Table 1. Diagnostic characteristics distinguishing Tricellaria inopinata, T. occidentalis and T in The distribution, origins and taxonomy of Tricellaria inopinata d'Hondt and Occhipinti Ambrogi, 1985, an invasive bryozoan new to the Atlantic

Table 1. Diagnostic characteristics distinguishing Tricellaria inopinata, T. occidentalis and T. porteri (the form and variation of the scutum can be regarded as the key diagnostic feature). CharacterT. inopinataT.occidentalisT. porteriInternode length (number of autozooids)very variable, recorded range 3-19majority of three, some fi vevariable, recorded range 3-13Marginal spines (excluding scuta)proximal external spine sometimes bi fi dproximal external spine never bi fi dproximal external spine sometimes bi fi dSpines within branch axilsone large, centrally positionedtwo large, central space betweentwo small, central space betweenScutum morphologyvary within a single colony from a slender projection, perhaps forked, to an extensive structure with wavy/spiky margin (often cervicorn-like)slender or slightly spatulateconsistently large and reniformLateral aviculariasometimes presentpresent on majoritypresent on aon majority of marginal autozooids (at least within proximal internodes), variable in sizeof marginal autozooidsminority of marginal autozooids