|
Aïstopods
Aistopoda (Greek for " avingnot-visible feet") is an order of highly specialised snake-like stegocephalians known from the Carboniferous and Early Permian of Europe and North America, ranging from tiny forms only , to nearly in length. They first appear in the fossil record in the Mississippian period and continue through to the Early Permian. The skull is small but very specialised, with large orbits, and large fenestrae. The primitive form ''Ophiderpeton'' has a pattern of dermal bones in the skull similar in respects to the temnospondyls. But in the advanced genus ''Phlegethontia'' the skull is very light and open, reduced to a series of struts supporting the braincase against the lower jaw, just as in snakes, and it is possible that the aistopods filled the same ecological niches in the Paleozoic that snakes do today. They had an extremely elongated body, with up to 230 vertebrae. The vertebrae were holospondylous, having only a single ossification per segment. They lac ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lethiscus
''Lethiscus'' is the earliest known representative of the Aistopoda, a group of very specialised snake-like tetrapodomorphs known from the early Carboniferous ( Mississippian). ''Lethiscus'' is known from only a single specimen from the Holkerian Stage (Middle Viséan) of the Early Carboniferous (Middle Mississippian) of Scotland, and is one of the oldest known post Devonian tetrapods. Despite its very early date, it was already a highly advanced animal. The skull is specialised and light, very like that of ''Ophiderpeton'', with the orbits, far forward, and the cheek region unossified (lacking bone). There are approximately 30 closely spaced teeth on the maxilla and dentary, and a sutural pattern of the skull closely resembles that of the Late Carboniferous aïstopod ''Oestocephalus''. There is no trace of limbs. However, unlike later members of the aïstopod lineage, the vertebrae still possess intercentra, and the pleurocentra are large. ''Lethiscus'' is the only represe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oestocephalidae
Oestocephalidae is an extinct family of Late Carboniferous aistopod tetrapodomorphs. Fossils have been found from Ohio, Illinois, and Colorado in the United States; England; and the Czech Republic. It includes the genera '' Coloraderpeton'' and ''Oestocephalus''. Oestocephalids have robust skulls and narrow, rounded snouts. They possess heavily ossified gastralia and dorsal osteoderms. Like other aïstopods, oestocephalids were elongate, having approximately 110 vertebrae. Oestocephalidae was named in 2003, with the type species In International_Code_of_Zoological_Nomenclature, zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the spe ... being ''Oestocephalus amphiuminus''. References Aistopoda Pennsylvanian first appearances Pennsylvanian extinctions Tetrapodomorph families {{paleo-tetrapodomorph-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oestocephalus
''Oestocephalus'' is an extinct genus of Aïstopoda, aïstopod tetrapodomorphs that lived during the Carboniferous period. Fossils have been found in the Czech Republic, and in Ohio and Illinois in the United States. It is the type genus of the family (biology), family Oestocephalidae, although it used to be assigned to the family Ophiderpetontidae, which is now considered paraphyletic.Anderson, J. S. (2003). Cranial anatomy of ''Coloraderpeton brilli'', postcranial anatomy of ''Oestocephalus amphiuminus'', and reconsideration of Ophiderpentontidae (Tetrapoda: Lepospondyli: Aistopoda). ''Journal of Vertebrate Paleontology'' 23(3):532-543. It was named by Edward Drinker Cope in 1868 and now contains two species, ''O. amphiuminus'' and ''O. nanum''. See also References Aistopoda Pennsylvanian sarcopterygians of North America Pennsylvanian sarcopterygians of Europe Taxa named by Edward Drinker Cope Fossil taxa described in 1868 {{paleo-tetrapodomorph-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fenestra (anatomy)
A fenestra (fenestration; : fenestrae or fenestrations) is any small opening or pore, commonly used as a term in the biological sciences. It is the Latin word for "window", and is used in various fields to describe a pore in an anatomical structure. Biological morphology In morphology, fenestrae are found in cancellous bones, particularly in the skull. In anatomy, the round window and oval window are also known as the ''fenestra rotunda'' and the ''fenestra ovalis''. In microanatomy, fenestrae are found in endothelium of fenestrated capillaries, enabling the rapid exchange of molecules between the blood and surrounding tissue. The elastic layer of the tunica intima is a fenestrated membrane. In surgery, a fenestration is a new opening made in a part of the body to enable drainage or access. Plant biology and mycology In plant biology, the perforations in a perforate leaf are also described as fenestrae, and the leaf is called a fenestrate leaf. The leaf window is also ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nectridea
Nectridea is an extinct order of lepospondyl tetrapods from the Carboniferous and Permian periods, including animals such as '' Diplocaulus''. In appearance, they would have resembled modern newts or aquatic salamanders, although they are not close relatives of modern amphibians. They were characterized by long, flattened tails to aid in swimming, as well as numerous features of the vertebrae. Description Nectrideans are a diverse group of tetrapods, including the aquatic Urocordylidae, the presumably terrestrial Scincosauridae, and the bizarre horned members of Diplocaulidae (also known as Keraterpetonidae), which includes the "boomerang-headed" ''Diplocaulus'', one of the most famous genera of prehistoric amphibians (in the traditional sense of the word). By the time the earliest known nectrideans appeared in the Late Carboniferous fossil record, they had already diversified into these families, indicating that basal nectrideans are unknown. These different families are ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Body Of Vertebra
Each vertebra (: vertebrae) is an irregular bone with a complex structure composed of bone and some hyaline cartilage, that make up the vertebral column or spine, of vertebrates. The proportions of the vertebrae differ according to their spinal segment and the particular species. The basic configuration of a vertebra varies; the vertebral body (also ''centrum'') is of bone and bears the load of the vertebral column. The upper and lower surfaces of the vertebra body give attachment to the intervertebral discs. The posterior part of a vertebra forms a vertebral arch, in eleven parts, consisting of two pedicles (pedicle of vertebral arch), two laminae, and seven processes. The laminae give attachment to the ligamenta flava (ligaments of the spine). There are vertebral notches formed from the shape of the pedicles, which form the intervertebral foramina when the vertebrae articulate. These foramina are the entry and exit conduits for the spinal nerves. The body of the vertebra an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Haemal Arch
A haemal arch, also known as a chevron, is a bony arch on the ventral side of a tail vertebra of a vertebrate. The canal formed by the space between the arch and the vertebral body is the haemal canal. A spinous ventral process emerging from the haemal arch is referred to as the haemal spine. Blood vessels to and from the tail run through the arch. In reptiles, the caudofemoralis longus muscle, one of the main muscles involved in locomotion, attaches to the lateral sides of the haemal arches. In 1956, Alfred Sherwood Romer hypothesized that the position of the first haemal arch was sexually dimorphic in crocodilians and dinosaurs. However, subsequent research established that the size and position of the first haemal arch was not sexually dimorphic in crocodilians and found no evidence of significant variation in tyrannosaurid dinosaurs, indicating that haemal arches could not be used to distinguish between sexes after all. Haemal arches play an important role in the taxonomy of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vertebra
Each vertebra (: vertebrae) is an irregular bone with a complex structure composed of bone and some hyaline cartilage, that make up the vertebral column or spine, of vertebrates. The proportions of the vertebrae differ according to their spinal segment and the particular species. The basic configuration of a vertebra varies; the vertebral body (also ''centrum'') is of bone and bears the load of the vertebral column. The upper and lower surfaces of the vertebra body give attachment to the intervertebral discs. The posterior part of a vertebra forms a vertebral arch, in eleven parts, consisting of two pedicles (pedicle of vertebral arch), two laminae, and seven processes. The laminae give attachment to the ligamenta flava (ligaments of the spine). There are vertebral notches formed from the shape of the pedicles, which form the intervertebral foramina when the vertebrae articulate. These foramina are the entry and exit conduits for the spinal nerves. The body of the vertebr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pseudophlegethontia Turnbullorum
''Pseudophlegethontia'' is an extinct genus of aïstopod tetrapodomorphs. It is the only member of the family Pseudophlegethontiidae. The only species is the type species ''P. turnbullorum'', named in 2003. Fossils of ''Pseudophlegethontia'' have been found from the Mazon Creek fossil beds in Grundy County, Illinois, a '' conservation lagerstätte'' well known for the exceptional preservation of middle Pennsylvanian taxa. ''Pseudophlegethontia'' has been considered to be morphologically intermediate between derived phlegethontiids and more basal "ophiderpetontids" such as ''Ophiderpeton''. It possesses basal characters such as a relatively short body, "k shaped" ribs, and distinctive skull roof bones while also possessing several more derived features such as a pointed snout, thin gastralia, and a lack of dorsal osteoderms. It is usually, but not unanimously, placed as the sister taxon In phylogenetics, a sister group or sister taxon, also called an adelphotaxon, comprises ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
