Chilarboreus (Pictarboreus) darwini, 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 : 1708-1711

Chilarboreus (Pictarboreus) darwini sp. nov.

( Figures 1C ; 2 E-I, K; 9-11)

Type material (502 males)

Holotype. Male ( MEUC): “ CHILE, NO Chiloé, Guabun / Malaise trap on Eucryphia / cordifolia , 11 II 2007 / leg. Maurice Peña ” [printed label].

Paratypes. 56 males ( MEUC): same data as holotype . 3 males ( NHM): “Chiloe I., / Chile. / C. Darwin. ” [printed label]; “ Darwin Coll. / 1885-119” [printed label]; “ Chiloe / 2523 (on reverse)” [handwritten label] . 4 males ( NHM): “Chiloe I., / Chile. / C. Darwin. ” [printed label]; “C. Darwin / 87–94” [printed label]; “ Chiloe / 2523 (on reverse)” [handwritten label] ; 1 specimen with additional label handwritten by G. C. Champion „tarsi 5-jointed /? Dascillid”. 2 males ( MEUC): “ Chile, Chiloe / Isla Redonda / 1.II.87 / J. Solervicens ” [printed label] . 1 male ( DBET): “ Chile W., ReG. X / Fresia , WWN of Parga / 480 m 27.1.2005 / M. Snižek lgt.” [printed label] . 1 male ( MEUC): “ CHILE, NO Chiloé, Guabun / Malaise trap on Eucryphia / cordifolia , 17 I 2007 / leg. Maurice Peña” [printed label] . 1 male ( MEUC): “ CHILE, NO Chiloé, Guabun / eclector trap / 24 III 2007 / leg. Maurice Peña” [printed label] . 7 males ( MEUC): “ CHILE, NO Chiloé, Guabun / Malaise trap on Eucryphia / cordifolia , 24 III 2007 / leg. Maurice Peña” [printed label] . 5 males ( MEUC): “ CHILE, NO Chiloé, Guabun / Malaise trap on Eucryphia / cordifolia , 5 III 2007 / leg. Maurice Peña” [printed label] . 1 male ( MNNC): “12- CHILE X REGION / Oncol Park. Site 2, 12.I.2006 / S39 ◦ 41.596 / W73 ◦ 19.110 / Fogging: Mañio / Arias et al. Berkeley” [printed label]; “ Scirtidae / Genero sp. 7 / det. G. Arriagada 2007” [printed label] . 1 male ( MNNC): “32- CHILE X REGION / Cipresal, Chinquen , 22.I.2006 / S42 ◦ 35.137 / W74 ◦ 05.500, 7 m. / Fogging: Nothofagus dombeyi / Arias et al. Berkeley” [printed label]; “ Scirtidae / Genero sp. 6 / det. G. Arriagada 2007” [printed label] . 6 males ( MNNC): “29- CHILE X REGION / Chinquen , 20.I.2006 / S42 ◦ 37.111 / W74 ◦ 05.973 / Fogging: Nothofagus dom- / beyi, Arias et al. Berkeley” [printed label]; “ Scirtidae / Genero sp. 6 / det. G. Arriagada 2007” [printed label] . 277 males ( EMEC): “ CHILE, X Region Los Rios, / Oncol Park, 20.03 / 3.04.2007 / Malaise trap T2 / Arias et Ruiz UC Berkeley ” [printed label] . 81 males ( EMEC): “ CHILE, X Region Los Rios, / Oncol Park, 6– 20.03.2007 / Malaise trap T2 / Arias et Ruiz UC Berkeley ” [printed label] . 54 males ( EMEC): “ CHILE, X Region Los Rios, / Oncol Park, 20.02 / 6.03.2007 / Malaise trap T1 / Arias et Ruiz UC Berkeley ” [printed label] . 1 male ( EMEC): “ CHILE, X Region Los Rios, / Curinanco point, 1–20.02. / 2007 Malaise trap T3 / Arias et Ruiz UC Berkeley ” [printed label] .

Diagnosis

Pronotal disc regularly convex, without fossulate depressions. Elytra often with brownish-black pattern. Penis enclosed within a tubular tegmen.

Description

Male. Body elongate, widening in posterior portion, moderately flattened, clothed with procumbent setae. Coloration from light to dark brown, head black; pronotum light brown to blackish-brown; elytra with variable dorsal pattern (see variation below). Head as long as wide, c.1.4 times wider than interocular space, concave, covered with normal punctures, eyes of moderate size, moderately protuberant. Antennae moderately long, extending to basal one-third of elytra; antennomere 1 globular, antennomere 2 cylindrical, slightly narrower than antennomere 1, antennomere 3 very long and narrow, c.1.5 times longer than antennomere 2; antennomeres 4–10 gradually shortening, triangularly widened, apical antennomere wide, oval, as long as antennomere 3. Pronotum transversely subtrapezoidal, sides sinuate, disc convex, sides regularly, narrowly depressed, anterolateral angles of pronotum right-angled, not produced, posterolateral angles slightly produced. Punctation of pronotum normal. Basal groove subtly marked, ended with indistinct fossae. Elytral punctation irregular, relatively dense, punctures oval, separated by c.1.0 diameter. Subfemoral grooves with indistinct squamose microreticulation. Aedeagus cylindrical, with well-developed tegmen, trigonium with truncate apex and distinct ventral denticle. Measurements of male genitalia: aedeagus (L 0.47, W 0.19); tergite 8 (L 0.35, W 0.26); tergite 9 (L 0.33, W 0.23).

Female. Unknown.

Variation

Several types of dorsal colour pattern can be distinguished ( Figure 11 A–G). They are listed in Table 1, together with frequency of each pattern calculated for n = 372. A single male ( Figure 11H ) with an unusually narrow pronotum was found among specimens from Oncol Park (label data: “ CHILE, X Region Los Rios, / Oncol Park , 6– 20.03.2007 / Malaise trap T2 / Arias et Ruiz UC Berkeley”). Its pronotum is less transverse ( PW / PL 1.2 ) and almost 2 times narrower than its EW ( EW / PW 1.9 , in majority of studied specimens EW / PW is around 1.6). Its genitalia do not show significant differences from those of other studied specimens, therefore it is concluded that it is an aberrant specimen of C. darwini .

Measurements and ratios

Males (n = 10) TL 2.23–2.50 (2.38), PL 0.40–0.47 (0.43), PW 0.57–0.67 (0.60), EL 1.83–2.0 (1.95), EW 0.93–1.10 (1.0), TL / EW 2.2–2.4 (2.3), PW / PL 1.3–1.5 (1.4), EL / EW 1.8–2.0 (1.9), EL / PL 4.3–5.0 (4.5).

Distribution

Oncol, Curiñanco, Provincia de Valdivia , Región de Los Ríos ; Fresia, Provincia de Llanquihue , Región de Los Lagos ; Guabun, Chinquén, Isla Redonda, Provincia de Chiloé , Región de Los Lagos .

Etymology

Dedicated to Charles R. Darwin (1809–1882), who was the first to collect the specimens on Chiloé Islands during the voyage of the Beagle.

Figures

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

Figure 2. Morphological details. (A–D, J) Chilarboreus (Chilarboreus) fossulatus; (E–I, K) Chilarboreus (Pictarboreus) darwini; (A, E) mandible; (B, F) maxilla; (C, G) labium; (D, H) labrum; (I) elytron; (J, K) wing. Abbreviations: lh, laciniar hook (uncus). Scale bars 0.1 mm (A–H), 0.6 mm (I), 0.7 mm (J, K).

Figure 11. Chilarboreus (Pictarboreus) darwini, variability of dorsal pattern. Scale bar 1.0 mm.