Exochomoscirtes dilaticornis, Ruta & Yoshitomi, 2010

Ruta, Rafał & Yoshitomi, Hiroyuki, 2010, Revision of the genus Exochomoscirtes Pic (Coleoptera: Scirtidae: Scirtinae) 2598, Zootaxa 2598 (1), pp. 1-80 : 65-67

Exochomoscirtes dilaticornis sp. nov.

( Figs. 1G , 3A , 5A , 13M , 14A , 53 , 54 )

Type material. Holotype, male ( NHM): “Sandakan / Borneo / Baker” [printed label]; “ C. F. Baker. / 1920– 79” [printed label] . Paratypes. Female ( NHM): “ BRUNEI, ii–iii 1992 / E 115 7 ° N4 34 ° / Kuala Belalong

FSC” [printed label]; “ Ground Malaise Trap / N. Mawdsley coll. / BMNH{E} 1991-173” [printed label]. Female ( NHM): “ BRUNEI: E115 7’ N4 34’ / Kuala Belalong FSC / Dipterocarp forest / BM(NH) 1991-173” [printed label]; “Ground Malaise 1B / 260m alt. 16.vi.91 / N. Mawdsley NM292” [printed label]; “3133” [printed pink label]. Female ( NHM): “ BRUNEI: E115 7’ N4 34’ / Kuala Belalong FSC / Dipterocarp forest / BM(NH) 1991-173” [printed label]; “Ground Malaise 13 / 440m alt. 8.ii.92 / N. Mawdsley NM299” [printed label]; “3130” [printed pink label]. Female ( NHM): “ BRUNEI: E115 7’ N4 34’ / Kuala Belalong FSC / Dipterocarp forest / BM(NH) 1991-173” [printed label]; “Ground Malaise 21 / 870m alt. 7.ii.92 / N. Mawdsley NM304” [printed label]. Female ( ITBC): “Tungud Forest Reserve, Upper / Kinabatangan, Sandakan, / Sabah BORNEO / 22–23. II. 2008 H. / Takizawa leg.” [printed label] .

Diagnosis. The species is similar to Exochomoscirtes buechei but the antennae are subserrate (filiform in E. buechei ) and apex of parameroids of tegmen is strongly dilated. Elytra of females bear yellow round macula in basal portion, which occurs in no other species of the genus.

Description. Holotype, male. Body hemispherical, TL/EW 1.1, very convex, covered with yellow suberect setae. Body light brown. Antennae bicolored: antennomeres 1–5 yellowish-brown, 6–11 black.

Head with distinct punctation, punctures separated by ca. 1.0 diameter. Eyes big, protuberant; head 1.8 X wider than interocular space. Antennae subserrate, reaching basal 1/3 of elytra. Antennomeres 2 and 3 of subequal lengths, antennomere 4 1.5 X longer than antennomere 3, antennomeres 5–10 subtriangular, gradually widening toward apex, apical antennomere oval, slightly longer than wide. Palpomeres of maxillary palpi moderately wide.

Pronotum small, slightly convex, covered with distinct punctation, punctures separated by 1.0 (rarely 2.0) diameters, anterolateral corners almost rectangular, somewhat obtuse, projecting anteriorly; lateral margins straight; posterolateral corners somewhat acute; base of pronotum subtrapezoidal, with complete margination along basal margin; PW/PL 3.1. 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 at the middle, punctation stronger than on pronotum, punctures separated by ca. 1.0 diameter; humeri well marked; EL/EW 0.9; EL/PL 4.6; EW/PW 1.7.

Legs moderately long. Hind tibial spurs well developed, dorsal one elongated and modified apically, 0.8 X as long as tarsomere 1 and slightly longer than ventral spur. Ventral spur is almost straight, slightly shorter than tarsomere 1. Apex of dorsal spur widened, obliquely truncate, armed with two hooked processes.

Ventrite 1with sparse setation in mesal portion, ventrite 2 with basal row of big punctures. Apex of tergite 7 unmodified. Apex of ventrite 5 with wide and relatively deep emargination.

Sternite 9 (L 0.70, W 0.30) subtriangular, apodemes fused basally, apex emarginated, with a few apical setae. Tergite 8 (L 1.15, W 0.78) moderately sclerotized, apical portion small, with arcuate apex, bearing row of short setae on apical margin, with a pair of very long apodemes diverging basally; tergite 9 (L 1.00, W 0.70) moderately sclerotized, apical portion small, emarginated at apex, bearing minute setae, with a pair of long apodemes diverging basally. Tegmen (L 0.69, W 0.26) well sclerotized, parameres sinuate, widening apically, with a small mesal denticle pointed inwardly, mesal process narrow, slightly widening at apex, ca. half as long as parameres. Penis (L 0.47, W 0.18) small, moderately sclerotized, pala moderately narrow, elongate, apical process evenly shorter than pala.

Female. Dorsum uniformly testaceous, each elytron with a yellow oval spot in adscutellar part of basal portion, which may become faint in specimens covered with lipids. Antennomeres 7–10 wide, subtriangular, apical antennomere oval. Maxillary palpomeres strongly widened. Hind tibial spurs well developed, dorsal one slightly curved, unmodified, as long as tarsomere 1, and nearly twice as long as ventral one; ventral spur slightly curved. Apex of ventrite 5 shallowly emarginated, ventrite 5 with a pair of small foveae. Prehensor very long (L 1.44), widened apically; bursal sclerite small (L 0.26); duct connecting prehensor with bursal sclerite creased, but not accordion-folded.

Variability. Females TL/EW 1.0–1.1 (1.1).

Measurements. Male (n = 1): TL 4.10, PL 0.76, PW 2.33, EL 3.50, EW 3.88. Females (n = 4): TL 3.60– 4.35 (3.88), PL 0.65–0.75 (0.68), PW 2.10–2.40 (2.20), EL 3.20–3.85 (3.45), EW 3.45–3.57 (3.66).

Distribution. N Borneo.

Etymology. Specific epithet refers to dilated antennomeres.

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 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 5. Abdominal details in Exochomoscirtes. A) E. dilaticornis sp. nov., ventrite 5; B) E. discoidalis (Pic), ventrite 5; C) E. jaechi sp. nov., tergite 7; D) E. klausnitzeri sp. nov., tergite 7; E) E. luteosuturalis sp. nov., tergite 7; F) E. luteosuturaloides sp. nov., tergite 7; G) E. maculatus (Waterhouse), abdomen; H) E. maculatus (Waterhouse), ventrites 3–5; I) E. nigromarginatus sp. nov., ventrite 5; J) E. quadripartitus sp. nov., tergite 7.; K) E. ruforotundus (Watts) (Australia), tergite 7; L) E. takizawai sp. nov., ventrite 5.

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

FIGURE 54. Exochomoscirtes dilaticornis sp. nov., female. A)–B) bursal sclerite and prehensor.