Porolepiformes is an order of prehistoric

lobe-finned fish Sarcopterygii (; ) — sometimes considered synonymous with Crossopterygii () — is a taxon (traditionally a class or subclass) of the bony fishes known as the lobe-finned fishes. The group Tetrapoda, a mostly terrestrial superclass includ ...

which lived during the Devonian

period Period may refer to: Common uses * Era, a length or span of time * Full stop (or period), a punctuation mark Arts, entertainment, and media * Period (music), a concept in musical composition * Periodic sentence (or rhetorical period), a concept ...

(about 416 to 359

million years ago The abbreviation Myr, "million years", is a unit of a quantity of (i.e. ) years, or 31.556926 teraseconds. Usage Myr (million years) is in common use in fields such as Earth science and cosmology. Myr is also used with Mya (million years ago) ...

). The group contains two

families Family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its members and of society. Ideal ...

: Holoptychiidae and Porolepididae. Porolepiformes was established by the Swedish paleontologist

Erik Jarvik Anders Erik Vilhelm Jarvik (30 November 1907 – 11 January 1998) was a Swedish paleontologist who worked extensively on the sarcopterygian (or lobe-finned) fish ''Eusthenopteron''. In a career that spanned some 60 years, Jarvik produced some ...

, and were thought to have given rise to the

salamander Salamanders are a group of amphibians typically characterized by their lizard-like appearance, with slender bodies, blunt snouts, short limbs projecting at right angles to the body, and the presence of a tail in both larvae and adults. All t ...

s and

caecilian Caecilians (; ) are a group of limbless, vermiform or serpentine amphibians. They mostly live hidden in the ground and in stream substrates, making them the least familiar order of amphibians. Caecilians are mostly distributed in the tropics o ...

s independently of the other

tetrapod Tetrapods (; ) are four-limbed vertebrate animals constituting the superclass Tetrapoda (). It includes extant and extinct amphibians, sauropsids ( reptiles, including dinosaurs and therefore birds) and synapsids ( pelycosaurs, extinct t ...

s. He based this conclusion on the shapes of the snouts of the aforementioned groups. This view is no longer in favour in

Paleontology Paleontology (), also spelled palaeontology or palæontology, is the scientific study of life that existed prior to, and sometimes including, the start of the Holocene epoch (roughly 11,700 years before present). It includes the study of fossi ...

. Jarvik also claimed the existence of

choanae The choanae (singular choana), posterior nasal apertures or internal nostrils are two openings found at the back of the nasal passage between the nasal cavity and the throat in tetrapods, including humans and other mammals (as well as crocodilia ...

in porolepiformes which linked them to tetrapods, but this has remained controversial. Recent phylogenetic reconstruction places porolepiformes close to lungfishes. More recent evidence has shown that at least one genus '' Laccognathus'' was most likely amphibious. Holoptychius quebecensis -

Phylogeny

Mikko's Phylogeny Archive

References

Prehistoric lobe-finned fish Prehistoric fish orders {{Paleo-lobefinned-fish-stub