Irish specimens are 5-6 mm in length with a rather narrow, parallel-sided body. Coloration is mottled yellow-brown to grey-brown, appearing slightly rough to the naked eye. It is perhaps most likely to be confused with a mottled juvenile Porcellio scaber (Anderson, 2007), though the stepped body outline is more akin to Philoscia muscorum.
Distribution and Habitat
This species is only known from a one-kilometre length of sea-cliff in Co. Dublin, Ireland, where it was observed between 1909 and 1934, and was assumed extinct until its re-discovery in 2002.
In 2006-07, Roy Anderson (2007) found specimens sheltering under lichen covered rocks on steep sparsely vegetated slopes near the cliff tops. This habitat is threatened by scrub encroachment and the long-term survival of this species is in doubt.
Anderson, R. (2007) Observations on the status and ecology of Acaeroplastes melanurus (Budde-Lund) (Crustacea: Oniscoidea) at Howth Head, Dublin. Irish Naturalists’ Journal, 28: 497-505.