Sympatric cryptic species in New Zealand Onychophora

Allozyme electrophoresis was used to examine genetic diversity within live-bearing Peripatopsid Onychophora from the North Island of New Zealand. Specimens of two previously described morpho-species that differ in leg number (Peripatoides suteri and P. novaezealandiae) were found to be genetically diverse. P. suteri showed little intraspecific genetic variation but were very distinct from specimens assignable to P. novaezealandiae. Within P. novaezealandiae five genetically differentiated species were identified although none showed any consistent morphological differentiation, thus P. novaezealandiae (Hutton) is a species complex. All of these species occur in sympatry or parapatry (in one instance) with other cryptic species of the P. novaezealandiae group or with P. suteri. Four new species are described on the basis of this genetic evidence, they are P. morgani, P. aurorbis, P. kawekaensis and P. sympatrica. Other genotypes encountered indicate further cryptic species remain unrecognized. Among the North Island species, P. suteri and P. aurorbis sp. nov. are both more closely related to undescribed species from the South Island than to others examined from the North Island. P. sympatrica sp. nov. exists in sympatry with at least three other species in different parts of its range. The complexity of relationships and distributions probably arose through the interaction of low vagility in peripatus and the active geophysical history of the region. How these cryptic species persist in sympatry is not known but may be linked to differences in ecology not evident in their morphology, and/or may indicate recent dispersal from allopatry.     

Mitochondrial DNA sequences support allozyme evidence for cryptic radiation of New Zealand Peripatoides (Onychophora)

A combination of single-strand conformation polymorphism analysis (SSCP) and sequencing were used to survey cytochrome oxidase I (COI) mitochondrial DNA (mtDNA) diversity among New Zealand ovoviviparous Onychophora. Most of the sites and individuals had previously been analysed using allozyme electrophoresis. A total of 157 peripatus collected at 54 sites throughout New Zealand were screened yielding 62 different haplotypes. Comparison of 540-bp COI sequences from Peripatoides revealed mean among-clade genetic distances of up to 11. 4% using Kimura 2-parameter (K2P) analysis or 17.5% using general time-reversible (GTR + I + Gamma) analysis. Phylogenetic analysis revealed eight well-supported clades that were consistent with the allozyme analysis. Five of the six cryptic peripatus species distinguished by allozymes were confirmed by mtDNA analysis. The sixth taxon appeared to be paraphyletic, but genetic and geographical evidence suggested recent speciation. Two additional taxa were evident from the mtDNA data but neither occurred within the areas surveyed using allozymes. Among the peripatus surveyed with both mtDNA and allozymes, only one clear instance of recent introgression was evident, even though several taxa occurred in sympatry. This suggests well-developed mate recognition despite minimal morphological variation and low overall genetic diversity.     

Support for vicariant origins of the New Zealand Onychophora

Aim The distribution of Onychophora across the southern continents has long been considered the result of vicariance events. However, it has recently been hypothesized that New Zealand was completely inundated during the late Oligocene (25–22 Ma) and therefore that the entire biota is the result of long-distance dispersal. We tested this assumption using phylogenetic and molecular dating of DNA sequence data from Onychophora. Location New Zealand, Australia, South Africa, Chile (South America). Methods We obtained DNA sequence data from the nuclear genes 28S and 18S rRNA to reconstruct relationships among species of Peripatopsidae (Onychophora). We performed molecular dating under a Bayesian relaxed clock model with a range of prior distributions using the rifting of South America and South Africa as a calibration. Results Our phylogenetic trees revealed that the New Zealand genera Ooperipatellus and Peripatoides, together with selected Australian genera (Euperipatoides, Phallocephale and an undescribed genus from Tasmania), form a monophyletic group that is the sister group to genera from Chile (Metaperipatus) and South Africa (Peripatopsis and Opisthopatus). The relaxed clock dating analyses yielded mean divergence times from 71.3 to 78.9 Ma for the split of the New Zealand Peripatoides from their Australian sister taxa. The 0.95 Bayesian posterior intervals were very broad and ranged from 24.5 to 137.6 Ma depending on the prior assumptions. The mean divergence of the New Zealand species of Ooperipatellus from the Australian species Ooperipatellus insignis was estimated at between 39.9 and 46.2 Ma, with posterior intervals ranging from 9.5 to 91.6 Ma. Main conclusions The age of Peripatoides is consistent with long-term survival in New Zealand and implies that New Zealand was not completely submerged during the Oligocene. Ooperipatellus is less informative on the question of continuous land in the New Zealand region because we cannot exclude a post-Oligocene divergence. The great age of Peripatoides is consistent with a vicariant origin of this genus resulting from the rifting of New Zealand from the eastern margin of Gondwana and supports the assumptions of previous authors who considered the Onychophora to be a relict component of the New Zealand biota.