New Zealand forest-dwelling skinks of the Oligosoma oliveri (McCann) species-complex (Reptilia: Scincidae): reinstatement of O. pachysomaticum (Robb) and an assessment of historical distribution ranges.

The forest-dwelling skinks of the Oligosoma oliveri ('marbled skink') species-complex, from the North Island of New Zealand, have proven difficult taxonomically because all mainland populations are extinct, obscuring patterns of distribution and population interaction. Twenty-four small insular populations have survived off the north-east coast of the North Island, which are at present classified into three species. In this paper I re-assess the available phenotypic, ecological, biogeographic and phylogenetic evidence associated with these skinks. As a result, O. pachysomaticum (Robb) is raised from synonymy with O. oliveri (McCann) and more precise historical distribution limits are inferred for each member of the group. Implications for the conservation management of each species are also discussed.

Phylogeographic history of the New Zealand stick insect Niveaphasma annulata (Phasmatodea) estimated from mitochondrial and nuclear loci.

We have assessed the utility of a single-copy nuclear locus and mitochondrial DNA (mtDNA) in a phylogeographic study of the New Zealand stick insect Niveaphasma annulata (Hutton). We amplified sequences from the mitochondrial cytochrome oxidase subunit I (COI) gene and the single-copy nuclear gene elongation factor-1alpha (EF1alpha) from 97 individuals. Allelic phase at the EF1alpha locus was determined using Denaturing Gradient Gel Electrophoresis. Phylogenetic analyses showed broad congruence between the geographic distribution of three major COI clades and EF1alpha alleles, which suggested that the phylogenetic patterns reflect population history rather than lineage sorting. However, the geographic boundaries of these clades were not always in exact agreement between the two loci. Our data indicate that Niveaphasma annulata was most likely separated into a number of refugia during Pleistocene glacial advances. Subsequent to glacial retreat these refugial populations have expanded and now form a number of zones of secondary contact. We contrast these patterns with those observed from other New Zealand taxa. Our study offers compelling evidence for the use of nuclear genes alongside mtDNA for future phylogeographic studies.

Investigating hybridization in the parthenogenetic New Zealand stick insect Acanthoxyla (Phasmatodea) using single-copy nuclear loci.

The New Zealand stick insect genus Acanthoxyla Uvarov is extremely unusual among higher taxa of animals in that all known species are obligate parthenogens. We have used a combination of the mitochondrial DNA genes cytochrome oxidase subunits I and II, 28S nuclear ribosomal RNA, and the two single-copy nuclear genes elongation factor 1alpha and phosphoglucose isomerase to test hypotheses on the role of hybridization in the evolution of this genus. Alleles at the single-copy nuclear loci in three sampled species of Acanthoxyla were resolved by cloning the PCR products. Analysis of multilocus genotypes shows that most sampled individuals of Acanthoxyla possess three alleles at the single-copy nuclear loci, which we have interpreted to indicate triploidy. Because most of the alleles from Acanthoxyla form a monophyletic group, including sets of alleles possessed by the putative triploids, we have inferred that the extant parthenogenetic lineages formed via hybridization between species of Acanthoxyla, at least one of which must have been sexual. More recently, there have been multiple introgression events from the related species Clitarchus hookeri White, although C. hookeri does not appear to be involved with the origin of parthenogenesis in Acanthoxyla. Our study demonstrates the utility of cloning alleles from multiple single-copy nuclear genes for resolving the origins of parthenogenetic lineages.