A Molecular and Morphological Phylogenetic Analysis of Afrotropical Monolepta Species and Related Galerucinae (Coleoptera: Chrysomelidae)

Abstract

The phylogenetic status of Afrotropical galerucines was investigated with molecular and morphological analyses. The taxon sample analysed comprised 15 species within Monolepta, three within Afrocandezea, two each within Afrocrania and Barombiella and one Pseudocrania species; all were originally placed in “Monoleptites”. Further galerucines outside the “Monoleptites” are Diacantha sp., Exosoma polita, Exosoma sp., Galerudolphia tenuicornis, and Parasbecesta ruwensorica. The chrysomeline Linaeidea nubila was included as outgroup. 35 morphological characters including 16 characters on genital morphology were analysed. A 540 bp mitochondrial DNA NADH dehydrogenase subunit 1 (ND1) fragment and the entire second internal transcribed spacer region ITS2 (519–709 bp) of the nuclear ribosomal DNA were sequenced from 22 and 24 taxa, respectively. Both molecular data sets were characterized by a high average A-T content of 86.4% (ND1) and 62.7% (ITS2). Trees of separate and combined data sets were reconstructed with Maximum Parsimony (MP) and Maximum Likelihood (ML) approaches. The congruent tree topologies of both morphological and molecular data sets strongly support the monophyly of Monolepta, Afrocrania and Afrocandezea with regard to recently revised Afrotropical representatives. Barombiella emerged as polyphyletic, on species showing close relationship to Galerudolphia tenuicornis, which is traditionally placed in the “Scelidites”. “Monoleptites” is most likely polyphyletic since its decisive character, the elongated metatarsus, obviously evolved more than once in the Galerucinae. Understanding of the phylogenetic position and delimitation of the taxa primarily based on morphological characters could be significantly improved by molecular data.