Population genetics and morphometrics of the black tunnelweb spider Porrhothele (Mygalomorphae, Porrhothelidae) : a thesis presented in partial fulfilment of the requirements for the degree of Master of Science in Zoology at Massey University, Palmerston North, New Zealand
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2020
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Massey University
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Abstract
The Mygalomorphae are a taxonomically challenging group due to their morphologically conserved nature. Similarly, the phylogenetic relationships of Mygalomorphae within New Zealand are poorly resolved. The Porrhothele (Mygalomorphae:Porrhothelidae) have poorly defined species that may not accurately represent the true diversity of the genus. This thesis utilizes genetics and morphometrics to 1) provide a hypothesis for how New Zealand’s Mygalomorphae relate to one another 2) clarify whether Porrhothele antipodiana is composed of multiple species 3) determine if traditionally used morphological traits can effectively separate Porrhothele mtDNA clades from one or another or even from Hexathele, a morphologically and ecologically similar group. Mygalomorphae were collected throughout New Zealand and had the CO1 mtDNA gene sequenced. Combined with online data, a phylogenetic tree representing all five of New Zealand’s Mygalomorphae genera was generated. The multiple genera tree hypothesizes that Migas is the closest relative to Porrhothele within New Zealand. CO1 mtDNA data from Porrhothele was used to generate phylogenetic trees for the genus. Morphological traits were measured and used in a principal components analysis to determine whether they could separate genera and mtDNA clades. An unsupervised cluster analysis was also used to determine whether mtDNA clades and genera could be separated. The Porrhothele phylogenetic trees provide some evidence that P. antipodiana may represent more than one species, but it still appears that P. antipodiana is a widespread species. Additionally, the Porrhothele phylogenetic trees provide some evidence for the presence of three undescribed species. The CO1 mtDNA clades within Porrhothele could not be separated from one another using the selected morphological traits in the PCA but were able to separate Porrhothele from Hexathele. However, the cluster analysis was unable to separate mtDNA clades and genera. Metatarsus length was found to be the most effective trait at separating Porrhothele from Hexathele but cannot completely separate them. It was also found that the number of spermatheca lobes in females provide support for the new mtDNA lineages being undescribed Porrhothele species, but caution is needed as some Porrhothele species and individuals are variable for this character.
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Figure 15 is re-used with permission. Figure 16 is modified from original.