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Chordate fossils have been found from as early as the Cambrian explosion, 539 million years ago. Cladistically (phylogenetically), vertebrates – chordates with the notochord replaced by a vertebral column during development – are a subgroup of the clade Craniata, which consists of chordates with a skull.
Evolution and paleontology. Many scientists maintain that chordates originated sometime earlier than 590 million years ago; that is, they predate the fossil record. Such early representatives were soft-bodied and therefore left a poor fossil record. The oldest known fossil chordate is Pikaia gracilens, a primitive cephalochordate dated to ...
22 apr 2015 · The interrelationships between major living vertebrate, and even chordate, groups are now reasonably well resolved thanks to a large amount of generally congruent data derived from molecular ...
- Philippe Janvier
- janvier@mnhn.fr
- 2015
22 apr 2015 · The mystery of chordate origins has endured for more than 150 years. Shortly after Darwin's On the Origin of Species, acorn worms were discovered to have chordate-like pharyngeal gill slits 1,...
- Christopher J. Lowe, D. Nathaniel Clarke, Daniel M. Medeiros, Daniel S. Rokhsar, John Gerhart
- 2015
1 gen 2024 · A scenario of chordate origins in which chordates evolved from hemichordate-like worms, rather than from tunicate larvae, has been presented. How does this new view affect understanding of the early evolution of chordate structures, especially of the nervous system?
- Jon Mallatt
19 giu 2008 · Lancelets (‘amphioxus’) are the modern survivors of an ancient chordate lineage, with a fossil record dating back to the Cambrian period. Here we describe the structure and gene content of the...
25 apr 2000 · Urochordate and hemichordate evolutionary relationships are central to understanding chordate evolution, but morphological disparities among taxa and a poor fossil record have hampered research efforts.
