At present there are many animal phyla that contain only a few species. The existence of these small phyla can be used to test assumptions about speciation and extinction in multicellular animals. We ...

Which group of animals evolved first? This problem has become a bone of contention among biologists. An international research team is now confident that the definitive answer is at hand: Sponges ...

The initial phases of animal evolution proceeded faster than hitherto supposed: New analyses suggest that the first animal phyla emerged in rapid succession -- prior to the global Ice Age that set in ...

Annual Review of Ecology and Systematics, Vol. 25 (1994), pp. 351-375 (25 pages) Most animal phyla appeared in the Cambrian radiation, and many have a rich fossil record. The phylogenetic ...

DNA sequence data from neglected animal groups support a controversial hypothesis of deep evolutionary history. Inferring that history using only whole-genome sequences can evidently be misleading.

Genetic analysis of an obscure, worm-like creature retrieved from the depths of the North Atlantic has led to the discovery of a new phylum, a rare event in an era when most organisms have already ...

Parasitism evolved at least 223 times, far more than the previous estimate of 60. It arose more times in certain phyla (e.g., arthropods, nematodes, flatworms, and mollusks) than in others. Today, ...