Metazoa comprises 35–40 phyla that include some 1.3 million described species.
Phylogenetic analyses of metazoan interrelationships have progressed in the past two …

▪ Abstract Molecular tools have profoundly rearranged our understanding of metazoan
phylogeny. Initially based on the nuclear small ribosomal subunit (SSU or 18S) gene, recent …

Molluscs comprise the second largest phylum of animals (after arthropods), occurring in
virtually all habitats. Some are commercially important, a few are pests and some carry …

Tunicates or urochordates (appendicularians, salps and sea squirts), cephalochordates
(lancelets) and vertebrates (including lamprey and hagfish) constitute the three extant …

A clear picture of animal relationships is a prerequisite to understand how the morphological
and ecological diversity of animals evolved over time. Among others, the placement of the …

One of the most brilliant scientists of our age gives us his definitive work: a synthesis of his
comprehensive vision of life. THE ANCESTOR'S TALE is a pilgrimage back through time; a …

Xenoturbellida and Acoelomorpha are marine worms with contentious ancestry. Both were
originally associated with the flatworms (Platyhelminthes), but molecular data have revised …

The evolutionary history of life includes two primary components: phylogeny and timescale.
Phylogeny refers to the branching order (relationships) of species or other taxa within a …

Xenoturbella and the acoelomorph worms (Xenacoelomorpha) are simple marine animals
with controversial affinities. They have been placed as the sister group of all other bilaterian …

Deuterostomes comprise vertebrates, the related invertebrate chordates (tunicates and
cephalochordates) and three other invertebrate taxa: hemichordates, echinoderms and …