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).