Abstract
In the harsh Antarctic terrestrial ecosystems, invertebrates are currently confined to sparse and restricted ice free areas, where they have survived on multi-million-year timescales in refugia. The limited dispersal abilities of these invertebrate species, their specific habitat requirements, and the presence of geographical barriers can drastically reduce gene flow between populations, resulting in high genetic differentiation. On continental Antarctica, mites are one of the most diverse invertebrate groups. Recently, two new species of the free living prostigmatid mite genus Stereotydeus Berlese, 1901 were discovered, bringing the number of Antarctic and sub-Antarctic species of this genus up to 15, of which 7 occur along the coast of Victoria Land and in the Transantarctic Mountains. To examine the biodiversity of Stereotydeus spp., the present study combines phylogenetic, morphological and population genetic data of specimens collected from nine localities in Victoria Land. Genetically distinct intraspecific groups are spatially isolated in northern Victoria Land, while, for other species, the genetic haplogroups more often occur sympatrically in southern Victoria Land. We provide a new distribution map for the Stereotydeus species of Victoria Land, which will assist future decisions in matters of the protection and conservation of the unique Antarctic terrestrial fauna.
Highlights
Due to Antarctica’s isolation and extreme environmental conditions, the continent’s terrestrial biota has limited species level diversity and many higher taxonomic groups are completely missing or very poorly represented [1,2]
We provide more than 150 new sequences for the mitochondrial barcode region cox1, and the nuclear 28S, of five different Stereotydeus species from Victoria Land
Using the cox1 haplotypes of the 50 S. mollis specimens already available on GenBank as templates, 495 bp of a uniform and unambiguous alignment from 159 sequenced individuals were used for all genetic analyses
Summary
Due to Antarctica’s isolation and extreme environmental conditions, the continent’s terrestrial biota has limited species level diversity and many higher taxonomic groups are completely missing or very poorly represented [1,2]. The challenging environmental conditions, isolation and the patchy distribution of ice free areas have been recognized as the main factors affecting and defining populations of the Antarctic terrestrial invertebrate fauna, both physiologically and genetically [8]. Continental Antarctic springtails (Collembola) and mites (Acari) are often found concentrated under rocks, where the environment tends to be moister, rich in organic carbon and with low salinity [13], and where microbial diversity is present, stabilizing mineral soils and allowing colonization by both micro-invertebrates and flora [2]. Temperature plays an important role in regulating microarthropod life cycles, the major factor regulating their survival and growth remains the availability of liquid water [5,14]. An additional challenge for microarthropod survival derives from the bottleneck caused by their dispersal abilities, especially over longer distances
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