Exochomoscirtes discoidalis (Pic, 1918) Ruta & Yoshitomi, 2010

Ruta, Rafał & Yoshitomi, Hiroyuki, 2010, Revision of the genus Exochomoscirtes Pic (Coleoptera: Scirtidae: Scirtinae) 2598, Zootaxa 2598 (1), pp. 1-80 : 50-52

Exochomoscirtes discoidalis (Pic, 1918) comb. nov.

Ora discoidalis Pic, 1918: 16

( Figs. 3B , 4B , 13B–C , 40 , 41 )

Type material. Holotype, female ( MNHN): “Java orient. / Montes Tengger / 4000’ 1890 / H. Fruhstorfer ” [blue label, printed]; “type” [yellowish label, handwritten]; “TYPE” [red label, typed]; “ Ora / discoidalis / Pic” [handwritten by Pic].

Additional material studied. Female ( NHM): “MALAYSIA-Pahang 350–550m / 20km NE Raub, Lata Jarom / Gg. Benom 19.– 22.2.1995 / leg. M. Strba & R. Hergovits ” [printed label]. Female ( ZMAN): “Boekit Gabah / Z. W. K. Sumatra / Leg. H. Lucht / 12.1918” [printed label]; “coll. F. C. / DRESCHER” [printed]. Female ( MIZ): “Java, Bogor, Ogród [garden] / Botaniczny [botanical] 21.IV.1959 / leg. B. Pisarski / et J. Prószy ṅski” [printed label]; “ Inst. Zool. P.A.N. Warszawa / 58-59” [printed label]. Female ( ITBC): “Poring, Ranau, / Sabah, Borneo, / Malaysia / 12.III.2009 / H. Takizawa leg.” [printed label]. Female ( ITBC): “Pulau Gaya, Kota / Kinabalu, Sabah / Borneo, Malaysia / 28.III.2008 / H. Takizawa leg.” [printed label]. Male ( ZMAN): “Boekit Gabah / Z. W. K. Sumatra / Leg. H. Lucht / 12. 1918” [printed & handwritten label]; “coll. F. C. / DRESCHER” [printed label]. Male ( NHMB): “ SUMATRA (W.), G. Singga- /lang S of BUKITTINGI / 14.–16.II.1991, 1300m / Bocák & Bocáková lgt.” [printed label]. Male ( NHMB): “ SUMATRA: LAM- PUNG prov.: / Bukit Barisan Selatan N. P., / 5 km SW LIWA; 5°4’ S 104°4’ E; / L. Dembický leg., 21.iii.2003; 600m ” [printed label]. 3 males, 2 females ( EUM): “Kabun Raya, / Bogor, Indonesia / C. H. S. Watts / April 2000 ” [printed label]. Female ( EUM): “Urung Tama / Sibolangit / E. Sumatra / 17–18.IX.1998 / H. Takizawa leg.” [printed label] .

Diagnosis. Species with peculiar sexual dichroism. Elytra of males are unicolored brownish-black, elytra of females are black with a wide orange to red sutural stripe. Dorsal metatibial spur of males is long, thin and distictly hooked, unlike in the other species of the genus.

Redescription (based on the specimen from Java ex coll. MIZ). Body hemispherical, TL/EW 1.3, moderately convex, covered with yellowish suberect setae. Head brown, pronotum and scutellum orange, elytra brownish-black with orange suture. Antennae yellowish, legs yellowish-brown.

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,

antennomeres 2 and 3 of subequal lengths, antennomeres 4–10 1.5 X longer than antennomere 3, subtriangular, apical antennomere absent in studied specimens. Palpomeres of maxillary palpi very wide.

Pronotum small, slightly convex, covered with distinct punctation, punctures separated by 1.0–1.5 diameters, anterolateral corners blunt, somewhat obtuse, slightly projecting anteriorly; lateral margins almost straight; posterolateral corners acute; base of pronotum subtrapezoidal, with complete margination along basal margin; PW/PL 2.9. Scutellum relatively big, punctured as on pronotum, equilaterally triangular. Angle between pronotum and elytra not marked in dorsal outline.

Elytra oval, with subtly explanate lateral margins, widest in the anterior 1/3, punctation stronger than on pronotum, punctures separated by ca. 1.0 diameter; humeri subtly marked; EL/EW 1.2; EL/PL 4.5; EW/PW 1.4.

Legs moderately long. Hind tibial spurs well developed, dorsal one almost straight, as long as tarsomere 1 and twice as long as ventral spur. Ventral spur is slightly curved.

Ventrite 1 with sparse setation in mesal portion, ventrite 2 with basal row of big punctures. Apex of ventrite 5 regularly rounded.

Prehensor long (L 1.20), narrow and sinuate, bursal sclerite relatively large (L 0.50, W 0.18), consisting of two plates, elongate, with bifid basal portion. Duct connecting prehensor with bursal sclerite accordionfolded.

Male. Head brown, pronotum and scutellum red, elytra black. Mouthparts, antennae and legs yellowishbrown, with the exception of metafemora which are dark brown.

Legs moderately long. Hind tibial spurs well developed, dorsal spur modified, elongated, longer than tarsomere 1 and curved apically. Ventral spur 0.7 X as long as tarsomere 1, almost straight.

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 shallowly emarginated, sinuate, with two small projections.

Sternite 9 (L 0.57, W 0.47) consisting of subtriangular paired plates with relatively long apical setae. Tergite 8 (L 0.93, W 0.60) moderately sclerotized, trapezoidal, bearing row of short setae on apical margin, with a pair of relatively long apodemes; tergite 9 (L 0.59, W 0.60) moderately sclerotized, apical portion narrow, with minute setae at apex, with a pair of long basally diverging apodemes. Tegmen (L 0.87, W 0.56) well sclerotized, basal part semicircular; parameres long, subparallel, relatively wide, widened and inwardly hooked at apices; apices subtriangular. Mesal process very narrow, slightly widened at apex, a bit longer than parameres. Penis (L 0.63, W 0.23) with elongate pala and narrow apical process, which is distinctly shorter than pala.

Variability. Males TL/EW 1.2–1.3 (1.2), females TL/EW 1.3.

Measurements. Males (n = 3): TL 2.53–3.73 (3.20), PL 0.50–0.75 (0.63), PW 1.47–2.05 (1.79), EL 2.12– 3.15 (2.77), EW 2.08–2.95 (2.58). Females (n = 3): TL 3.15–3.75 (3.43), PL 0.58–0.73 (0.65), PW 1.74–2.10 (1.90), EL 2.80–3.10 (2.95), EW 2.42–2.90 (2.62).

Distribution. Java, Sumatra, Pahang.

Biology. The larvae were collected from bamboo phytotelmata in Bogor (Watts pers. com.) together with larvae of E. klausnitzeri sp. nov.

Remarks. The specimen from Pahang has a shorter (L 0.96) and wider prehensor. The species was described on the basis of a female specimen, therefore the main portion of the above description is based on the female, and the description of male is treated as a supplementary part. The extraordinary variation of the prehensor may suggest that E. discoidalis is a group of cryptic species. Studies based on more numerous material are needed to verify this hypothesis.

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 4. Exochomoscirtes pectinatus sp. nov., metatibia.

FIGURE 13. Habitus illustrations of Exochomoscirtes. A) E. quadripartitus sp. nov.; B) E. discoidalis (Pic), male; C) E. discoidalis (Pic), female; D) E. thailandicus sp. nov.; E) E. serricornis sp. nov.; F) E. cambodiensis sp. nov.; G) E. bezdeki sp. nov., male; H) E. bezdeki sp. nov., female; I) E. nigromarginatus sp. nov.; J) E. sphaericus (Champion); K) E. globosus sp. nov.; L) E. buechei sp. nov.; M) E. dilaticornis sp. nov., male. Scale bar = 2.0 mm.

FIGURE 40. Exochomoscirtes discoidalis (Pic), male. A) sternite 9; B) tergite 8; C) tergite 9; D) tegmen; E) penis. Scale bar = 0.5 mm.

FIGURE 41. Exochomoscirtes discoidalis (Pic), female. A) prehensor and bursal sclerite (Java); B) prehensor and bursal sclerite (Sumatra); C) prehensor and bursal sclerite (Pahang); D) bursal sclerite (Pahang); E) prehensor and bursal sclerite (Sabah); F) prehensor and bursal sclerite (Sabah).