Phylum Arthropoda


The Trenton Group, particularly where exposed at the type location along West Canada Creek in New York , is one of the richest series of strata containing the extinct arthropods known as trilobites. Ostracodes, living representatives of the arthropods within the class Crustacea, are also found throughout these rocks. The great majority of specimens illustrated in the following pages were collected by C. D. Walcott, during the late 1800's, and Thomas E. Whiteley, during the early 1990's, from the Walcott-Rust Quarry near West Canada Creek. The specimens housed in the Museum of Comparative Zoology include 22 species of trilobites and four species of Ostracoda.

The Walcott-Rust Quarry limestone is rich in trilobites, many of which are well studied and researched. The four most abundant species in this fauna are Ceraurus pleurexanthemus Green, Flexicalymene senaria Conrad, Isotelus gigas Dekay, and Meadowtownella trentonensis Hall. Many exceptionally well preserved specimens of Isotelus gigas make up a large portion of the collection, the neotype of the species being one of them. Enrolled specimens of Ceraurus pleurexanthemus Green and Flexicalymene senaria Conrad are also numerous and were of significant importance to C.D. Walcott. It was in thin sections of these trilobites that he discovered preserved appendages inside the carapaces. In a 1999 issue of the Journal of Paleontology completed by Brett et al. a detailed study of the beds and trilobite fauna showed the trilobites were a useful tool in estimating paleo-current direction and the conditions and speed of burial.

Aside from the trilobites, there are many well-preserved specimens of ostracodes in the collection. Those found are mostly leperditids and beyrichids that are exposed on the bedding planes or within the limestone matrix.


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Specimen of Beyrichia bella, MCZ 109611 Specimen of Meadowtownella trentonensis, MCZ 111709 An unidentified ostracode,  MCZ 145806 Specimen of Sphaerocoryphe robusta, MCZ 111723