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Chordonia

(Infrakingdom)

Overview

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A taxonomic infrakingdom.

Photos

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Taxonomy

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The Infrakingdom Chordonia is a member of the Branch Deuterostomia. Here is the complete "parentage" of Chordonia:

The Infrakingdom Chordonia is further organized into finer groupings including:

Phyla

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Chordata

Chordates (phylum Chordata) are animals which are either vertebrates or one of several closely related invertebrates. They are united by having, for at least some period of their life cycle, a notochord, a hollow dorsal nerve cord, pharyngeal slits, an endostyle, and a post-anal tail. The phylum Chordata consists of three subphyla: Tunicata, represented by tunicates; Cephalochordata, represented by lancelets; and Craniata, which includes Vertebrata. The Hemichordata have been presented as a fourth chordate subphylum, but they are now usually treated as a separate phylum. Tunicate larvae have both a notochord and a nerve cord which are lost in adulthood. Cephalochordates have a notochord and a nerve cord (but no brain or specialist sensory organs) and a very simple circulatory system. Craniates are the only sub-phylum whose members have skulls. In all craniates except for hagfish, the dorsal hollow nerve cord is surrounded with cartilaginous or bony vertebrae and the notochord is generally reduced; hence, hagfish are not regarded as vertebrates. The chordates and three sister phyla, the Hemichordata, the Echinodermata and the Xenoturbellida, make up the deuterostomes, one of the two superphyla that encompass all fairly complex animals. [more]

At least 204,522 species and subspecies belong to the Phylum Chordata.

More info about the Phylum Chordata may be found here.

Sources

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Last Revised: October 03, 2013
2013/10/03 15:23:29