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Amargasaurus
''Amargasaurus'' (; "La Amarga lizard") is a genus of sauropod dinosaur from the Early Cretaceous epoch (129.4–122.46 mya) of what is now Argentina. The only known skeleton was discovered in 1984 and is virtually complete, including a fragmentary skull, making ''Amargasaurus'' one of the best-known sauropods of its epoch. ''Amargasaurus'' was first described in 1991 and contains a single known species, ''Amargasaurus cazaui''. It was a large animal, but small for a sauropod, reaching in length. Most distinctively, it sported two parallel rows of tall spines down its neck and back, taller than in any other known sauropod. In life, these spines could have stuck out of the body as solitary structures that supported a keratinous sheath. An alternate hypothesis, now more favored, postulates that they could have formed a scaffold supporting a skin sail. They might have been used for display, combat, or defense. ''Amargasaurus'' was discovered in sedimentary rocks of the La A ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dicraeosauridae Scale
Dicraeosauridae is a family of diplodocoid sauropods who are the sister group to Diplodocidae. Dicraeosaurids are a part of the Flagellicaudata, along with Diplodocidae. Dicraeosauridae includes genera such as ''Amargasaurus'', ''Suuwassea'', ''Dicraeosaurus'', and ''Brachytrachelopan''. Specimens of this family have been found in North America, Asia, Africa, and South America. Their temporal range is from the Early or Middle Jurassic to the Early Cretaceous. Few dicraeosaurids survived into the Cretaceous, the youngest of which was ''Amargasaurus''. The group was first described by German paleontologist Werner Janensch in 1914 with the discovery of ''Dicraeosaurus'' in Tanzania. Dicraeosauridae are distinct from other sauropods because of their relatively short neck size and small body size. The clade is monophyletic and well-supported phylogenetically with thirteen unambiguous synapomorphies uniting it. They diverged from Diplodocidae in the Mid-Jurassic, as evidenced by the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dicraeosauridae
Dicraeosauridae is a family of diplodocoid sauropods who are the sister group to Diplodocidae. Dicraeosaurids are a part of the Flagellicaudata, along with Diplodocidae. Dicraeosauridae includes genera such as ''Amargasaurus'', ''Suuwassea'', ''Dicraeosaurus'', and ''Brachytrachelopan''. Specimens of this family have been found in North America, Asia, Africa, and South America. Their temporal range is from the Early or Middle Jurassic to the Early Cretaceous. Few dicraeosaurids survived into the Cretaceous, the youngest of which was ''Amargasaurus''. The group was first described by German paleontologist Werner Janensch in 1914 with the discovery of ''Dicraeosaurus'' in Tanzania. Dicraeosauridae are distinct from other sauropods because of their relatively short neck size and small body size. The clade is monophyletic and well-supported phylogenetically with thirteen unambiguous synapomorphies uniting it. They diverged from Diplodocidae in the Mid-Jurassic, as evidenced by the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Neural Spine Sail
A neural spine sail is a large, flattish protrusion from the back of an animal formed of a sequence of extended vertebral spinous processes and associated tissues. Such structures are comparatively rare in modern animals, but have been identified in many extinct species of amphibians and amniotes. Paleontologists have proposed a number of ways in which the sail could have functioned in life. Function Varying suggestions have been made for the function of the sail. Thermoregulation The structure may have been used for thermoregulation. The base of the spines have a channel which may have contained a blood vessel supplying abundant blood to the sail. The animal could have used the sail's large surface area to absorb heat from the sun in the morning. As ectotherms they required heat from an external source before their muscles would start to function properly. A predator would thus have an advantage over its slower moving prey. The sail could be used in reverse if the animal wa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Brachytrachelopan
''Brachytrachelopan'' is a short-necked sauropod dinosaur from the Late Jurassic ( Oxfordian to Tithonian) of Argentina. The holotype and only known specimen (Museo Paleontológico Egidio Feruglio MPEF-PV 1716) was collected from an erosional exposure of fluvial sandstone within the Cañadón Calcáreo Formation on a hill approximately north-northeast of Cerro Cóndor, Chubut Province, in west-central Argentina, South America. Though very incomplete, the skeletal elements recovered were found in articulation and include eight cervical, twelve dorsal, and three sacral vertebrae, as well as proximal portions of the posterior cervical ribs and all the dorsal ribs, the distal end of the left femur, the proximal end of the left tibia, and the right ilium. Much of the specimen was probably lost to erosion many years before its discovery. The type species is ''Brachytrachelopan mesai''. The specific name honours Daniel Mesa, a local shepherd who discovered the specimen while searching ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
La Amarga Formation
The La Amarga Formation is a geologic formation with outcrops in the Argentine provinces of Río Negro, Neuquén, and Mendoza. It is the oldest Cretaceous terrestrial formation in the Neuquén Basin. The type locality is La Amarga Arroyo and China Muerta Hill.Musacchio, 1970 The La Amarga Formation unconformably overlies the marine Agrio Formation of the Mendoza Group. It is in turn overlain by the Lohan Cura Formation, separated by another unconformity. Composition There are three members within the La Amarga Formation. # The oldest is the Puesto Antigual Member, which is approximately thick and consists mainly of sandstone deposited in the channels of a braided river system. Paleosols, or soil deposits, are well-developed. # The Bañados de Caichigüe Member is the next highest, approximately thick. Alternating limestones, shales, and siltstones make up this member, indicating a lacustrine (lake) environment. # Youngest and thickest is the Piedra Parada Member, appro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sauropod
Sauropoda (), whose members are known as sauropods (; from '' sauro-'' + '' -pod'', 'lizard-footed'), is a clade of saurischian ('lizard-hipped') dinosaurs. Sauropods had very long necks, long tails, small heads (relative to the rest of their body), and four thick, pillar-like legs. They are notable for the enormous sizes attained by some species, and the group includes the largest animals to have ever lived on land. Well-known genera include ''Brachiosaurus'', ''Diplodocus'', ''Apatosaurus'' and ''Brontosaurus''. The oldest known unequivocal sauropod dinosaurs are known from the Early Jurassic. ''Isanosaurus'' and ''Antetonitrus'' were originally described as Triassic sauropods, but their age, and in the case of ''Antetonitrus'' also its sauropod status, were subsequently questioned. Sauropod-like sauropodomorph tracks from the Fleming Fjord Formation (Greenland) might, however, indicate the occurrence of the group in the Late Triassic. By the Late Jurassic (150 million yea ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Early Cretaceous
The Early Cretaceous ( geochronological name) or the Lower Cretaceous (chronostratigraphic name), is the earlier or lower of the two major divisions of the Cretaceous. It is usually considered to stretch from 145 Ma to 100.5 Ma. Geology Proposals for the exact age of the Barremian-Aptian boundary ranged from 126 to 117 Ma until recently (as of 2019), but based on drillholes in Svalbard the defining early Aptian Oceanic Anoxic Event 1a (OAE1a) was carbon isotope dated to 123.1±0.3 Ma, limiting the possible range for the boundary to c. 122–121 Ma. There is a possible link between this anoxic event and a series of Early Cretaceous large igneous provinces (LIP). The Ontong Java-Manihiki-Hikurangi large igneous province, emplaced in the South Pacific at c. 120 Ma, is by far the largest LIP in Earth's history. The Ontong Java Plateau today covers an area of 1,860,000 km2. In the Indian Ocean another LIP began to form at c. 120 Ma, the Kerguelen P ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Herbivore
A herbivore is an animal anatomically and physiologically adapted to eating plant material, for example foliage or marine algae, for the main component of its diet. As a result of their plant diet, herbivorous animals typically have mouthparts adapted to rasping or grinding. Horses and other herbivores have wide flat teeth that are adapted to grinding grass, tree bark, and other tough plant material. A large percentage of herbivores have mutualistic gut flora that help them digest plant matter, which is more difficult to digest than animal prey. This flora is made up of cellulose-digesting protozoans or bacteria. Etymology Herbivore is the anglicized form of a modern Latin coinage, ''herbivora'', cited in Charles Lyell's 1830 ''Principles of Geology''.J.A. Simpson and E.S.C. Weiner, eds. (2000) ''The Oxford English Dictionary'', vol. 8, p. 155. Richard Owen employed the anglicized term in an 1854 work on fossil teeth and skeletons. ''Herbivora'' is derived from Latin ''herba' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Inner Ear
The inner ear (internal ear, auris interna) is the innermost part of the vertebrate ear. In vertebrates, the inner ear is mainly responsible for sound detection and balance. In mammals, it consists of the bony labyrinth, a hollow cavity in the temporal bone of the skull with a system of passages comprising two main functional parts: * The cochlea, dedicated to hearing; converting sound pressure patterns from the outer ear into electrochemical impulses which are passed on to the brain via the auditory nerve. * The vestibular system, dedicated to balance The inner ear is found in all vertebrates, with substantial variations in form and function. The inner ear is innervated by the eighth cranial nerve in all vertebrates. Structure The labyrinth can be divided by layer or by region. Bony and membranous labyrinths The bony labyrinth, or osseous labyrinth, is the network of passages with bony walls lined with periosteum. The three major parts of the bony labyrinth are the vestib ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dicraeosaurus
''Dicraeosaurus'' (Gr. , ' "bifurcated, double-headed" + Gr. , ' "lizard") is a genus of diplodocoid sauropod dinosaur that lived in what is now Lindi Region, Tanzania during the late Jurassic period. The genus was named for the neural spines on the back of its neck. The first fossil was described by paleontologist Werner Janensch in 1914. Description Unlike most diplodocoids, ''Dicraeosaurus'' had a comparatively large head with a relatively short and wide neck. The neck contained 12 unusually short vertebrae, likely indicating a low-level browser of vegetation no more than off the ground. ''Dicraeosaurus'' also lacked the "whiplash" tail tip typical of diplodocoids. It was smaller than many other diplodocoids, at only in length and , though this still makes it among the larger known members of the family Dicraeosauridae. The genus is notable for the rather tall neural spines protruding from its vertebrae, which it is named for. They were not straight as in some members of th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Body Plan
A body plan, ( ), or ground plan is a set of morphological features common to many members of a phylum of animals. The vertebrates share one body plan, while invertebrates have many. This term, usually applied to animals, envisages a "blueprint" encompassing aspects such as symmetry, layers, segmentation, nerve, limb, and gut disposition. Evolutionary developmental biology seeks to explain the origins of diverse body plans. Body plans have historically been considered to have evolved in a flash in the Ediacaran biota; filling the Cambrian explosion with the results, and a more nuanced understanding of animal evolution suggests gradual development of body plans throughout the early Palaeozoic. Recent studies in animals and plants started to investigate whether evolutionary constraints on body plan structures can explain the presence of developmental constraints during embryogenesis such as the phenomenon referred to as phylotypic stage. History Among the pioneering zoologist ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vertebral Column
The vertebral column, also known as the backbone or spine, is part of the axial skeleton. The vertebral column is the defining characteristic of a vertebrate in which the notochord (a flexible rod of uniform composition) found in all chordata, chordates has been replaced by a segmented series of bone: vertebrae separated by intervertebral discs. Individual vertebrae are named according to their region and position, and can be used as anatomical landmarks in order to guide procedures such as Lumbar puncture, lumbar punctures. The vertebral column houses the spinal canal, a cavity that encloses and protects the spinal cord. There are about 50,000 species of animals that have a vertebral column. The human vertebral column is one of the most-studied examples. Many different diseases in humans can affect the spine, with spina bifida and scoliosis being recognisable examples. The general structure of human vertebrae is fairly typical of that found in mammals, reptiles, and birds. Th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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