structural:scholar_edition
Evolution

Skates belong to the ancient lineage of cartilaginous fishes. Fossil denticles (tooth-like scales in the skin) resembling those of today's chondrichthyans date at least as far back as the Ordovician, with the oldest unambiguous fossils of cartilaginous fish dating from the middle Devonian. A clade within this diverse family, the Neoselachii, emerged by the Triassic, with the best-understood neoselachian fossils dating from the Jurassic. This clade is represented today by sharks, sawfish, rays and skates.

The body plan of skates is caused by skate-specific genomic rearrangements that have altered the three-dimensional regulatory landscape of genes. These changes arose about 286–221 million years ago when skates diverged from sharks.