Wooster’s Fossils of the Week: Eurypterids (Late Silurian of New York)

Few fossils are more dramatic than the long-extinct eurypterids. Above is one of Wooster’s best fossils: Eurypterus remipes De Kay 1825 from the Bertie Waterlime (Upper Silurian) of New York. (Thanks to Roy Plotnick for help with the identification.) As far as eurypterid fossils go, it is average (see Samuel J. Ciurca’s wonderful eurypterid pages for superb specimens), but for our little teaching collection it is a gem. Note that some of the fine details on the appendages are preserved.

Here’s looking at you: a eurypterid head showing the pair of compound eyes. The anterior margin “lip” indicates that this is a “carcass” specimen and not a molt fragment.

Eurypterids are commonly called the “sea scorpions” because of their long segmented body (opisthosoma), fused head segments (prosoma), sharp tail piece (telson) and claws (chelicerae). The scorpions and eurypterids, in fact, likely share a similar common ancestor. It should be no surprise to learn that eurypterids were swimming predators. The name comes from the Greek eury- for “broad” and -pteron for “wing”, referring to the large swimming appendages. Most eurypterids were relatively small like our specimen above, but some were almost two meters in length. They lived from the Ordovician to the end of the Permian Period.

Eurypterid reconstruction in Clarke and Ruedemann (1912). The artist is the famous paleontological illustrator Charles R. Knight.

Eurypterus remipes was the first eurypterid fossil formally described. The American zoologist James Ellsworth De Kay (1792-1851) did the honors while working in upstate New York. De Kay was orphaned at a young age but still managed to attend Yale (but no degree) and then complete an MD at the University of Edinburgh. He was not excited by medicine (one time he said it was “repugnant” to him), so he found himself doing many other things, such as traveling through Turkey (about which he wrote a book) and negotiating ship building contracts with emerging South American countries. Eventually he landed a job with the new Geological Survey of New York, publishing a multi-volume set called Zoology of New York State. Back then the boundaries between the natural sciences were less strict.

James Ellsworth De Kay (1792-1851)

Eurypterus fischeri (Eichwald) from the 47th plate of Ernst Haeckel’s Kunstformen der Natur (1904).

De Kay’s Eurypterus remipes was so charismatic that it became the state fossil of New York (although it took them until 1984 to declare it), and it was a global sensation in the mid-nineteenth century. Our little specimen is certainly one of Wooster’s paleontological treasures.


Clarke, J.M. and Ruedemann, R. 1912. The Eurypterida of New York. Volume 1. New York State Museum Memoir 14.

De Kay, J.E. 1825. Observations on a Fossil Crustaceous Animal of the Order Branchiopoda. Annals of the Lyceum of Natural History of New York, i, 1825, p. 375, pl. 29.

Kjellesvig-Waering, E.N. 1963. Note on Carcinosomatidae (Eurypterida) in the Silurian Bertie Formation of New York. Journal of Paleontology 37: 495-496.

Tetlie, O.E. 2006. Two new Silurian species of Eurypterus (Chelicerata: Eurypterida) from Norway and Canada and the phylogeny of the genus. Journal of Systematic Palaeontology 4: 397-412.

About Mark Wilson

Mark Wilson is a Professor of Geology at The College of Wooster. He specializes in invertebrate paleontology, carbonate sedimentology, and stratigraphy. He also is an expert on pseudoscience, especially creationism.
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1 Response to Wooster’s Fossils of the Week: Eurypterids (Late Silurian of New York)

  1. Pingback: Wooster Geologists » Blog Archive » Wooster’s Fossil of the Week: a trilobite burrow (Upper Ordovician of Ohio)

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