Molecules, morphology and Mimeoma scarabs: evolutionary and taxonomic implications for a palm-associated scarab group
Authors
Advisors
Issue Date
Type
Keywords
Citation
Abstract
Cyclocephaline scarabs, the second largest tribe of rhinoceros beetles, are important pollinators of early-diverging angiosperm families in the tropics. The evolutionary history of cyclocephaline genera is poorly resolved and several genera are thought to be nonmonophyletic. We assess the monophyly of MimeomaCasey, a group of Neotropical palm-feeding scarabs, and its relationship to Cyclocephala with a phylogenetic analysis of 2899bp of DNA sequence data and 18 morphological characters. All five species of Mimeoma were included in analyses along with species of CyclocephalaDejean, DyscinetusHarold and TomarusErichson as outgroup taxa. Nearly complete 28S, 12S and CO1 data were collected from 26 of 29 specimens, of which 16 samples were pinned, museum specimens. 28S data strongly support a nonmonophyletic Mimeoma; mitochondrial data (CO1 and 12S) suggest that Mimeoma species are nested within an apical clade of other Cyclocephala species; combined molecular and morphological data identify two strongly supported clades of Mimeoma species but do not support their sister relationship. Combined data show that Mimeoma species are nested within Cyclocephala, thus rendering Cyclocephala paraphyletic. Mimeoma is synonymized within Cyclocephala resulting in the following new combinations:Cyclocephala acutaArrow ., Cyclocephala englemani (Ratcliffe) ., Cyclocephala maculataBurmeister ., Cyclocephala nigra (Endrodi) . and Cyclocephala signatoidesHohne . Our results demonstrate that pinned, museum specimens can be used to obtain DNA sequence data (particularly high-copy gene regions) for evolutionary studies, and provide the first empirical support that host-plant associations within cyclocephaline scarab clades are conserved at the plant family-level.