Britannica
Sources used in this answer
How are chimaeras classified within Holocephali?
Created from Britannica articles
using AI.
AI can make mistakes, so verify using Britannica articles.
chondrichthyan
Southern stingrays (Dasyatis americana or Hypanus americanus) are found in the western Atlantic Ocean.
Chimaeras are classified within the subclass Holocephali, which belongs to the class Chondrichthyes (cartilaginous fishes). While they share a cartilaginous skeleton and the presence of pelvic claspers with sharks and rays, they are distinguished by a single external gill opening covered by a skin flap.12
Within the subclass Holocephali, the approximately 47 extant species of chimaeras are categorized into three distinct families based on their physical characteristics:1
- Chimaeridae: Characterized by a rounded or cone-shaped snout; this family includes species commonly known as rabbit fish.1
- Callorhinchidae: Known as elephant fishes, these are identified by an unusual, hoe-shaped, flexible snout.1
- Rhinochimaeridae: Also referred to as long-nosed chimaeras, they possess an extended, pointed snout.1
While these families represent the modern survivors, the evolutionary history of Holocephali is complex, with fossil records indicating that the group was significantly more diverse during the Mesozoic Era.3