Vetulicolia
Extinct Cambrian group of animals / From Wikipedia, the free encyclopedia
Vetulicolia[note 1] is a phylum of bilaterian animals encompassing several extinct species belonging to the Cambrian period.[1][2] The phylum was created by Degan Shu and his research team in 2001,[3] and named after Vetulicola cuneata, the first species of the phylum described in 1987.[4]
Vetulicolia | |
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Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Superphylum: | Deuterostomia |
Phylum: | †Vetulicolia Shu et al. 2001 |
Type species | |
†Vetulicola cuneata Hou, 1987 | |
Classes | |
The vetulicolian body plan comprises two parts: a voluminous rostral (anterior) forebody, tipped with an anteriorly positioned mouth and lined with a lateral row of five round to oval-shaped openings on each side, which have been interpreted as gills (or at least orifices in the vicinity of the pharynx); and a caudal (posterior) section that primitively comprises seven body segments and functions as a tail. All vetulicolians lack preserved appendages of any kind, having no legs, feelers or even eye spots.[5] The area where the anterior and posterior parts join is constricted.[6]
Their taxonomic affinity has been uncertain; they have been considered to represent stem- and crown-group arthropods, stem-group vertebrates,[7] and early deuterostomes (a group which as a whole includes the vertebrates, other invertebrate chordates, echinoderms and hemichordates). The general scientific consensus before 2001 considered them early limbless arthropods but now considers them early deuterostomes.[8] Vetulicolian fossils examined in 2014 show the presence of notochord-like structures, and it was concluded that vetulicolians are crown-group chordates and probably related to modern tunicates.[9] Research from 2017 rather indicates vetulicolians are related to Saccorhytus, another basal deuterostome group,[10] although another study shows possibility that Saccorhytus is ecdysozoan instead of deuterostome.[11]