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Mitochondrial DNA analyses reveal widespread tardigrade diversity in Antarctica

journal contribution
posted on 2023-05-18, 19:17 authored by Velasco-Castrillon, A, McInnes, SJ, Schultz, MB, Arroniz-Crespo, M, D'Haese, CA, Gibson, JAE, Adams, BJ, Page, TJ, Austin, AD, Cooper, SJB, Stevens, MI
Antarctica contains some of the most challenging environmental conditions on the planet due to freezing temperatures, prolonged winters and lack of liquid water. Whereas 99.7% of Antarctica is permanently covered by ice and snow, some coastal areas and mountain ridges have remained ice-free and are able to sustain populations of microinvertebrates. Tardigrades are one of the more dominant groups of microfauna in soil and limno-terrestrial habitats, but little is known of their diversity and distribution across Antarctica. Here, we examine tardigrades sampled from across an extensive region of continental Antarctica, and analyse and compare their partial mitochondrial cytochrome c oxidase subunit 1 (COI) gene sequences with those from the Antarctic Peninsula, maritime and sub-Antarctica, Tierra del Fuego and other worldwide locations in order to recognise operational taxonomic units (OTUs). From 439 new tardigrade COI sequences, we identified 98 unique haplotypes (85 from Antarctica) belonging to Acutuncus, Diphascon, Echiniscus, Macrobiotus, Milnesium and unidentified Parachela. Operational taxonomic units were delimited by Poisson tree processes and general mixed Yule coalescent methods, resulting in 58 and 55 putative species, respectively. Most tardigrades appear to be locally endemic (i.e. restricted to a single geographic region), but some (e.g. Acutuncus antarcticus (Richters, 1904)) are widespread across continental Antarctica. Our molecular results reveal: (i) greater diversity than has previously been appreciated with distinct OTUs that potentially represent undescribed species, and (ii) a lack of connectivity between most OTUs from continental Antarctica and those from other Antarctic geographical zones.

History

Publication title

Invertebrate Systematics

Volume

29

Issue

6

Pagination

578-590

ISSN

1445-5226

Department/School

Institute for Marine and Antarctic Studies

Publisher

CSIRO Publishing

Place of publication

150 Oxford St, Po Box 1139, Collingwood, Australia, Victoria, 3066

Rights statement

Copyright 2015 CSIRO

Repository Status

  • Restricted

Socio-economic Objectives

Expanding knowledge in the biological sciences

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