Molecules, morphology and Mimeoma scarabs: evolutionary and taxonomic implications for a palm‐associated scarab group

Abstract

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 Mimeoma Casey, a group of Neotropical palm-feeding scarabs, and its relationship to Cyclocephala with a phylogenetic analysis of 2899 bp of DNA sequence data and 18 morphological characters. All five species of Mimeoma were included in analyses along with species of Cyclocephala Dejean, Dyscinetus Harold and Tomarus Erichson 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 acuta Arrow n.comb., Cyclocephala englemani (Ratcliffe) n.comb., Cyclocephala maculata Burmeister n.comb., Cyclocephala nigra (Endrödi) n.comb. and Cyclocephala signatoides Höhne n.comb. 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.

Synopsis of the cyclocephaline scarab beetles (Coleoptera, Scarabaeidae, Dynastinae)

“…These species were placed into the “ helleri species-group” based on the bidentate form of the protibial margin in males. This male protibial character is shared with species formerly included in Mimeoma and some Cyclocephala species (like C. amazona ) (see Moore et al 2015). The dorsal coloration of the “ helleri species-group”, especially the elongated, triangular maculae found along the elytral suture, is like that found in some former Mimeoma species (especially Cyclocephala acuta Arrow and C. englemani (Ratcliffe)).…”

“…Breeschoten et al (2013) presented a morphological phylogeny of cyclocephaline genera, but few details of the analysis were provided and the support for recovered relationships were not reported. Moore et al (2015) suggested that Mimeoma species were nested among a clade of Cyclocephala that included the type species of the genus, C. amazona . These data also provided evidence of two major clades of Cyclocephala based on morphological and molecular evidence (Moore et al 2015).…”

“…Moore et al (2015) suggested that Mimeoma species were nested among a clade of Cyclocephala that included the type species of the genus, C. amazona . These data also provided evidence of two major clades of Cyclocephala based on morphological and molecular evidence (Moore et al 2015). However, the relationship of Cyclocephala to the other cyclocephaline genera is completely unevaluated.…”

Annotated catalog and bibliography of the cyclocephaline scarab beetles (Coleoptera, Scarabaeidae, Dynastinae, Cyclocephalini)

“… Arrow 1902 , 1937b , Blackwelder 1944 , Pike et al 1976 , Endrődi 1966 , 1985a , Bullock 1981 , Beach 1984 , Morón et al 1985 , Thomas 1993 , Ratcliffe and Morón 1997 , Ratcliffe 2002a , 2003 , Restrepo et al 2003, Ratcliffe and Cave 2006 , Neita-Moreno 2011 , Krajcik 2005 , 2012 , Moore 2012 , Ratcliffe et al 2013 , Moore et al 2015 , Gasca-Álvarez and Deloya 2016 .…”

“… Burmeister 1847 , Harold 1869b , Höhne 1923b , Arrow 1937b , Blackwelder 1944 , Pike et al 1976 , Endrődi 1966 , 1985a , Silberbauer-Gottsberger et al 2001 , Ratcliffe 2002a , 2003 . Neita-Moreno et al 2006 , Ratcliffe and Cave 2006 , Neita-Moreno 2011 , Otavo et al 2013 , Ratcliffe et al 2013 , López-García et al 2015 , Moore et al 2015 , Deloya et al 2014a , 2016 , Gasca-Álvarez and Deloya 2016 , Hielkema 2017 .…”