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Lagerpetonidae
Lagerpetidae (; originally Lagerpetonidae) is a family of basal avemetatarsalians. Though traditionally considered the earliest-diverging dinosauromorphs (reptiles closer to dinosaurs than to pterosaurs), fossils described in 2020 suggest that lagerpetids may instead be pterosauromorphs (closer to pterosaurs). Lagerpetid fossils are known from the Late Triassic of Argentina, Arizona, Brazil, Madagascar, New Mexico, and Texas. They were typically small, although some lagerpetids, like ''Dromomeron gigas'' and a specimen from the Santa Rosa Formation attributed to ''Dromomeron'' sp., were able to get quite large (femoral length ). Lagerpetid fossils are rare; the most common finds are bones of the hindlimbs, which possessed a number of unique features. Description As with most early avemetatarsalians, the most characteristic adaptations of lagerpetids occurred in their hip, leg and ankle bones, likely as a result of these being the bones most commonly preserved. Hip material is on ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dromomeron Gregorii
''Dromomeron'' (meaning "running femur") is a genus of lagerpetid avemetatarsalian which lived around 220 to 211.9 ± 0.7 million years ago. The genus contains species known from Late Triassic-age rocks of the Southwestern United States and northwestern Argentina. It is described as most closely related to the earlier ''Lagerpeton'' of Argentina, but was found among remains of true dinosaurs like ''Chindesaurus'', indicating that the first dinosaurs did not immediately replace related groups. Based on the study of the overlapping material of ''Dromomeron'' and ''Tawa hallae'', Christopher Bennett proposed that the two taxa were conspecific, forming a single growth series of ''Dromomeron''. However, noting prominent differences between their femurs which cannot be attributed to variation with age, Rodrigo Muller rejected this proposal in 2017. He further noted that, while ''D. romeri'' is known from juveniles only, it shares many traits in common with ''D. gigas'', which is known f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dromomeron
''Dromomeron'' (meaning "running femur") is a genus of lagerpetid avemetatarsalian which lived around 220 to 211.9 ± 0.7 million years ago. The genus contains species known from Late Triassic-age rocks of the Southwestern United States and northwestern Argentina. It is described as most closely related to the earlier '' Lagerpeton'' of Argentina, but was found among remains of true dinosaurs like '' Chindesaurus'', indicating that the first dinosaurs did not immediately replace related groups. Based on the study of the overlapping material of ''Dromomeron'' and '' Tawa hallae'', Christopher Bennett proposed that the two taxa were conspecific, forming a single growth series of ''Dromomeron''. However, noting prominent differences between their femurs which cannot be attributed to variation with age, Rodrigo Muller rejected this proposal in 2017. He further noted that, while ''D. romeri'' is known from juveniles only, it shares many traits in common with ''D. gigas'', which is kno ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dromomeron Gigas
''Dromomeron'' (meaning "running femur") is a genus of lagerpetid avemetatarsalian which lived around 220 to 211.9 ± 0.7 million years ago. The genus contains species known from Late Triassic-age rocks of the Southwestern United States and northwestern Argentina. It is described as most closely related to the earlier ''Lagerpeton'' of Argentina, but was found among remains of true dinosaurs like ''Chindesaurus'', indicating that the first dinosaurs did not immediately replace related groups. Based on the study of the overlapping material of ''Dromomeron'' and ''Tawa hallae'', Christopher Bennett proposed that the two taxa were conspecific, forming a single growth series of ''Dromomeron''. However, noting prominent differences between their femurs which cannot be attributed to variation with age, Rodrigo Muller rejected this proposal in 2017. He further noted that, while ''D. romeri'' is known from juveniles only, it shares many traits in common with ''D. gigas'', which is known ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lagerpeton
''Lagerpeton'' is a genus of lagerpetid avemetatarsalian, comprising a single species, ''L. chanarensis''. First described from the Chañares Formation of Argentina by A. S. Romer in 1971, ''Lagerpeton'' anatomy is somewhat incompletely known, with fossil specimens accounting for the pelvic girdle, hindlimbs, posterior presacral, sacral and anterior caudal vertebrae. Skull and shoulder material has also been described. The name comes from the Greek (, "hare") plus (, "reptile"). Discovery ''Lagerpeton'' fossils have only been collected from the Chañares Formation in La Rioja Province, Argentina. The first of these fossils were discovered in a 1964-1965 expedition by the Museum of Comparative Zoology (MCZ) and Museo de la Plata (MLP), although some were also discovered in 1966 by paleontologists from the Miguel Lillo Institute (PVL) of the University of Tucuman. Alfred Romer named ''Lagerpeton chanarensis'' in 1971, based on a complete right hindlimb discovered dur ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Archosaurs
Archosauria () is a clade of diapsids, with birds and crocodilians as the only living representatives. Archosaurs are broadly classified as reptiles, in the cladistic sense of the term which includes birds. Extinct archosaurs include non-avian dinosaurs, pterosaurs, and extinct relatives of crocodilians. Modern paleontologists define Archosauria as a crown group that includes the most recent common ancestor of living birds and crocodilians, and all of its descendants. The base of Archosauria splits into two clades: Pseudosuchia, which includes crocodilians and their extinct relatives, and Avemetatarsalia, which includes birds and their extinct relatives (such as non-avian dinosaurs and pterosaurs). Older definitions of the group Archosauria rely on shared morphological characteristics, such as an antorbital fenestra in the skull, serrated teeth, and an upright stance. Some extinct reptiles, such as proterosuchids and euparkeriids, possessed these features yet originate ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ixalerpeton Skeletal
''Ixalerpeton'' (meaning "leaping reptile") is a genus of lagerpetid avemetatarsalian containing one species, ''I. polesinensis''. It lived in the Late Triassic of Brazil alongside the sauropodomorph dinosaur ''Buriolestes''. Discovery and naming The holotype specimen of ''Ixalerpeton'', numbered ULBRA-PVT059, consists of parts from the skull, vertebral column, and all four limbs. The specimen comes from the Carnian Santa Maria Formation of Brazil, and it was found alongside two individuals of ''Buriolestes'' as well as a set of femora belonging to second individual of ''Ixalerpeton''. The genus name of ''Ixalerpeton'' combines the Greek words ''ixalos'' ("leaping") and ''erpeton'' ("reptile"), and the species name ''polesinensis'' references the town of São João do Polêsine, where the dig site is located. Description ''Ixalerpeton'' was similar to other lagerpetids (namely ''Dromomeron'' and ''Lagerpeton'') in having long hindlimbs with well-developed muscle attachment ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sacrum
The sacrum (plural: ''sacra'' or ''sacrums''), in human anatomy, is a large, triangular bone at the base of the spine that forms by the fusing of the sacral vertebrae (S1S5) between ages 18 and 30. The sacrum situates at the upper, back part of the pelvic cavity, between the two wings of the pelvis. It forms joints with four other bones. The two projections at the sides of the sacrum are called the alae (wings), and articulate with the ilium at the L-shaped sacroiliac joints. The upper part of the sacrum connects with the last lumbar vertebra (L5), and its lower part with the coccyx (tailbone) via the sacral and coccygeal cornua. The sacrum has three different surfaces which are shaped to accommodate surrounding pelvic structures. Overall it is concave (curved upon itself). The base of the sacrum, the broadest and uppermost part, is tilted forward as the sacral promontory internally. The central part is curved outward toward the posterior, allowing greater room for the pel ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ornithischia
Ornithischia () is an extinct order of mainly herbivorous dinosaurs characterized by a pelvic structure superficially similar to that of birds. The name ''Ornithischia'', or "bird-hipped", reflects this similarity and is derived from the Greek stem ' (), meaning "of a bird", and ' (), plural ', meaning "hip joint". However, birds are only distantly related to this group as birds are theropod dinosaurs. Ornithischians with well known anatomical adaptations include the ceratopsians or "horn-faced" dinosaurs (e.g. ''Triceratops''), the pachycephalosaurs or "thick-headed" dinosaurs, the armored dinosaurs (Thyreophora) such as stegosaurs and ankylosaurs, and the ornithopods. There is strong evidence that certain groups of ornithischians lived in herds, often segregated by age group, with juveniles forming their own flocks separate from adults. Some were at least partially covered in filamentous (hair- or feather- like) pelts, and there is much debate over whether these filaments fou ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Madagascar
Madagascar (; mg, Madagasikara, ), officially the Republic of Madagascar ( mg, Repoblikan'i Madagasikara, links=no, ; french: République de Madagascar), is an island country in the Indian Ocean, approximately off the coast of East Africa across the Mozambique Channel. At Madagascar is the world's List of island countries, second-largest island country, after Indonesia. The nation is home to around 30 million inhabitants and consists of the island of Geography of Madagascar, Madagascar (the List of islands by area, fourth-largest island in the world), along with numerous smaller peripheral islands. Following the prehistoric breakup of the supercontinent Gondwana, Madagascar split from the Indian subcontinent around 90 million years ago, allowing native plants and animals to evolve in relative isolation. Consequently, Madagascar is a biodiversity hotspot; over 90% of wildlife of Madagascar, its wildlife is endemic. Human settlement of Madagascar occurred during or befo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pubis (bone)
In vertebrates, the pubic region ( la, pubis) is the most forward-facing (ventral and anterior) of the three main regions making up the coxal bone. The left and right pubic regions are each made up of three sections, a superior ramus, inferior ramus, and a body. Structure The pubic region is made up of a ''body'', ''superior ramus'', and ''inferior ramus'' (). The left and right coxal bones join at the pubic symphysis. It is covered by a layer of fat, which is covered by the mons pubis. The pubis is the lower limit of the suprapubic region. In the female, the pubic region is anterior to the urethral sponge. Body The body forms the wide, strong, middle and flat part of the pubic region. The bodies of the left and right pubic regions join at the pubic symphysis. The rough upper edge is the pubic crest, ending laterally in the pubic tubercle. This tubercle, found roughly 3 cm from the pubic symphysis, is a distinctive feature on the lower part of the abdominal wall; important ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acetabulum
The acetabulum (), also called the cotyloid cavity, is a concave surface of the pelvis. The head of the femur meets with the pelvis at the acetabulum, forming the hip joint. Structure There are three bones of the ''os coxae'' (hip bone) that come together to form the ''acetabulum''. Contributing a little more than two-fifths of the structure is the ischium, which provides lower and side boundaries to the acetabulum. The ilium forms the upper boundary, providing a little less than two-fifths of the structure of the acetabulum. The rest is formed by the pubis, near the midline. It is bounded by a prominent uneven rim, which is thick and strong above, and serves for the attachment of the acetabular labrum, which reduces its opening, and deepens the surface for formation of the hip joint. At the lower part of the ''acetabulum'' is the acetabular notch, which is continuous with a circular depression, the acetabular fossa, at the bottom of the cavity of the ''acetabulum''. The re ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ilium (bone)
The ilium () (plural ilia) is the uppermost and largest part of the hip bone, and appears in most vertebrates including mammals and birds, but not bony fish. All reptiles have an ilium except snakes, although some snake species have a tiny bone which is considered to be an ilium. The ilium of the human is divisible into two parts, the body and the wing; the separation is indicated on the top surface by a curved line, the arcuate line, and on the external surface by the margin of the acetabulum. The name comes from the Latin (''ile'', ''ilis''), meaning "groin" or "flank". Structure The ilium consists of the body and wing. Together with the ischium and pubis, to which the ilium is connected, these form the pelvic bone, with only a faint line indicating the place of union. The body ( la, corpus) forms less than two-fifths of the acetabulum; and also forms part of the acetabular fossa. The internal surface of the body is part of the wall of the lesser pelvis and gives ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
