Eurypterids - Specimen of the Month
Samuel J. Ciurca, Jr., Rochester, New York by Eurypterids.net
|Erettopterus osiliensis (Schmidt,1883)
The specimen illustrated here represents the only known, nearly-complete pterygotid from the Pittsford (Black Shale)
Member of the lower Vernon Formation, Salina Group in western New York. It is an unusually nice specimen for
material preserved in black shale. This pterygotid was previously known as "Pterygotus monroensis" - Ciurca and
Tetlie (2007) consider the animal to be conspecific with the eurypterid described by Schmidt from Estonia.
SEE: "PTERYGOTIDS (CHELICERATA; EURYPTERIDA) FROM THE SILURIAN VERNON FORMATION OF NEW YORK" Samuel J. Ciurca,
Jr. and O. Erik Tetlie, Journal of Paleontology, 81(4), 2007, pp. 725-736.
The specimen shown here is preserved in an unusual fashion - the carapace was dislocated to reveal ventral structures beneath. The
specimen is about 20 cm. in length and was recovered from the Tastings Site (Wegmans) adjacent to the original Erie Canal in Pittsford,
New York. When Clifton Sarle first described the Pittsford Fauna in 1903, he reported only a few pterygotid parts among the prolific re-
mains of Hughmilleria socialis and Eurypterus pittsfordensis he collected. Why he did not recover more is not quite understood as in
recent years many more remains seem to have been evident.
LEFT: Within the anterior (ventral) region of
the specimen shown above, two large coxae
are well-preserved. Note the large teeth,
these would have surrounded the mouth of
the animal. Not preserved on the specimen
are the swimming legs that would have been
attached to these coxae.
Unfortunately, the chelicerae were not
preserved with the specimen, but much is
known about the structure of these - see
TO MY WEBSITE VISITORS: This is the last page to the series, EURYPTERID OF THE MONTH. I've kept it going for 2 years and
now it is time to move to something else - not quite sure what that is yet, but I have a lot to do with eurypterids, yet.
While doing this series, I worked on a book, now published, and I hope you will order a copy. Click on 23 below, and the link will take
you to an order form. Thanks for visiting my pages. UPDATE: THE BOOK IS NOW AVAILABLE AT AMAZON.COM.
ABOVE & RIGHT: Closer views of the posterior showing the bilobed
telson. The telson is quite like that of the well-known Erettopterus
bilobus of the Silurian of Lesmahagow in Scotland. Several isolated
"bilobed" telsons have been found in the Pittsford beds, but the spec-
imen shown here is the first example of a nearly perfectly preserved
molt. In the photo above, a portion of Hughmilleria socialis is also
present - the species being the most common eurypterid occurring in
|A FINAL SUGGESTION
Read Chapter 5 The Bertie Waterlime
in "Fossil Ecosystems of North America" A GUIDE TO THE
SITES AND THEIR EXTRAORDINARY BIOTAS
by John R. Nudds and Paul A. Selden
MANSON PUBLISHING 2008