An unusually large Cyclostome Bryozoan (<i>Pennipora anomalopora</i>) from the Upper Cretaceous of Maastricht

Pennipora anomalopora (UBAGHS, 1858) is an erect branching species of cyclostome bryozoan (Family Cerioporidae BUSK) found rarely and only in the Maastrichtian of the Maastricht region. A large and spectacular colony was discovered in 1994 by Fred Michon in the Meerssen Mbr of the Maastricht Fm in the ENCI NV Quarry. This may be the largest Mesozoic cyclostome colony ever found. The branches have well-developed monticules, and sectioned branches reveal the characteristic difference in orientation between autozooecia and kenozooecia, as well as numerous brood chambers which are partially subdivided by internal septa-like walls. Dark growth bands observed within the endozone of a longitudinally sectioned branch are an average of 2.9 mm apart. These bands appear to coincide with levels of brood chambers in the exozone. If larval brooding occurred annually then a distal branch growth rate of about 3 mm per year can be inferred, indicating that the colony lived for more than 35 years