Cotasterosoma coronus, Grebennikov, Vasily V. & Morimoto, Katsura, 2016

Grebennikov, Vasily V. & Morimoto, Katsura, 2016, Flightless litter-dwelling Cotasterosoma (Coleoptera: Curculionidae: Cossoninae) found outside of Japan, with mtDNA phylogeography of a new species from Southwest China, Zootaxa 4179 (1), pp. 133-138 : 135-136

Cotasterosoma coronus sp.n.

Figs 1–3 .

Diagnosis. This species differs from the type species by having six (not seven, but see Discussion) antennomeres in antennal funicle and by the lack of any signs of minute spicules in the internal sac of the aedeagus ( Figs. 1 E–F; they are present in the type species and seemingly all congeners from Japan seen by the second author).

Description. Holotype, male ( Figs 1 A–H). GenBank accession: HQ987058 . Length: 2.0 mm (from anterior margin on pronotum to elytral apex). With characters of the genus given above; antennal funicle with 6 antennomeres. Intraspecific variation. Females are similar to males ( Figs 2 A–K); GenBank accessions as in Fig. 3 . Length: 1.74–2.2 mm.

Material examined. Holotype (in IZCAS): “P.R. CHINA, Yunnan, E slope Cangshan at Dali , N25°40′ 15.1″ E100°07′ 39.9″, 10.v.2010, 2711m, sifting04, V.Grebennikov ”, “CNCCOLVG00000787” . Paratypes (in CNC, IZCAS; specimen numbers as in Fig. 3 ): 12 exx in total: five from Cang Shan Mountain Range in Yunnan (collected in 2010 and 2011) and six from Mount Emei in Sichuan (collected in 2010 and 2011). Additional specimens (collected in 2008–11): 30 exx in total, 18 from Cang Shan and 12 from Mount Emei .

Distribution. This species is known from two localities separated by about 530 km: eastern slope of Cang Shan Mountain Range in Yunnan (2600–2764 m) and Mount Emei in Sichuan, Southwest China (1829–2440 m) ( Fig. 3 ).

Biology. Adults of this species have been repeatedly discovered by sifting wet litter in deciduous forests in the midaltitude zone. Host plants or immature stages are unknown.

Etymology. The species epithet is the Latinized Greek mythical name of Coronus , an Argonaut; his son Leonteus was Helene's suitor and fought in the Trojan War. It is a noun in apposition.

Results of DNA analysis. Phylogeographic analysis grouped 13 mtDNA sequences from specimens of C. coronus sp.n. in two geographical clusters diverging about 2.45 Mya ( Fig. 3 ). Unlike the Cang Shan population homogenous in its mtDNA, that on Mount Emei is formed by two sister lineages diverging about 1.53 Mya ( Fig. 3 ).

Figures

FIGURE 1. Cotasterosoma coronus sp. n., holotype, male. A – D: habitus; E: genitalia and abdominal tergites 7 and 8, ventral; F – H: genitalia (F: dorsal, G: ventral, H: lateral).

FIGURE 2. Cotasterosoma coronus sp. n., paratype, female, specimen # 1110 from Mt. Emei. A – D: habitus; E – F: head and prothorax (E: ventral, F: lateral); G – I: distal part of right legs (G: fore-, H: mid-, I: hind-); J: genitalia, ventral; K: spermatheca.

FIGURE 3. Distribution of both named species of Cotasterosoma and ultrametric time tree obtained from BEAST analysis to date evolutionary events of C. coronus sp. n. First four digits of terminals denote specimen number, followed by a GenBank accession number. Note that the population on Mount Emei consists of two discrete mtDNA lineages separated by about 1.53 Mya.