Document Type

Honors Project On-Campus Access Only

Abstract

Species are an integral unit of the biological world and are the primary means by which biodiversity can be measured and quantified. Given modern day conservation efforts rely closely on the implementation of the species rank, it is essential to describe as many species as possible in the most efficient manner. Mite harvesters (suborder Cyphophthalmi) are a type of tiny arachnid known to be extremely poor dispersers with species ranges typically no larger than 50km in any dimension. These animals commonly inhabit leaf litter environments throughout New Zealand, one of the world’s biodiversity hotspots. In 2021, mite harvesters in the genus Aoraki Boyer & Giribet, 2007 were collected from a cave in the northern South Island; these, along with a poorly documented specimen from 1973, represent the first ever record of cave-dwelling mite harvesters in New Zealand. A comparison of ratios taken from appendage measurements of the cave animals and thirteen other Aoraki species showcases trends characteristic of cave-adapted arthropods. Specifically, the elongated appendages of the cave specimens suggest adaptation to subterranean environments. We sequenced the mitochondrial loci COI and 16S from one of the cave populations and populations of the closely related species Aoraki westlandica (Forster, 1952) in order to better define the cave population’s phylogenetic position and assess the possibility that it represents a new species. Because species in the genus Aoraki display high levels of morphological conservatism and are difficult to distinguish from appearance alone, the use of non- morphological data types, like genetic information, are crucial in informing species hypotheses. We used data derived from the mitochondrial locus COI to assess genetic diversity within and between eleven species of Aoraki to gauge whether there exists a genetic threshold that can be used to define effective species boundaries in the genus. There was considerable overlap between interspecific and intraspecific differences in our dataset, suggesting there is no such threshold capable of delimiting species within Aoraki. Despite this, the patterns of genetic diversity observed within Aoraki offer much insight into understanding how biogeographical processes impact speciation, with potential implications for other ecologically similar organisms.

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