Zyras (Zyras) russiceps Assing 2017, spec. nov.

Zyras (Zyras) russiceps spec. nov.

urn:lsid:zoobank.org:act: 0F8B55FE-9FAD-4393-8C10-94FBC35FCD77

(Figs 14, 61, 114, 187–190)

Type material: Holotype ♂: “W. THAILAND: 300 m., Thung Yai Wildlife Sanctuary. 15°28'N – 98°48'E. / Tak Province, Umphang District, Song Bae Stream. 18–27.iv.1988. / Evergreen rain forest. M.J.D. Brendell. B.M. 1988-183 / / Holotypus ♂ Zyras russiceps sp. n. det. V. Assing 2016” (BMNH). Paratypes: 2 ♂♂: same data as holotype (BMNH, cAss); 1 ♂: “ MALAYSIA: Selangor, Ulu Gombak Field Studies Centre (250 m), 2–18.III.2004 (FIT), Maruyama M. et al.” (cMar).

Etymology: The specific epithet is a noun in apposition and alludes to the distinctive coloration of the head (russus: red).

Description: Rather large species; body length 7.5–8.3 mm; length of forebody 3.3–3.4 mm. Coloration (Figs 14, 61, 114) distinctive: head and pronotum reddish; elytra blackish-brown to black, with only the anterior margin (visible in antero-dorsal view) narrowly reddish; abdomen bicoloured: tergites II–V reddish, VI reddish with the median portion extensively black, and VII–VIII blackish except for the reddish antero-lateral portions, segments IX–X brownish; legs pale-yellowish; antennae black with the basal two antennomeres reddish to reddish-brown and the apical 2–4 antennomeres pale-yellow to dark-yellow, more or less sharply contrasting with the black preceding antennomeres; maxillary palpi reddish with the terminal palpomere yellowish.

Head (Fig. 61) distinctly transverse, middle and anterior portion extensively impunctate; punctation in lateral and posterior dorsal portions sparse and rather coarse. Eyes very large, nearly twice as long as postocular region in dorsal view. Antenna (Fig. 14) 2.5–2.6 mm long; antennomeres IV–V weakly oblong, VI approximately as broad as long, VII–X of gradually increasing width and increasingly transverse, X approximately 1.5 times as broad as long, and XI approximately as long as the combined length of IX and X.

Pronotum (Fig. 61) approximately 1.15 times as broad as long and 1.3 times as broad as head, broadest near anterior angles, distinctly tapering posteriad; lateral margins straight in posterior two-thirds (dorsal view); punctation coarse and nearly regularly distributed, with or without impunctate patches in antero-lateral portion; impunctate median band narrow or indistinct; lateral margins each with five long black setae, antero-lateral portion of disc with several additional long black setae.

Elytra (Fig. 61) approximately 0.8 times as long as pronotum; punctation very coarse and very dense, slightly sparser at posterior margin; interstices much narrower than diameter of punctures (except at posterior margin). Hind wings fully developed. Metatarsomere I elongate, slightly longer than the combined length of II–IV.

Abdomen (Fig. 114) approximately as broad as elytra, with moderately deep anterior impressions on tergites III–V; anterior impressions of tergites III–V each with a row of non-setiferous punctures; tergite III with a lateral setiferous puncture on either side, with or without scattered additional setiferous punctures on disc, and with approximately twelve setiferous punctures at posterior margin; tergite IV with a transverse row of approximately eight setiferous punctures across disc and with 14 setiferous punctures at posterior margin; tergite V with a transverse row of approximately ten setiferous punctures across disc and with 12–16 setiferous punctures at posterior margin; tergite VI with a transverse band of numerous non-setiferous punctures anteriorly, with a transverse row of 10–12 setiferous punctures across disc and with 12–14 setiferous punctures at posterior margin; tergite VII with a broad transverse band of numerous non-setiferous punctures in anterior portion, and with two transverse series of setiferous punctures each composed of 10–14 punctures in posterior portion, posterior margin with palisade fringe; tergite VIII (Fig. 189) with numerous long black setae in posterior third, posterior margin convex or obtusely pointed in the middle, without median concavity; sternites III–VIII with numerous long dark setae in posterior portion.

♂: sternite VIII (Fig. 190) with strongly convex posterior margin and with numerous long black setae in posterior half; median lobe of aedeagus (Figs 187–188) 0.98 mm long; ventral process apically acute both in lateral and in ventral view, subapically abruptly bent; paramere as long as median lobe and with conspicuously short apical lobe.

Comparative notes: Zyras russiceps belongs to the Z. hirtus group, as can be inferred from the chaetotaxy of the body, the morphology of the median lobe of the aedeagus, and the short apical lobe of the paramere. It is distinguished from other species of this group recorded from Thailand and adjacent regions by the distinctive coloration (particularly of the head) alone. In addition, it is characterized by the conspicuously dense and coarse punctation of the elytra, by the punctation pattern of the abdomen, and by the shape of the median lobe of the aedeagus.

Distribution and natural history: The known distribution is confined to the type locality in West Thailand and one locality in Selangor, Peninsular Malaysia. The specimens from Thailand were probably collected on the wing (Malaise trap?) in an evergreen rain forest at an altitude of 300 m, the paratype from Malaysia was taken with a flight interception trap at 250 m, in both cases together with several other species of Zyras sensu strictu.