Rhabdoderma sp.
Middle Pennsylvanian (Missourian)
Atrasado Formation, Tinajas Member
Kinney Brick Quarry
New Mexico, United States

137mm coelacanth on 195mm slab

Rhabdoderma sp. from New Mexico is a rare fossil example of a coelacanth, a group of ancient lobe-finned fish that date back over 300 million years to the Carboniferous period. Unlike modern ray-finned fish, Rhabdoderma had fleshy, limb-like fins supported by bones—traits that link it to the early evolution of land vertebrates. Fossils from New Mexico show this ancient fish once swam in freshwater swamps and rivers. As a member of the long-lived coelacanth lineage, Rhabdoderma is a living fossil’s ancient ancestor—an extraordinary survivor from deep time.