Specimen of the Month
Samuel J. Ciurca, Jr., Rochester, New York by Eurypterids.net
Second in abundance and widespread occurrence only to Eurypterus remipes (the State Fossil of New York) is a
wonderful eurypterid with a wide carapace, very small eyes and very pointed (nail-like) telson, viz. 'Eurypterus'
laculatus. Originally described from a finely crystalline dolostone at Morganville, New York, 'E.' laculatus is now
known from hundreds of specimens found across New York State and southwestern Ontario, Canada.
The specimen shown below was collected from the thin waterlime near the base of the Scajaquada Formation north
of Batavia, New York. The waterlime bears small salt hopper structures indicating the extreme salinity of the
sediment at the time of deposition. The occurrence at the site is the highest, stratigraphically, of the species - a
species that almost dominates the eurypterid fauna of parts of the Fiddlers Green Formation (especially the Ellicott
Creek Breccia of western New York and adjacent parts of Ontario, Canada.
'Eurypterus' laculatus is replaced (evolution) by 'Eurypterus' dekayi in the stratigraphically higher Williamsville
Formation of the Bertie Group.
The eurypterid in the photos above is 6.7 cm long. Width of the carapace (at base) is 1.5 cm. Note the conchoidal
fracturing exhibited by the waterlime.