Cytochrome b gene based phylogeny and genetic divergence of Tetraophasis of China

Tetraophasis (Galliformes; Phasianidae) includes T. obscurus and T. szechenyii, which are endemic and distributed in the west and central parts of China. The phylogenetic status of Tetraophasis in the Phasianidae and the divergence of the two species are still controversial. We performed a phylogenetic study using DNA sequences of 828bp of the mitochondrial cytochrome b (Cytb) genes of Tetraophasis and of selected species of several other genera of Phasianidae. The phylogenetic trees suggest that Tetraophasis species belong to Phasianinae, which is inconsistent with the traditional taxonomic view that these species belong to Perdicinae. Sequence difference between T. obscurus and T. szechenyii was 3.0-3.1% and the divergence time was 1.88-1.94 Myr based on molecular clock estimate. Compared with other genera, T. obscurus and T. szechenyii should be classified as two distinct species. Our data suggest that the divergence of Tetraophasis may have been induced by the uplift of the Qinghai-Tibet Plateau and by environmental changes.

The tusked king cricket, Libanasidus vittatus (Kirby, 1899) (Anostostomatidae), from South Africa: morphological and molecular evidence suggest two cryptic species

An evaluation of genetic structuring and morphometric variation within tusked king crickets, Libanasidus vittatus (Kirby, 1899), from South Africa suggests two main population assemblages. Maximum likelihood (ML), Parsimony, Bayesian and phenetic analyses of mitochondrial cytochrome oxidase I (COI) sequence data recovered two well-supported clades corresponding to two biogeographically distinct populations. Canonical variates (discriminant) analysis (CVA) also showed evidence of two phenetic assemblages that correspond to the genetically delineated groups. Libanasidus vittatus is the recognized species occurring within an eastern population in South Africa (Mpumalanga and Eastern Cape Provinces), while a possible novel species occurs within a north–western population in South Africa (Limpopo and Gauteng Provinces). Using a molecular clock estimate of 2.0% divergence per million years, suggests isolation of the two populations at approx. 1.65 million years ago, possibly due to the formation of isolating forest pockets during the dry Pleistocene Epoch. The average genetic divergence of 3.3% between the two populations, and low migration rate estimates corresponding to less than one female migration per generation further support the presence of two cryptic tusked king cricket species in South Africa.