Largest order of amphibians

The largest taxonomic order of amphibians is Anura, aka Salientia (frogs and toads). It includes some 7,735 species as of the September 2024 version of the American Museum of Natural History's Amphibian Species of the World checklist. This figure constitutes 88% of all known living amphibian species (i.e., 8,781).

The other two extant orders of amphibian are considerably smaller: Urodela, aka Caudata (salamanders and newts) number 824 species (9% of all known living amphibian species), and Gymnophiona (caecilians) number 222 species (2.5%).

Those species of amphibian that exhibit exclusively fossorial (burrowing) or exclusively arboreal (tree-dwelling) lifestyles are more difficult to observe than ground-dwelling species, hence are more likely to include species still undiscovered and undescribed by science.

Moreover, due to the devastating worldwide effects upon amphibian numbers in recent years by chytridiomycosis, an infectious fungal disease, as well as by climate change and habitat destruction, it is possible that some species have been wiped out without their actual existence ever having been made known to science.