Eupholus mimicus, Riedel, Alexander, 2010

Riedel, Alexander, 2010, Two new species of Eupholus Boisduval (Coleoptera, Curculionidae, Entiminae), with observations on coloured cuticular exudates in weevils, Zootaxa 2338, pp. 23-34 : 26-29

Eupholus mimicus sp. n.

( Figs. 1 , 7 , 16, 19, 22 , 25, 28, 29 , 32–33 )

Diagnosis. A Eupholus species with two transverse yellow bands on black elytra. Easily distinguished from E. euphrosyne by the yellow bands being composed of scales ( Figs. 32–33 ), not of extracuticular particles, by median furrow of rostrum ( Fig. 7 ) and by simple pronotum lacking conspicuous median impression.

Description. Holotype, female ( Fig. 1 ). Length. Total length 22.5 mm; pronotum + elytron 18.5 mm. Coloration greyish-black, elytra with two transverse yellow bands, one behind base, one in front of apical declivity; legs bluish-grey. Head sparsely setose with transparent, recumbent to suberect scales and setae arranged more densely bordering eye; surface dull, micro-reticulate, rugose-punctate. Vertical diameter of eye 1.44 X horizontal diameter. Rostrum ( Fig. 7 ) 2.08 X longer than wide at base; maximum width in front of antennal insertion, there 1.36 X width at base; dorsum with median furrow terminating at indistinct fovea between eyes; with pair of sublateral furrows in front of eyes; sparsely setose with transparent, recumbent to suberect setae not concealing dull, rugose-punctate surface; epistome heart-shaped, sunken ventrad posteriorly, but not bordered by distinct ridge; scrobes sinuate, reaching eyes; venter more densely covered with suberect white setae, with median furrow and pair of sublateral furrows, anteriorly behind prementum with 6 stiff erect setae, subequal to length of prementum. Antenna: funicle + club 2.14 X longer than scape; scape sparsely setose; funicle covered with recumbent pale bluish scales and with dense long dehiscent setae; club short, 2.22 X as long as wide. Pronotum 1.06 X wider than long; evenly convex; with sparse vestiture of subrecumbent setae not concealing surface; dull, micro-reticulate, weakly punctate-rugose; in middle with small knob; behind this knob midline impressed, in front weakly costate. Scutellum circular, posteriorly covered with erect setiform yellowish-transparent scales. Thoracic venter subglabrous, sparsely squamose, sparsely interspersed with lanceolate grey suberect setae; medially between coxae vestiture slightly denser but not concealing coriaceous surface. Elytron 3.66 X longer than width at humerus; greatest width near middle, there 1.13 X wider than at humerus; humerus evenly rounded, simple, without protruding knob; interval 5 in apical third with obtuse tubercle, other intervals simple; extensive areas of elytral surface dull, minutely coriaceous, sparsely covered with suberect yellowish-transparent setae; striae distinct, punctures with one cylindrical yellow scale; in anterior and posterior half with transverse band of densely arranged cylindrical yellow scales fully concealing integument, anterior band laterally reaching interstria 10, slightly wider than posterior band, posterior band laterally reaching interstria 8, area between bands slightly wider than a band; epipleural edge without fringe of lanceolate scales. Ala relatively long, 20 mm. Legs with uniform vestiture of pale bluish amygdaloid scales, interspersed with dense suberect yellow setae. Abdomen subglabrous, sparsely covered with short recumbent setae interspersed with longer suberect setae except centre of ventrites 1 and 2 polished; sides of ventrites 1 and 2 and ventrites 3–5 sparsely setose, coriaceous, punctate. Sternite VIII narrow, as in fig. 25. Tergite VIII ( Fig. 28 ) narrow, sides converging to pointed apex. Hemisternite ( Fig. 22 ) 3.1 X longer than high, apex weakly concave, dorsally extended, stylus inserted in middle of apex, 2.3 X longer than wide, straight, subapically with cluster of moderately long setae pointing laterad. Vagina ( Fig. 19 ) without sclerites. Ductus spermathecae thin, weakly widened at base, inserted at junction of bursa copulatrix and oviduct; terminal portion of bursa dorsally anterior of this junction. Spermatheca as in fig. 29.

Intraspecific variation (females). Length 22.5–26.0 mm (n=3, =24.5 ± 1.8), pronotum + elytron 18.5– 20.0 mm (n=3, =19.2 ± 0.8). Coloration greyish black or brownish; transverse elytral bands either pale yellow or more intense yolk-coloured; legs bluish-grey or more distinctly bluish. Rostrum 2.08–2.16 X longer than wide at base (n=3, =2.11 ± 0.04); maximum width in front of antennal insertion, there 1.29–1.36 X wider than at base (n=3, =1.33 ± 0.04). Antenna: funicle + club 1.88–2.14 X longer than scape (n=3, =1.97 ± 0.15). Pronotum 1.06–1.13 X wider than long (n=3, =1.09 ± 0.04); either with sparse vestiture of subrecumbent setae or with denser vestiture of thicker cream-coloured setae giving surface brownish appearance. Elytron 3.45–3.61 X longer than wide at humerus (n=3, =3.50 ± 0.09); greatest width 1.11– 1.14 X that at humerus (n=3, =1.12 ± 0.02); swelling of interval 5 more or less distinct, hardly projecting or dentiform; intervals outside of transverse bands subglabrous or with short subrecumbent to suberect creamcoloured setae not concealing surface.

Material examined. Holotype, female: PAPUA NEW GUINEA, Morobe Prov., Aseki, 1000–1300 m, leg. A. Riedel, 19.X.1992 ( SMNK) [pinned through right elytron; genitalia in glycerol in microvial attached to pin; left ala cut at base, on cardboard attached to pin; left metatarsus broken and glued separately]. Paratypes: PAPUA NEW GUINEA, Morobe Prov.: 1 female, Aseki, V.1990 ( TPCJ); 1 female, Aseki – Kabuanga, IV.1996 ( TPCJ); 1 female Aseki, II.1972, leg. H. Ohlmus ( ANIC).

Distribution. Only known from Aseki, a village in Morobe Province ( Papua New Guinea).

Etymology. This epithet is based on the Latin adjective mimicus (imitative) and refers to the close resemblance with E. euphrosyne , possibly caused by a mimicry effect.

Notes. This species appears to be closely related to the members of the schoenherrii -group of Riedel (2002), based on the dorsally furrowed rostrum and the structure of the female genitalia (basally thickened ductus spermathecae, dorsally extended hemisternite apex), although its coloration is very different. The genital structure of the superficially similar E. euphrosyne , on the contrary, agrees with that of the loriae - group ( Figs. 14, 17, 20 ).

Figures

FIGURES 1 – 4. Habitus of Eupholus spp.: (1) E. mimicus, holotype (2) E. sedlaceki, holotype; (3) E. euphrosyne, female (Aseki); (4) E. sedlaceki, female (Wau).

FIGURES 5 – 7. Head and rostrum of Eupholus spp.: (5) E. euphrosyne; (6) E. sedlaceki; (7) E. mimicus.

FIGURES 14 – 22. Female genitalia of Eupholus spp., upper row: overview in ventral aspect; middle row: vagina, bursa copulatrix and base of hemisternites in ventral aspect; lower row: left hemisternite. (14, 17, 20) E. euphrosyne; (15, 18, 21) E. sedlaceki; (16, 19, 22) E. mimicus.

FIGURES 23 – 31. Female genitalia of Eupholus spp.: (23 – 25) sternite VIII; (26 – 28) tergite VIII; (29 – 31) spermatheca. (23, 26, 30) E. euphrosyne; (24, 27, 31) E. sedlaceki; (25, 28, 29) E. mimicus.

FIGURES 32 – 37. Base of left elytron of Eupholini with yellow coloration; overview (left); detail (right): (32 – 33) Eupholus mimicus; note yellow scales; (34 – 35) Eupholus euphrosyne; note cream-coloured setae holding yellow particles; (36 – 37) Rhinoscapha cf. thomsoni; note incrustation of yellow substance.