Exochomoscirtes longispinus, Ruta & Yoshitomi, 2010

Ruta, Rafał & Yoshitomi, Hiroyuki, 2010, Revision of the genus Exochomoscirtes Pic (Coleoptera: Scirtidae: Scirtinae) 2598, Zootaxa 2598 (1), pp. 1-80 : 69-70

Exochomoscirtes longispinus sp. nov.

( Figs. 3C , 14C , 56 )

Type material. Holotype, male ( NHM): “ BRUNEI; x-1992 / Temburong District / Ridge NE of Kuala / Belalong , 300m. ” [printed label]; “125W MV Light Trap / J H Martin coll. / BMNH(E)1992-172” [printed label].

Diagnosis. Similar to several uniformly brown species, from which it can be distinguished by the presence of a long, hooked, dorsal metatibial spur ( Fig. 3C ) in the males. Another distinctive feature is extraordinarily elongated penis.

Description. Holotype, male. Body oval, TL/EW 1.3, slightly convex, covered with yellow suberect setae. Head dark brown, with lightened posterior margin, pronotum, scutellum and elytra brown, elytra with subtly darkened lateral and apical margins. Antennae and mouthparts yellowish-brown, legs yellowish-brown, metafemora darkened, dark brown.

Head with distinct punctation, punctures separated by ca. 1.0 diameter. Eyes big, protuberant; head twice width of interocular space. Antennae filiform, reaching basal 1/3 of elytra. Antennomeres 2 and 3 of subequal lengths, antennomeres 4–11 as long as antennomeres 2 and 3 combined. Palpomeres of maxillary palpi moderately widened.

Pronotum slightly convex, covered with distinct punctation, punctures separated by 1.0–2.0 diameters, anterolateral corners almost right-angled, projecting anteriorly; lateral margins straight; posterolateral corners acute; base of pronotum subtrapezoidal, with incomplete margination along basal margin; PW/PL 0.4. Scutellum relatively big, punctured as on pronotum, equilaterally triangular. Angle between pronotum and elytra not marked in dorsal outline.

Elytra oval, stronger diverging in posterior half, than in anterior portion, with slightly explanate lateral margins, widest at basal 1/3, punctation stronger and denser than on pronotum, punctures separated by ca. 1.0 diameter; humeri well marked; EL/EW 1.1; EL/PL 4.6; EW/PW 1.4.

Legs moderately long. Hind tibial spurs well developed, dorsal one extremely elongated, almost twice as long as ventral one, curved; ventral almost straight, slightly shorter than tarsomere 1.

Ventrite 1 with sparse setation in mesal portion, ventrite 2 with basal row of big punctures. Apex of tergite 7 unmodified, apex of ventrite 5 truncate.

Sternite 8 (L 0.22, W 0.18) small, widely U-shaped; sternite 9 (L 0.59, W 0.33) consisting of two subtriangular hemisternites, with a row of very short apical setae. Tergite 8 (L 1.47, W 0.80) moderately sclerotized, bearing row of short setae on apical margin, with a pair of extraordinarily elongated apodemes diverging basally; tergite 9 (L 0.73, W 0.45) moderately sclerotized, apical portion small, with minute setae at apex, with a pair of moderately long apodemes diverging basally. Tegmen (L 0.70, W 0.58) well sclerotized, parameres straight, widening apically, with oval apical portions, mesal process narrow and slightly shorter than parameres. Penis (L 0.75, W 0.15) relatively long, moderately sclerotized, pala oval, transforming apically into elongated narrow process pointed at apex.

Female unknown.

Measurements. Male (n = 1): TL 3.78, PL 0.70, PW 2.02, EL 3.20, EW 2.90.

Distribution. Kuala Belalong, Borneo.

Etymology. Specific epithet refers to extremely elongated dorsal metatibial spur.

Figures

FIGURE 3. Metatibial spurs in Exochomoscirtes. A) E. dilaticornis sp. nov.; B) E. discoidalis (Pic); C) E. longispinus sp. nov.; D) E. nigromarginatus sp. nov.; E) E. picturatus sp. nov.; F) E. takizawai sp. nov.

FIGURE 14. Habitus illustrations of Exochomoscirtes. A) E. dilaticornis sp. nov., female; B) E. pectinatus sp. nov.; C) E. longispinus sp. nov.; D) E. nipponicus sp. nov.; E) E. nahangensis sp. nov.; F) E. arunachalensis sp. nov.; G) E. meghalayensis sp. nov. Scale bar = 2.0 mm.

FIGURE 56. Exochomoscirtes longispinus sp. nov., male. A) sternite 8; B) sternite 9; C) tergite 8; D) tergite 9; E) tegmen; F) penis. Scale bar = 0.5 mm.