(Carlson & Hoff, 1977)
Known only from Guam.
Upper: 27mm long alive. Guam, Cocos Lagoon, reef flat. 1 m. 13 May 1971 Host: Caulerpa racemosa. Lower: 19 mm long alive, showing open parapodia ; Guam, Cocos Lagoon, Sand Island; 13 Oct 1973. Photographer: Carlson & Hoff.
Animals are described as heavy bodied and range in size up to 32 mm in length. The body and parapodia are covered in conical projections. The most distinctive feature is the band of large transverse lamellae which occupy the outer half of of the inside face of the parapodia. The colour is brownish with white and reddish brown markings. The foot is a yellowish green.and the internal dorsal surface is a translucent pale green.
The animals have only been found in shallow lagoonal deposits buried just under the surface of the sand amongst the rhizoids of the green algae Caulerpa cupressoides and C. racemosa.
Carlson, C. H. and Hoff, P. J. (1977) A sand-dwelling Elysia from Guam (Opisthobranchia: Sacoglossa). The Veliger, 20: 14-16.
Carlson, C.H. & Hoff, P.J. (1978) The identifiable Elysia from Guam (Elysiidae, Sacoglossa, Opisthobranchia). Micronesica, 14: 89-113.
Jensen, K.R. (1992) Anatomy of some Indo-Pacific Elysiidae (Opisthobranchia: Sacoglossa (=Ascoglossa), with a discussion of the generic division and phylogeny. Journal of Molluscan Studies,. 58(3), 257-296.
Rudman, W.B., 2006 (April 20) Pattyclaya arena (Carlson & Hoff, 1977). [In] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/factsheet/pattaren