Nanomias skodai ( Białooki, 2007 ) Yunakov, 2022

Yunakov, Nikolai, 2022, A review of the genus Brachysomus Schoenherr (Coleoptera: Curculionidae: Entiminae), Zootaxa 5193 (1), pp. 1-165 : 76-77

Nanomias skodai ( Białooki, 2007) , comb. n.

Figs. 158–160 , 232 A-D

Brachysomus skodai Białooki, 2007: 160 . Type locality: Romania, vicinity of Baltagesti

Described in the genus Brachysomus without placement to subgenus the author stated that B. skodai is similar to members of the genus Nanomias in general appearance. Brachysomus skodai distinctly differs from all known Brachysomus species in head structure (antennifer and antennal scrobes well visible in dorsal aspect, epistome without V-shaped carina), tarsi and genitalia of both sexes. A comparison with Nanomias terricola ( Figs. 232E–I ) reveals strong similarity with this genus in the following characters: rostrum very broad, as wide as head capsule; antennal scrobes fully visible in dorsal view; 3rd tarsomere with completely separated ventroterminal lobes (weakly separated in Brachysomus ); pretarsus with claws divergent from midlength (parallel-sided in Brachysomus ); median lobe similar in shape to Nanomias ; spermatheca, female abdominal sternite VIII and ovipositor showing morphology typical for Nanomias . Moreover, N. skodai resembles N. terricola in its life history: it inhabits xerothermic grassy habitats in association with Thymus and other subterranean taxa under stones. In contrast to Nanomias , most Brachysomus species occur in moderately humid habitats, particularly in leaf litter.

Type material. ROMANIA: Paratype ♀ (PBc) Alah Bair res. Baltagesti env., N 44.498262 E 28.21171, 2 May 2007, P. Białooki leg.

Distribution

Range-diversity plotting for all 508 cells reveals inverse proportionality between species richness and range size. Therefore, as the proportional range-size of the species occurring in a given cell increases the proportional speciesrichness in this cell decreases.

Range size. There are several clusters of endemicity with the maximum number of endemics occurring in the Balkan Peninsula. Several species have disjunct distributions. Thus, the Carpathian cluster demonstrates a remarkable pattern with both minimum average range-size and maximum proportional richness ( Figs. 233 , 234A ). The single island endemic, B. samos , is known exclusively from Greece ( Fig. 239B ).

Species richness. Heat mapping of species numbers shows that local richness varies from 1 to 5 species per cell. The maximum richness was detected at the eastern tip of the Alps (Vienna hotspot) and in the Southern Carpathians (Orsova hotspot), with five species per cell. Those spots both coincide with places where the Danube separates the Carpathians from the Alps and the Carpathians from the Balkan Mountains. A second group, with four species per cell is detected in Brasov (Southern Carpathians) and Kotor hotspots (Dinarides) ( Fig. 234B ).

Habitat preferences. Most Brachysomus species inhabit leaf litter in humid to xerothermic deciduous and mixed forests; several species occur in grass litter of subalpine and alpine meadows as well as in xerothermic grassland. For example, in the Western Caucasus the beetles inhabit humid and semixerothermic forests from sea level up to 2200 m a.s.l., but the majority inhabit forests at between 300–1500 m a.s.l. Brachysomus is absent from extremely wet forests, such as Buxus mossy forest or Fagus-Castanea-Rhododendron-Prunus laurocerasus forest in deep canyons, and from deserts and tundra.

Phenology. Adults of Brachysomus appear at the end of the spring or in early summer when leaf litter gets to be the appropriate wetness and temperature. Probably, there is a second period of adult activity during the autumnwinter rainy season in the Mediterranean biomes with warm-temperate, summer-arid climate.

Morphological trends of scale vestiture

Scale vestiture of Brachysomus reflects adaptations which appear in different lineages independently. It is strongly incongruent with the classification into subgenera and species groups, and with most of the other morphological characters, and thus likely also with phylogenetic relationships (which, however, are still quite unclear). More generalized species are densely covered with scales with a distinct metallic reflection and brownish scales forming an obscure maculate pattern on the prothorax and elytra. Typical habitats for those species are scattered shrublands and grasslands. Such scales are typical for presumable basal Brachysomus and mostly winged Polydrusini. Thus, scales with a metallic reflection are plesiomorphic for Brachysomus . In general apearance these species resemble Argoptochus Weise, 1883 and Foucartia .

Trend 1. ( Figs. 58, 60 ). Species resembling Trachyphloeus Germar, 1817 (Entiminae, Trachyphloeini ) in scale vestiture. The dorsal side of the head, body, legs, and antennal scape is densely covered with scales. The shape of the scales is extensively variable, but usually they are broad-ovate or round, thick, with a distinct spongy consistency (filled with air), and denticulate or excised apically. Their colour is grey-brown, without a metallic reflection, and quite uniform across the body (no spotty pattern). The spongy microstructure, with numerous furrows and channels, might be an adaptation for the absorption either of water or adherence of soil particles (author’s personal observations in the laboratory). The scale vestiture has a strong camouflaging effect (cryptic), whereby the beetles are very difficult to see in their native habitats (leaf/grass litter). Similar characteristics of the scale vestiture are also found in Archeophloeus Iablokoff-Khnzorian, 1959 (Sciaphilini) . These similarities are certainly homoplastic because all ‘trachyphloeoid’ Brachysomus species lack apomorphies characterizing Trachyphloeini , such as a sharply protruded V-shaped carina around the epistome, additional occurrence of asterisk-shaped scales, and antennal scrobe margins that diverge proximally to pass above and below the eye, often beyond it. Typical habitats are grass- and leaf-litter in xerothermic (Mediterranean) grasslands and bushlands; e.g., Brachysomus ponticus and B. commutatus .

Trend 2. ( Figs. 136-141 ). Species resembling Pseudoptochus Formánek, 1905 (Entiminae, Sciaphilini ). The integument is dark and heavily sclerotized. The scale vestiture comprises scattered, white, recumbent scales and also white, very long, slender, erect setae arranged in regular rows along the elytral interstriae and evenly covering the pronotum. The erect scales are spongy and distinctly longer than the interstrial width. These species inhabit scattered xerothermic deciduous forests and forest steppes; e.g. Brachysomus erinaceus and B. setiger .

Trend 3. ( Figs. 164-171 ). Species resembling Exomias Bedel, 1883 (Entiminae, Sciaphilini ). In these species the vestiture is sparse, consisting of light, recumbent to weakly erect hairs, or rarely hair-like gray scales, without a metallic reflection, and uniform in colour (not forming a spotty pattern). The integument is delicately sculptured, brownish, weakly pigmented. Typical habitats are humid biomes such as montane deciduous forests and the (sub)alpine zone; e.g., Brachysomus simplex and B. deceptorius .

Trend 4. ( Figs. 43-57 ). Species resembling Brachysomus kubanensis . In these species the vestiture is dense and consists of broad-lanceolate, brown, non-metallic scales, which usually form an obscure spotty pattern on the discal surfaces of the elytra and the pronotum. Typical habitat is leaf litter of temperate montane and submontane forests; e.g., Brachysomus ellipticus and B. albanicus .

Figures

FIGURE 232. Nanomias skodai comb. n., details: A, B: head, dorsal and ventral view; C: tarsus; D: spermatheca. Nanomias terricola: E: ventrites of female, F: spermatheca; G: abdominal sternite VIII; H: ovipositor; I: tarsus. Abbreviations: bc—bursa copulatrix, cxt—coxite, ds—ductus spermaticus, sp—spermatheca, vag—vagina.

FIGURE 233. Distribution analysis of Brachysomus: A: proportional range size vs. proportional richness; B: proportional range size vs. proportional richness by region.

FIGURE 234. Distribution analysis of Brachysomus: A: range size, B: species richness.

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

FIGURES 156–163. Brachysomus and Nanomias, details: 156, 157: Scaling of anterior margin of pronotum, indicated by arrow: 156: B. mikati. 157: B. albanicus. 158: Nanomias skodai. 159: idem, head dorsal view. 160: idem, head lateral view. 161: B. merkli, male. 162: idem, head dorsal view. 163: idem, head lateral view.

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 136–141. Brachysomus, main view. 136: B. erinaceus, male. 137: B. erinaceus, female. 138: B. setiger, male. 139: B. setiger, female. 140: B. hegyessyi, male. 141: B. hegyessyi, female.

FIGURES 164–172. Brachysomus, details: 164: B. deceptorius, male. 165: simplex, female. 166: B. longipterus, male. 167: idem, female. 168: B. deceptorius, male head dorsal view. 169: simplex female. 170: B. deceptorius, male head lateral view. 171: B. longipterus, male head dorsal view.

FIGURES 43–50. Brachysomus, dorsal habitus: 43: B. transsylvanicus. 44: B. carpathicus female. 45: B. laticollis. 46: B. carpathicus male. 47: B. ellipticus. 48: B. kubanensis. 49: B. verae. 50: B. kovali.

FIGURES 51–56. Brachysomus, dorsal habitus: 51: B. oertzeni (lectotype) 52: B. moczarskii, female. 53: B. assingi, 54: B. moczarskii, male, 55: B. curvimanus. 56: B. fallax.