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Eotetrapodiforms
Eotetrapodiformes is an unranked clade of tetrapodomorphs including the four-limbed vertebrates ("tetrapods" in the traditional sense) and their closest finned relatives, two groups of stem tetrapods called tristichopterids and elpistostegalids. Description This clade is defined as "the node-based clade arising from the most recent common ancestor of ''Eusthenopteron'' and ''Ichthyostega'' plus all of its descendants," for their litany of shared morphological characteristics, such as similarities in their lower jaws and endocrania. Utilizing the holotype FMNH PF 610 of the sarcopterygian ''Litoptychus bryanti,'' paleontologists highlighted the division between the ethmoid and sphenoid processes, as well as vomeral and parasphenoid processes similar to those of more derived tetrapods. Eotetrapodiformes are considered a sister taxon to Megalichthyiformes and Rhizodontida. History The clade was named in 2010 by Michael I. Coates and Matt Friedman. Paleoecology Biogeogr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Middle Devonian
In the geological timescale, the Middle Devonian epoch (from 393.3 ± 1.2 million years ago to 382.7 ± 1.6 million years ago) occurred during the Devonian period, after the end of the Emsian age. The Middle Devonian epoch is subdivided into two stages: Eifelian and Givetian. Life in the Middle Devonian In the middle Devonian the armored jawless fish known as ostracoderms were declining in diversity and instead the jawed fish were thriving and increasing in diversity in both the oceans and freshwater. The shallow, warm, oxygen-depleted waters of Devonian inland lakes, surrounded by primitive plants, provided the environment necessary for certain early fish to develop essential characteristics such as well developed lungs, ability to crawl out of the water and onto the land for short periods of time, possibly in search of food which would be developed by the tetrapods later in the Late Devonian which are descendents of these early fish. The earliest forest grew in the Middle De ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Endocranium
The endocranium in comparative anatomy is a part of the skull base in vertebrates and it represents the basal, inner part of the cranium. The term is also applied to the outer layer of the dura mater in human anatomy. Structure Structurally, the endocranium consists of a boxlike shape, open at the top. The posterior margin exhibits the '' foramen magnum'', an opening for the spinal cord. The floor of the endocranium has several paired openings for the cranial nerves, and the anterior margin holds a spongy construction, allowing for the external nasal nerves to pass through. Romer, A.S. & T.S. Parsons. 1977. ''The Vertebrate Body.'' 5th ed. Saunders, Philadelphia. (6th ed. 1985) All bones of the structure derive from the cranial neural crest during fetal development. Endocranial elements in humans In humans and other mammals, the endocranium forms during fetal development as a cartilaginous neurocranium, that ossifies from several centers. Several of these bones merge, and in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Platycephalichthys Bischoffi
''Platycephalichthys'' is a genus of tristichopterid lobe-finned fish which lived during the Upper Devonian, Frasnian stage. Phylogeny Below is a cladogram A cladogram (from Greek language, Greek ''clados'' "branch" and ''gramma'' "character") is a diagram used in cladistics to show relations among organisms. A cladogram is not, however, an Phylogenetic tree, evolutionary tree because it does not s ... from Swartz, 2012: See also * References Prehistoric lobe-finned fish genera Eotetrapodiformes Devonian bony fish {{paleo-lobefinned-fish-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tinirau Clackae
''Tinirau'' is an extinct genus of sarcopterygian fish from the Middle Devonian of Nevada. Although it spent its entire life in the ocean, ''Tinirau'' is a stem tetrapod close to the ancestry of land-living vertebrates in the crown group Tetrapoda. Relative to more well-known stem tetrapods, ''Tinirau'' is more closely related to Tetrapoda than is ''Eusthenopteron'', but farther from Tetrapoda than is ''Panderichthys''. The type and only species of ''Tinirau'' is ''T. clackae'', named in 2012. Description ''Tinirau'' was a fairly large, predatory fish about a meter long and with a deep, compact body. The head was large, with a large terminal mouth and numerous teeth. The tail was heterocercal. The remaining fins with the exception of the pectoral fins were situated behind the middle of the body similar to the situation seen in pikes, giving the animal a large tail surface suitable for great bursts of speed. It shares many advanced features with later tetrapodomorphs in the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eusthenopteron BW
''Eusthenopteron'' (from 'stout', and 'wing' or 'fin') is an extinct genus of prehistoric marine lobe-finned fish known from several species that lived during the Late Devonian period, about 385 million years ago. It has attained an iconic status from its close relationship to tetrapods. Early depictions of animals of this genus show them emerging onto land, but paleontologists now think that ''Eusthenopteron'' species were strictly aquatic animals, though this is not completely known.M. Laurin, F. J. Meunier, D. Germain, and M. Lemoine 2007A microanatomical and histological study of the paired fin skeleton of the Devonian sarcopterygian ''Eusthenopteron foordi'' ''Journal of Paleontology'' 81: 143–153. The genus was first described by J. F. Whiteaves in 1881, as part of a large collection of fishes from Miguasha, Quebec, Canada. Some 2,000 ''Eusthenopteron'' specimens have been collected from Miguasha, one of which was the object of intensely detailed study and several ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gogonasus BW
''Gogonasus'' (meaning "snout from Gogo") 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 coral reef off the Kimberley coast surrounding north-western Australia. ''Gogonasus'' was a small fish reaching in length. Its skeleton shows several features that were like those of a four-legged land animal (tetrapod). They included the structure of its middle ear, and its fins show the precursors of the forearm bones, the radius and ulna. Researchers believe it used its forearm-like fins to dart out of the reef to catch prey. ''Gogonasus'' was first described from a single snout (ethmosphenoid) by John A. Long (1985). On Long's 1967 expedition to Gogo the first relatively complete skull of ''Gogonasus'' was found by Chris Nelson and after being prepared by Sheila Mahala Andrews solved a scientific controversy by showing that the inn ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Euramerica
Laurasia () was the more northern of two large landmasses that formed part of the Pangaea supercontinent from around ( Mya), the other being Gondwana. It separated from Gondwana (beginning in the late Triassic period) during the breakup of Pangaea, drifting further north after the split and finally broke apart with the opening of the North Atlantic Ocean 56 Mya. The name is a portmanteau of Laurentia and Eurasia. Laurentia, Avalonia, Baltica, and a series of smaller terranes, collided in the Caledonian orogeny c. 400 Mya to form Laurussia. Laurussia then collided with Gondwana to form Pangaea. Kazakhstania and Siberia were then added to Pangaea 290–300 Mya to form Laurasia. Laurasia finally became an independent continental mass when Pangaea broke up into Gondwana and Laurasia. Terminology and origin of the concept Laurentia, the Palaeozoic core of North America and continental fragments that now make up part of Europe, collided with Baltica and Aval ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rhizodontida
Rhizodontida is an extinct group of predatory tetrapodomorphs known from many areas of the world from the Givetian through to the Pennsylvanian - the earliest known species is about 377 million years ago (Mya), the latest around 310 Mya. Rhizodonts lived in tropical rivers and freshwater lakes and were the dominant predators of their age. They reached huge sizes - the largest known species, '' Rhizodus hibberti'' from Europe and North America, was an estimated 7 m in length, making it the largest freshwater fish known. Description The upper jaw had a marginal row of small teeth on the maxilla and premaxilla, medium-sized fangs on the ectopterygoid and dermopalatine bones, and large tusks on the vomers and premaxillae. On the lower jaw were marginal teeth on the dentary, with fangs on the three coronoids and a huge tusk at the symphysial tip of the dentary. Apparently, the left and right mandibles rotated inwards towards each other on biting. This may have been a kinetic me ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Megalichthyiformes
Megalichthyiformes is an extinct clade of basal tetrapodomorphs which first appeared during the Devonian period. It was named in 2010 by Michael I. Coates and Matt Friedman, who defined it as a stem-based taxon containing all tetrapodomorphs closer to ''Megalichthys'' than to ''Eusthenopteron''. Below is a cladogram A cladogram (from Greek language, Greek ''clados'' "branch" and ''gramma'' "character") is a diagram used in cladistics to show relations among organisms. A cladogram is not, however, an Phylogenetic tree, evolutionary tree because it does not s ... showing Megalichthyiformes modified from Swartz (2012). References {{Taxonbar, from=Q19833404 Tetrapodomorpha Devonian sarcopterygians Carboniferous sarcopterygians Permian bony fish ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Parasphenoid
The parasphenoid is a bone which can be found in the cranium of many vertebrates. It is an unpaired dermal bone which lies at the midline of the roof of the mouth. In many reptiles (including birds), it fuses to the endochondral (cartilage-derived) basisphenoid bone of the lower braincase, forming a bone known as the parabasisphenoid. Early mammals have a small parasphenoid, but for the most part its function has been replaced by the vomer bone. The parasphenoid has been lost in placental mammals and caecilian amphibians. See also *Ossification of frontal bone *Terms for anatomical location Standard anatomical terms of location are used to describe unambiguously the anatomy of humans and other animals. The terms, typically derived from Latin or Greek language, Greek roots, describe something in its standard anatomical position. Thi ... References Bones of the head and neck {{musculoskeletal-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vomer
The vomer (; ) is one of the unpaired facial bones of the skull. It is located in the midsagittal line, and articulates with the sphenoid, the ethmoid, the left and right palatine bones, and the left and right maxillary bones. The vomer forms the inferior part of the nasal septum in humans, with the superior part formed by the perpendicular plate of the ethmoid bone. The name is derived from the Latin word for a ploughshare and the shape of the bone. In humans The vomer is situated in the median plane, but its anterior portion is frequently bent to one side. It is thin, somewhat quadrilateral in shape, and forms the hinder and lower part of the nasal septum; it has two surfaces and four borders. The surfaces are marked by small furrows for blood vessels, and on each is the nasopalatine groove, which runs obliquely downward and forward, and lodges the nasopalatine nerve and vessels. Borders The ''superior border'', the thickest, presents a deep furrow, bounded on eith ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sphenoid Bone
The sphenoid bone is an unpaired bone of the neurocranium. It is situated in the middle of the skull towards the front, in front of the basilar part of occipital bone, basilar part of the occipital bone. The sphenoid bone is one of the seven bones that articulate to form the orbit (anatomy), orbit. Its shape somewhat resembles that of a butterfly, bat or wasp with its wings extended. The name presumably originates from this shape, since () means in Ancient Greek. Structure It is divided into the following parts: * a median portion, known as the body of sphenoid bone, containing the sella turcica, which houses the pituitary gland as well as the paired paranasal sinuses, the sphenoidal sinuses * two Greater wing of sphenoid bone, greater wings on the lateral side of the body and two Lesser wing of sphenoid bone, lesser wings from the anterior side. * Pterygoid processes of the sphenoides, directed downwards from the junction of the body and the greater wings. Two sphenoidal co ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
