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Phylogeography of the New Zealand whelks Cominella maculosa and C. virgata

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Version 2 2023-09-26, 23:56
Version 1 2021-11-22, 22:06
posted on 2023-09-26, 23:56 authored by Walton, Kerry

Cominella maculosa and C. virgata are common rocky shore whelk species from New Zealand. This study used DNA sequences from the mitochondrial gene cytochrome c oxidase subunit 1 (CO1) to expand an earlier unpublished dataset and examine the phylogeographic structure of both species in the Cook Strait region, of C. maculosa in the Chatham Islands, and of C. virgata in the northern North Island. Both species are found to have a considerable degree of phylogeographic structure, concordant with that reported by an earlier study and for other species with direct development.  South Island sites sampled for C. maculosa had several private haplotypes and a high frequency haplotype that is shared with populations from the southern North Island. Together, these formed a ‘southern haplogroup’. Low diversity in ‘southern’ populations may reflect founder effects that would have occurred as part of a southward range expansion during the onset of the present interglacial period. The Chatham Islands samples had two haplotypes that formed a separate sub-group to the ‘southern haplogroup’, suggesting Chatham Islands populations are moderately isolated from those on mainland New Zealand but may have been founded from ‘southern’ populations relatively recently.  The high frequency haplotype present in South Island samples of C. virgata is absent in Wellington samples but widespread in those from the north-eastern North Island. South Island populations may have been founded from the Hauraki Gulf through human-mediated translocation events. Phylogenetic analyses with a focus on C. virgata were conducted using the mitochondrial genes CO1 and 16SrRNA, and the nuclear gene 18S rRNA, to expand an earlier published dataset. The purported northern subspecies C. virgata brookesi does not form a monophyletic lineage and voucher specimens fluidly intergrade with the nominal subspecies, with which it is synonymised. A lectotype is designated for Buccinum lineolatum Quoy & Gaimard, 1833, for which Cominella virgata is a replacement name. Potential causes of the disjunct distribution patterns of C. virgata and other mollusc taxa are discussed with particular reference to the formation and timing of marine straits through the Auckland Isthmus and Cook Strait.


Copyright Date


Date of Award



Te Herenga Waka—Victoria University of Wellington

Rights License


Degree Discipline

Marine Biology

Degree Grantor

Te Herenga Waka—Victoria University of Wellington

Degree Level


Degree Name

Master of Science

ANZSRC Type Of Activity code


Victoria University of Wellington Item Type

Awarded Research Masters Thesis



Alternative Title

Phylogeography of Cominella maculosa and C. virgata

Victoria University of Wellington School

School of Biological Sciences


Ritchie, Peter; Phillips, Nicole