Morionini

Introduction

Presently there are 87 named species in the tribe, the majority (69) in Morion Latreille and Stereostoma Murray. Most species are found in tropical or subtropical regions with a few taxa reaching low latitude temperate areas.

Characteristics

The combination of moniliform antennomeres, prominent eyes (except in Hyperectenus Alluaud), elytral plica not externally visible, expanded apex of the protibia with an apico-laterally produced spine (except in Morionidius Chaudoir) and projecting dentiform process above the insertion point of the antenna is characteristic of members of this tribe.

All species in the tribe are deep black to piceus brown, rather shiny and typically large sized, most about 15-30mm (range 8-80mm). Most species are Morion-like in general form, elongate, parallel-sided and somewhat depressed and subpedunculate. However, many of the genera, which contain about a third of the species, are much more compact and convex in form. All have deeply impressed frontal impressions on the head and deep, linear pronotal basal impressions.

Allen (1968) presented five features he considered to characterize the tribe: moniliform antennae, elytral plica internal, 4-12 setae on lateral margin of the pronotum, stria 8 with alternating setigerous punctures and the rod-like process of the endophallus. Many taxa do have these features, however, aside from the moniliform antennae, none of these characters is found to be definitive for the tribe as a whole. Most of these are known only in the more derived Morion-like genera and exceptions are common, e.g., Hyperion Laporte de Castelnau lacks pronotal setae, Buderes Murray and Hyperectenus lack the additional setigerous punctures of stria 8 and Stereostoma does not have the process of the endophallus.

Discussion of Phylogenetic Relationships

Monophyly for the tribe is supported by a single synapomorphy, moniliform antennomeres, a characteristic found in several other groups of Carabidae, and in Hyperion the antennae are submoniliform. Other characters of the eyes and head, under specific optimization hypotheses may support the monophyly of Morionini. Overall there is little support for a monophyletic Morionini including Stereostoma and Morionidius.

Information on the Internet

• Key to the Genera of Morionini - Kipling Will, UC Berkeley