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

Abstract

Our phylogenetic analysis of three endemic species of the Australian tiger beetle genus Pseudotetracha (Fleutiaux, 1864) from South Australia used sequences of two fragments of the mitochondrial genes 16S rRNA and cytochrome oxidase III. A matrix for each gene and two combined matrices were constructed. We compared these three riparian species, together with data from nine taxa of this genus available in GenBank, using parsimony and Bayesian methods. These molecular results are in agreement with the phylogenetic hypothesis for the blackburni/murchisona species complex previously proposed based on morphology, whereas other recent molecular analyses have questioned the existence of this species complex. In all of our analyses, samples of P. blackburni divided into two statistically supported clades, one of which is more closely related to P. mendacia and P. pulchra than to the other P. blackburni clade. This suggests the existence of a cryptic new species. Additionally, we analysed chromosomes of the second metaphase cells of members of the two clades. The observations showed different karyotypes as blackburni‐1 has two types of second meiotic metaphase cells with 11 and 12 chromosomes, whereas in blackburni‐2, all cells have 12 chromosomes, adding evidence for the putative existence of two species.

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

“…Currently, 19 species of Pseudotetracha have been described but only those occurring in Southern Australia are well known. A recent phylogeny of the genus by López‐López, Hudson & Galián () based on analysis of nuclear and mitochondrial genes supports the existence of the blackburni/murchisona species complex described by Sumlin () and illustrated the existence of two clades in samples morphologically identified as P. blackburni , which corresponded to two different lakes with evidence of different karyotypes in metaphase II cells. Pseudotetracha whelani had previously been cytogenetically studied (Galián & Hudson, ) from Lake Acraman, showing a karyotype with a meioformula n = 12 + XY, but no data of the other Pseudotetracha species are available.…”

“…) in general confirms the phylogenetic relationships reported previously by López‐López et al . (). The only difference was the position of P. pulchra , which, in this work, is sister to clades of P. blackburni + P. mendacia , while in the previous work, it is situated inside this group as sister to P. mendacia .…”

“…The material analyzed in this study was collected from different localities in South Australia during the months of March and April of 2004. Localities of the 89 sequenced individuals have been previously reported (Supplementary Material in López‐López et al ., ). The localities of the 19 male specimens that provided cytogenetic data are listed in Table .…”

“…The aim of this work was to confirm the existence of two cytogenetically differentiated clades in P. blackburni, extend the previous cytogenetic survey in P. whelani to more populations from different lakes and report first karyotypic data for P. australis from Lake Barker. These data will be interpreted in the context of a time-calibrated phylogeny obtained using the sequence information of previous papers (Zerm et al, 2007;López-López et al, 2012).…”

Systematic review of the “Chromodoris quadricolorgroup” of East Africa, with descriptions of two new species of the genusChromodorisAlder & Hancock, 1855 (Heterobranchia, Nudibranchia)

“…In the SDGP analysis (Table ), the ratio between the average distance of the specimens in one clade (Intra Dist) and the average distance of samples to the closest clade (Inter Dist) was all ≤0.30, revealing that the genetic differences within the clades were smaller than the differences between the clades; that is, the clades were well supported (López‐López, Hudson, & Galián, ; Masters et al, ).…”