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Powellophis
''Powellophis'' is a genus of extinct Madtsoiid snake from the Mealla Formation of Argentina, dating back to the Paleocene. It is a monospecific genus, with the only species being ''P. andina''. The genus name means " Jaime Powell's Snake". The name is contructed from the words Powell and ophis, the first in honor of the scientist who recovered the specimen, the late Dr. Jaime Powell, and the second meaning snake in Greek. The species name andina is named for the Andes region of Northwestern Argentina, where the fossil remains of the animal were discovered. The holotype of ''Powellophis'', specimen PVL 4714, preserves a nearly complete and articulated skeleton in nine continuous siltstone blocks. However, only blocks 4714-2 to 4714-9 were available for study. This means that other blocks from the holotype specimen are not included in the paper naming the genus. The animal shares some features of its vertebral morphology with other mid to large sized madtsoiids. ''Powellophis'' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Madtsoiidae
Madtsoiidae is an extinct family of mostly Gondwanan snakes with a fossil record extending from early Cenomanian (Upper Cretaceous) to late Pleistocene strata located in South America, Africa, India, Australia and Southern Europe. Madtsoiidae include very primitive snakes, which like extant boas and pythons would likely dispatch their prey by constriction. Genera include '' Madtsoia'', one of the longest snakes known, at an estimated , and the Australian '' Wonambi'' and '' Yurlunggur''. As a grouping of basal forms the composition and even the validity of Madtsoiidae is in a state of flux as new pertinent finds are described, with more recent evidence suggesting that it is paraphyletic as previously defined. Although madtsoiids persisted on Australia until the Pleistocene, they largely went extinct elsewhere during the Eocene. However, some species persisted in South America and India through the Oligocene. Description Madtsoiidae was first classified as a subfamily ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Selandian
The Selandian is a stage in the Paleocene. It spans the time between . It is preceded by the Danian and followed by the Thanetian. Sometimes the Paleocene is subdivided in subepochs, in which the Selandian forms the "middle Paleocene". Stratigraphic definition The Selandian was introduced in scientific literature by Danish geologist Alfred Rosenkrantz in 1924. It is named after the Danish island of Zealand (Danish: ''Sjælland'') given its prevalence there.Selandien The base of the Selandian is close to the boundary between |
Skeleton
A skeleton is the structural frame that supports the body of an animal. There are several types of skeletons, including the exoskeleton, which is the stable outer shell of an organism, the endoskeleton, which forms the support structure inside the body, and the hydroskeleton, a flexible internal skeleton supported by fluid pressure. Vertebrates are animals with a vertebral column, and their skeletons are typically composed of bone and cartilage. Invertebrates are animals that lack a vertebral column. The skeletons of invertebrates vary, including hard exoskeleton shells, plated endoskeletons, or Sponge spicule, spicules. Cartilage is a rigid connective tissue that is found in the skeletal systems of vertebrates and invertebrates. Etymology The term ''skeleton'' comes . ''Sceleton'' is an archaic form of the word. Classification Skeletons can be defined by several attributes. Solid skeletons consist of hard substances, such as bone, cartilage, or cuticle. These can be further ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fossils Of Argentina
A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved in amber, hair, petrified wood and DNA remnants. The totality of fossils is known as the ''fossil record''. Paleontology is the study of fossils: their age, method of formation, and evolutionary significance. Specimens are usually considered to be fossils if they are over 10,000 years old. The oldest fossils are around 3.48 billion years old to 4.1 billion years old. Early edition, published online before print. The observation in the 19th century that certain fossils were associated with certain rock strata led to the recognition of a geological timescale and the relative ages of different fossils. The development of radiometric dating techniques in the early 20th century allowed scientists to quantitatively measure the absolute ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paleocene Reptiles Of South America
The Paleocene, ( ) or Palaeocene, is a geological epoch that lasted from about 66 to 56 million years ago (mya). It is the first epoch of the Paleogene Period in the modern Cenozoic Era. The name is a combination of the Ancient Greek ''palaiós'' meaning "old" and the Eocene Epoch (which succeeds the Paleocene), translating to "the old part of the Eocene". The epoch is bracketed by two major events in Earth's history. The K–Pg extinction event, brought on by an asteroid impact and possibly volcanism, marked the beginning of the Paleocene and killed off 75% of living species, most famously the non-avian dinosaurs. The end of the epoch was marked by the Paleocene–Eocene Thermal Maximum (PETM), which was a major climatic event wherein about 2,500–4,500 gigatons of carbon were released into the atmosphere and ocean systems, causing a spike in global temperatures and ocean acidification. In the Paleocene, the continents of the Northern Hemisphere were still connected via som ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Madtsoia
''Madtsoia'' is an extinct genus of madtsoiid snakes. It is known from the Eocene of Argentina (''M. bai''), the Paleocene of Brazil (''M. camposi''), the Late Cretaceous (Maastrichtian) of India (''M. pisdurensis''), and the Late Cretaceous (Maastrichtian) of Madagascar (''M. madagascariensis''). The type species (''M. bai'') was the largest with an estimated length of , and the other three species were smaller. A long ''M. madagascariensis'' would have weighed , but an isolated specimen suggests that this species reached in maximum length. Distribution Fossils of ''Madtsoia'' have been found in:''Madtsoia'' at .org ;Coniacian * |
Wonambi
''Wonambi'' is an extinct genus of madtsoiid snakes that lived in late Neogene to late Quaternary Australia. Species of ''Wonambi'' were constrictor snakes unrelated to Australian pythons. Description ''Wonambi'' was a fairly large snake, with the type species (''W. naracoortensis'') exceeding long and the other species (''W. barriei'') reaching less than long. It was a non-venomous, constrictor snake, and may have been an ambush predator that killed its prey by constriction. The head of the animal was small, restricting the size of its prey. Taxonomy and naming ''Wonambi naracoortensis'' was first described from fossils collected at Naracoorte, South Australia, the first extinct snake to be found in Australia. It was given the name Wonambi from the description, by the local Aboriginal people, of a serpent of the Dreamtime. This serpent, a mythological being commonly referred to by both Aboriginal people and Europeans as the Rainbow Serpent, was often held responsible ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gigantophis
''Gigantophis'' is an extinct genus represented by its sole member ''Gigantophis garstini'', a giant snake. Before the Paleocene constrictor genus ''Titanoboa'' was described from Colombia in 2009, ''Gigantophis garstini'' was regarded as the largest snake ever recorded. It lived about 40 million years ago during the Eocene epoch of the Paleogene Period, in the Paratethys Sea, within the northern Sahara, where Egypt and Algeria are now located. Description Size Jason Head, of the Smithsonian Institution in Washington, DC, has compared fossil ''Gigantophis garstini'' vertebrae to those of the largest modern snakes, and concluded that the extinct snake could grow from in length. If , it would have been more than 10% longer than its largest living relatives. Later estimates, based on allometric equations scaled from the articular processes of tail vertebrae referred to ''Gigantophis garstini'', revised the length of ''Gigantophis garstini'' to . Discovery The species is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phylogenetic Tree
A phylogenetic tree (also phylogeny or evolutionary tree Felsenstein J. (2004). ''Inferring Phylogenies'' Sinauer Associates: Sunderland, MA.) is a branching diagram or a tree showing the evolutionary relationships among various biological species or other entities based upon similarities and differences in their physical or genetic characteristics. All life on Earth is part of a single phylogenetic tree, indicating common ancestry. In a ''rooted'' phylogenetic tree, each node with descendants represents the inferred most recent common ancestor of those descendants, and the edge lengths in some trees may be interpreted as time estimates. Each node is called a taxonomic unit. Internal nodes are generally called hypothetical taxonomic units, as they cannot be directly observed. Trees are useful in fields of biology such as bioinformatics, systematics, and phylogenetics. ''Unrooted'' trees illustrate only the relatedness of the leaf nodes and do not require the ancestral root to b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Morphology (biology)
Morphology is a branch of biology dealing with the study of the form and structure of organisms and their specific structural features. This includes aspects of the outward appearance (shape, structure, colour, pattern, size), i.e. external morphology (or eidonomy), as well as the form and structure of the internal parts like bones and organs, i.e. internal morphology (or anatomy). This is in contrast to physiology, which deals primarily with function. Morphology is a branch of life science dealing with the study of gross structure of an organism or taxon and its component parts. History The etymology of the word "morphology" is from the Ancient Greek (), meaning "form", and (), meaning "word, study, research". While the concept of form in biology, opposed to function, dates back to Aristotle (see Aristotle's biology), the field of morphology was developed by Johann Wolfgang von Goethe (1790) and independently by the German anatomist and physiologist Karl Friedrich Burdach ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vertebra
The spinal column, a defining synapomorphy shared by nearly all vertebrates,Hagfish are believed to have secondarily lost their spinal column is a moderately flexible series of vertebrae (singular vertebra), each constituting a characteristic irregular bone whose complex structure is composed primarily of bone, and secondarily of hyaline cartilage. They show variation in the proportion contributed by these two tissue types; such variations correlate on one hand with the cerebral/caudal rank (i.e., location within the backbone), and on the other with phylogenetic differences among the vertebrate taxa. The basic configuration of a vertebra varies, but the bone is its ''body'', with the central part of the body constituting the ''centrum''. The upper (closer to) and lower (further from), respectively, the cranium and its central nervous system surfaces of the vertebra body support attachment to the intervertebral discs. The posterior part of a vertebra forms a vertebral arch ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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