Integrative Taxonomy: A study on some of Victoria Land’s Antarctic mite species

• Main Author: Brunetti, Claudia
• Other Authors: FANCIULLI, PIETRO PAOLO
• Format: Doctoral or Postdoctoral Thesis
• Language: English
• Published: Università degli Studi di Siena 2021
• Subjects: Acari; terrestrial invertebrate; taxonomy; taxonomic key; Stereotydeus ineffabilis sp. nov; Stereotydeus nunatakis sp. nov.; Stereotydeus spp; molecular phylogeny; biogeography; Settore BIO/05 - Zoologia; Antarctic; Transantarctic Mountains; Victoria Land; Antarc*; Antarctica; Mite
• Online Access: http://hdl.handle.net/11365/1144409; https://doi.org/10.25434/brunetti-claudia_phd2021

The extremely inhospitable Antarctic ecosystems confine plants and invertebrates to sparse and restricted ice-free areas. These species survived for millions of years in isolated refugia where population divergence and differentiation can occur, potentially resulting in speciation. The limited dispersal abilities of invertebrate species combined with their specific habitat requirements and the substantial geographical barriers can drastically reduce the gene flow between different populations, resulting in high genetic differentiation between clusters of individuals. With more than 100 described species, mites are surely the most diverse invertebrate group of Continental Antarctica. Among them, the free-living genus Stereotydeus Berlese, 1901 (Acari: Prostigmata) is represented by 6 Antarctic species of which 5 occur along the coastal zones of Victoria Land and the Transantarctic Mountains. In order to examine the biodiversity and the phylogeographic distribution ranges of Stereotydeus spp. across Victoria Land, I conducted an integrated analysis of the genus through phylogenetic, morphological and population genetics studies on specimens collected from nine localities in Victoria Land. I sequenced the second part of the cytochrome c oxidase subunit I mitochondrial gene (cox1) and a fragment of the 28S ribosomal RNA-encoding gene using mite-specific primers. I morphologically identified and described two novel Stereotydeus species from central and south Victoria Land. While the relationships between the cox1 haplotypes from North Victoria Land are well defined, the distribution of the central-southern species appears more complex. This suggests a possible common evolutionary history in many isolated glacial refugia, with scarce gene flow even within populations probably resulting from inter/intra-specific events influenced by several abiotic/biotic factors. Recent threats to Antarctic biodiversity like accelerated climate change, pollution, biological invasions and the increase of human activities have caused ...