Tardigrades, or Water Bears, are a distinctive group of small (usually less than 1 mm) invertebrates related to Arthropods, Nematodes and Velvet Worms. They have a simple segmented body with four pairs of limbs, and are remarkably resilient to environmental stress, being able to withstand extremely high and low temperatures, complete desiccation and even exposure to vacuum. To date about 1200 species of Tardigrade have been described, from marine, freshwater and terrestrial environments. To date only a single Tardigrade has been described from Borneo, despite this landmass being the world's third largest landmass and an area of extremely high biodiversity.
In a paper published in the Raffles Bulletin of Zoology on 26 June 2018, Piotr Gąsiorek of the Institute of Zoology and Biomedical Research at Jagiellonian University described a new species of Tardegrade from the Bako Peninsula of Sarawak in Malaysian Borneo.
The new species is placed in the genus Bryodelphax, and given the specific name arenosus, meaning 'sandy'; the species was found dwelling in moss growing on a tree in an area of coastal lowland rainforest with sandy soil - something unusual in rainforests. The species is described from fifteen adult female specimens, no males were located leading Gąsiorek to speculate that the species may be parthenogenetic (able to reproduce without males, by development of unfertilized eggs). The specimens ranged from 543 μm to 648 μm in length, and are yellowish and pearly opalescent in colour. The species lacked any visible eyes.
Bryodelphax arenosus, dorsal view. Gąsiorek (2018).
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