We describe a terrestrial faunal community including only Tardigrada and Rotifera, present on inland nunataks of Ellsworth Land, Antarctica (∼75°–77° S, 70°–73° W). The fauna is exceptional in its si...

This paper is the second monograph of nine that describes the global records of limno-terrestrial water bears (Tardigrada). Here, we provide a comprehensive list of non-marine tardigrades recorded from South America, providing an updated and revised taxonomy accompanied by geographic co-ordinates, habitat, and biogeographic comments. It is hoped this work will serve as a reference point and background for further zoogeographical and taxonomical studies.

Annotated zoogeography of non-marine Tardigrada. Part I: Central America

Introduction Zoologists always hope to find unusual and interesting new animals in exotic places. Over the last few centuries, scientific expeditions in remote places outside Europe and North America have indeed discovered new species and even higher taxa of vertebrates, insects and other macroscopic animals, completely different from the ones previously known in the home country. In contrast, scientists working on microscopic animals, looking at samples from remote areas, have often found organisms that could be ascribed to familiar species. Microscopic animals have thus been considered not interesting in biogeography, as their distribution may not be limited by geography. Are microscopic animals really widely distributed? Is their cosmopolitanism an actual biological property or only a common misconception based on false assumptions and unreliable evidence? Is the scenario more complex than the claimed clear-cut difference between micro- and macroscopic animals? This chapter will review all the faunistic knowledge gathered so far on the global distribution of free-living microscopic animals smaller than 2 mm (gastrotrichs, rotifers, tardigrades, micrognathozoans, cycliophorans, loriciferans, kinorhynchs and gnathostomulids). Moreover, we will deal with microscopic free-living species in other groups of animals such as nematodes and flatworms, which have both micro- and macroscopic species. The focus will be on species identification from traditional taxonomy based on morphology, whereas Chapter 14 will deal with more recent evidence gathered from analyses on molecular phylogeny and phylogeography from the same groups.

Meiofauna – multicellular animals captured between sieve size 45 μm and 1000 μm – are a fundamental component of terrestrial, and marine benthic ecosystems, forming an integral element of food webs, and playing a critical roll in nutrient recycling. Most phyla have meiofaunal representatives and studies of these taxa impact on a wide variety of sub-disciplines as well as having social and economic implications. However, studies of variation in meiofauna are presented with several important challenges. Isolating individuals from a sample substrate is a time consuming process, and identification requires increasingly scarce taxonomic expertise. Finding suitable morphological characters in many of these organisms is often difficult even for experts. Molecular markers are extremely useful for identifying variation in morphologically conserved organisms. However, for many species markers need to be developed de novo, while DNA can often only be extracted from pooled samples in order to obtain sufficient quantity and quality. Importantly, multiple independent markers are required to reconcile gene evolution with species evolution. In this primarily methodological paper we provide a proof of principle of a novel and effective protocol for the isolation of meiofauna from an environmental sample. We also go on to illustrate examples of the implications arising from subsequent screening for genetic variation at the level of the individual using ribosomal, mitochondrial and single copy nuclear markers.