Porolepiformes is an order of prehistoric lobe-finned fish which lived during the Devonian period (about 416 to 359 million years ago). They are thought to represent the sister group to lungfish (class Dipnoi). The group contains two families: Holoptychiidae and Porolepididae.
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.Jarvik, Erik. 1980. Basic structure and evolution of vertebrates. Vol. 1–2. Academic Press (London). He based this conclusion on the shapes of the snouts of the aforementioned groups. This view is no longer in favour in paleontology.
Jarvik also claimed the existence of choanae in porolepiformes which linked them to tetrapods, but this has remained controversial.Clement, G., 2001. Evidence for lack of choanae in the Porolepiformes. Journal of Vertebrate Paleontology, 21: 795–802. Recent phylogenetic reconstruction places porolepiformes close to lungfishes.Janvier, P., Early vertebrates. Oxford science publications. 1996, Oxford, New York: Clarendon Press; Oxford University Press.
More recent evidence has shown that at least one genus Laccognathus was most likely amphibious.
Taxonomy Based on Schultze, 2000 & Mondéjar-Fernández et al (2020):
†Durialepis Otto, 2007 †Heimenia Orvig, 1969 †"Porolepidae" †Porolepis Woodward, 1891 †Holoptychiidae Owen, 1860 ?†Duffichthys Ahlberg, 1992 †Glyptolepis Agassiz, 1843 ?†Hamodus Obruchev, 1933 †Holoptychius Agassiz, 1839 †Laccognathus Gross, 1941 †Quebecius Schultze & Arsenault, 1987 †Nasogaluakus Schultze, 2000 ?†Paraglyptolepis Vorobyeva, 1987 †Pseudosauripterus White, 1961 †Ventalepididae Lebedev & Luksevics, 2018 †Ventalepis Schultze, 1980
Phylogeny Mikko's Phylogeny Archive:
References