The zootype and the phylotypic stage.
What is it that defines an animal? The definition provided here, made on the basis of developmental biology, suggests methods for resolving phylogenetic problems.
Slack
J M
JM
Department of Zoology, University of Oxford, UK.
Holland
P W
PW
Graham
C F
CF
D000818:Animals; D015870:Gene Expression; D005801:Genes, Homeobox; D009024:Morphogenesis; D010802:Phylogeny