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Saharastega
''Saharastega'' is an extinct genus of basal temnospondyl which lived during the Late Permian period, around 251 to 260 million years ago. Remains of ''Saharastega'', discovered by paleontologist Christian A. Sidor at the Moradi Formation in Niger, were described briefly in 2005 and more comprehensively in 2006. The description is based on a skull lacking the lower jaws. Description Skull roof The skull is somewhat wide and gradually narrows towards the snout, with the portion of the skull in front of the orbits (eye sockets) longer than that behind them. It was 36.8 centimeters (14.5 inches) in length and 30 centimeters (11.8 inches) in width at its widest point. The cranial bones are somewhat eroded, but preserved portions are finely textured with pits and ridges as in most adult temnospondyls, but lacking the unornamented areas adjacent to the midline which characterize edopoids. The skull lacks lateral line grooves, which may indicate terrestriality, but the overall s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Temnospondyli
Temnospondyli (from Greek τέμνειν, ''temnein'' 'to cut' and σπόνδυλος, ''spondylos'' 'vertebra') is a diverse order of small to giant tetrapods—often considered primitive amphibians—that flourished worldwide during the Carboniferous, Permian, and Triassic periods. A few species continued into the Jurassic and Cretaceous periods. Fossils have been found on every continent. During about 210 million years of evolutionary history, they adapted to a wide range of habitats, including freshwater, terrestrial, and even coastal marine environments. Their life history is well understood, with fossils known from the larval stage, metamorphosis, and maturity. Most temnospondyls were semiaquatic, although some were almost fully terrestrial, returning to the water only to breed. These temnospondyls were some of the first vertebrates fully adapted to life on land. Although temnospondyls are considered amphibians, many had characteristics, such as scales and armour-like bo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Moradi Formation
The Moradi Formation is a geological formation in Niger. It is of Late Permian age. It is informally divided into three subunits. The lower portion of the formation consists of red mudstone, with muddy calcareous sandstone and quartz-granlule conglomerate present as lenses. The middle portion consists of muddy siltstone in thick beds interbedded with red argillaceous sandstone. The lower two thirds of the upper portion of the formation consist of red siltstone intercalated with channel lag intraformational conglomerates, while the upper third consists of barchanoid shaped lenses of conglomeratic sandstone with ventifacts. These facies are indicatived of deposition under arid conditions, with less than of annual rainfall in the Central Pangean desert, with annual temperatures of , but with ephemeral water presence including lakes. Fossil content The formation is known for its fossils, including the temnospondyls ''Nigerpeton'' and ''Saharastega, ''the pareiasaur ''Bunostego ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Edopoidea
Edopoidea is a clade of primitive temnospondyl amphibians including the genus '' Edops'' and the family Cochleosauridae. Edopoids are known from the Late Carboniferous and Early Permian of North America and Europe, and the Late Permian of Africa. They are among the most basal temnospondyls, and possess a number of primitive features that were lost in later members of the group. Description Edopoids are relatively large temnospondyls, with many species estimated to have grown several meters in length. The skull of ''Edops'' is broad while those of cochleosaurids are narrower and elongated. Distinguishing features of edopoids include the presence of an intertemporal bone that is absent in all other temnospondyls, and the lack of a pineal foramen, a small hole on the skull roof of many early tetrapods (young individuals still possess this hole). Relative to other temnospondyls, edopoids also have enlarged premaxillae, maxillae, and nasal bones in the snout region, which constrict ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Intertemporal Bone
The Intertemporal bone is a paired cranial bone present in bony fish and certain extinct amphibian-grade tetrapods. It lies in the rear part of the skull, behind the eyes. Many lineages of four-limbed vertebrates ("tetrapods" in the broad sense) have lost the intertemporal bone. These include ''Acanthostega'', '' Icththyostega'', colosteids (except for a vestigial intertemporal in ''Greererpeton''), diadectomorphs, lepospondyls, and amniotes. Lissamphibians (i.e. modern amphibians like frogs, salamanders, and caecilians) also lack an intertemporal. Most temnospondyls lack an intertemporal, though several early groups like edopoids, dvinosaurs, and various other basal taxa retain the bone. Tetrapod groups which do possess an intertemporal typically have it contact the parietal bone along its inner edge, the postfrontal and postorbital bones along its front and/or outer edge, and the supratemporal bone along its rear edge. Rarely, the intertemporal may also contact the squamosal b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Parietal Bone
The parietal bones () are two bones in the skull which, when joined at a fibrous joint, form the sides and roof of the cranium. In humans, each bone is roughly quadrilateral in form, and has two surfaces, four borders, and four angles. It is named from the Latin ''paries'' (''-ietis''), wall. Surfaces External The external surface ig. 1is convex, smooth, and marked near the center by an eminence, the parietal eminence (''tuber parietale''), which indicates the point where ossification commenced. Crossing the middle of the bone in an arched direction are two curved lines, the superior and inferior temporal lines; the former gives attachment to the temporal fascia, and the latter indicates the upper limit of the muscular origin of the temporal muscle. Above these lines the bone is covered by a tough layer of fibrous tissue – the epicranial aponeurosis; below them it forms part of the temporal fossa, and affords attachment to the temporal muscle. At the back part and clos ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lacrimal Bone
The lacrimal bone is a small and fragile bone of the facial skeleton; it is roughly the size of the little fingernail. It is situated at the front part of the medial wall of the orbit. It has two surfaces and four borders. Several bony landmarks of the lacrimal bone function in the process of lacrimation or crying. Specifically, the lacrimal bone helps form the nasolacrimal canal necessary for tear translocation. A depression on the anterior inferior portion of the bone, the lacrimal fossa, houses the membranous lacrimal sac. Tears or lacrimal fluid, from the lacrimal glands, collect in this sac during excessive lacrimation. The fluid then flows through the nasolacrimal duct and into the nasopharynx. This drainage results in what is commonly referred to a runny nose during excessive crying or tear production. Injury or fracture of the lacrimal bone can result in posttraumatic obstruction of the lacrimal pathways. Structure Lateral or orbital surface The lateral or orbital surface i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chenoprosopus
''Chenoprosopus'' is a genus of extinct cochleosauridae that lived during late Carboniferous and early Permian periods.Reisz, R.R. (2005). "A New Skull of the Cochleosaurid Amphibian Chenoprosopus (Amphibia: Temnospondyli) from the Early Permian of New Mexico". ''New Mexico Museum of Natural History and Science Bulletin No. 30'' Two known species of ''Chenoprosopus'' are ''C. milleri'' and ''C. lewisi. Chenoprosopus lewisi'' was described in the basis of a virtually complete skull with maximum skull length of 95 mm. It is significantly smaller than ''Chenoprosopus milleri'' and was differentiated from that taxon by Hook (1993) based on sutural patterns of the skull roof. Hook also mentioned the reduced size of the vomerine tusks differentiated ''C. lewisi'' from ''C. milleri,'' but the different size of these tusks may be different ontogenetic stages of growth. Many of other cochleosaurids from the same time period have an elongated vomer and wide and elongate choana. Howeve ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Postparietal
Postparietals are cranial bones present in fish and many tetrapods. Although initially a pair of bones, many lineages possess postparietals which were fused into a single bone. The postparietals were dermal bones situated along the midline of the skull, behind the parietal bones. They formed part of the rear edge of the skull roof, and the lateral edge of each postparietal often contacts the tabular and supratemporal bones. In fish, the postparietals are elongated, typically the largest components of the skull roof. Tetrapods possessed shorter postparietals, which were reduced further and shifted towards the braincase in amniotes. At several points in synapsid evolution, the postparietals fused to each other and the tabulars during embryological development. This fusion produces the interparietal bone, which is inherited by mammals. Postparietals are common in extinct amphibians and early reptiles. However, most living amphibians (of the group Lissamphibia) and living reptiles (of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Upper Permian
The Permian ( ) is a geologic period and stratigraphic system which spans 47 million years from the end of the Carboniferous Period million years ago (Mya), to the beginning of the Triassic Period 251.9 Mya. It is the last period of the Paleozoic Era; the following Triassic Period belongs to the Mesozoic Era. The concept of the Permian was introduced in 1841 by geologist Sir Roderick Murchison, who named it after the region of Perm in Russia. The Permian witnessed the diversification of the two groups of amniotes, the synapsids and the sauropsids (reptiles). The world at the time was dominated by the supercontinent Pangaea, which had formed due to the collision of Euramerica and Gondwana during the Carboniferous. Pangaea was surrounded by the superocean Panthalassa. The Carboniferous rainforest collapse left behind vast regions of desert within the continental interior. Amniotes, which could better cope with these drier conditions, rose to dominance in place of their amphibian ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Supratemporal Bone
The supratemporal bone is a paired cranial bone present in many tetrapods and tetrapodomorph fish. It is part of the temporal region (the portion of the skull roof behind the eyes), usually lying medial (inwards) relative to the squamosal and lateral (outwards) relative to the parietal and/or postparietal. It may also contact the postorbital or intertemporal (which lie forwards), or tabular (which lies backwards), when those bones are present. The supratemporal is a common component of the skull in many extinct amphibians, though it is apparently absent in the lightweight skulls of living lissamphibians (frogs and salamanders). Embryological studies of salamanders suggests that the supratemporal fuses with the squamosal in early development. A separate supratemporal was retained by early synapsids and reptiles, but was strongly reduced in many groups. Squamates (lizards and snakes) still possess a small supratemporal, though archosaurs (crocodilians and birds) and mammals lack it ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nasal Bone
The nasal bones are two small oblong bones, varying in size and form in different individuals; they are placed side by side at the middle and upper part of the face and by their junction, form the bridge of the upper one third of the nose. Each has two surfaces and four borders. Structure The two nasal bones are joined at the midline internasal suture and make up the bridge of the nose. Surfaces The ''outer surface'' is concavo-convex from above downward, convex from side to side; it is covered by the procerus and nasalis muscles, and perforated about its center by a foramen, for the transmission of a small vein. The ''inner surface'' is concave from side to side, and is traversed from above downward, by a groove for the passage of a branch of the nasociliary nerve. Articulations The nasal articulates with four bones: two of the cranium, the frontal and ethmoid, and two of the face, the opposite nasal and the maxilla. Other animals In primitive bony fish and tetr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tabular Bone
The tabular bones are a pair of triangular flat bones along the rear edge of the skull which form pointed structures known as tabular horns in primitive Teleostomi Teleostomi is an obsolete clade of jawed vertebrates that supposedly includes the tetrapods, bony fish, and the wholly extinct acanthodian fish. Key characters of this group include an operculum and a single pair of respiratory openings, feat .... References Fish anatomy Amphibian anatomy {{vertebrate-anatomy-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
