Porolepiformes

Porolepiformes; Temporal range: 416–359 Ma PreꞒ Ꞓ O S D C P T J K Pg N Devonian
	Various genera
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Clade:	Sarcopterygii
Order:	†Porolepiformes; Jarvik 1942
Genera
	† †Heimenia ØRvik 1969; †Porolepis; ; †Holoptychiidae Owen 1860 ?†Duffichthys Ahlberg 1992; ?†Ventalepis Schultze 1980; †Pseudosauripterus ; †Glyptolepis; †Holoptychius; †Laccognathus; ;

Porolepiformes is an order of prehistoric lobe-finned fish which lived during the Devonian period (about 416 to 359 million years ago). The group contains two families: Holoptychiidae and .

Porolepiformes was established by the Swedish paleontologist Erik Jarvik, and were thought to have given rise to the salamanders and caecilians independently of the other tetrapods.^[1] He based this conclusion on the shapes of the snouts of the aforementioned groups. This view is no longer in favour in Paleontology.^[2]

Jarvik also claimed the existence of choanae in porolepiformes which linked them to tetrapods, but this has remained controversial.^[3] Recent phylogenetic reconstruction places porolepiformes close to lungfishes.^[4]

More recent evidence has shown that at least one genus Laccognathus was most likely amphibious.^[5]

Porolepiform fossil (cast) from a Swedish natural history museum. Note that the description calls it a "Salamander fish", in accordance with Jarvik's obsolete hypothesis.

Phylogeny[]

Mikko's Phylogeny Archive ^[6]

†

†Heimenia ensis ØRvik 1969

†Porolepis

	† Jarvik 1937

	† Jarvik 1937

	† (Kade 1858)

	† Gross 1935

	† Jarvik 1937

†

?†Ventalepis ketleriensis Schultze 1980

?†Duffichthys mirabilis Ahlberg 1992

†Pseudosauripterus anglicus (Woodward 1891)

†Glyptolepis

	†G. baltica

	† Jarvik 1972

	† Agassiz 1844

	†

†Holoptychius

	† Leidy 1843

	† Agassiz 1844

	† Agassiz 1839

	† Newberry 1889

	† M'Coy 1844

	† Agassiz 1835

	†

†Laccognathus

	†L. panderi^T Gross 1941

	†L. grossi Vorobyeva 2006

	†L. embryi Downs et al. 2011

References[]

^ Jarvik, Erik. 1980. Basic structure and evolution of vertebrates. Vol. 1-2. Academic Press (London).
^ Schultze, Hans-Peter & Trueb, Linda (1991). Origins of the higher groups of tetrapods: controversy and consensus. Cornell University Press. p. 37. ISBN 978-0-8014-2497-7.
^ Clement, G., 2001. Evidence for lack of choanae in the Porolepiformes. Journal of Vertebrate Paleontology, 21: 795–802.
^ Janvier , P., Early vertebrates. Oxford science publications. 1996, Oxford, New York: Clarendon Press; Oxford University Press.
^ (2006). "A new species of Laccognathus (Porolepiform Crossopterygii) from the Devonian of Latvia". Paleontol. J. Physorg.com. 40 (3): 312–322. doi:10.1134/S0031030106030129. S2CID 129696592.
^ Haaramo, Mikko (2003). "Porolepiformes". In Mikko's Phylogeny Archive. Retrieved November 4, 2013.

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[1] Jarvik, Erik. 1980. Basic structure and evolution of vertebrates. Vol. 1-2. Academic Press (London).

[schultze-2] Schultze, Hans-Peter & Trueb, Linda (1991). Origins of the higher groups of tetrapods: controversy and consensus. Cornell University Press. p. 37. ISBN 978-0-8014-2497-7.

[3] Clement, G., 2001. Evidence for lack of choanae in the Porolepiformes. Journal of Vertebrate Paleontology, 21: 795–802.

[4] Janvier , P., Early vertebrates. Oxford science publications. 1996, Oxford, New York: Clarendon Press; Oxford University Press.

[vorobyeva-5] (2006). "A new species of Laccognathus (Porolepiform Crossopterygii) from the Devonian of Latvia". Paleontol. J. Physorg.com. 40 (3): 312–322. doi:10.1134/S0031030106030129. S2CID 129696592.

[6] Haaramo, Mikko (2003). "Porolepiformes". In Mikko's Phylogeny Archive. Retrieved November 4, 2013.

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