Jung-Chan Chen olive leaf beetle (Argopistes jungchani), Mei-Hua Tsou (A. tsoui) and Su-Fang Yu (A. yuae)
NEWS - Three species from Taiwan were described, Jung-Chan Chen olive leaf beetle (Argopistes jungchani sp. nov.), Mei-Hua Tsou olive leaf beetle (Argopistes tsoui sp. nov.) and Su-Fang Yu olive leaf beetle (Argopistes yuae sp. nov.) along with 4 species were redescribed: A. biplagiatus Motschulsky 1860, A. rufus Chen 1934, A. tsekooni Chen 1934 and A. unicolor Jacoby 1885.
This study proposes that A. rufus Chen 1934 stat. nov. be elevated to species status from variety of A. biplagiatus Motschulsky 1860. A. coccinelliformis Csiki 1940 syn. nov. and A. ryukyuensis Shigetoh & Suenaga 2022 syn. nov. as a junior synonym of A. rufus Chen 1934 Lectotypes assigned to A. undecimmaculata Jacoby 1885, A. unicolor Jacoby 1885 and A. biplagiatus var. Rufus Chen 1934.
A. jungchani is named after Jung-Chan Chen (陳榮章), the first person to collect specimens. Distribution is known only from the type locality. Adults are easily recognized by color pattern. Body black with yellowish brown lateral edges of pronotum and elytra.
Genital characters are diagnostic: apex of aedeagus tubular, but parallel-sided from near apex to middle (vs. narrowing apically from near apex to middle in A. tsekooni). Paired elongate tectum small, 0.76 of anterior aperture (vs. paired elongate tectum long, 0.85 of anterior aperture in A. tsekooni).
Anterior aperture from apex 1/13–2/5 (vs. anterior aperture from apex to apex 2/5 in A. tsekooni). Only two pairs of long setae on apical margin of VIII ventrite of abdomen in females (vs. more than two pairs of setae on apical margin of VIII ventrite in females of other species) and cylindrical gonocoxae.
A. tsoui hosts Osmanthus heterophyllus, O. kaoi, O. enervius and O. fragrans. The species appears to be univoltine. Larvae were only found in late March. Epithet after Mei-Hua Tsou (曹美華), the first person to collect specimens. Widespread distribution in lowland Taiwan.
Adults have reddish brown elytra with broad black lateral margins, but differ in reddish brown pronotum with broad black lateral margins (vs. entire pronotum black in A. biplagiatus). Diagnostic genital characters include pointed apex of aedeagus (vs. relatively narrower in lateral view in A. biplagiatus).
Longer, longitudinal paired sclerites of tectum (vs. short, curved paired sclerites of tectum in A. biplagiatus), anterior opening from apical 1/10 to midline (vs. anterior opening from apex to apical 3/10 in A. biplagiatus).
Gonocoxae triangular, but extend inward on basal 1/3 (vs. extend outward on basal 1/3 in A. rufus). Setae dense along apical edge of VIIIth ventrite of abdomen, but much denser and shorter (vs. less dense and longer setae on apical edge of VIIIth ventrite of abdomen in A. biplagiatus).
A. yuae hosts Chionanthus ramiflorus Roxb. This species appears to be univoltine. Larvae were found only in late March. Epithet after Su-Fang Yu (余素芳), the first person to collect the specimen. Distribution is endemic to Lanyu Island.
Adults are inseparable from A. rufus except by genital characters, including parallel-sided apex of the aedeagus with anterior opening very close to the apex of the aedeagus, from 1/12–3/5 apical (vs. apically narrowed aedeagus with anterior opening not so close to the apex of the aedeagus, from 1/8–3/5 apical in A. rufus).
The apical margin of the VIII ventrite of the abdomen is deeply notched in females (vs. the apical margin of the VIII ventrite of the abdomen is shallowly notched in females of A. rufus). The new species is restricted to Lanyu Island and is geographically isolated from other species. Larvae and adults feed on leaves of C. ramiflorus but not O. fragrans. Thus, both species are ecologically allopatric because O. fragrans is one of the host plants for A. rufus.
Original research
Lee C-F, Chiang M-Y, Suenaga H (2024). The genus Argopistes Motschulsky from Japan and Taiwan, with descriptions of three new species from Taiwan (Coleoptera, Chrysomelidae, Galerucinae, Alticini). ZooKeys 1215: 151-183, DOI:10.3897/zookeys.1215.134871
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