Tricellaria porteri ( MacGillivray, 1889 )

Dyrynda, P. E. J., Fairall, V. R., Ambrogi, A. Occhipinti & d’Hondt, J. - L., 2000, The distribution, origins and taxonomy of Tricellaria inopinata d’Hondt and Occhipinti Ambrogi, 1985, an invasive bryozoan new to the Atlantic, Journal of Natural History 34 (10), pp. 1993-2006 : 2001

Tricellaria porteri ( MacGillivray, 1889)

Tricellaria porteri , which is, to date, only known from southern Australia, was highlighted by Occhipinti Ambrogi and d’ Hondt (1994) as a possible senior synonym of T. inopinata . The original description of Menipea porteri by MacGillivray (1889) refers to the presence of reniform (kidney-shaped) scuta, variable internode lengths and bi®d spines. It also refers to the ovicell pores as forming a single transverse row. We have examined paratype specimens of T. porteri , all from South Australia (including slides 65508, 65509, Rev. Porter collection; 65511, 65513, Museum of Victoria, Melbourne) and have come to the conclusion that this taxon is morphologically diOEerentiable from the other two taxa. The most striking characteristic is the consistently large and highly reniform scuta, quite unlike those encountered in the other two taxa (®gure 2). Only a small minority of scuta bear irregular margins. We observed 3±13 autozooids per internode and proximal external bi®d spines on many autozooids. Lateral avicularia were sparsely present. We found the arrangement of ovicell pores to be very variable, usually scattered but occasionally forming a row in the manner described by MacGillivray (1889).

Two recent published descriptions from South Australia attributed to T. porteri present di culties. Bock (1982) made reference to variable internodes and`ovate’ scuta (but ®gured more irregularly-shaped ones) and made no mention of bi®d spines. This material needs re-appraising. Brock (1985) ®gured a variety of scuta morphologies and some bi®d spines. The former is only consistent with our characterization of T. inopinata . A more recent study makes reference to the presence of T. porteri as a fouling species in Port Kembla, New South Wales ( Moran and Grant, 1993) although the information provided is insu cient to con®rm its identity according to the criteria de®ned here.