A new Echinoderes (Kinorhyncha : Cyclorhagida) from a submarine cave in New South Wales, Australia.

The cyclorhagid kinorhynch Echinonderes cavernus sp. nov, is described from a submarine cave in New South Wales, Australia. This finding represents th e first kinorhynch, which probably lives in caves, exclusively. The usual s exual dimorphism in Echinoderes is absent in the new species, i.e. lateral terminal accessory spines are present in both sexes. Further sexually pecul iar characters in E. cavernus sp. nov. are genital setae on the arthrocoriu m between segments 12 and 13 in both sexes, and the presence of only two pe nile spines in the males. The new species has interstitial placids and blun t (short and broad) lateral terminal spines. The blunt lateral terminal spi nes are proposed to be an autapomorphic character for a monophyletic clade consisting of Echinoderes abbreviatus, E. brevicaudatus and E. cavernus sp. nov. which all inhabit coarse coralligenous sand.