Placodermi is a class of armoured prehistoric fish, known from fossils, which lived from the Silurian to the end of the Devonian period. Their head and thorax were covered by articulated armoured plates and the rest of the body was scaled or naked, depending on the species. Placoderms were among the first jawed fish; their jaws likely evolved from the first of their gill arches.
Protaspididae is an extinct family of pteraspidid heterostracan agnathans. Fossils of the various genera are found in early Devonian-aged marine strata. Protaspidids were once thought to represent a transitional form between the Pteraspididae and the Psammosteida, bearing the broad head shield shape of the latter, due to a more benthic (bottom-dwelling) existence, but recent phylogenical comparisons demonstrate that the protaspidids are actually highly derived pteraspidids, and that the anchipteraspidids, the most primitive of pteraspidids, are the sister-group of the Psammosteids.
Dunkleosteus is an extinct genus of large arthrodire ("jointed-neck") fish that existed during the Late Devonian period, about 382–358 million years ago. It was a pelagic fish inhabiting open waters, and one of the first apex predators of any ecosystem.
Arthrodira is an order of extinct armored, jawed fishes of the class Placodermi that flourished in the Devonian period before their sudden extinction, surviving for about 50 million years and penetrating most marine ecological niches. Arthrodires were the largest and most diverse of all groups of placoderms.
Groenlandaspis is an extinct genus of arthrodire from the Late Devonian. Fossils of the different species are found in late Devonian strata in all continents except eastern Asia. The generic name commemorates the fact that the first specimens of the type species were found in Greenland.
Dinichthys is an extinct monospecific genus of large marine arthrodire placoderm from the Late Devonian measuring around 3 metres (9.8 ft) long. Fossils were recovered from the Ohio Shale Formation along the Olentangy River in Delaware County, Ohio.
Dorfopterus is a genus of eurypterid, a group of extinct aquatic arthropods. Only one fossil of the single and type species, D. angusticollis, has been discovered in deposits of the Early Devonian period in the Beartooth Butte Formation in Wyoming, in the United States. The first half of the name of the genus honors the discoverer of this formation, Erling Dorf, while the second half consists in the Ancient Greek word πτερόν (pteron), meaning "wing". The species name angusticollis is composed by the Latin words angustus ("narrow") and collum ("neck").
Holonema is an extinct genus of relatively large, barrel-shaped arthrodire placoderms that were found in oceans throughout the world from the Mid to Late Devonian, when the last species perished in the Frasnian-Fammian extinction event. Most species of the genus are known from fragments of their armor, but the Gogo Reef species, H. westolli, is known from whole, articulated specimens.
Incisoscutum is an extinct genus of arthrodire placoderm from the Early Frasnian Gogo Reef, from Late Devonian Australia. The genus contains two species I. ritchiei, named after Alex Ritchie, a palaeoichthyologist and senior fellow of the Australian Museum, and I. sarahae, named after Sarah Long, daughter of its discoverer and describer, John A. Long.
Deinodus is a form genus that includes two species: the form found in the Onondaga Formation of western New York, Deinodus bennetti, and the form found in the Columbus and Limestone of central Ohio, Deinodus ohioensis. Both species are limited to the Eifelian age of the middle Devonian Period, which occurred 398-391 million years ago.
Bahndwivici is an extinct genus of lizard known from a nearly complete and articulated skeleton discovered in rocks of the Green River Formation of Wyoming, United States. The skeleton is very similar to that of the modern Chinese crocodile lizard, Shinisaurus.
Lechriaspis is an extinct genus of poraspid heterostracan agnathan known from the Early Devonian of northern Utah, western United States.
Buchanosteus is an extinct genus of arthrodire placoderm. Its fossils have been found in Early Devonian-aged marine strata throughout Asia and Australia. It contains the following species:
Buchanosteidae is a family of arthrodire placoderms that lived from the Early to Middle Devonian. Fossils appear in various strata in Russia, Central Asia, Australia, and China.
Cardipeltis is an extinct genus of heterostracan agnathan from marine strata of early Devonian of Utah, and Wyoming. Species of Cardipeltis superficially resemble those of cyathaspids in having a flattened body and indistinct head covered by a large, broad, guitar pick or heart-shaped dorsal shield, and a long, scaly tail. Unlike cyathaspids, which all have a single ventral plate, however, the ventral shield of Cardipeltis is a mosaic composed of large scales.
Simblaspis is an extinct monospecific genus of arthrodire placoderm fish of the Early Devonian period. The type species Aleosteus eganensis was described in 1958, and was found in Pragian strata of the Qasr Limestone in Saudi Arabia.
Anarthraspis is an extinct genus of arthrodire placoderm fishes which lived during the Early Devonian period. It contains two species described in 1932, Anarthraspis chamberlini and Anarthraspis montanus, both found in the Beartooth Butte Formation of Wyoming and Montana, USA, and assigned to the genus in 1934.
Murmur is a genus of placoderm. The type species is Murmur arctatum. It was described from a fossil found at Beartooth Butte, Wyoming.
Kujdanowiaspis is an extinct genus of arthrodire placoderm fish from the Early Devonian of Podolia (Ukraine), Poland and Spain. Kujdanowiaspis is known from many fragmentary head shields and body armours.
