New and known extinct species of Rhyzobius Stephens, 1829 shed light on the phylogeny and biogeography of the genus and the tribe Coccidulini (Coleoptera: Coccinellidae)

Abstract

Rhyzobius Stephens, 1829 is a diverse genus of ladybird beetles (Coccinellidae) with more than 100 extant species distributed in the Old World. Despite recent revision of that genus its internal classification has been unclear. However, based on morphological differences, four main evolutionary lineages could be expected, two distributed in Euro-African and two in the Australo-Oriental regions. The oldest representatives of Rhyzobius were described quite recently from early Eocene amber deposited in Oise, France. Three more species belonging to this genus were found in Baltic amber and are described here as R. groehni sp. nov., R. sontagae sp. nov. and R. szwedo sp. nov. In order to test the systematic placement of extinct taxa, a phylogenetic analysis was conducted, combining extant and extinct species of Rhyzobius. A dataset of 74 morphological characters scored for 29 recent and four extinct species across the genus Rhyzobius was analysed using maximum parsimony and Bayesian inference methods. This is the first morphology-based phylogeny of the genus Rhyzobius supporting the existence of four evolutionary lineages of modern taxa. All extinct taxa, from both the Oise and Baltic ambers, form a distinct group in the single clade within the African group of species. Based on the results of the phylogenetic analysis, a discussion on the historical biogeography of the genus is provided.https://zoobank.org:pub:7CAE0F5B-F03E-4E07-A59D-7985AB7B452F