BRYOZOAN  COLONIES

 

Bryozoans are colonial lophophorates, most of which make a calcareous skeleton.  Many bryozoan skeletons have complex shapes that cannot be fully appreciated from the fossil record.  Bryozoans are abundant fossils, especially in Paleozoic and Mesozoic limestones, but their skeletons usually get busted up during the storm events resulting in their final burial.

 

There have been successful attempts at reconstructing bryozoan colonies from the Upper Ordovician of the Cincinnati, Ohio area in recent years, especially by Ron Fine, a fossil collector in southwestern Ohio, and by paleontologists at Kent State University (see, for example, Waugh & Erickson, 2002 - Bryozoan Studies 2001, Proceedings of the Twelfth International Bryozoology Association Conference, Dublin, Ireland, 16-21 July 2001, pp. 331-338 and Cuffey, 2005 - Ohio Geology 2005(1): 1, 3-4).  These attempts require time, patience, and luck.

 

Shown below are complete to near-complete bryozoan colonies. The first two specimens were buried more-or-less intact. The last two colonies are reconstructions.

 


 

Bryozoan - naturally intact colony attributed to Hallopora multitabulata (Ulrich, 1886), weathered out from Ordovician rocks near Frankfort, Illinois, USA (UC 13533, University of Chicago, Chicago, Illinois, USA).

 


 

Bryozoan - naturally intact colony attributed to Fistulipora neglecta Rominger, 1866, weathered out from Silurian rocks near Waldron, Indiana, USA (UC 15011, University of Chicago, Chicago, Illinois, USA).

 


 

 

Bryozoans (left: 9.1 cm tall; right: 8.2 cm tall) - small reconstructed colonies from the near-uppermost Sunset Member of the Arnheim Formation (lower Richmondian Stage, upper Cincinnatian Series, upper Upper Ordovician) at Flat Run Quarry, Ohio (immediately adjacent to the intersection of Ellis Road & Fry Road, far-southern Clay Township, far-southwestern Highland County, just east of Sicily, east of Mt. Orab, southwestern Ohio, USA; 39 1.676 North, 83 50.847 West).

 


 

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