Species of Tetracanthella are characterised by possession of four prominent anal spines. Tetracanthella arctica Cassagnau, 1959 is very similar to the common Tetracanthella wahlgreni. However, Tetracanthella arctica only has 2+2, 2+2, 3+3 macrosetae on the dorsal side of abdominal segments 1, 2 and 3 respectively whereas in Tetracanthella wahlgreni the setae are 2+2, 3+3, 3+3. Arne Fjellberg (personal communication) identified specimens of Tetracanthella arctica collected by Juliane Filser in 1996 from moss on a vertical rock face at Sneem, Co. Kerry, Southwest Ireland. It is clear that Tetracanthella arctica could have been overlooked in the past although all the Tetracanthella wahlgreni I have checked in the NHML collection have 3+3 macrosetae on abd2.

Back to main page