Tardigrades of the Australian Antarctic Territories: the Larsemann Hills, East Antarctica

Abstract

A survey of the terrestrial tardigrades inhabiting algae, lichens, and mosses in the Larsemann Hills, East Antarctica was conducted at 61 sites during the austral summer of 1987. Five genera and six species of Tardigrada were recovered. Statistical analysis of biotic association was conducted and for most species-pairs, tardigrades occur randomly with respect to each other. The hypothesis is proposed that distribution of tardigrades in the Antarctic is more strongly influenced by dispersal capabilities than by climatic factors or biotic interactions. East Antarctica is a series of widely dispersed, small, ice-free areas surrounded by a continuous sea of mostly frozen water. These islands, scattered along the Antarctic circle, provide a discontinuous habitat for terrestrial organisms. Tardigrade research in East Antarctica has been conducted entirely within the current century. Richters (1904, 1907) described the first tardigrades from this area, and later he listed 13 species, providing also the first discussion of distribution. Over 50 years passed before Morikawa (1962) and Sudzuki (1964) reported finding tardigrades near the Japanese base at Syowa, Queen Maud Land. Korotkevich (1964) found, but did not identify, tardigrades in bodies of freshwater in the Bungar Hills and the Obruchev Hills of Wilkes Land. Thomas (1965) found an unidentified Macrobiotus in the meltwater pools near the abandoned Wilkes Base on the Clark Peninsula. Another decade passed without reports of tardigrades from East Antarctica, until Sudzuki (1979) again described the animals from the Syowa area. In the early 1980's, the ecology of Antarctic tardigrades was discussed by Everitt (1981) and Miller (1983). Dastych (1984) expanded the list of species known from Antarctica and the sub-Antarctic islands and described eight species new to science. Gardiner & Pidgeon (1987) reported collections at sites in East Antarctica; this paper is the culmination of that work. The tardigrade fauna of the Vestfold We are grateful to the Australian National Antarctic Research Expeditions (ANARE) and to the personnel of the Australian Antarctic Division, especially Martin Betts, for logistical support and advice, and for making the expedition possible, and to Dr. Rod Seppelt for identification of the mosses and lichens. Publication costs, in part, are being met by a grant from the Spencer-Tolles Fund of the American Microscopical Society. TRANS. AM. MICROSC. SOC., 113(2): 142-160. 1994. ? Copyright, 1994, by the American Microscopical Society, Inc. This content downloaded from 157.55.39.251 on Thu, 14 Jul 2016 06:20:29 UTC All use subject to http://about.jstor.org/terms VOL. 113, NO. 2, APRIL 1994 Hills near Davis Base was surveyed by Miller et al. (1988); they discussed the ecology, distribution, and association patterns. Dastych (1989) reported on specimens collected in the area of Casey Station. Ryan et al. (1989) extended the known distribution of five species with a report from Robertskollen near the South African base of Sanae. Dastych et al. (1990) described two new species from the same area of Robertskollen. Dastych (1991) redescribed the species Hypsibius antarcticus, reducing confusion between this very common species and Hypsibius arcticus. Tardigrade research at locations other than East Antarctica was reviewed by Miller et al. (1988). Despite these efforts, many of the ice-free areas of East Antarctica remain unexplored and unsurveyed for tardigrades. The present report constitutes the first records of tardigrades from the Larsemann Hills on the Ingrid Christensen Coast of East Antarctica.