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Ossirarus
''Ossirarus'' is an extinct genus of four-limbed stem-tetrapod from the Mississippian (mid-Tournaisian) of Scotland. It contains a single species, ''Ossirarus kierani'', based on a disarticulated skull and postcranial bones from the Ballagan Formation at Burnmouth. It would have had a large, pointed tabular horn and several minor traits shared with Devonian stem-tetrapods. ''Ossirarus'' was described in a 2016 study which was devised to fill in the tetrapod and stem-tetrapod faunas of Romer's gap, an interval of the early Carboniferous with few tetrapod fossils. It was one of five new genera named in this study, along with ''Aytonerpeton'', ''Diploradus'', '' Koilops'', and ''Perittodus''. Discovery The holotype and only known specimen of ''Ossirarus'', UMZC2016.3, was collected in 2010 from a mid-Tournaisian layer of cliffs in Burnmouth, in Scotland's Ballagan Formation. The strata belong to Romer's Gap, a hiatus between the Late Devonian and the Viséan where comparativel ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ballagan Formation
The Ballagan Formation is a Formation (geology), geologic formation in Scotland and England. It preserves fossils dating back to the early part of the Carboniferous Period (geology), period (Tournaisian – early Visean). Its name comes from the "Ballagan Beds" of Ballagan Glen, near Strathblane, which has a good example of this geological formation. The Ballagan Formation was historically known as the Cementstone Group, but more recently it has been placed as the middle formation of the Inverclyde Group. This change was motivated by the recognition that the youngest parts of the Devonian Upper Old Red Sandstone (now known as the Kinnesswood Formation) were geologically continuous with the lowest parts of the Lower Carboniferous Calciferous Sandstone Measures (now known as the Ballagan and Clyde Sandstone Formation, Clyde Sandstone formations). This interval of Devonian-Carboniferous overlap was named the Inverclyde Group, and the cementstone-rich "drab beds" in the middle of the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Romer's Gap
Romer's gap is an apparent gap in the Paleozoic tetrapod fossil record noted in the studies of paleontology and evolutionary biology, which represent periods in the Early Carboniferous from which excavators have not yet found relevant transitional fossils. It is named after American paleontologist Alfred Romer, who first recognised it in 1956. Recent discoveries in Scotland and Australia are beginning to close this gap in palaeontological knowledge. Age Romer's gap runs from approximately 360 to 345 million years ago, corresponding to the first 15 million years of the Carboniferous, the early Mississippian (starting with the Tournaisian and moving into the Visean). The gap forms a discontinuity between the primitive forests and high diversity of fishes at the end Devonian and more modern aquatic and terrestrial assemblages of the early Carboniferous. Mechanism behind the gap There has been long debate as to why there are so few fossils from this time period. Some have ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Perittodus
''Perittodus'' is an extinct genus of four-limbed stem-tetrapod from the Mississippian (mid-Tournaisian) of Scotland. It contains a single species, ''Perittodus apsconditus'', based on disarticulated skull and postcranial bones from the Ballagan Formation. The lower jaw of the holotype specimen was about 6.8 cm (2.7 in.) in length and had a pattern of dentition similar to the Devonian taxon '' Ymeria''. ''Perittodus'' was described in a 2016 study which was devised to fill in the tetrapod and stem-tetrapod faunas of Romer's gap, an interval of the early Carboniferous with few vertebrate fossils. It was one of five new genera named in this study, along with ''Aytonerpeton'', ''Diploradus ''Diploradus'' is an extinct genus of four-limbed stem-tetrapod from the Mississippian (mid-Tournaisian) of Scotland. It contains a single species, ''Diploradus austiumensis'', based on an incomplete skull and jaw fragments from the Ballagan F ...'', '' Koilops'', and '' Ossirarus''. R ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Koilops
''Koilops'' is an extinct genus of four-limbed stem-tetrapod from the Mississippian (mid-Tournaisian) of Scotland. It contains a single species, ''Koilops herma'', based on a mold of an 8.0 cm (3.1 in.)-long skull from the Ballagan Formation. A phylogenetic analysis in its original description places ''Koilops'' as a close relative of '' Tulerpeton'' and colosteids. ''Koilops'' was described in a 2016 study which was devised to fill in the tetrapod and stem-tetrapod faunas of Romer's gap, an interval of the early Carboniferous with few vertebrate fossils. It was one of five new genera named in this study, along with ''Aytonerpeton'', ''Diploradus'', ''Ossirarus'', and ''Perittodus ''Perittodus'' is an extinct genus of four-limbed stem-tetrapod from the Mississippian (mid-Tournaisian) of Scotland. It contains a single species, ''Perittodus apsconditus'', based on disarticulated skull and postcranial bones from the Ballagan ...''. References Stegocephali Tournaisian ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diploradus
''Diploradus'' is an extinct genus of four-limbed stem-tetrapod from the Mississippian (mid-Tournaisian) of Scotland. It contains a single species, ''Diploradus austiumensis'', based on an incomplete skull and jaw fragments from the Ballagan Formation at Burnmouth. The most complete part of the specimen, the lower jaw, was about 3.0 cm (1.2 in.) in length and possessed several rows of small, numerous teeth. It likely represents a juvenile animal. ''Diploradus'' was described in a 2016 study which was devised to fill in the tetrapod and stem-tetrapod faunas of Romer's gap, an interval of the early Carboniferous The Carboniferous ( ) is a Geologic time scale, geologic period and System (stratigraphy), system of the Paleozoic era (geology), era that spans 60 million years, from the end of the Devonian Period Ma (million years ago) to the beginning of the ... with few vertebrate fossils. It was one of five new genera named in this study, along with '' Aytonerpeton'', '' Ko ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Romer's Gap
Romer's gap is an apparent gap in the Paleozoic tetrapod fossil record noted in the studies of paleontology and evolutionary biology, which represent periods in the Early Carboniferous from which excavators have not yet found relevant transitional fossils. It is named after American paleontologist Alfred Romer, who first recognised it in 1956. Recent discoveries in Scotland and Australia are beginning to close this gap in palaeontological knowledge. Age Romer's gap runs from approximately 360 to 345 million years ago, corresponding to the first 15 million years of the Carboniferous, the early Mississippian (starting with the Tournaisian and moving into the Visean). The gap forms a discontinuity between the primitive forests and high diversity of fishes at the end Devonian and more modern aquatic and terrestrial assemblages of the early Carboniferous. Mechanism behind the gap There has been long debate as to why there are so few fossils from this time period. Some have ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Siltstone
Siltstone, also known as aleurolite, is a clastic sedimentary rock that is composed mostly of silt. It is a form of mudrock with a low clay mineral content, which can be distinguished from shale by its lack of fissility. Although its permeability and porosity is relatively low, siltstone is sometimes a tight gas reservoir rock, an unconventional reservoir for natural gas that requires hydraulic fracturing for economic gas production. Siltstone was prized in ancient Egypt for manufacturing statuary and cosmetic palettes. The siltstone quarried at Wadi Hammamat was a hard, fine-grained siltstone that resisted flaking and was almost ideal for such uses. Description There is not complete agreement on the definition of siltstone. One definition is that siltstone is mudrock (clastic sedimentary rock containing at least 50% clay and silt) in which at least 2/3 of the clay and silt fraction is composed of silt-sized particles. Silt is defined as grains 2–62 μm in diam ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gleysol
A gleysol or gley soil is a hydric soil that unless drained is saturated with groundwater for long enough to develop a characteristic colour pattern. The pattern is essentially made up of reddish, brownish, or yellowish colours at surfaces of soil particles and/or in the upper soil horizons mixed with greyish/blueish colours inside the peds and/or deeper in the soil. Gleysols are also known as ''Gleyzems'', ''meadow soils'', ''Aqu''-suborders of Entisols, Inceptisols and Mollisols (USDA soil taxonomy), or as ''groundwater soils'' and ''hydro-morphic soils''. The term gley, or glei, is derived from , and was introduced into scientific terminology in 1905 by the Ukrainian scientist Georgy Vysotsky. Gleysols occur within a wide range of unconsolidated materials, mainly fluvial, marine and lacustrine sediments of Pleistocene or Holocene age, having basic to acidic mineralogy. They are found in depression areas and low landscape positions with shallow groundwater. Wetness is t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Palaeosol
In geoscience, paleosol (''palaeosol'' in Great Britain and Australia) is an ancient soil that formed in the past. The definition of the term in geology and paleontology is slightly different from its use in soil science. In geology and paleontology, a paleosol is a former soil preserved by burial underneath either sediments (alluvium or loess) or volcanic deposits (lava flows or volcanic ash), which in the case of older deposits have lithified into rock. In Quaternary geology, sedimentology, paleoclimatology, and geology in general, it is the typical and accepted practice to use the term "paleosol" to designate such "''fossil soils''" found buried within sedimentary and volcanic deposits exposed in all continents. In soil science the definition differs slightly: paleosols are soils formed long ago that have no relationship in their chemical and physical characteristics to the present-day climate or vegetation. Such soils are found within extremely old continental cratons, or ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Maxilla
In vertebrates, the maxilla (: maxillae ) is the upper fixed (not fixed in Neopterygii) bone of the jaw formed from the fusion of two maxillary bones. In humans, the upper jaw includes the hard palate in the front of the mouth. The two maxillary bones are fused at the intermaxillary suture, forming the anterior nasal spine. This is similar to the mandible (lower jaw), which is also a fusion of two mandibular bones at the mandibular symphysis. The mandible is the movable part of the jaw. Anatomy Structure The maxilla is a paired bone - the two maxillae unite with each other at the intermaxillary suture. The maxilla consists of: * The body of the maxilla: pyramid-shaped; has an orbital, a nasal, an infratemporal, and a facial surface; contains the maxillary sinus. * Four processes: ** the zygomatic process ** the frontal process ** the alveolar process ** the palatine process It has three surfaces: * the anterior, posterior, medial Features of the maxilla include: * t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Premaxilla
The premaxilla (or praemaxilla) is one of a pair of small cranial bones at the very tip of the upper jaw of many animals, usually, but not always, bearing teeth. In humans, they are fused with the maxilla. The "premaxilla" of therian mammals has been usually termed as the incisive bone. Other terms used for this structure include premaxillary bone or ''os premaxillare'', intermaxillary bone or ''os intermaxillare'', and Goethe's bone. Human anatomy In human anatomy, the premaxilla is referred to as the incisive bone (') and is the part of the maxilla which bears the incisor teeth, and encompasses the anterior nasal spine and alar region. In the nasal cavity, the premaxillary element projects higher than the maxillary element behind. The palatal portion of the premaxilla is a bony plate with a generally transverse orientation. The incisive foramen is bound anteriorly and laterally by the premaxilla and posteriorly by the palatine process of the maxilla. It is formed from ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
