Published online by Cambridge University Press: 29 August 2016
Micracidini (Coleoptera: Curculionidae: Scolytinae) is an unusual tribe of mainly bigynous bark beetles found in dry forests and scrublands in Afrotropical and Neotropical regions. Their phylogenetic relationship to other bark beetle groups is poorly known with few clues from external morphology. Hence, a phylogenetic analysis of five genes (COI, EF-1a, 28S, CAD, ArgK) and morphological (internal and external) data was conducted to test potential sister group relationships, including 56 outgroup genera in 22 tribes, and 18 species in 10 genera of Micracidini. Cactopinus Schwarz – a genus with many cactus feeding species – was nested within a clade of all Neotropical and Nearctic genera. The New World was colonised by an Afrotropical ancestor about 75–85 million years ago, where cactus feeding in Cactopinus evolved much later. All analyses indicated a paraphyletic clade of Afrotropical micracidines, strongly supporting inclusion of the Ipini genus Dendrochilus Schedl in Afromicracis Schedl. Hypoborini appear to be one of the more plausible sistergroup candidates to Micracidini, and revealed morphological similarity in protibial and proventricular characters. Most phylogenetic results were supported independently by morphological and molecular data and therefore document the power of thorough examination of morphological characters analysed properly in a phylogenetic context.
Subject editor: Derek Sikes