Despite the extreme level of human-induced habitat destruction on Earth, which has resulted in more than 16,000 species worldwide being threatened with extinction, the last decade has seen a dramatic boom in the discovery of new vertebrate species. Such unprecedented taxonomic discoveries are the result of increased use of molecular biology in taxonomic studies and, most importantly, of increased numbers of scientific expeditions in regions (such as the Amazon and the Congo) that have been rarely, or never, surveyed previously.

Although many of the newly described species are small and cryptic (appearing identical but genetically quite distinct), some very large and unlikely animals, such as petrels, cats, elephants, pandas, and whales, are being newly described. In the present article, the state-of-the-knowledge in species and subspecies discoveries is discussed, and information is compiled from published taxonomic revisions—essentially a reinterpretation of the taxonomy of known animals—and from new field discoveries of animals. In particular, special attention is paid to tetrapod vertebrates, that is, amphibians, reptiles, mammals, and birds.