Bryozoans: more than meets the eye

By Paul D Taylor A few years ago a survey was undertaken of the changing proportion of bryozoans relative to other fossils at an Ordovician locality near Cincinnati popular with fossil collectors. The site was revisited annually over a ten-year period, random collections of fossils were made and the numbers of crinoids, trilobites, brachiopods, bryozoans and other fossils were counted. At the beginning of the study, about 25% of the fossils consisted of bryozoans, by the end the proportion had gone up to 75%. The author of the study referred to this phenomenon as “bryo-enhancement”. Of course, the bryozoans had not been increasing in an absolute sense, rather visitors to the site had preferentially collected other fossil groups, causing the proportion of bryozoans left behind to rise. The Cincinnati study is a fair reflection of the unpopularity of bryozoans among fossil collectors. Fossil bryozoans generally languish unloved among the sponges and trace fossils in the bottom drawers of collectors’ cabinets and are seldom seen for sale in fossil shops or on the Internet. Why should this be? Part of the reason is that few bryozoans have the aesthetic appeal of such fossils as ammonites or trilobites – well at least to the naked eye. They are also difficult to identify and all too often mistaken as corals, sponges or algae. But another reason is that bryozoans have a low public profile. Unlike molluscs and crustaceans, you won’t find bryozoans on the menu at fish restaurants, even in the Far East. … Read More