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Pederpes
''Pederpes'' ("Peter's Foot") is an extinct genus of early Carboniferous tetrapod, dating from 348 to 347.6 Ma in the Tournaisian age (lower Mississippian). ''Pederpes'' contains one species, ''P. finneyae'', 1 m long. This most basal Carboniferous tetrapod had a large, somewhat triangular head, similar to that of later American sister-genus '' Whatcheeria'', from which it is distinguished by various skeletal features, such as a spike-like latissimus dorsi (an arm muscle) attachment on the humerus and several minor skull features. The feet had characteristics that distinguished it from the paddle-like feet of the Devonian Ichthyostegalia and resembled the feet of later, more terrestrially adapted Carboniferous forms. ''Pederpes'' is the earliest-known tetrapod to show the beginnings of terrestrial locomotion and despite the probable presence of a sixth digit on the forelimbs it was at least functionally pentadactyl. Discovery and classification ''Pederpes'' was discovered in 19 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pederpes Fossil Illustration
''Pederpes'' ("Peter's Foot") is an extinct genus of early Carboniferous tetrapod, dating from 348 to 347.6 Ma in the Tournaisian age (lower Mississippian). ''Pederpes'' contains one species, ''P. finneyae'', 1 m long. This most basal Carboniferous tetrapod had a large, somewhat triangular head, similar to that of later American sister-genus ''Whatcheeria'', from which it is distinguished by various skeletal features, such as a spike-like latissimus dorsi (an arm muscle) attachment on the humerus and several minor skull features. The feet had characteristics that distinguished it from the paddle-like feet of the Devonian Ichthyostegalia and resembled the feet of later, more terrestrially adapted Carboniferous forms. ''Pederpes'' is the earliest-known tetrapod to show the beginnings of terrestrial locomotion and despite the probable presence of a sixth digit on the forelimbs it was at least functionally pentadactyl. Discovery and classification ''Pederpes'' was discovered in 197 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pederpes NT Small
''Pederpes'' ("Peter's Foot") is an extinct genus of early Carboniferous tetrapod, dating from 348 to 347.6 Ma in the Tournaisian age (lower Mississippian). ''Pederpes'' contains one species, ''P. finneyae'', 1 m long. This most basal Carboniferous tetrapod had a large, somewhat triangular head, similar to that of later American sister-genus ''Whatcheeria'', from which it is distinguished by various skeletal features, such as a spike-like latissimus dorsi (an arm muscle) attachment on the humerus and several minor skull features. The feet had characteristics that distinguished it from the paddle-like feet of the Devonian Ichthyostegalia and resembled the feet of later, more terrestrially adapted Carboniferous forms. ''Pederpes'' is the earliest-known tetrapod to show the beginnings of terrestrial locomotion and despite the probable presence of a sixth digit on the forelimbs it was at least functionally pentadactyl. Discovery and classification ''Pederpes'' was discovered in 197 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Whatcheeriidae
Whatcheeriidae is an extinct family of tetrapods which lived in the Mississippian sub-period, a subdivision of the Carboniferous period. It contains the genera ''Pederpes'', '' Whatcheeria'', and possibly '' Ossinodus''. Fossils of a possible whatcheeriid have been found from the Red Hill locality of Pennsylvania. If these remains are from a whatcheeriid, they extend the range of the family into the Late Devonian and suggest that advanced tetrapods may have lived alongside primitive tetrapod ancestors like ''Hynerpeton'' and ''Densignathus''. They also imply that a very long ghost lineage of whatcheeriids lived through Romer's gap, a period during the Early Carboniferous conspicuously lacking in tetrapod remains. Classification Currently, using modern cladistic taxonomy, Whatcheeriidae is not placed in Amphibia Amphibians are four-limbed and ectothermic vertebrates of the class Amphibia. All living amphibians belong to the group Lissamphibia. They inhabit a wide va ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tetrapod
Tetrapods (; ) are four-limbed vertebrate animals constituting the superclass Tetrapoda (). It includes extant and extinct amphibians, sauropsids ( reptiles, including dinosaurs and therefore birds) and synapsids (pelycosaurs, extinct therapsids and all extant mammals). Tetrapods evolved from a clade of primitive semiaquatic animals known as the Tetrapodomorpha which, in turn, evolved from ancient lobe-finned fish (sarcopterygians) around 390 million years ago in the Middle Devonian period; their forms were transitional between lobe-finned fishes and true four-limbed tetrapods. Limbed vertebrates (tetrapods in the broad sense of the word) are first known from Middle Devonian trackways, and body fossils became common near the end of the Late Devonian but these were all aquatic. The first crown-tetrapods (last common ancestors of extant tetrapods capable of terrestrial locomotion) appeared by the very early Carboniferous, 350 million years ago. The specific aquatic ancestors ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carboniferous
The Carboniferous ( ) is a geologic period and system of the Paleozoic that spans 60 million years from the end of the Devonian Period million years ago ( Mya), to the beginning of the Permian Period, million years ago. The name ''Carboniferous'' means "coal-bearing", from the Latin '' carbō'' ("coal") and '' ferō'' ("bear, carry"), and refers to the many coal beds formed globally during that time. The first of the modern 'system' names, it was coined by geologists William Conybeare and William Phillips in 1822, based on a study of the British rock succession. The Carboniferous is often treated in North America as two geological periods, the earlier Mississippian and the later Pennsylvanian. Terrestrial animal life was well established by the Carboniferous Period. Tetrapods (four limbed vertebrates), which had originated from lobe-finned fish during the preceding Devonian, became pentadactylous in and diversified during the Carboniferous, including early amphibian line ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Jennifer Clack
Jennifer Alice Clack, (''née'' Agnew; 3 November 1947 – 26 March 2020) was an English palaeontologist and evolutionary biologist. She specialised in the early evolution of tetrapods, specifically studying the "fish to tetrapod" transition: the origin, evolutionary development and radiation of early tetrapods and their relatives among the lobe-finned fishes. She is best known for her book ''Gaining Ground: the Origin and Early Evolution of Tetrapods'', published in 2002 (second edition, 2012) and written with the layperson in mind. Clack was curator at the Museum of Zoology and Professor of Vertebrate Palaeontology at the University of Cambridge, where she devoted her career to studying the early development of tetrapods, the "four-legged" animals said to have evolved from Devonian lobe-finned fishes and colonised the freshwater swamps of the Carboniferous period. Early life and education Clack was born on 3 November 1947, the only child of Ernest and Alice Agnew. She was ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Whatcheeria
''Whatcheeria'' is an extinct genus of early tetrapod from the Mississippian (Early Carboniferous) of Iowa. Fossils have been found in 340 million year old fissure fill deposits in the town of Delta. The type species, ''Whatcheeria deltae'' was named in 1995. It is classified within the family Whatcheeriidae, along with the closely related ''Pederpes'' and possibly ''Ossinodus.'' ''Whatcheeria'' is named after What Cheer, Iowa, the hometown of Pat McAdams, the geologist who discovered the first skeletons of the animal. The species is named after Delta, Iowa, the location where the fossils were uncovered. Description ''Whatcheeria'' possesses a mixture of both primitive and derived traits. It shares with earlier stem tetrapods a series of lateral lines across the skull, rows of teeth on the palate, and small Meckelian groove, Meckelian foramina across the surface of the lower jaw. It has a cleithrum, a bone in the pectoral girdle that extends from the scapula. The cleithrum o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Romer's Gap
Romer's gap is an example of an apparent gap in the tetrapod fossil record used in the study of evolutionary biology. Such gaps represent periods from which excavators have not yet found relevant fossils. Romer's gap is named after paleontologist Alfred Romer, who first recognised it. Recent discoveries in Scotland are beginning to close this gap in palaeontological knowledge. Age Romer's gap ran 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 in 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 suggested the problem was of fossilization itself, suggesting that there may ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Crown Group
In phylogenetics, the crown group or crown assemblage is a collection of species composed of the living representatives of the collection, the most recent common ancestor of the collection, and all descendants of the most recent common ancestor. It is thus a way of defining a clade, a group consisting of a species and all its extant or extinct descendants. For example, Neornithes (birds) can be defined as a crown group, which includes the most recent common ancestor of all modern birds, and all of its extant or extinct descendants. The concept was developed by Willi Hennig, the formulator of phylogenetic systematics, as a way of classifying living organisms relative to their extinct relatives in his "Die Stammesgeschichte der Insekten", and the "crown" and "stem" group terminology was coined by R. P. S. Jefferies in 1979. Though formulated in the 1970s, the term was not commonly used until its reintroduction in 2000 by Graham Budd and Sören Jensen. Contents of the crown gr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carboniferous Tetrapods
Carboniferous tetrapods include amphibians and reptiles that lived during the Carboniferous Period. Though stem-tetrapods originated in the preceding Devonian, it was in the earliest Carboniferous that the first crown tetrapods appeared, with full scaleless skin and five digits. During this time, amphibians (including many extinct groups unrelated to modern forms, referred to as "basal tetrapods") were the predominant tetrapods, and included the Temnospondyli, Lepospondyli, and Anthracosauria. The first amniotes appeared during the middle Carboniferous ( Early Pennsylvanian) from the lattermost group, and included both sauropsids and synapsids, but it was not until the very end of the Carboniferous, during a rainforest collapse, and afterwards that they began to diversify. Classification The following list of families of Carboniferous tetrapods is based mostly on Benton ed. 1993. The classification followBenton 2004 Superclass Tetrapoda * Basal Tetrapods ** Family Whatch ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Amphibians
Amphibians are four-limbed and ectothermic vertebrates of the class Amphibia. All living amphibians belong to the group Lissamphibia. They inhabit a wide variety of habitats, with most species living within terrestrial, fossorial, arboreal or freshwater aquatic ecosystems. Thus amphibians typically start out as larvae living in water, but some species have developed behavioural adaptations to bypass this. The young generally undergo metamorphosis from larva with gills to an adult air-breathing form with lungs. Amphibians use their skin as a secondary respiratory surface and some small terrestrial salamanders and frogs lack lungs and rely entirely on their skin. They are superficially similar to reptiles like lizards but, along with mammals and birds, reptiles are amniotes and do not require water bodies in which to breed. With their complex reproductive needs and permeable skins, amphibians are often ecological indicators; in recent decades there has been a dramatic decli ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lungs
The lungs are the primary organs of the respiratory system in humans and most other animals, including some snails and a small number of fish. In mammals and most other vertebrates, two lungs are located near the backbone on either side of the heart. Their function in the respiratory system is to extract oxygen from the air and transfer it into the bloodstream, and to release carbon dioxide from the bloodstream into the atmosphere, in a process of gas exchange. Respiration is driven by different muscular systems in different species. Mammals, reptiles and birds use their different muscles to support and foster breathing. In earlier tetrapods, air was driven into the lungs by the pharyngeal muscles via buccal pumping, a mechanism still seen in amphibians. In humans, the main muscle of respiration that drives breathing is the diaphragm. The lungs also provide airflow that makes vocal sounds including human speech possible. Humans have two lungs, one on the left and one on the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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