Pearly Ammonite Fossil on Matrix — Hoploscaphites
No reserve
Auction Closed
July 28, 03:27 PM GMT
Estimate
900 - 1,200 USD
Lot Details
Description
Pearly Ammonite Fossil on Matrix — Hoploscaphites
Hoploscaphites species
Late Cretaceous
Fox Hills Formation, South Dakota
3¼ inches by 2½ inches (8.3 x 6.4 cm).
A brilliant rainbow of pearly iridescence colors are clear in this almost metallic ammonite. The tubercles, ridges, and sutures are well-preserved in this fossil shell. Kept in its original rock, this Hoploscaphites specimen was prepared, sculpted, and signed by well-known invertebrate paleontologist, Neil Larsen: “collected 7/2020 Trask Ranch prepared 11/2022”.
This Hoploscaphites shell is a superb example from one of the most beautiful of all fossil groups, the ammonites. Much like a submarine, ammonites employed gas and fluid-filled chambers to regulate their position in the water column. The animals themselves lived only in the outermost compartment, employing their tubular siphuncle to connect its chambers along their shell's ventral surface.
The now-extinct ammonites are some of the oldest cephalopods—a group that includes today's octopus, squid, cuttlefish, and nautilus—and are of central importance to the study of paleontology. Acting as a "defining biological marker", they provide a reference for determining the age of select sedimentary rock layers.