Exochomoscirtes picturatus, Ruta & Yoshitomi, 2010

Ruta, Rafał & Yoshitomi, Hiroyuki, 2010, Revision of the genus Exochomoscirtes Pic (Coleoptera: Scirtidae: Scirtinae) 2598, Zootaxa 2598 (1), pp. 1-80 : 27-29

Exochomoscirtes picturatus sp. nov.

( Figs. 1D–E , 2A–B , 3E , 11F–I , 20 , 21 )

Type material. Holotype, male ( NMW): “ MALAYSIA – Sabah prov. / Banjaran Crocker Mts. / GUNUNG ALAB peak / 30.IV.–27.V.1996, 1650– 1800m / M. Štrba & R. Hergovits leg.” [printed label] . Paratypes. 2 males, 1 female ( NMW): same data as holotype . 1 male, 3 females ( DBET): “ MALAYSIA, Sabah prov. / Banjaran Crocker Mts. / GUNUNG ALAB peak 30 IV –27 V / 1996, 1650– 1800m / M. Štrba & R. Hergovits leg.” [printed label]. Female ( NHM): “N BORNEO / Mt. Kinabalu ” [printed label]; “Pinosuk Plateau. / 19– 28.iii.1964. / 5, 225ft. ” [printed label]; “Royal.Soc.Exped. / coll. S. Kueh. / B.M. 1964-250” [printed label] .

Diagnosis. Specimens with tricolor dorsal pattern cannot be mistaken with any other known Exochomoscirtes . Rare forms with black & red pattern can be distinguished from related species by the peculiar dorsal metatibial spur in the male which is somewhat similar to the one in E. dilaticornis sp. nov. and E. takizawai sp. nov.

Description. Holotype, male. Body hemispherical, TL/EW 1.2, convex, covered with yellow suberect setae. Head black with brownish anterior margin of clypeus, pronotum black, elytra with color pattern. Posterior portion of elytra, humeri, and oval macula in adsutural portion of anterior half of elytra black. Remaining parts of elytra yellow and orange. Legs light brown. Mouthparts brownish, antennomeres 1–3 yellowish, 4–11 black.

Head with distinct punctation, punctures separated by ca. 1.0 diameter. Eyes big, protuberant; head 1.7 X wider than interocular space. Antennae filiform, reaching basal 1/3 of elytra. Antennomere 1 cylindrical, curved, antennomere 2 short, globular, antennomere 3 distinctly longer than antennomere 2, narrow, antennomere 4–10 1.5 X longer than antennomere 3, apical antennomere ca. 1.5 X longer than preapical one. Palpomeres of maxillary palpi moderately wide.

Pronotum small, slightly convex, covered with distinct punctation, punctures separated by 1.0–2.0 diameters, anterolateral corners almost rectangular, somewhat obtuse, projecting anteriorly; lateral margins straight; posterolateral corners acute; base of pronotum subtrapezoidal, with incomplete margination along basal margin; PW/PL 2.8. Scutellum relatively big, punctured as on pronotum, equilaterally triangular. Angle between pronotum and elytra not marked in dorsal outline.

Elytra oval, with distinctly explanate lateral margins, widest in the middle, punctation stronger than on pronotum, punctures separated by 1.0–2.0 diameters; humeri well marked; EL/EW 1.1; EL/PL 5.2; EW/PW 1.6.

Legs moderately long. Hind tibial spurs well developed, dorsal one elongate, apex modified – widened and tridentate, 0.9 X as long as tarsomere 1 and slightly longer than ventral spur. Ventral spur almost straight, somewhat shorter than tarsomere 1. Apex of dorsal spur widened, hooked, trifid apically.

Ventrites 1 and 2 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 9 (L 0.72, W 0.30) subtriangular, apodemes fused basally, apex deeply emarginated, with a few apical setae. Tergite 8 (L 1.38, W 0.50) moderately sclerotized, apical portion small, deeply and narrowly emarginated, with arcuate apex, bearing row of short setae on apical margin, with a pair of very long apodemes diverging basally; tergite 9 (L 0.84, W 0.56) moderately sclerotized, apical portion small, with minute setae at apex, with a pair of long apodemes diverging basally. Tegmen (L 0.78, W 0.61) well sclerotized, parameres straight, widening apically, inwardly pointed at apices, mesal process very narrow and short, much shorter than parameres. Penis (L 0.39, W 0.09) small, moderately sclerotized, pala very narrow and elongate, apical process evenly shorter than pala.

Female. Metatibial spurs unmodified, dorsal spur almost straight, slightly shorter than tarsomere 1, ventral spur half as long as dorsal one. Dorsal pattern lighter (see: variability). Prehensor tubular, narrow and moderately long.

Variability. TL/EW in males 1.2, TL/EW in females 1.2–1.3 (1.3). Dorsal pattern extremely variable. Males with black pronotum and usually tricolor elytral pattern: humeral portion, postscutellar macula and posterior portion of elytra black, stripes connecting black maculae orange, remaining area yellow. One specimen is dark with bicolor elytra, each elytron black with two orange maculae: an oval basal one and a transversely oval one in the middle of the elytra. Females with pronotum yellow to brown, elytra orange with black pattern consisting of humeral maculae, postscutellar macula and transverse stripe in posterior portion of elytra. One female specimen (coll. NHM) is darker, anterior 2/3 of elytra are brownish-black with oval orange macula in basal portion of elytra and transversely oval macula in the middle length of elytra, posterior 1/3 of elytra orange. Several color variations are shown on Figs. 11F–I .

Measurements. Males (n = 4): TL 3.78–4.50 (4.25), PL 0.65–0.80 (0.73), PW 1.85–2.35 (2.13), EL 3.40– 4.15 (3.83), EW 3.13–3.70 (3.50). Females (n = 4): TL 4.00–4.27 (4.17), PL 0.70–0.75 (0.74), PW 1.95–2.13 (2.08), EL 3.68–3.92 (3.81), EW 3.20–3.40 (3.28).

Distribution. Borneo.

Etymology: Lat. picturatus = painted, from colorful pattern on elytra.

Figures

FIGURE 1. Morphological details of Exochomoscirtes. A) Exochomoscirtes rufomaculatus Pic, labium; B) Exochomoscirtes rufomaculatus Pic, maxilla; C) Exochomoscirtes rufomaculatus Pic, mandible; D) Exochomoscirtes picturatus sp. nov., meso- and metaventrite; E) Exochomoscirtes picturatus sp. nov., meso- and metaventrite, closeup; F) Exochomoscirtes maculatus (Waterhouse), wing; G) Exochomoscirtes dilaticornis sp. nov., wing.

FIGURE 2. Exochomoscirtes picturatus sp. nov., maxilla. A) male; B) female.

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 11. Habitus illustrations of Exochomoscirtes. A) E. bimaculatus Pic; B) E. basipunctatus sp. nov.; C) E. binotatus Pic; D) E. rufomaculatus Pic; E) E. ephippiatus (Champion); F)–I) E. picturatus sp. nov., color forms; J)–L) E. takizawai sp. nov., color forms; M) E. tetrastigma (Champion). Scale bar = 2.0 mm.

FIGURE 20. Exochomoscirtes picturatus sp. nov., male. A) sternite 9; B) tergite 8; C) tergite 9; D) aedeagus. Scale bar = 0.5 mm.

FIGURE 21. Exochomoscirtes picturatus sp. nov., female A)–B) prehensor and bursal sclerite.