Article contents
Lyre-shaped hornerid bryozoan colonies: homeomorphy in colony form between Paleozoic Fenestrata and Cenozoic Cyclostomata
Published online by Cambridge University Press: 20 May 2016
Abstract
Reticulate Hornera reteramae (Bryozoa, order Cyclostomata) have been discovered as free-lying, lyre-shaped colonies in the Castle Hayne Limestone (Eocene) in North Carolina. These specimens represent a striking instance of homeomorphy in colony form with the Late Mississippian genera Lyropora and Lyroporella of the order Fenestrata.
Bryozoans with reticulate growth habit most commonly develop upright colonies. Living representatives generally grow in quiet environments or microenvironments, and fossils are generally found in situ in quiet-water deposits. However, lyre-shaped Hornera reteramae occur in skeletal packstones inferred to have been deposited in a moderate-energy, shallow, open shelf environment near normal wave base. Upper Mississippian lyre-shaped colonies are preserved in skeletal packstones and grainstones in localized channels or on upper surfaces of low-angle cross-bedded sheets interpreted as high-energy, marine shoal deposits. Modification of the reticulate growth habit to low, peripherally weighted, free-lying structures apparently allowed invasion of higher energy sand bottoms, both in Mississippian and Eocene times.
- Type
- Research Article
- Information
- Copyright
- Copyright © The Paleontological Society
References
- 11
- Cited by