Chilarboreus (Chilarboreus) acuticollis, Ruta, 2011

Ruta, Rafał, 2011, Chilarboreus gen. nov., a new genus of Chilean Scirtidae (Coleoptera: Scirtoidea), with descriptions of three new species, Journal of Natural History 45 (27 - 28), pp. 1689-1713 : 1701-1704

Chilarboreus (Chilarboreus) acuticollis sp. nov.

( Figures 1B , 7 , 8 )

Type material (11 males)

Holotype. Male ( MNNC): “ Chile X Región / Oncol Park, 23.XII.2005 / 6.01.2006, Malaise Trap-T1 / Arias & Ruiz UC Berkeley” [printed label]; “ Scirtidae / Genero sp. 5 / det. G. Arriagada 2007” [printed label].

Paratypes. 1 male ( MNNC): same data as holotype . 1 male ( MNNC): “Chile X Región / Oncol Park , 4–18.XI.2005 / Malaise Trap-T2 / Arias & Ruiz UC Berkeley” [printed label]; “ Scirtidae / Genero sp. 5 / det. G. Arriagada 2007” [printed label] . 1 male ( MNNC): same data as above, but date “6– 22.01.2006 ” . 1 male ( MNNC): “Chile X Región / Oncol Park , 6 / 23.XII.2005 / Malaise Trap-T1 / Arias & Ruiz UC Berkeley” [printed label]; “ Scirtidae / Genero sp. 5 / det. G. Arriagada 2007” [printed label] . 6 males ( EMEC): “ CHILE, X Region Los Rios, / Oncol Park, 5– 19.01.2007 / Malaise trap T1 / Arias et Ruiz UC Berkeley ” [printed label] .

Diagnosis

Similar to C. fossulatus , but pronotum with shallow anterior fossae and well-marked, acute anterior pronotal angles, aedeagus elongate, with bifid trigonium.

Description

Male. Body elongate, widening in posterior portion, moderately flattened, clothed with procumbent setae. Coloration from light to dark brown, without contrasting dorsal pattern. Head as long as wide, 1.5 times wider than interocular space, concave, covered with subtly granulate punctures; eyes small, moderately protuberant. Antennae moderately long, extending to basal third of elytra; antennomere 1 globular, subquadrate; antennomere 2 cylindrical, slightly narrower than antennomere 1; antennomere 3 long, c.1.3 times longer than antennomere 2; antennomeres 4–10 gradually shortening, triangularly widened, apical antennomere very wide, oval, as long as antennomere 3. Pronotum transversely rectangular, 1.4–1.5 times wider than long, sides subparallel, disc convex, sides depressed, with moderately deep fossae in anterolateral angles, anterolateral angles of pronotum right-angled, not produced but well marked. Punctation of pronotum subtly granulate on disc, distinctly granulate on sides. Basal groove well marked, ended with deep basal fossae. Elytra 1.6–1.7 times longer than their width, 4.1–4.4 times longer than pronotum; punctation irregular, relatively sparse, punctures slightly elongated, separated by c.2.0 diameters. Subfemoral grooves with distinct hexagonal microreticulation. Aedeagus long (L / W = 3.9), parameroids slightly widening apically, trigonium bifid, with deep emargination. Measurements of male genitalia: aedeagus (L 0.62, W 0.16); sternite 9 (L 0.26, W 0.17); tergite 8 (L 0.33, W 0.20); tergite 9 (L 0.33, W 0.14).

Female. Unknown.

Variation

Total length of body only slightly variable.

Measurements and ratios

Males (n = 10). TL 2.33–2.43 (2.37), PL 0.43–0.47 (0.45), PW 0.63–0.67 (0.64), EL 1.90–2.00 (1.94), EW 1.13–1.20 (1.17), TL / EW 2.0–2.1 (2.0), PW / PL 1.4–1.5 (1.4), EL / EW 1.6–1.7 (1.7), EL / PL 4.1–4.4 (4.3).

Distribution

Oncol Park, Oncol, Provincia de Valdivia , Región de Los Ríos .

Etymology

Latin acutus – sharp; lat. collum – neck, refering to sharp anterior angles of pronotum.

Note

The rarest species of the genus, known only from Oncol Park in Valdivia.

Figures

Figure 1. Habitus. (A) Chilarboreus (Chilarboreus) fossulatus; (B) Chilarboreus (Chilarboreus) acuticollis; (C) Chilarboreus (Pictarboreus) darwini. Scale bar 1.0 mm.

Figure 7. Chilarboreus (Chilarboreus) acuticollis, male. (A) Dorsal view; (B) apical portion of antenna; (C) subfemoral groove; (D) head, dorsal view; (E) mouthparts; (F) eye, detail; (G) pronotum; (H) basal portion of pronotum; (I) ventral view. Scale bars 0.5 mm (A), 0.05 mm (C), 0.1 mm (B, D–I).

Figure 8. Chilarboreus (Chilarboreus) acuticollis, male. (A) Aedeagus; (B) tegmen, closeup; (C) sternite 9; (D) tergite 8; (E) tergite 9. Abbreviations: pe, penis; tg, tegmen. Scale bar 0.1 mm.