Exquisitely-Preserved Eldredgeops Trilobite from New York

Phacops rana crassituberculata = Eldredgeops rana crassituberculata

Trilobite Order Phacopida, Family Phacopidae

Geological Time: Middle Devonian

Size: 41 mm long

Fossil Site: Hamilton Group, Moscow Formation, Erie County, New York

Eldredgeops TrilobiteDescription: This is a very fine, 3-D prone example of a trilobite previously assigned to the genus Phacops, with few in such a pristine, undistorted shape. Phacops is particularly well known for its Schizochroal eyes. This type of trilobite eye typically has fewer lenses, but they are much larger, with each lens separated from its neighbors and having an individual cornea. The details to this specimen are readily evident in the photos. The Moscow Formation is the youngest formation in the Hamilton Group, and is known for the largest known examples of several trilobite taxa. While this may not be the largest of its type, there can be no dispute as to the quality of the preservation of this specimen.

The genus name for this trilobite is variously called Phacops or Eldredgeops, with the latter named after Niles Eldredge, whose study of Phacops trilobites from Ohio led him to hypothesize that modifications to the arrangement of the trilobite’s eye lenses proceeded in rapid change followed by stasis over millions of years during the Devonian. Eldredge's interpretation of the Phacops fossil record was that the aftermaths of the lens changes, but not the rapidly occurring evolutionary process, were fossilized. This and other data led Gould and Eldridge to publish the initial paper explaining punctuated equilibrium in 1971.

click trilobite pictures to enlarge

l Fossil Mall Home l Fossils Science Section l
l Trilobites for Sale l