Cephalopod and vertebrate neural-systems are often highlighted as a traditional example of
convergent evolution. Their large brains, relative to body size, and complexity of sensory …

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

Diverse bilaterian clades emerged apparently within a few million years during the early
Cambrian, and various environmental, developmental, and ecological causes have been …

The position of Xenacoelomorpha in the tree of life remains a major unresolved question in
the study of deep animal relationships. Xenacoelomorpha, comprising Acoela …

Despite rapid advances in the study of metazoan evolutionary history [1], phylogenomic
analyses have so far neglected a number of microscopic lineages that possess a unique …

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 …

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 …

It has been hypothesized that a condensed nervous system with a medial ventral nerve cord
is an ancestral character of Bilateria. The presence of similar dorsoventral molecular …

Eye evolution is driven by the evolution of visually guided behavior. Accumulation of
gradually more demanding behaviors have continuously increased the performance …