Identification of a Rare Gecko from North Island New Zealand, and Genetic Assessment of Its Probable Origin: A Novel Mainland Conservation Priority?
The largest extant New Zealand gecko, Hoplodactylus duvaucelii (Duvaucel's Gecko), is a nocturnal, viviparous species of conservation concern. Hoplodactylus duvaucelii, once widespread throughout New Zealand, is now confined to offshore islands, the majority of which are free from all introduced mammalian predators (mice, rats, cats, mustelids, brushtail possums). A single H. duvaucelii, caught within a fenced reserve on North Island in 2010 was genotyped to determine whether it represents a recent introduction or a previously unknown native relict population. Genotypes from seven nuclear loci and a minimum spanning network of mtDNA haplotypes revealed two clusters representing southern (Cook Strait) and northern island populations. This genetic structure is concordant with variation between these two groups observed in body size, color pattern, and scalation. The mainland specimen was found to possess a mixture of morphological character states typical of northern and southern island populations. Although the individual possessed a unique mitochondrial haplotype, high heterozygosity, and a private nuclear allele, it was no more genetically distinct than conspecifics from isolated island populations. Comparisons with live captive geckos failed to provide evidence that the aberrant specimen represented a recent translocation. We infer that H. duvaucelii has survived naturally on North Island at very low population densities since the human-mediated introduction of novel predators 800 years ago. Our findings suggest a novel conservation priority, which should be prioritized for additional study in the immediate future.Abstract
The extensive prehuman distribution of the New Zealand gecko Hoplodactylus duvaucelii, inferred from bone deposits and museum records.
The single Hoplodactylus duvaucelii specimen, captured in a mouse trap, in 2010 in the Maungatautari reserve, four years after eradication of most introduced mammalian predators. This is the first record of this species on mainland New Zealand in more than 60 yr.
Genetic structure within the New Zealand Hoplodactylus duvaucelii is concordant with their location on offshore islands. Identified island groups (A) and sample size is included in brackets. A minimum spanning network of mtDNA haplotypes, 1,900 bp (B). Circle size corresponds to haplotype frequency, and sample IDs match those presented in Table 1. Inferred but unsampled haplotypes are indicated by small circles, and captive specimens are indicated with prefix “c.” The 7-locus NeighborNet splits tree network (C). Genetic distances were inferred from pairwise FST (captive geckos excluded). The Maungatautari individual is colored yellow.
Heterozygosity levels of wild (grey) and captive (white) Hoplodactylus duvaucelii derived from seven nuclear loci. Note relatively high heterozygosity in the mainland New Zealand specimen (black). A captive animal resulting from crossing northern and southern (Cook Strait) parents was heterozygous at six loci.
Genetic structure within the New Zealand gecko Hoplodactylus duvaucelii inferred from seven nuclear loci using STRUCTURE analysis. (A) K = 2; (B) K = 3. Maungatautari individual indicated with arrow and *. Localities are: Poor Knights (1), Hen and Chickens (2–4), Great Barrier (5), Shoe and Slipper (6), Mercuries (7–11), Aldermans (12–16), Brothers (18–26), Trios (27–29).
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