"Craniata" redirects here. For a class of Brachiopod, see Craniforma.
For an explanation of its other name, see Vertebrate.
Craniates
Temporal range: Early Cambrian - Recent
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A Pacific hagfish, an example of (what was thought to be) a "non-vertebrate craniate"
Scientific classification
Domain:
Eukaryota
Kingdom:
Animalia
Phylum:
Chordata
Clade:
Olfactores
Clade:
Craniata Lankester, 1877[1]
Included groups
Agnatha
Hyperoartia (lampreys) (disputed vertebrates)
Myxini (hagfishes)
Cephalaspidomorphi (possible vertebrates)
Gnathostomata (emerged from within Cephalaspidomorphi)[2]
Synonyms
Craniota Haeckel, 1866
Pachycardia Haeckel, 1866
Vertebrata J-B. Lamarck, 1801
A craniate is a member of the Craniata (sometimes called the Craniota), a proposed clade of chordate animals with a skull of hard bone or cartilage. Living representatives are the Myxini (hagfishes), Hyperoartia (including lampreys), and the much more numerous Gnathostomata (jawed vertebrates).[3][4] Formerly distinct from vertebrates by excluding hagfish, molecular and anatomical research in the 21st century has led to the reinclusion of hagfish as vertebrates, making living craniates synonymous with living vertebrates.
The clade was conceived largely on the basis of the Hyperoartia (lampreys and kin) being more closely related to the Gnathostomata (jawed vertebrates) than the Myxini (hagfishes). This, combined with an apparent lack of vertebral elements within the Myxini, suggested that the Myxini were descended from a more ancient lineage than the vertebrates, and that the skull developed before the vertebral column. The clade was thus composed of the Hyperoartia and the vertebrates, and any extinct chordates with skulls.
However recent studies using molecular phylogenetics have contradicted this view, with evidence that the Cyclostomata (Hyperoartia and Myxini) is monophyletic; this suggests that the Myxini are degenerate vertebrates, and therefore the vertebrates and craniates are cladistically equivalent, at least for the living representatives. The placement of the Myxini within the vertebrates has been further strengthened by recent anatomical analysis, with vestiges of a vertebral column being discovered in the Myxini.[5]
^Nielsen, C. (July 2012). "The authorship of higher chordate taxa". Zoologica Scripta. 41 (4): 435–436. doi:10.1111/j.1463-6409.2012.00536.x. S2CID 83266247.
^Miyashita, Tetsuto (2019). "Hagfish from the Cretaceous Tethys Sea and a reconciliation of the morphological–molecular conflict in early vertebrate phylogeny". Proceedings of the National Academy of Sciences of the United States of America. 116 (6): 2146–2151. Bibcode:2019PNAS..116.2146M. doi:10.1073/pnas.1814794116. PMC 6369785. PMID 30670644.
^Campbell & Reece 2005 p. 676
^Cracraft & Donoghue 2004 p. 390
^Janvier, Philippe (2011). "Comparative Anatomy: All Vertebrates Do Have Vertebrae". Current Biology. 21 (17): R661–R663. doi:10.1016/j.cub.2011.07.014. ISSN 0960-9822. PMID 21920298. S2CID 17652802.
A craniate is a member of the Craniata (sometimes called the Craniota), a proposed clade of chordate animals with a skull of hard bone or cartilage. Living...
Haikouichthys /ˌhaɪkuˈɪkθɪs/ is an extinct genus of craniate (animals with notochords and distinct heads) that lived 518 million years ago, during the...
chordates Craniates all have distinct skulls. They include the hagfish, which have no vertebrae. Michael J. Benton commented that "craniates are characterized...
reason, the vertebrate subphylum is sometimes referred to as Craniata or "craniates" when discussing morphology. Molecular analysis since 1992 has suggested...
fossil, Haikouella lanceolata, is interpreted as a chordate and possibly a craniate, as it shows signs of a heart, arteries, gill filaments, a tail, a neural...
systems have used the term Amphirhina. It is a sister group of the jawless craniates Agnatha. Vertebrate classes The appearance of the early vertebrate jaw...
Cambrian period. The Myllokunmingiids are the earliest known group of craniates. The group contains three genera, Haikouichthys, Myllokunmingia, and Zhongjianichthys...
jaws. Finally, throughout geologic time, invertebrates have remained non-craniate creatures; that is, they never developed a cranium, nerve-chord brain,...
chordates developed the skull and the vertebral column, leading to the first craniates and vertebrates. The first fish lineages belong to the Agnatha, or jawless...
because it seems to possess most of the characteristics attributed to craniates. It lacked fins and it had a weakly developed cranium, but it did possess...
ISBN 978-0-03-008914-5. Butler, AB (2000). "Chordate Evolution and the Origin of Craniates: An Old Brain in a New Head". Anatomical Record. 261 (3): 111–125. doi:10...
marks the transition from invertebrate to vertebrates. Haikouichthys is craniates (animals with backbones and distinct heads). Unlike Pikaia, they had eyes...
Moreover, some analyses do not regard conodonts as either vertebrates or craniates, because they lack the main characteristics of these groups. More recently...
endoskeleton, namely the cranium (hence a synonym word for vertebrates, the craniates) and the spinal canal. The hollow cavity inside the neural tube is filled...
environments. There are a couple of examples of osmoconformers that are craniates such as hagfish, skates and sharks. Their body fluid is isosmotic with...
animals, namely the arthropods, cephalopod molluscs, and vertebrates (craniates). Cnidaria, such as the radially symmetrical Hydrozoa, show some degree...
Valdiviathyris is a genus of craniate brachiopods that has changed little since the Silurian, from when fossils are known. The extant species V. quenstedti...
dead colonies to pieces of meat. Tunicates are more closely related to craniates (including hagfish, lampreys, and jawed vertebrates) than to lancelets...
during the Ordovician period. Arandaspids represent the oldest known craniates, a proposed group of chordates that contain all chordates with a cartilage-derived...
because it seems to possess most of the characteristics attributed to craniates. It lacked fins and it had a weakly developed cranium, but it did possess...
lagerstätte in China. These creatures are the earliest known group of craniates (chordates with a skull of hard bone or cartilage). Currently the group...
groups are still actively debated. Tardigrade, Lobopodia, (Onychophora) Non-craniate (non-vertebrate) chordates: Cephalochordate, Tunicata and Haikouella. These...
invertebrates and chordates. Haikouella lanceolata is described to be the earliest craniate-like chordate. This fish-like animal has many similarities to Y. lividum...
paraphyletic group of organisms that consist of all gill-bearing aquatic craniate animals that lack limbs with digits. Included in this definition are the...
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