Family CALOHYPSIBIIDAE Pilato, 1969

Calohypsibiidae: Calohypsibius ornatus, habitus, bucco-pharyngeal apparatus, claws of the fourth leg

© Copyright Dr S. Claxton, Camden, NSW

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Introduction

The family Calohypsibiidae is characterised by claws which are asymmetric with respect to the median plane of the leg, but similar to each other and of Calohypsibius-type, that is, consisting of two branches fused together from the base and at times with an extremely shortened secondary branch. The claws are often reduced in size or even missing. Members of the family may have the bucco-pharyngeal apparatus of Hypsibiidae or ‘Macrobiotus’ type. Pilato (1989) included the genera Calohypsibius, Parhexapodibius, Haplomacrobiotus, Hexapodibius and Haplohexapodibius after confirming that all have six peribuccal lobes in them. Only members of the first two genera have so far been found in Australia. In Calohypsibius, the diploclaws are not greatly reduced and the buccal tube does not have a ventral strengthening bar. In the other genera the diploclaws and legs are all more or less reduced and the buccal tube has a strengthening bar. Two cosmopolitan species of Calohypsibius, C. caelatus (Pilato, Claxton & Binda 1989a) and C. ornatus, have been found in Australia. They have been found so far only in temperate rainforest mosses at elevation above 650 m in New South Wales and Tasmania. Smooth eggs are laid in the exuvium.

Members of this family are often found in soil or sand and the reduction in size of legs and claws is purported to be an adaptation to soil living (Dastych 1990). Three species of Parhexapodibius have been found in sand and leaf litter on Bribie Island, Queensland (Claxton unpubl. data). Parhexapodibius ramazzotti has short but normal diploclaws on all legs, the shortest being on the fourth pair of legs. Parhexapodibius pilatoi and an unidentified species have only one small diploclaw on each of the hind legs. Parhexapodibius ramazzotti has only otherwise been found in Italy in soil where smooth eggs laid in the exuvium were found. In the Bribie Island samples, no eggs were found but a high proportion of animals were encysted (24 in 26 specimens). V pilatoi has been found in Italy and North America in soil and moss on soil and in moss from Korea.

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