Chilarboreus, 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 : 1690-1691

Chilarboreus gen. nov.

Type species. Chilarboreus fossulatus sp. nov., by present designation.

Diagnosis

Males. Body small (2.1–2.5), elongated ( TL / EW 2.0–2.4), well sclerotized, brownish, elytra occasionally with distinct brownish-black pattern. Head as long as broad; eyes small, oval, relatively coarsely faceted; tempora well marked, slightly converging basally; supraantennal ridges slightly elevated, oblique, joined mesally to clypeal margin; eyes surrounded by trough-shaped groove. Eyes small, distance from posterior margin of eye to occipital ridge slightly larger than maximal diameter of eye. Frontoclypeal suture absent; clypeus very short, transverse, in some species with transversely rectangular emargination; anteclypeus present. Subgenal ridge well marked, without indentation in anterior portion. Antennae moniliform, antennomeres subtly widened apically, covered with long setae, distinctly microreticulated. Labrum clearly visible, transverse; mandibles symmetrical, abruptly curved in apical third, molar region not developed. Galea with long, fringed, irregularly arranged setae at apex; lacinia with distinct apical hook; apical palpomere of labial palpi situated on apex of preapical one. Mentum transverse, trapezoidal; ligula widening apically, apical portion bilobed. Pronotum moderately transverse, distinctly narrower than elytral base, sides subparallel or slightly widening in the anterior portion, in some species with fossulate depressions in anterolateral portion; a pair of foveae near posterior margin, lying in a distinct transverse groove. Elytra elongated; humeri well marked. Wings without CuA+AA 1+2 vein. Tibiae with paired longitudinal carinae. Aedeagus variable, either tubular or flattened; penis fused with tegmen.

Female. Known only for C. fossulatus , flightless; elytral humeri absent, abdominal ventrite 4 with a pair of setal tufts, coxites membranous, prehensor distinct.

The genus resembles Roraiman Exagonthus Waterhouse, 1900 in several aspects (long tempora, pronotum much narrower than elytral bases, moniliform antennae, similar morphology of meso- and metaventrite), but the sides of pronotum are simple, never extended into distinct lobes, hind wings lack CuA+AA 1+2 vein (present in Exagonthus ) and the lacinia has an apical hook (absent in Exagonthus ). The New Zealand Mesocyphon Sharp is externally similar to Chilarboreus , although it differs in several characters: antennal fossae deep, basal groove of pronotum absent, laciniar hook absent, CuA+AA 1+2 vein present.

The genus is divided into Chilarboreus subgen. nov. and Pictarboreus subgen. nov.

Biology

Biological data are limited to the collecting data. The genus inhabits Chilean temperate forests, numerous specimens were collected by fogging, therefore it can be suspected that they dwell in tree tops of several species ( Saxegothaea conspicua , Aextoxicon punctatum , Pseudopanax sp., Nothofagus spp., Laureliopsis philippiana and Eucryphia cordifolia ).

Etymology

Name of the terra typica ( Chile) combined with latin arboreus; an allusion to the occurrence in the tree-tops of Nothofagus forests; gender masculine.

Key to subgenera and species of Chilarboreus gen. nov.

1. Pronotum with depressions at sides, widest at base, sides straight, surface rugose, punctures granulate; clypeus with distinct transverse emargination; femoral groove with distinct, hexagonal microreticulation; aedeagus flattened, dorsum uniformly brown ( Chilarboreus subgen. nov.)............... 2

Pronotum even, without depressions at sides, widest in anterior portion, sides sinuate, surface smooth, punctures not granulate; clypeus truncate, without emargination; femoral groove rugose, without microreticulation; aedeagus tubular; elytra with more or less visible, variable dark pattern ( Pictarboreus subgen. nov.)................... Chilarboreus (Pictarboreus) darwini sp. nov.

2. Anterior angles of pronotum well marked, rectangular; anterior fossae shallow; trigonium of penis bifid....................................................................... Chilarboreus (Chilarboreus) acuticollis sp. nov.

Anterior angles of pronotum not marked, obtuse; anterior fossae deep; aedeagus short, trigonium of penis subrectangular...................................................... Chilarboreus (Chilarboreus) fossulatus sp. nov.