Abstract
The extant holocephalans are represented by Chimaeriformes, containing three families: Chimaeridae, Rhinochimaeridae, and Callorhinchidae. The family Chimaeridae, i.e. commonly shortnose chimaeras, ratfishes, and ghost sharks, comprises 43 species belonging to two genera,
Chimaera
(20 species) and
Hydrolagus
(23 species). All the species are marine, inhabiting all the world's oceans with the exception of Arctic and Antarctic waters, ranging from near‐shore surface waters to deeper than 2000 m.