An investigation into the genetic variation of, and evolutionary relationships among, five mussel species of the family Mytilidae (Bivalvia) in New Zealand

Abstract

The phylogenetic relationships within the family Mytilidae are at present unclear, though genera have traditionally been assigned to four subfamilies. This study presents allozyme and partial 16s rRNA gene sequence data for several members of the family Mytilidae in New Zealand, some of which have not previously been investigated. Adult Aulacomya maoriana, Mytilus galloprovincialis, Perna canaliculus and Xenostrobus pulex were obtained from the Wellington Harbour area, New Zealand; samples of Xenostrobus securis, Modiolarca impacta and Modiolus areolatus, preserved in alcohol, were obtained from collections at Te Papa, the National Museum of New Zealand, Wellington, New Zealand. Preserved samples could not be used for allozyme analysis. The species successfully assayed for allozyme variation were: Aulacomya maoriana, Mytilus galloprovincialis, Perna canaliculus, Xenostrobus pulex and Musculista senhousia. Partial 16s rRNA gene sequence data was obtained for A. maoriana, Mytilus galloprovincialis and Perna canaliculus, and was compared with published Mytilid 16s sequence data. The electrophoretic evidence from seven loci indicates that the New Zealand Mytilids do not cluster in their traditional subfamily groupings. In addition, both allozyme and DNA analysis showed Mytilus galloprovincialis clustering with Perna canaliculus, rather than the more morphologically similar Aulacomya maoriana. This study also looked at the evidence regarding the taxonomic status of the New Zealand species of Mytilus, with the conclusion that the allocation of this species to M. galloprovincialis is still uncertain.