In recent years, scientists have made remarkable progress reconstructing the animal
phylogeny. There is broad agreement regarding many deep animal relationships, including …

Animal evolution is often presented as a march toward complexity, with different living
animal groups each representing grades of organization that arose through the progressive …

Proper biological interpretation of a phylogeny can sometimes hinge on the placement of
key taxa—or fail when such key taxa are not sampled. In this light, we here present the first …

Identifying our most distant animal relatives has emerged as one of the most challenging
problems in phylogenetics. This debate has major implications for our understanding of the …

This revision of the classification of unicellular eukaryotes updates that of Levine et al.(1980)
for the protozoa and expands it to include other protists. Whereas the previous revision was …

The earliest evolution of the animals remains a taxing biological problem, as all extant
clades are highly derived and the fossil record is not usually considered to be helpful. The …

Mucus layers often provide a unique and multi-functional hydrogel interface between the
epithelial cells of organisms and their external environment. Mucus has exceptional …

Molecular phylogenetic analyses have produced a plethora of controversial hypotheses
regarding the patterns of diversification of non-bilaterian animals. To unravel the causes for …

SUMMARY A review of the old and new literature on animal morphology/embryology and
molecular studies has led me to the following scenario for the early evolution of the …

The phylogenetic placement of the morphologically simple placozoans is crucial to
understanding the evolution of complex animal traits. Here, we examine the influence of …