Distribution, body size, genetic structure and conservation of <i>Siphlaenigma janae</i> (Insecta: Ephemeroptera)

<p>Distribution, body size and genetic structure of the poorly known New Zealand mayfly <i>Siphlaenigma janae</i> were investigated to improve understanding of its conservation status. It has now been recorded from 42 locations, 22 of which are reported for the first time. The distribution of <i>S. janae</i> extends from Northland to the central North Island, and also into the northwestern South Island. Population structure consisted of three distinct haplotype networks; two in the North Island and one in the South Island. Maximum uncorrected genetic distance was 6.1% but no strong evidence for the presence of sibling species was found. The specialist nymphs predominantly live in low-gradient first- and second-order forested streams, a habitat that is increasingly being threatened by land-use modification. We recommend <i>S. janae</i> remain classified as Nationally Vulnerable due to its unique taxonomic position, regionally distinct genetic structure and fragmented population that is likely experiencing ongoing decline.</p>