HETEROPORIDAE Heteropora alaskensis Heteropora magda MOLLUSCA, POLYPLACOPHORA ISCHNOCHITONIDAE Callistochiton gabbi Ischnochiton acrior Stenoplax magdalenensis Stenoplax sp.
Among bryozoans there are representatives of the Stenolaemata Lichenoporidae, Gymnolaemata Cupuladriidae and numerous erect forms, which are locally very abundant and well-preserved, but not yet studied (Figs.
Bryozoa Ehrenberg, 1831 Stenolaemata Borg, 1926 Lichenoporidae indet.
The oldest class, Stenolaemata, has only one extant order: the marine calcified Cyclostomatida with characteristic tube-shaped zooids forming colonies that vary from encrusting to branched to massive.
Regional studies (particularly Schopf and Manheim, 1967; Rucker and Carver, 1969; Schopf and Allan, 1970; Siesser, 1972; Poluzzi and Sartori, 1973, 1974; Smith et al., 1998) revealed a complex mineralogical suite in the marine bryozoan classes Gymnolaemata and Stenolaemata. Later workers tried to summarize bryozoan mineralogy, noting the dominance of calcite (e.g., Lowenstam and Weiner, 1989); the addition of aragonite in secondary calcification (Sandberg, 1983); the presence of entirely aragonitic bryozoans (Sandberg, 1983); and the presence of bimineralic forms, some with highly organized biominerals and others with fairly amorphous mixtures (Bone and James, 1993).
Faunistisch overzicht van de mosdiertjes van Nederland (Bryozoa: Stenolaemata
X Native Hincks, 1880 Bryozoa Stenolaemata
Cyclostomata Crisiidae Crisia X X X Native Johnston, pseudosolena 1838 (Marcus, 1937) Cnidaria Anthozoa Hexacorallia Actiniaria Actiniidae Bunodosoma X X Native Gosse 1858 caissarum Correa in Belem, 1987 Cnidaria Anthozoa Hexacorallia Scleractinia Rhizangiidae Astrangia sp.
The older of the two clades, the cyclostomes, are the sole survivors of the class Stenolaemata; they were the dominant bryozoans for 100 million years, throughout most of the Mesozoic (Lidgard et al., 1993) and are still locally important (e.g., Harmelin, 1976).
A faster paced world?: contrasts in biovolume and life process rates in cyclostome (Class Stenolaemata) and cheilostome (Class Gymnolaemata) bryozoans.
The earlier of these events marked the origin of the class Stenolaemata
, of which the Cyclostomata are the only extant order; the later event marked the origin of the order Cheilostomata (of the class Gymnolaemata).