Class CHONDRICHTHYES


Common name: Sharks, rays, skates and chimaeras
Summary:

Sharks, rays, skates and chimaeras of the Class Chondrichthyes are the oldest group of living jawed vertebrates. Studies have shown that chondrichthyans diverged from the common ancestor of bony fishes and higher vertebrates about 530 million years ago.

Although there are an estimated 1250 shark, ray and chimaera species worldwide, this number may seriously underestimate the actual number of species. 

Naylor et al. (2012) sequenced DNA from more than 4000 shark and ray specimens, representing 574 species. Of these, about 14% may be undescribed - presumably because they closely resemble known species.

Sharks and rays are key predators in the marine environment, but life cycles and population numbers of many species are poorly understood.

According to the IUCN (International Union for the Conservation of Nature), many sharks and rays are under threat from overfishing. The finding of many undescribed species may mean that some sharks and rays are even more endangered than previously thought.

Author: Bray, D.J. 2017

Cite this page as:
Sharks, rays ..., CHONDRICHTHYES in Fishes of Australia, accessed 11 Apr 2025, https://fishesofaustralia.net.au/home/class/4