Acutiramus cummingsi   CIURCA 051001-5
Large coxa collected from the Williamsville Waterlime (A)  (Bertie Group),  Ridgemount Quarry,  Fort Erie, Ontario, Canada.  Note the large teeth.  The coxa is covered by fishlike scales and was attached  to the swimming leg of the animal. Measurements:
In New York, pterygotids first appear in the Late Silurian Vernon Formation (Salina Group) but an unusual structure found within the Maplewood Shale of the Genesee Gorge at Rochester, N.Y., if proven to be the sexual appendage of some early pterygotid,  could make this the earliest oc- currence (Clinton Group). A fossil recently found in Pennsylvania, associated with the peculiar eurypterid, Rhinocarcinosoma, suggests that in New York we will find a pterygotid within Lockport Group dolomitic rocks. The Rhinocarcinosoma horizon is well known in New York and occurs  from Sodus eastward to the Illion area of New York State.
Acutiramus macrophthalmus
The largest specimen found to date. This specimen was discovered in 1964 and may  be the largest arthropod fossil known. Collected from the Phelps Member of the Fiddlers Green Formatiion (Bertie Group), Eastern N.Y. Acutiramus macrophthalmus evolved into Acutiramus cummingsi of the Williamsville Waterlime of New York and Ontario, Canada. It appears that this form became a wider, more robust pterygotid through time.  I have  discovered a new Acutiramus in the Early Devonian sequence of the Syracuse area that continues the line of evolution of this eurypterid.  Interestingly, Eurypterus (and the many other eurypterids found within the zone of Eurypterus lacustris) did not make it into the Early Devonian.  Eurypterus was replaced by  Erieopterus. See Ciurca 1978 NYSGA Field Trip Guide Book pp. 225-249.
CIURCA 051001-5
Acutiramus cummingsi CIURCA COLLECTION
Windrow of pterygotid remains.  Disarticulated Acutiramus collected into this area by currents, probably storm currents. Note telson, pincer with teeth, coxae, etc.  Williamsville Formation, Bertie Group of the Niagara Peninsula, Ontario, Canada.
Errettopterus monroensis
Carapace found during discovery of the Harris Hill Member of the lower Vernon Formation, (Salina Group) in Penfield, New York. This new member is believed to be older than the Pittsford Member. It occurs to the north of Pittsford; the general dip of the strata is to the south, so it is assumed that this unit is older. The main body of this eurypterid has also been found (unknown to Sarle) and will be shown on these pages in the near future.
CIURCA 050592-1
At right: Pincer of Acutiramus cummingsi from the Williamsville Waterlime, Brompton Road Site near Buffalo, New York.  Pincer is 5 cm. long and was found next to the anteror portion of a spec- men preserving a carapace with an attached operculum. Note the large, forward-directed teeth. These teeth are usually serrated. Pterygotids are generally found in Silurian and Devonian strata.