UNUSUALLY LARGE REASSEMBLED FOSSIL BRYOZOAN COLONIES (AMONG THE LARGEST KNOWN) FROM THE UPPER ORDOVICIAN NEAR CINCINNATI

Most bryozoans in Ordovician strata near Cincinnati occur as widely separated fragments, remnants of larger bush-like colonies, scattered taphonomically and further fragmented by diagenesis and weathering/erosion. In contrast, a few colonies were fossilized (quiet water or rapid burial) with their fragments so close together that they can be reassembled, fitted back together like puzzle pieces, and glued to reconstruct the original colony's shape and size.

The roadside bank across from 6800 Powerline Drive, in Florence, 9 miles southwest of downtown Cincinnati, yielded many bryozoan fragments which Fine reassembled, Cuffey identified, and Ohio Geology 2005(1):1-4 published. The locality, since removed by road construction, was 2.4 mi N95°E from the junction (exit 180) of I-71+75 to US 42 (Union and Independence 7.5' quads). The bryozoans were in the Corryville interbedded shales and thin limestones (upper Maysvillian).

Three reassembled bryozoans from here, all the trepostome Heterotrypa frondosa, grew along the substrate, with most branches flaring into leaf-like fronds, and prove to be unusually large, among the largest known anywhere. They were found very close together in the ground, occupying a combined space of 77x53x18 cm. The largest is 66x35x15 cm; maximum dimensions of the others are 53 and 33 cm. They may have originally been a single larger colony fractured during life, or independent colonies from three separate founding larvae. In contrast, most bryozoan colonies grew to only 10-15 cm sizes, as shown by other reassembled specimens, physical modeling, and statistical analyses.

A few other unusually large bryozoans have been reported, some almost as large as the Heterotrypa frondosa herein, but not quite: Heterotrypa patera, H. enormis, Monotrypa benjamini, Leptotrypella asterica, Tabulipora carbonaria, T. sp., Archimedes owenanus, A. valmeyeri, Fenestella spp., Polypora spp., Pennipora anomalopora, Celleporaria gambierensis, C. palmata, C. agglutinans, Adeonellopsis sp., Schizoporella errata, Pectinatella magnifica. Two additional are slightly larger (~1 m): Stenopora tasmaniensis, Archimedes wortheni, and another three may be (Hyporosopora portlandica, Fenestella? sp., other C. gambierensis).