite absent.

Remarks on systematics. Brachysomus is similar to Foucartia , Amicromias , Eurosphalmus , and Nanomias in general appearance (see Table 1 for a more complete comparison of characters). Eurosphalmus differs from Brachysomus in the shape of the pterygia which are moderately projecting from their lateral contour andin the structure of the aedeagus (ventral membranes large, projecting from preputial field, apical part of median lobe with lateral prominences including the armature of endophallus). Amicromias differs from Brachysomus by the constriction of the head behind the eyes and a depression on the epistome of the rostrum, and by dorsally fully opened and visible antennal scrobes. Foucartia differs from Brachysomus by the body, legs including tarsi, and antennae being more slender, and the antennae relatively longer, by the complete scutellar shield, and by a less steep basal declivity of the elytra. Nanomias differs from Brachysomus by the rostrum significantly shorter than wide, tarsal claws diverging from midlength onward, ventroterminal lobes of 3rd tarsomere separated down to base, antennal scrobes clearly visible in dorsal aspect, posterior margin of abdominal ventrite 1 slightly or not emarginate, that of ventrite 2 rounded.

Character Rhinomias Nanomias Foucartia Brachysomus Hippomias Eurosphalmus Amicromias

Temple absent absent absent absent absent absent present constriction Epistomal absent absent present present present absent absent carina Epistome flat flat flat flat flat flat depressed HW/PWa ≤1 ≤1>1 ≤1 ≤1 ≤1 ≤1 Pterygia strongly not not slightly slightly strongly slightly

projecting projecting projecting projecting projecting projecting projecting Antennal vestigial vestigial distinct distinct vestigial vestigial distinct scrobes N omm /ELD ≥10 ≤7 ≥10 ≥10 ≥10 ≥10 ≥10 Head developed absent absent absent absent absent absent striation ibt absent absent absent present absent absent absent ventral not not not not not protruding not membranes protruding protruding protruding protruding protruding protruding (ligulae) apical lobes absent absent absent absent absent present absent of aedeagus paramera well vestigial well well vestigial vestigial well

developed developed developed developed Scutellar invisible invisible visible invisible invisible invisible invisible shield

Subgenus Brachysomus s. str.

Diagnosis. Brachysomus s. str. differs from and Hippomias in presence of intero-basal tooth of mandibular process ( Fig. 10); epifrons parallel-sided and at the level of the antennal insertion almost as wide as the vertex between eyes; pterygia slightly project from the contour of the rostrum and in dorsal view are partly covered by the lateral margin of the epifrons ( Fig. 1); ventral and dorsal margins of antennal scrobe are both distinct and long ( Fig. 194F); antennal scape finely punctate, does not extend beyond the anterior margin of the pronotum, generally only reaches the posterior margin of the eye.; tegmen and the dorsal and ventral walls of the aedeagal median lobe are all strongly sclerotised; median lobe anterior to base of endophallus with distinctly modified tip: spear- or stick-shaped protruding, generally acute; paramera distinctly developed; aedeagal apodemes as long as or 1.5x as long as median lobe.