Due to the continuing corona virus situation, this meeting will be held online through Zoom.
OLD FOSSILS, NEW TECHNIQUES:
Recent Discoveries in Fossil Arthropod
Respiration Using CT-scanning
Dr. Melanie Hopkins
Curator-in-Charge, Fossil Invertebrates & Associate Professor, Richard Gilder
Graduate School, American Museum of Natural History, New York City
Sunday, May 16, 2021 2:00 P.M.
THIS TALK WILL BE ONLINE
Most of the fossil record consists of the biomineralized (“hard-part”) remains of once-living organisms. Very occasionally, exceptional depositional circumstances led to the preservation of “soft-body” remains, including appendages and traces of digestive, neural, and respiratory systems.
Until recently, what we could learn about the anatomy and biology of organisms from these “Lagerstätten” was limited by what could be exposed using traditional mechanical preparation. The advancement and increased availability of digital preparation and imaging methods, such as CT-scanning, has dramatically impacted our interpretations of these fossils. In this talk, Dr. Hopkins will describe recent work using CT scanning to re-examine museum specimens in order to better understand the structure and evolution of respiratory structures in trilobites and eurypterids.
In the case of trilobites, CT scanning of pyritized specimens from the famed Ordovician Beecher’s Bed locality in upstate New York revealed the 3D micron-scale structure of filaments associated with walking appendages. The shape of these filaments, in combination with the re-examination of the arrangement of appendages and filaments on trilobite specimens from specimens preserved in the Burgess Shale, provides evidence that these structures represented a well-developed gill and were unlikely to have served a locomotory functions as previously debated.
In the case of eurypterids, CT scanning of a complete phosphatized specimen from the Carboniferous Lydiennes Formation in France, revealed structures associated with subaerial breathing as well as 3D preservation of walking legs, genital appendages, and the digestive system. These findings have implications for our understanding of the evolution of arthropods, both on land and in the sea.