Eustylus puber (Olivier) 1807

Franz, Nico M., 2010, Redescriptions of critical type species in the Eustylini Lacordaire (Coleoptera: Curculionidae: Entiminae), Journal of Natural History 44 (1 - 2), pp. 41-80 : 56-61

Eustylus puber (Olivier) 1807 , p 367

( Figures 8 and 9 )

Description

Male ( Figure 8A–F ). Length 6.80–8.49 mm, width 2.47–3.20 mm, length/width ratio 2.65–2.75 (n = 2); greatest width at humeri to central region of elytra. Integument reddish brown; setae sparsely and evenly arranged throughout, setae more dense on head, metasternum, legs and venter, brownish white; scales densely and evenly arranged throughout, completely covering integument, subcircular, appressed to semierect; with distinct pattern of alternating regions with creamy white or light green metallic (iridescent) scales: head, margins of pronotum and elytra, sterna, legs, and ventral sterna with creamy white scales, more whitish towards ventral side, yet pronotum and elytra centrally with light green metallic scales; dominating scale type lightly interspersed with alternating scale type.

Mouthparts. Maxillae with cardo angulate, apically strongly oblique; stipes apically triangularly narrowed, lateral margin with four to six setae; maxillary palpomere I nearly twice as long as II; II similar in length to III. Labium with prementum subtriangular to cordate, apical margin medially slightly projected; ventrally with two long setae in each apicolateral region; labial palpomere III slightly protruding from apical margin of prementum; I nearly twice as long as II; II slightly shorter than III.

Rostrum. Length 1.03–1.21 mm, rostrum/pronotum length ratio 0.62–0.70, rostrum length/width ratio 1.02–1.06. Dorsal outline of rostrum trapezoidal, anteriorly widened; dorsolateral margins subparallel, slightly undulate, evenly convex; apical margin bisinuate, medially weakly incised. Nasal plate as in C. argyreus , posterior carina with evenly spaced, alternating short and long, aurate setae. Epistoma depressed, glabrous. Dorsal surface of rostrum subplane, relatively narrow, median sulcus extending from posterior margin of epistoma to midpoint between eyes, dorsolateral sulci absent, scales directed anterolaterally; ventrolateral margins slightly arcuate, anteriorly diverging. Ventrolateral sulci short, arcuate. Scrobe dorsolateral, initiating in apicodorsal region, not passing through basidorsal region, terminating dorsolaterally near midpoint of rostrum; scrobe extending to midpoint of rostrum, glabrous.

Antennae with scape extending beyond anterolateral margin of pronotum, very stout, in cross-section slightly basally depressed, apically subcircular, slightly wider than protibia; scape extending (in idealized position) through central region of eye. Funicular antennomeres progressing from distinctly to slightly elongate, and from clavate to cylindrical; II slightly longer than I; VII slightly longer than VI.

Eyes elliptical, oriented horizontally, anterior and posterior margins nearly straight; eyes separated from anterolateral margin of pronotum by minimally 5 rows of scales, interocular distance shorter than maximum width of eye; with nearly 20 facets along maximum diameter.

Head with anterodorsal margins surrounding eye impressed, scales surrounding eye whitish.

Thorax. Pronotum conical to globular, length/width ratio 0.89–0.93, pronotum/ elytra length ratio 0.28–0.30; greatest width near central region or at posterior margin; dorsal surface slightly convex, punctate; scales creamy white along anterior and posterior margins, otherwise light green metallic; median sulcus absent. Anterodorsal margin nearly two-thirds the length of posterodorsal margin; dorsolateral margins anteriorly converging, posteriorly subparallel; posterodorsal margin slightly bisinuate, with three to five rows of densely arranged, plumose scales. Pronotum in lateral view conical; anterolateral margin straight, without postocular lobe, setation indistinct, postocular vibrissae absent. Metascutum glabrous. Scutellum subquadrate, posteriorly truncate. Mesepimeron with anterodorsal edge acute-triangular, covered with scales and sparsely arranged, recurvate setae.

Mesosternum with densely arranged, whitish scales; mesocoxal cavities narrowly separated by distance nearly one-sixth width of each mesocoxal cavity; Metasternum with median sulcus reduced to a shallow, transverse-triangular fovea near posterior margin, lateral regions with densely arranged scales similar to those of epipleura; metacoxal cavities separated by distance nearly three-quarters the width of each metacoxal cavity.

Metendosternite with anterior tendons inserted near midpoint of lamina, onefifth removed towards base of furcal arms; furcal arms dorsally strongly diverging.

Legs. Integument (light) reddish brown, with creamy-white (to iridescent) scales, interspersed with recurvate setae. Profemur/pronotum length ratio 1.31–1.44; profemur straight, in cross-section elliptical, ventral margin with one small tooth near apical two-fifths. Protibia/profemur length ratio 0.98–1.04; protibia relatively stout, slightly arcuate, in cross-section elliptical, width similar throughout; ventral margin with one very long, recurvate, aurate seta near apical third, otherwise as in C. argyreus ; protibial apex with anterior margin obliquely truncate; setal comb present. Mesothoracic legs shorter than metathoracic legs. Mesofemur shorter than metafemur. Mesotibia shorter than metatibia, straight. Metatibial apex with anterior margin arcuate to obliquely truncate, setal comb ventrally short, longer towards dorsal region, minimally ascending along outer metatibial margin.

Elytra. Length/width ratio 2.02–2.11; greatest width at humeri or near central region; anterior margins jointly wider than posterior margin of pronotum, slightly elevated, emarginate; lateral margins subparallel along anterior half, gradually converging along posterior half. Elytra in lateral view with nine complete striae; striae slightly narrower than intervals; stria X absent; punctures widely separated by distance longer than width of each puncture, spaced regularly yet with small positional modifications along each stria resulting in diagonal lines running slightly anteriorly from mesal to lateral margin; intervals slightly convex; cuticular projections absent; setae shorter than width of intervals; sparsely and irregularly arranged; scales creamy white to light-brown with pinkish iridescence along anterior margin, mesal margin, and along intervals (VII-) VIII and IX, otherwise predominantly light green-metallic.

Wings with wing/body length ratio 1.18–1.31, wing length/width ratio 2.95–2.97; anterior margin slightly sinuate; anal lobe present.

Abdomen. Ventral sternum III centrally subplane, laterally slightly convex; suture separating III + IV shallow, slightly emarginate, with one small, mesal fovea; VII posteriorly slightly concave, posterior margin slightly arcuate; ventral sterna covered with whitish scales. Pygidium subquadrate, posterior margin truncate, deeply and widely emarginate.

Terminalia. Sternum VIII consisting of two pyriform to triangular sclerites; posterior margin of each sclerite with two to four longer setae. Spiculum gastrale ( Figure 9B ) longer than median lobe; posteriorly bifurcate (Y-shaped), furcal arms triangular, outer margins sinuate, posteriorly slightly diverging. Tegmen longer than median lobe. Aedeagus ( Figure 9A ) with median lobe length/width ratio 3.2–3.38 (n = 2); anteroventral emargination nearly one-quarter length of median lobe; lateral margins slightly angulate to sinuate, converging along anterior one-third, subparallel along posterior two-thirds; apex triangular, narrowly rotundate. Median lobe in lateral view evenly deflexed; anterior quarter continuously narrowed, posterior one-fifth gradually narrowed; apex nearly straight. Internal sac basally with one to two small, W-shaped, denticulate sclerites, and with one large, explanate, triangular sclerite positioned along ostium, apically widened, apical margin truncate, each apicolateral edge continuing as a small, arcuate ramus. Adeagal apodemes slightly longer than median lobe.

Female. Length 8.25–9.37 mm, width 3.01–3.83 mm; length/width ratio 2.45–2.74 (n = 2); greatest width at humeri or near central region of elytra. Rostrum length 1.16–1.28 mm, rostrum/pronotum length ratio 0.64–0.65, rostrum length/width ratio 1.02–1.06. Pronotum length/width ratio 0.85–0.93; pronotum/elytra length ratio 0.27–0.30; greatest width near central region or at posterior margin. Metasternum centrally widely concave, laterally angulate to convex. Protibia/profemur length ratio 1.36– 1.38. Elytra length/width ratio 1.88–2.04; outline of declivity straight to slightly arcuate. Venter with sternum III centrally slightly concave, laterally slightly convex; IV centrally subplane; VII equilateral to transverse, posterior margin slightly arcuate. Pygidium trapezoidal, ventrally not emarginate.

Terminalia. Tergum VII with each posterolateral region with longitudinal section of densely arranged, short, stridulatory setae, mesal region covered with microsetae interspersed with longer setae, particularly at posterior edge. Sternum VIII ( Figure 9C ) with anterior half stylate; posterior half triangular, spatulate, medially fused (not bifurcate); otherwise as in C. argyreus . Coxites with styli long. Genital chamber slightly longer than sternum VIII. Spermatheca ( Figure 9D ) U-shaped; ramus and collum short, nearly contiguous, with similar orientation; corpus short and globular; cornu (apical three-fifths) narrowly arcuate, apex slightly deflected.

Variation

The examined specimens exhibit slight differences in the colour and relative density of creamy white scales on the pronotum and elytra.

Specimens examined

“ Venezuela, Mon. [Monagas], 11 km S. Maturín, 350’ [ft.], Aug. 1, 1998, C.W. and L. O’Brien and G. Wibmer ” (one male and one female, CWOB) ; “ Trinidad, N.[orth] Range, Cooker Trace, 3 mi. E. Arima-Blanchisseuse Rd. , 1900’ [ft.], May 11, 1985 / Collectors: L.B. and C.W. O’Brien ” (one male and one female, CWOB) .

Figures

Figure 8. Habitus of Eustylus puber, male. (A) Dorsal view; (B) lateral view; (C) ventral view; (D) head, dorsal view; (E) head, lateral view; (F) metatibia, lateral view.

Figure 9. Terminalia of Eustylus puber. (A) Aedeagus, ventral and lateral view; (B) spiculum gastrale, ventral view; (C) posterior region of female sternum VIII, ventral view; (D) spermatheca.