The eurypterids were mostly aquatic arthropods commonly having a pair of swimming and digging appendages (see illustrations) and an anterior pair of food-gathering pincers, usually small, termed chelicerae. See illustration at right.
Accompanying illustrations in the exhibit, Prehistoric Pittsford, show the morphological features of two common eurypterid forms (Hughmilleria and Eurypterus. Note the head region having a carapace with two eyes present. Often, the eyes are located somewhat centrally as in Eurypterus; sometimes marginally as in Hughmilleria. Behind the head region are several body segments (tergites) ending in a spiked 'tail', the telson. Many other features are noted in the drawings EURYPTERID STRUCTURE..
Two distinctly different eurypterids were common during Silurian time as represented by the fossils found in the rocks of the Lower Salina Group of western New York. Both are described in the exhibit "Prehistorid Pittsford." The slender Hughmilleria socialis Sarle is the most common form found in the Pittsford Member and may have been actively swimming in nearby rivers. Eurypterus pittsfordensis Sarle appears to have been a more sluggish creature, perhaps swimming and digging along the bottom of shallow lagoons and embayments between "algal" reefs or barriers (ie. stromatolite tracts) and nearby very lowlying lands.
Many different types of eurypterids have been described from rocks around the world, especially from Great Britain, Canada, Germany and the Baltic Region. They are found in rocks of Ordovician to Permian age, having become extinct in the latter Period. We are left to speculate upon the behavior of these wonderful creatures, and our only clues really come from a knowledge of modern forms like the horseshoe crabs and the scorpions and related arthropods. The present is really the key to the past.
Copyright 2000 Samuel J. Ciurca, Jr.
|Hughmilleria socialis Sarle
Clarke & Ruedemann 1912
|Clifton James Sarle (1875 - 1960) discovered the eurypterids of the Pittsford Shale during deepening of the Erie Canal and published his findings in 1903 in New York State Museum publications.|
Fossils of Pittsford
| Eurypterus pittsfordensis
shows the anterior portion of this segmented arthropod that inhabited the area over 400 million years ago in western New York. This animal reached a length of at least 17 inches, based upon the molted parts discovered thus far in the Pittsford Member of the Vernon Formation, Salina Group.
From Clarke & Ruedemann
|WHAT'S IN A NAME?
Ever wonder where those names of fossils come from? The person who describes the fossil for the first time gets to name the fossil. Most fossil names are latinized, eg. Endophyllum ciurcai, a fossil coral named after this author. But where did Hughmilleria and the Eurypterus of the Pittsford Shale get their names? Find out on the page: WHATS IN A NAME?
And find out about a famous Scottish geologist. What's he got to do with anything? Check out
WHAT'S IN A NAME?
|THANKS FOR VISITING THIS SITE
Samuel J. Ciurca, Jr., Rochester, New York
--- October 3, 2000 ---
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The Silurian Eurypterid Fauna
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