Molecular phylogeny of Megacephalina Horn, 1910 tiger beetles (Coleoptera: Cicindelidae)

Abstract

The pantropical subtribe Megacephalina represented by more than 100 species is the most diverse of the basal cicindelid groups. Today, most taxonomists recognize eight genera within the subtribe. This is in contrast to Horn who, back in 1910, conceded only two genus-level taxa: the monospecific Aniara and Megacephala sensu Horn (a genus which united the seven other taxa). In the present study we provide a molecular phylogeny of Megacephalina based on the nuclear 18S and the mitochondrial 16S and cytochrome oxidase III genes. The dataset includes 60 specimens of more than 40 mostly South American and Australian taxa. Three cicindelid species of derived lineages were used as outgroups. The resulting phylogenetic trees are basically in agreement with the current classification system. Megacephala and Grammognatha are placed basal in the dendrogram. Pseudotetracha and Australicapitona form a monophyletic Australian clade. Phaeoxantha, Tetracha and Aniara also form a monophyletic group. The position of Metriocheila remains uncertain. The most striking deviation from the traditional classification is the well-supported placement of Aniara within Tetracha, rendering the latter a paraphyletic taxon. Several monophyletic subgeneric species groups are observed in Pseudotetracha, Phaeoxantha and Tetracha/Aniara. Within the latter the monophyletic sobrina, carolina and brasiliensis clades together represent a monophyletic group. Additionally, habitat types were assigned to the taxa and mapped on the phylogenetic tree. The basal African species inhabit non-flooded uplands. The Australian species moved to inland and/or coastal salt plains. The American groups were most likely first confined to river margins and then colonized secondarily and independently non-flooded uplands and/or coastal habitats

The blackburni/murchisona species complex in Australian Pseudotetracha (Coleoptera: Carabidae: Cicindelinae: Megacephalini): evaluating molecular and karyological evidence

“…One of them includes Pseudotetracha pulchra , P. mendacia , P. australis , P. cuprascens , P. corpulenta and the samples we identified as P. blackburni . A second clade contains P. whelani samples, including the sample studied by Zerm et al. (2007).…”

“…The samples analysed in this work (Table S1) included the Pseudotetracha sequences used by Zerm et al. (2007) and available from the GenBank database, along with those from 89 Pseudotetracha samples collected in South Australia in 2004.…”

“…2007). Sequences of Neocollyris sp., Pentacomia discrepans , Odontocheila confusa , Grammognatha euphratica and Megacephala virginica from the work of Zerm et al. (2007) were used as outgroups.…”

“…On the basis of morphological characters, Sumlin (1997) suggested the existence of several closely related species within the blackburni / murchisona complex, including Pseudotetracha blackburni , Pseudotetracha murchisona , Pseudotetracha corpulenta , Pseudotetracha mendacia and Pseudotetracha cuprascens . However, a subsequent analysis based on nuclear 18S, mitochondrial 16S and cytochrome oxidase III genes of 40 South American and Australian taxa (Zerm et al. 2007) determined that P. blackburni should not be grouped with other members of Sumlin’s blackburni / murchisona complex.…”

Recent origin of a chiasmatic sex trivalent in Australian Pseudotetracha tiger beetles

“… K aryotypic data available for M egacephalini in the context of a phylogenetic tree based on the works of Z erm et al . () and L ópez‐ L ópez et al . ().…”