Phylogeny recapitulates geography, or why New Zealand has so many species of skinks

Abstract

The evolutionary history of 25 New Zealand scincid lizards in the endemic genera Oligosoma and Cyclodina was examined using 12s rRNA sequence data. Phylogenetic resolution was poor, despite there being up to 9% sequence divergence between taxa. Lack of resolution was not attributable to biases in the data, such as site saturation or differences in sites free to vary, so we infer that New Zealand skinks underwent two relatively rapid phases of divergence. The rate of substitution for the skink sequences appears to be similar to some bird and mammal groups for which times of divergence have been estimated. Using these calibrations diversification of Olzgosorna skinks probably began at least 23 million years ago (Mya). The pattern of relationships and the timing of this diversification are interpreted as resulting from rapid allopatric speciation during the Oligocene (25-35 Mya) when New Zealand was fragmented into many low lying islands.

Taxonomic revision of the marbled skink (Cyclodina oliveri, Reptilia: Scincidae) species complex, with a description of a new species

“…our morphological and mitochondrial sequence data for the "Mokohinau" skink are concordant with previous mitochondrial DNa (hay 1988;hickson et al 2000) and allozyme data (vos 1988; ChD unpubl. data), supporting our description of this taxon as C. townsi.…”

Miocene skinks and geckos reveal long-term conservatism of New Zealand's lizard fauna

“…They provide the first minimum age constraints for the divergence of the endemic NZ scincid and gekkotan clades from their extralimital sister groups (Chapple et al 2009). Molecular divergence dating using other calibration points has thus far yielded highly disparate dates for the age of NZ skinks, suggesting that they diverged from New Caledonian relatives 20 Myr ago (Hickson et al 2000) or either 22.9 -19.9 or 7.9 Myr ago, depending on calibrations and genes employed (Smith et al 2007). For geckos, the only study suggests NZ geckos diverged from (primarily) New Caledonian relatives about 30 Myr ago (Chambers et al 2001; see §1).…”

“…Kumazawa 2007), this extrapolation would underestimate (by half) divergence dates within skinks. Thus, the deeper molecular estimates for NZ skink origins (more than 20 Myr ago: Hickson et al 2000;Chapple et al 2009) are best supported by the fossil record, phylogeography and methodological considerations.…”

“…There has been no direct evidence for the antiquity of this fauna, with fossils currently limited to the Quaternary (Worthy 1987(Worthy , 1991. However, independent molecular dating suggested that NZ skinks diverged from their New Caledonian relatives as early as more than 20 Myr ago (Hickson et al 2000) or as recently as 7.9 Myr ago (Smith et al 2007). A more extensive study by Chapple et al (2009), calibrated using preliminary announcements of St Bathans lizards (e.g.…”

The character of the New Zealand land snail fauna and communities: some evolutionary and ecological perspectives

“…Throughout the late Cretaceous and early Tertiary steady erosion and marine transgression reduced both the extent and topology of New Zealand's landscape, so that during the late Oligocene-early Miocene only a scattered archipelago of low-lying islands remained. Several authors have highlighted the possible substantive extinction and genetic bottlenecks faced by the flora and fauna resident at that time (Cooper and Cooper, 1995;Cooper, 1998;Hickson et al, 2000), although Lee et al (2001) point out that the extent of land at the height of the Oligocene transgression was still considerable at around 20,000 km 2 and that there is no evidence in angiosperms of significant biotic loss.…”