Dactylosternum frater Mai et Jia 2022, sp. nov.
Creators: name: Mai, Zuqi
name: Hu, Jian
name: Minoshima, Yûsuke N.
name: Jia, Fenglong
name: Fikáček, Martin
Publisher: name: Zenodo
Year: 2022
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Coleoptera
Hydrophilidae
Dactylosternum
Dactylosternum frater

description: Dactylosternum frater Mai et Jia, sp. nov.
(Figs. 10, 26, 55, 59, 63)
Type material examined. HOLOTYPE: male (SYSU), Yunnan, Honghe Autonomous Prefecture, Luchun County, Pinghe Village, 28.VII.2004, Jing Li & Caixia Yuan leg.
Diagnosis. Length 7.1 mm. Body oval, anterior half of elytra nearly parallel-sided (Fig. 10), moderately convex. Dorsal black, surface with densely arranged fine punctures, comparatively shiny. Anterior margin of clypeus without marginal rim. Antenna yellow-brown, club compact. Elytron with sutural stria and ten distinct rows of serial punctures, all nearly reaching elytral base. Anteromedial portion of metaventral process with a slightly drepressed pit (Fig. 59). Posterior margin of ventrite 5 without marginal bead (Fig. 63). Aedeagus (Fig. 26): Phallobase shorter than parameres. Parameres slightly sinuate on outer margin. Median lobe a little shorter than parameres, apex pointed; gonopore situated apically.
Description. Total length 7.1 mm; maximum width 4.1 mm; body oval, moderately convex.
Coloration. Dorsal black, with lateral margin of elytron reddish brown (Fig. 10). Maxillary palps and antenna yellowish brown. Ventral black, legs reddish brown.
Head. Clypeus weakly convex, surface with dense and fine punctures, anterior portion with denser punctures. Interstices between punctures smooth. Anterior margin of clypeus without marginal rim. Frons with punctures sparser than those on clypeus. Eyes of moderate size, separated by ca. 5× as wide as one eye, distinctly emarginate anteriorly in lateral view, smooth medially. Maxilla with glabrous basistipes. Mentum transverse, glabrous, strongly impressed anteromedially, lateral sides with series of fine setae. Submentum reddish brown, pubescent. Labial palps rather stout, palpomere 1 minute, palpomere 2 strongly widened distally, with dense brush of long yellow setae on its inner face and distal margin, palpomere 3 longest. Antennal scapus longest, rather thick, ca. 7.5× as long as pedicellus, antennomere 3 thin and a little shorter than pedicellus, antennomeres 4 and 5 almost equal in length, slightly widening distally, club densely pubescent, with few long setae, compact, ca. 2.5× as long as wide.
Prothorax. Pronotum moderately convex, widest basally, arcuately narrowed in front, with punctures sparser than those on vertex intervals without microculpture, posterior margin slightly arcuate. Prosternum strongly tectiform, with median carina and a distinct tooth anteromedially.
Meso- and metathorax. Scutellum distinctly longer than wide, apex rounded, in shape of isosceles triangle, with punctures similar to those on pronotum. Elytron moderately convex, sutural stria deeply impressed in posterior half; each elytron with 10 longitudinal serial punctures, deeply impressed in posterior half, intervals with fine ground punctures, each puncture with two short transverse lines especially in posterior half (Fig. 55), series 3+4 and 6+7 linked together subposteriorly, other serial punctures reaching end of elytron, lateral four series with punctures larger and deeper than the inner six series. Anteromedial portion of metaventral process slightly depressed (Fig. 59).
Legs. Reddish brown, rather short. Procoxae globular, pubescent; profemora without pubescence ventrally; protarsomeres not pubescent ventrally. Ventral surface of meso- and metafemora without pubescence, with sparse punctures and microsculpture; meso- and metatarsomeres with sparse pubescence ventrally, almost equal in length.
Abdomen. Pubescent, ventrite 1 with complete median carina, other ventrites uniformly convex. Posteromedial portion of ventrite 5 not pubescent, with fine punctures, posterior margin of ventrite 5 rounded, without marginal bead and stria (Fig. 62).
Male genitalia (Fig. 26). Aedeagus 1.26 mm long, ca. 3.2× as long as wide. Phallobase shorter than parameres, with short, rounded manubrium posteriorly. Parameres slightly curved inwards apically, pointed at apex, slightly sinuate on outer margin. Median lobe ca. 0.8× as long as parameres, widest in the basal 0.25, gradually narrowing towards apex, pointed apically; ventral plate slender, widest basally, almost parallel-sided in apical half (Fig. 26c). Gonopore triangular, reaching subapical of median lobe.
Etymology. This new species is derived from the Latin adjective frater, meaning a brother, reflecting that this species is very similar to the other three species in China: Dactylosternum salvazai Orchymont, 1925, D. pseudolatum sp. nov. and D. latum (Sharp, 1873).
Biology. Unknown.
Remarks. This species is very similar to Dactylosternum latum (Sharp). It can be distinguished from the latter by anteromedial portion of metaventral process slightly drepressed pit (Fig. 59) (with a strongly depressed pit in D. latum (Fig. 58)), gonopore reaching apical of median lobe (Fig. 26) (gonopore reaching ca. 0.8 of median lobe in D. latum (Figs. 30–38))
Distribution. China (Yunnan).
description: Published as part of Mai, Zuqi, Hu, Jian, Minoshima, Yûsuke N., Jia, Fenglong & Fikáček, Martin, 2022, Review of Dactylosternum Wollaston, 1854 from China and Japan (Coleoptera, Hydrophilidae, Sphaeridiinae), pp. 269-300 in Zootaxa 5091 (2) on pages 293-294, DOI: 10.11646/zootaxa.5091.2.3, http://zenodo.org/record/5843837