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New Amphibian Tree of Life

Credit: Taran Grant, AMNH

Scientists revise outdated taxonomy

Six American Museum of Natural History biologists, including Darrel Frost, and 13 colleagues have completed the largest analysis ever of the evolutionary relationships among all living amphibians, a project so ambitious that it also represents the largest analysis of its kind of any group of vertebrate animals. Click to enlarge.
Credit: Taran Grant, AMNH

Scientists revise outdated taxonomy

The new tree of life will provide biologists with a unifying framework to the study amphibian evolution and extinction. Shown: Atelopus spurelli. Click to enlarge.
Credit: Frost et al., 2006

Scientists revise outdated taxonomy

It took more than six months of parallel computing time to crunch genetic and other data to arrive at a proposed evolutionary tree. Click to enlarge.
Credit: Taran Grant, AMNH

Scientists revise outdated taxonomy

The new taxonomy names 33 new groups and 2 new families, and includes dozens of new groupings among amphibians. Click to enlarge.
Credit: Mick Ellison, AMNH

Scientists revise outdated taxonomy

Prior knowledge of this ancient and ecologically important group of animals was speculative. A fossil frog, Mesophryne beipiaoensis, from the Cretaceous Period from Liaoning Province, China, is shown. Click to enlarge.
Credit: Taran Grant, AMNH

Scientists revise outdated taxonomy

The number of recognized amphibian species has grown enormously in recent years and has included the discovery of Dendrobates castaneoticus. Click to enlarge.
Credit: Taran Grant, AMNH

Scientists revise outdated taxonomy

Amphibian populations have undergone massive, global declines due to factors including habitat loss, as in the Western Andes, Colombia. Click to enlarge.
Taran Grant, AMNH

Scientists revise outdated taxonomy

Another factor in the global decline of amphibians is the fragmentation of populations into smaller groups isolated in the remaining habitat fragments, such as these forest patches in the Western Andes. Click to enlarge.
Credit: Taran Grant, AMNH

Scientists revise outdated taxonomy

Some declines are the result of a fungal disease that can occur in amphibians that live along streams, such as Colosthesus nubicola. Click to enlarge.
Credit: Ronald Nussbaum, University of Michigan

Scientists revise outdated taxonomy

The new tree was based on data from 522 amphibian species, with equivalent samples of frogs, caecilians, and salamanders and newts. Tylototriton shanjing, or Mandarin newt, shown. Click to enlarge.
Credit: Taran Grant, AMNH

Scientists revise outdated taxonomy

Caecilians are amphibians that resemble snakes without external scales. Shown: Caecilia thompsoni. Click to enlarge.
Credit: Taran Grant, AMNH

Scientists revise outdated taxonomy

The study shows that tree frogs, such as Phyllomedusa hypochondrialis, are relatively primitive compared with other amphibian groups. Click to enlarge.
Credit: Taran Grant, AMNH

Scientists revise outdated taxonomy

Parental care (shown here in a father of Phylobates bicolor carrying his tadpole on his back) also occurs near the base of the amphibian tree, a finding that was not necessarily anticipated. Click to enlarge.
Credit: Taran Grant, AMNH

Scientists revise outdated taxonomy

Rain frogs, such as Eleutherodactylus sp., are a large group of some 800 species. These frogs skip the tadpole stage. The new results suggest this is an ancient group with fewer species than its closest relative, and that the lack of a tadpole stage prevented more species from evolving. Click to enlarge.
Credit: Taran Grant, AMNH

Scientists revise outdated taxonomy

This study is one of the first large-scale initiatives to understand the diversity of life on Earth, and will help efforts to conserve all frogs, including Eleutherodactylus elegans (shown). Click to enlarge.