Analogues
of organs of special sense may develop
in lower chordates.
Shu DG et al.
Nature 430: 422-428, 2004
Phylogeny of
early deuterostomes
Green arrow:
Jeffery WR et al, Nature 431:696-699, 2004
Suggests that
neural crest cell evolution (migration from neural tube to body wall,
differentiation into pigment cells) began in common ancestor of urochordates
and vertebrates.