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This is due to the development of paired fins, and their complicated cranial anatomy. The osteostracans were more similar to lampreys than to jawed vertebrates in possessing two pairs of semicircular canals in the inner ear, as opposed to the three pairs found in the inner ears of jawed vertebrates. They are thought to be the sister-group of ...
There is an erectile spine in front of the dorsal fin, sometimes poisonous. There is no stomach (that is, the gut is simplified and the 'stomach' is merged with the intestine), and the mouth is a small aperture surrounded by lips, giving the head a parrot-like appearance. The fossil record of the Holocephali starts in the Devonian period. The ...
The word Coelacanth is an adaptation of the Modern Latin Cœlacanthus ('hollow spine'), from the Greek κοῖλ-ος (koilos, 'hollow') and ἄκανθ-α (akantha, 'spine'), [12] referring to the hollow caudal fin rays of the first fossil specimen described and named by Louis Agassiz in 1839, belonging to the genus Coelacanthus. [8]
Benton, M.J. (1998) "The quality of the fossil record of the vertebrates" Archived 25 August 2012 at the Wayback Machine Pages 269–303 in Donovan, S.K. and Paul, C.R.C. (eds), The adequacy of the fossil record. Wiley. ISBN 9780471969884. Cloutier, R. (2010). "The fossil record of fish ontogenies: Insights into developmental patterns and ...
Ichthyostega (from Greek: ἰχθῦς ikhthûs, 'fish' and Greek: στέγη stégē, 'roof') is an extinct genus of limbed tetrapodomorphs from the Late Devonian of what is now Greenland. It was among the earliest four-limbed vertebrates ever in the fossil record and was one of the first with weight-bearing adaptations for terrestrial locomotion.
It shows the progression of evolution in fossil fish, and amphibians and reptiles through comparative anatomy, including a list of all the (then) known fossil vertebrate genera. Romer became the first president of the Society of Vertebrate Paleontology in 1940, alongside co-founder Howard Chiu.
All of the earliest chordate fossils have been found in the Early Cambrian Chengjiang fauna, and include two species that are regarded as fish, which implies that they are vertebrates. Because the fossil record of early chordates is poor, only molecular phylogenetics offers a reasonable prospect of dating their emergence.
Pteraspidomorphi is an extinct class of early jawless fish. The fossils show extensive shielding of the head. Many had hypocercal tails to generate lift to increase ease of movement through the water for their armoured bodies, which were covered in dermal bone. They also had sucking mouth parts and some species may have lived in fresh water ...