Lungfish are freshwater rhipidistian fish belonging to the order Dipnoi. Lungfish are best known for retaining ancestral characteristics within the Osteichthyes, including the ability to breathe air, and ancestral structures within Sarcopterygii, including the presence of lobed fins with a well-developed internal skeleton. Lungfish represent the closest living relatives of the tetrapods.
The choanae, 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. They are considered one of the most important synapomorphies of sarcopterygians, that allowed the passage from water to land.
Silvisaurus, from the Latin silva "woodland" and Greek sauros "lizard", is a nodosaurid ankylosaur from the middle Cretaceous period.
Macroplata is an extinct genus of Early Jurassic rhomaleosaurid plesiosaur which grew up to 4.5 metres (15 ft) in length. Like other plesiosaurs, Macroplata probably lived on a diet of fish, using its sharp needle-like teeth to catch prey. Its shoulder bones were fairly large, indicating a powerful forward stroke for fast swimming. Macroplata also had a relatively long neck, twice the length of the skull, in contrast to pliosaurs.
Westlothiana is a genus of reptile-like tetrapod that lived about 338 million years ago during the latest part of the Visean age of the Carboniferous. Members of the genus bore a superficial resemblance to modern-day lizards. The genus is known from a single species, Westlothiana lizziae. The type specimen was discovered in the East Kirkton Limestone at the East Kirkton Quarry, West Lothian, Scotland in 1984. This specimen was nicknamed "Lizzie the lizard" by fossil hunter Stan Wood, and this name was quickly adopted by other paleontologists and the press. When the specimen was formally named in 1990, it was given the specific name "lizziae" in homage to this nickname. However, despite its similar body shape, Westlothiana is not considered a true lizard. Westlothiana's anatomy contained a mixture of both "labyrinthodont" and reptilian features, and was originally regarded as the oldest known reptile or amniote. However, updated studies have shown that this identification is not entirely accurate. Instead of being one of the first amniotes, Westlothiana was rather a close relative of Amniota. As a result, most paleontologists since the original description place the genus within the group Reptiliomorpha, among other amniote relatives such as diadectomorphs and seymouriamorphs. Later analyses usually place the genus as the earliest diverging member of Lepospondyli, a collection of unusual tetrapods which may be close to amniotes or lissamphibians, or potentially both at the same time.
Pareiasaurus is an extinct genus of pareiasauromorph reptile from the Permian period. It was a typical member of its family, the pareiasaurids, which take their name from this genus.
Dipterus is an extinct genus of lungfish from the middle Devonian period of Europe and North America.
Griphognathus ("hook-jaw") is an extinct genus of lungfish from the late Devonian period of Europe and Australia.
Placochelys is an extinct genus of placodont reptiles erected by Otto Jaekel in 1902.
Imagotaria is an extinct monotypic genus of walrus with the sole species Imagotaria downsi. Fossils of Imagotaria are known from the early late Miocene of California.
Kenichthys is a genus of sarcopterygian fish from the Devonian period, and a member of the clade tetrapodomorpha. The only known species of the genus is Kenichthys campbelli, the first remains of which were found in China in 1993. The genus is important to the study of the evolution of tetrapods due to the unique nature of its nostrils, which provide vital evidence regarding the evolutionary transition of fish-like nostrils to the vertebrate choanae.
Gogonasus was a lobe-finned fish known from three-dimensionally preserved 380-million-year-old fossils found from the Gogo Formation in Western Australia. It lived in the Late Devonian period, on what was once a 1,400-kilometre coral reef off the Kimberley coast surrounding the north-west of Australia. Gogonasus was a small fish reaching 30–40 cm (1 ft) in length.
A nose is a protuberance in vertebrates that houses the nostrils, or nares, which receive and expel air for respiration alongside the mouth. Behind the nose are the olfactory mucosa and the sinuses. Behind the nasal cavity, air next passes through the pharynx, shared with the digestive system, and then into the rest of the respiratory system. In humans, the nose is located centrally on the face and serves as an alternative respiratory passage especially during suckling for infants.
Diabolepis is an extinct genus of very primitive lungfish which lived about 400 million years ago, in the Early Devonian period of South China. Diabolepis is the most basal known dipnoan.
Uranocentrodon is an extinct genus of the family Rhinesuchidae. Known from a 50 centimetres (20 in) skull, Uranocentrodon was a large predator with a length up to 3.75 metres (12.3 ft). Originally named Myriodon by van Hoepen in 1911, it was transferred to a new genus on account of the name being preoccupied in 1917. It has been synonymized with Rhinesuchus, but this has not been widely supported. It was also originally considered to be of Triassic age, but more recent analysis has placed its age as just below the Permian-Triassic boundary.
Loxomma is an extinct genus of Loxommatinae and one of the first Carboniferous tetrapods. They were first described in 1862 and further described in 1870 when two more craniums were found. It is mostly associated with the area of the United Kingdom. They share features with modern reptiles as well as with fish. They had 4 paddle-like limbs that they used to swim in lakes, but they breathed air. Their diet consisted mostly of live fish. They are of the order Baphetidae which are distinguished by their keyhole shaped orbits, while Loxomma themselves are distinguished by the unique texture on their skulls, said to be honeycomb-like.
Dipnorhynchidae is an extinct family of prehistoric lungfishes which lived during the Devonian period.
Rhinesuchidae is a family of tetrapods that lived primarily in the Permian period. They belonged to the broad group Temnospondyli, a successful and diverse collection of semiaquatic tetrapods which modern amphibians are probably descended from. Rhinesuchids can be differentiated from other temnospondyls by details of their skulls, most notably the interior structure of their otic notches at the back of the skull. They were among the earliest-diverging members of the Stereospondyli, a subgroup of temnospondyls with flat heads and aquatic habits. Although more advanced stereospondyls evolved to reach worldwide distribution in the Triassic period, rhinesuchids primarily lived in the high-latitude environments of Gondwana during the Guadalupian and Lopingian epochs of the Permian. The taxonomy of this family has been convoluted, with more than twenty species having been named in the past; a 2017 review recognized only eight of them to be valid. While several purported members of this group have been reported to have lived in the Triassic period, most are either dubious or do not belong to the group. However, at least one valid genus of rhinesuchid is known from the early Triassic, a small member known as Broomistega. The most recent formal definition of Rhinesuchidae, advocated by Mariscano et al. (2017) is that of a stem-based clade containing all taxa more closely related to Rhinesuchus whaitsi than to Lydekkerina huxleyi or Peltobatrachus pustulatus. A similar alternate definition is that Rhinesuchidae is a stem-based clade containing all taxa more closely related to Uranocentrodon senekalensis than to Lydekkerina huxleyi, Trematosaurus brauni, or Mastodonsaurus giganteus.
Cranial kinesis is the term for significant movement of skull bones relative to each other in addition to movement at the joint between the upper and lower jaw. It is usually taken to mean relative movement between the upper jaw and the braincase.
Innovations conventionally associated with terrestrially first appeared in aquatic elpistostegalians such as Panderichthys rhombolepis, Elpistostege watsoni, and Tiktaalik roseae. Phylogenetic analyses distribute the features that developed along the tetrapod stem and display a stepwise process of character acquisition, rather than abrupt. The complete transition occurred over a period of 25 million years beginning with the tetrapodomorph diversification in the Middle Devonian.
