Chordate - Wikipedia
Chordata is the third-largest phylum of the animal kingdom (behind only the protostomal phyla Arthropoda and Mollusca) and is also one of the most ancient taxons. Chordate fossils have been found from as early as the Cambrian explosion over 539 million years ago. [11]
Chordate - Evolution, Paleontology, Anatomy | Britannica
2024年10月22日 · The oldest known fossil chordate is Pikaia gracilens, a primitive cephalochordate dated to approximately 505 million years ago. There is disagreement over whether older animals—such as Yunnanozoon lividum and Haikouella (both of which date to 530 million years ago and possess several chordate features)—should be considered chordates.
Chordate evolution and the three-phylum system - PMC
Historically, the first scenario of sessile ancestry received much support, as ascidians had long been believed to be the most basal chordates. It was just 10 years ago that molecular phylogeny first gave support for the second, free-living ancestor scenario, by positioning cephalochordates as basal among chordates [ 43 , 44 ].
Facts and fancies about early fossil chordates and vertebrates
2015年4月22日 · Most of these fossils have been referred to as chordates because they show at least some indication of either a notochord (the axial support of chordates, and precursor of the vertebral...
Chordate evolution and the three-phylum system
2014年11月7日 · Traditional metazoan phylogeny classifies the Vertebrata as a subphylum of the phylum Chordata, together with two other subphyla, the Urochordata (Tunicata) and the Cephalochordata. The Chordata, together with the phyla Echinodermata and Hemichordata, comprise a major group, the Deuterostomia.
Chordata: Overview and Basal Taxa - Digital Atlas of Ancient Life
2020年5月29日 · Chordates also include a great variety of bizarre lineages of fish-like forms that went extinct early in the history of the phylum. This chapter provides a very broad and generalized overview of the diversity and evolutionary history of Chordata, which originated during the Cambrian period alongside most of the other animal phyla.
Evolution and Phylogeny of Chordates | SpringerLink
2024年1月1日 · Their early evolution is of interest to neuroscientists because this was when the basic structure of the vertebrate brain and spinal cord was assembled. Early chordates were soft-bodied so they seldom fossilized, but we reconstruct their origin using the modern chordates and their relatives plus some miraculously preserved fossils.
Evolution of the chordate body plan: New insights from ... - PNAS
2000年4月25日 · One of the most cited theories of chordate origins is Garstang's hypothesis that the aboral ciliated band of an auricularian-like larva could evolutionarily form a dorsal tubular nerve cord, such as that found in an ascidian tadpole larva (13).
(PDF) The origin and early evolution of chordates: The ‘Hydroskelett ...
The ‘Hydroskelett-Theory’ (Gutmann 1972) was the first coherent model for chordate evolution, based on the principles of engineering and constructional...
The origin and early evolution of chordates: The ... - Springer
The ‘Hydroskelett-Theory’ (Gutmann 1972) was the first coherent model for chordate evolution, based on the principles of engineering and constructional morphology. As a result of further investigations, the ‘Hydroskelett-Theory’ is revived, broadened, and stated more precisely.
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