"Cephalorhyncha" redirects here. For the kinorhynch genus, see Cephalorhyncha (genus).
Scalidophora
Ottoia prolifica from the Walcott Quarry of the Burgess Shale (Middle Cambrian) near Field, British Columbia, Canada.
Scientific classification
Domain:
Eukaryota
Kingdom:
Animalia
Subkingdom:
Eumetazoa
Clade:
ParaHoxozoa
Clade:
Bilateria
Clade:
Nephrozoa
(unranked):
Protostomia
Superphylum:
Ecdysozoa
Clade:
Scalidophora Lemburg, 1995
Phyla
Kinorhyncha
Priapulida
Loricifera
possible stem groups: Palaeoscolecida[1]†, Archaeopriapulida†
Synonyms
Cephalorhyncha, Priapozoa
Scalidophora is a group of marine pseudocoelomate protostomes that was proposed on morphological grounds to unite three phyla: the Kinorhyncha, the Priapulida and the Loricifera.[2][3] The three phyla have four characters in common — chitinous cuticle that is moulted, rings of scalids on the introvert, flosculi, and two rings of introvert retracts.[4] The introvert and abdomen are separated by a distinct neck region in all groups, but in adult macroscopic priapulids it becomes rudimentary in Priapulus and is completely absent in Halicryptus.[5] However, the monophyly of the Scalidophora was not supported by two molecular studies, where the position of the Loricifera was uncertain[2] or as sister to the Panarthropoda.[3] Both studies supported a reduced Scalidophora comprising the Kinorhyncha and Priapulida as sister phyla. Their closest relatives are the Panarthropoda, Nematoda and Nematomorpha; thus, they are placed in the group Ecdysozoa.
The two species in the genus Markuelia, known from fossilized embryos from the middle Cambrian, are thought to be stem scalidophorans.
The group has also been considered a single group, Cephalorhyncha,[6] with three classes.
The group is named after the spines (scalids) covering the introvert (head that can be retracted into the trunk).[7]
^Harvey, T. H.; Dong, X.; Donoghue, P. C. (March–April 2010). "Are palaeoscolecids ancestral ecdysozoans?". Evolution & Development. 12 (2): 177–200. doi:10.1111/j.1525-142X.2010.00403.x. PMID 20433458. S2CID 16872271.
^ abTelford, M. J.; Bourlat, S. J.; Economou, A.; Papillon, D.; Rota-Stabelli, O. (27 April 2008). "The evolution of the Ecdysozoa". Philosophical Transactions of the Royal Society B. 363 (1496): 1529–1537. doi:10.1098/rstb.2007.2243. PMC 2614232. PMID 18192181.
^ abYamasaki, Hiroshi; Fujimoto, Shinta; Miyazaki, Katsumi (2015-06-30). "Phylogenetic position of Loricifera inferred from nearly complete 18S and 28S rRNA gene sequences". Zoological Letters. 1: 18. doi:10.1186/s40851-015-0017-0. ISSN 2056-306X. PMC 4657359. PMID 26605063.
^Heiner, I., Kristensen, R.H. 2005. Two new species of the genus Pliciloricus (Loricifera, Pliciloricidae) from the Faroe Bank, North Atlantic. Zoologischer Anzeiger. 243: 121–138.
^Multicellular Animals: Volume III: Order in Nature - System Made by Man, Volum 3
^Dirnberger, J. "Explanations and Difficulties in Invertebrate Phylogeny". Invertebrate Zoology. Kennesaw State University. Retrieved 2012-08-11.
^Dunn, C. W.; Hejnol, A.; Matus, D. Q.; Pang, K.; Browne, W. E.; Smith, S. A.; Seaver, E.; Rouse, G. W.; Obst, M.; et al. (10 April 2008). "Broad Phylogenomic Sampling Improves Resolution of the Animal Tree of Life". Nature. 452 (7188): 745–749. Bibcode:2008Natur.452..745D. doi:10.1038/nature06614. PMID 18322464. S2CID 4397099.
Scalidophora is a group of marine pseudocoelomate protostomes that was proposed on morphological grounds to unite three phyla: the Kinorhyncha, the Priapulida...
relatives are Kinorhyncha and Loricifera, with which they constitute the Scalidophora clade named after the spines covering the introvert (scalids). They feed...
since it is currently impossible to ally it with the Priapulids or other scalidophora. Zhang, X. G.; Pratt, B. R.; Shen, C. (2011). "Embryonic Development...
Cycloneuralia is a clade of ecdysozoan animals including the Scalidophora (Kinorhynchans, Loriciferans, Priapulids), the Nematoida (nematodes, Nematomorphs)...
Cycloneuralia hypothesis, the nematoids are considered to be closest to Scalidophora, named for the ring-shaped brains found in these animals. However, this...
be the phyla Loricifera and Priapulida. Together they constitute the Scalidophora. The two groups of Kinorhynchs are generally characterized as classes...
some species of Loricifera and Priapulida, all members of the group Scalidophora. The earliest Nematomorph could be Maotianshania, from the Lower Cambrian;...
with the Priapulida; this plus the Kinorhyncha constitutes the taxon Scalidophora. The three phyla share four characters in common – chitinous cuticle...
parasitic Nematomorpha; together, they make up the Nematoida. Along with the Scalidophora (formerly Cephalorhyncha), the Nematoida form the clade Cycloneuralia...
Waloszek, D., Haug, J.T. & Müller, K.J., 2009:12:24. Loricate larvae (Scalidophora) from the Middle Cambrian of Australia. Memoirs of the Association of...
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