This chiton is a southern species with a recorded distribution from five Sea Areas off SW England [Seaward, Distribution of the marine molluscs of north west Europe, NCC, Peterborough (1990)]. Also included was a record from Donegal (Light & Baxter, J. Conch., Lond., 33 (1990), p. 318) thus extending the known range of this species. Further specimens have been found by David McGrath in Galway Bay (J. Baxter, pers. comm.)
During the course of fieldwork for our Isle of Wight survey, specimens of Leptochiton scabridus were found living at Bembridge Foreland, on the east coast of the Island (50°41'N, 01°03'W). In many respects the habitat resembles that of the Donegal site at Broad W ater (55°10'N, 07°03'W), discovered in June 1989. The Bembridge Ledge system is very sheltered consisting of an extensive series of slow-draining Bembridge Limestone terraces. At low water there are numerous pools and larger areas of standing water. The effect of continual draining during ebb gives rise to rapids at the lowest level of the ledge system. Several specimens of the chiton were found attached to the undersides of large, relatively flat limestone boulders which were well embedded in coarse sand and shell gravel within one of the lowest, larger pools. Further work will determine the extent of the colony.
It is interesting to note that this is the second so-called rare species with an apparently restricted distribution which includes the Channel Islands, that has been recorded from the southern side of the Isle of Wight. This follows our discovery of Arculus sykesi at Compton in 1989 (J. Conch., Lond., 33 (1990), p. 317). It may be that these finds are the result of detailed fieldwork uncovering small previously overlooked species. However it is also possible that they are species which are extending their range northwards.
We would like to thank John Baxter for looking at the specimens and confirming our identification.