Trilobite Phacops Rana Milleri measures 1.0 inches. Trilobite Phacops Rana Milleri is museum quality polyurethane cast. Made in USA. Devonian Medusa Quarry, Ohio. Trilobites are very well-known, and possibly the second-most famous fossil group after the dinosaurs with some 15,000 known species.

Phacops rana Milleri (Eldredgeops rana) is a species of trilobite from the middle Devonian period. Their fossils are found chiefly in the northeastern United States, southwestern Ontario, and in Morocco.

Phacops rana Milleri or Eldredgeops rana can be recognized by its large eyes (which remind some observers of a frog’s eyes—the specific name rana is a reference to a common frog), its fairly large size (up to 6 inches long), and its habit of rolling up into a ball like a pill bug (“volvation”).

In order to protect themselves from predators, Phacops rana would roll into a ball with its hard exoskeleton on the outside as protection.

Many other trilobites possessed the same ability, but Phacops rana Milleri nearly perfected it. The slightest amount of sediment would trigger their senses, and Phacops rana or Eldredgeops rana would be hidden in a tiny shelter made of its own body.

Although this safety feature often helped them to evade predators, occasionally it backfired and the trilobite would be buried under heavy sediment. Eldredgeops rana fossils can still be found in balled-up positions 400 million years later.

Phacops rana Milleri is found both in the northeastern U.S. and in Morocco; North America was attached to the African plate during the Devonian. Because of its abundance and popularity with collectors, Phacops rana or Eldredgeops rana was designated the Pennsylvania state fossil by the state’s General Assembly on December 5, 1988.

The most striking feature of the morphology of Phacops rana Milleri or Eldredgeops rana and its relatives is their eyes. These differed from the eyes of most trilobites in having comparatively few lenses spaced between deep sclera.

The lenses themselves were very rounded instead of largely flat. The eyes were mounted on turret-like structures which could swivel, providing the animal with an almost 360-degree field of view. This type of eye is known as the schizochroal eye.

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Additional information

Weight 1 lbs
Dimensions 1.0 in
Phacops Rana Milleri Facts

Kingdom: Animalia
Phylum: Arthropoda
Class: †Trilobita
Order: †Phacopida
Family: †Phacopidae
Genus: †Phacops
Species: †P. rana
Binomial name: †Phacops rana