A revised six-kingdom system of life is presented, down to the level of infraphylum. As in my
1983 system Bacteria are treated as a single kingdom, and eukaryotes are divided into only …

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

Nematodes are important: parasitic nematodes threaten the health of plants, animals and
humans on a global scale,; interstitial nematodes pervade sediment and soil ecosystems in …

The arthropods constitute the most diverse animal group, but, despite their rich fossil record
and a century of study, their phylogenetic relationships remain unclear1. Taxa previously …

Phylogenomic studies have improved understanding of deep metazoan phylogeny and
show promise for resolving incongruences among analyses based on limited numbers of …

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

Insight into the origin and early evolution of the animal phyla requires an understanding of
how animal groups are related to one another. Thus, we set out to explore animal phylogeny …

DNA sequence analysis dictates new interpretation of phylogenic trees. Taxa that were once
thought to represent successive grades of complexity at the base of the metazoan tree are …

Animals have evolved diverse appendages adapted for locomotion, feeding and other
functions. The genetics underlying appendage formation are best understood in insects and …

Cladistic analysis of traditional (ie morphological, developmental, ultrastructural) and
molecular (18S rDNA) data sets (276+ 501 informative characters) provides a hypothesis …