Olfactores

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Olfactores
Temporal range:
FortunianHolocene, 535–0 Ma
Tunicate komodo.jpg
The gold-mouth sea squirt (Polycarpa aurata) a member of the olfactores clade, with a heart and a respiratory system.
Scientific classification e
Kingdom: Animalia
Clade: Bilateria
Clade: Nephrozoa
Superphylum: Deuterostomia
Phylum: Chordata
Clade: Olfactores

Olfactores is a subphylum within the Chordata that comprises the Tunicata (Urochordata) and the Vertebrata (sometimes referred to as Craniata). Olfactores represent the overwhelming majority of the phylum Chordata, being the Cephalochordata the only chordates not included in the clade.

Olfactores hypothesis[edit]

For long, the hypothesis that cephalochordata is sister taxon to craniata seemed to be widely accepted[1], likely influenced by the morphological distinction of turnicata from other chordates, with cephalochordates even being nicknamed ‘honorary vertebrates’[2]. However, since 2006, studies based on the analysis of large sequence datasets strongly supported the Olfactores as a clade[3][4]. The name olfactores comes from Latin olfactus ("to smell"), due to the pharynx delevopment as to include respiratory functions, in contrast to the lack of respiratory system and specialized sense organs seen in cephalochordates such as the lancelet[5].

References[edit]

  1. ^ Stach, Thomas (2008). "Chordate phylogeny and evolution: a not so simple three‐taxon problem". Journal of Zoology. 276, Issue2.
  2. ^ Ax, P (2001). "Das System der Metazoa: ein Lehrbuch der phylogenetischen Systematik". Cite journal requires |journal= (help)
  3. ^ Delsuc, F (2006). "Tunicates and not cephalochordates are the closest living relatives of vertebrates". Nature. 439.
  4. ^ Dunn, C.W. "Broad phylogenetic sampling improves resolution of the animal tree of life". Nature. 452.
  5. ^ Benton, M.J. (14 April 2000). "Vertebrate Palaeontology: Biology and Evolution". Blackwell Publishing.