Ocyolinus

Introduction

Ocyolinus occurs in tropical rain and montane forests and similarly to Isanopus, it appears to be quite rare in collections. Most specimens have been collected in flight intercept traps and fewer in leaf litter. Ocyolinus is distributed from Guatemala to Venezuela. Ocyolinus was described by Sharp in 1884. The genus included two species, O. rugatus Sharp, 1884 from Venezuela and O. amethystinus Sharp, 1884 from Costa Rica. Later, Bernhauer (1906) described two more species, O. vulneratus Bernhauer, 1906 and O. ganglbaueri Bernhauer, 1906, both from Venezuela. Chatzimanolis (2009) in the revision of the genus described three additional species (O. astenos, O. dimoui and O. nebulosus), and placed into synonymy O. vulneratus with O. rugatus.

Characteristics

Ocyolinus can be distinguished from other genera in the subtribe Xanthopygina by the combination of the following characters:

• mandibles extremely elongate, each with a single triangular tooth that is typically slightly different in right and left mandible
• maxillary and labial palpi expanded, but never as dilated as in Dysanellus Bernhauer, 1911
• antennomere 11 with a distal white patch of setae
• head subquadrate, never trapezoid (as in Dysanellus or Torobus Herman, 2001)
• integument of head and pronotum with microsculpture
• terga V–VI without subbasal carinae
• median lobe of aedeagus with a pair of dorsal teeth.

Due to body coloration, Ocyolinus looks superficially similar to several species of Gastrisus Sharp, 1876, Nausicotus Sharp, 1884 and Torobus, but can be easily distinguished from them because the latter species do not have elongate mandibles.

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Top row, from left to right: O. amethistinus, O. astenos and O. dimoui.
Bottom row, from left to right: O. ganglbaueri, O. nebulosus and O. rugatus. © 2009 Stylianos Chatzimanolis

With the exception of O. rugatus (rugose sculpture) and O. amethystinus (very few punctures on head and pronotum) species of Ocyolinus may be challenging to identify. The remaining species can be reliably identified based on the shape of the mandibles and the shape of their aedeagi.

References

Bernhauer, M. 1906. Neue Staphyliniden aus Südamerika. Dtsch. Entomol. Z., 1906:193–202.

Chatzimanolis, S and J. S. Ashe. 2009. A revision of the neotropical genus Ocyolinus (Coleoptera: Staphylinidae: Staphylinini). Zootaxa 2162:1–23

Sharp, D. 1884. Staphylinidae. In: Biologia Centrali-Americana. Insecta. Coleoptera 1(2). Taylor & Francis, London, pp. 313–392.

Information on the Internet

• MorphBank gallery