New Records of Antarctic Tardigrada with Comments on Interpopulation Variability of the Paramacrobiotus fairbanksi Schill, Förster, Dandekar and Wolf, 2010

Łukasz Kaczmarek,Ivan Parnikoza,Katarzyna Kubska,Milena Roszkowska,Monika Mioduchowska,Uroš Kačarević,Bartłomiej Gołdyn

doi:10.3390/d12030108

Abstract

Studies on Antarctic tardigrades started at the beginning of the twentieth century and have progressed very slowly and ca. 75 tardigrade species are known from this region. Paramacrobiotus fairbanksi was described from USA based on genetic markers and later reported from Italy, Poland, and Spain. The “everything is everywhere” hypothesis suggests that microscopic organisms have specific features which help them to inhabit most of environments and due to this they can be considered cosmopolitan. In the present paper, we report eight tardigrade taxa from Antarctic, including the first report of Pam. fairbanksi from Southern Hemisphere, which could suggest that the “everything is everywhere” hypothesis could be true, at least for some tardigrade species. Moreover, we also genetically and morphologically compare a few different populations of Pam. fairbanksi. The p-distances between COI haplotypes of all sequenced Pam. fairbanksi populations from Antarctica, Italy, Spain, USA and Poland ranged from 0.002% to 0.005%. In the case of COI polymorphism analyses, only one haplotype was observed in populations from Antarctica, USA and Poland, two haplotypes were found in population from Spain, and six haplotypes were observed in population from Italy. We also found some statistically significant morphometrical differences between the populations of Pam. fairbanksi from different regions and designed a new specific primers for Paramacrobiotus taxa.

Highlights

Antarctic is the coldest and most extreme region on the planet with the lack of surface liquid freshwater
In eight of eleven samples, 461 tardigrades, 102 exuviae and 127 eggs belonging to eight taxa were found, i.e., Acu. antarcticus; Barbaria pseudowendti (Dastych [52]); Das. improvisus; Hebesuncus mollispinus
Hebesuncus mollispinus has quite recently been described as a species from Charcot Island, close to Antarctic Peninsula (West Antarctica) [15]

Summary

Introduction

Antarctic is the coldest and most extreme region on the planet with the lack of surface liquid freshwater. Continental Antarctic with an area of ca. The entire continent is divided into three main units, i.e., East Antarctica, West Antarctica, and the Antarctic Peninsula [1]. Our knowledge of micro-invertebrates in this region is patchy and fragmented, because most studies have focused on accessible regions that are close to research stations [2]. Many of Antarctic invertebrates are endemic, some of them have a continental distribution, others are restricted only to maritime Antarctic and only a few can be characterized as pan-Antarctic species such as eutardigrade Acutuncus antarcticus (Richters [3]) e.g., [4,5]. The phylum tardigrada currently consists of ca. 1300 species [6,7,8,9] that inhabit terrestrial and aquatic environments throughout the world [10,11]

Methods

Results

Conclusion