Tetrapod

The amphibian's ancestral fish must have possessed similar traits to those inherited by the early amphibians, including internal nostrils (to separate the breathing and feeding passages) and a large fleshy fin built on bones that could give rise to the tetrapod limb. The rhipidistian crossopterygians fulfill every requirement for this ancestry. Their palatal and jaw structures were identical to those of amphibians, and their dentition was identical too, with labyrinthine teeth fitting in a pit-and-tooth arrangement on the palate. The crossop ...

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Tetrapod, Tetrapod - Devonian Tetrapods, Tetrapod - Carboniferous Tetrapods, Tetrapod - Permian Tetrapods, Tetrapod - Classification of Tetrapods, Tetrapod - Anatomical features of early tetrapods, Tetrapod - Classification, Tetrapod - Skull, Tetrapod - Dentition, Tetrapod - Sensory Organs, Tetrapod - Hearing, Tetrapod - Girdles, Tetrapod - Limbs, Tetrapod - Feeding, Tetrapod - Respiration, Tetrapod - Locomotion

Read more here: » Tetrapod: Encyclopedia II - Tetrapod - Anatomical features of early tetrapods

Tetrapod - Anatomical features of early tetrapods. The amphibian's ancestral fish must have possessed similar traits to those inherited by the early amphibians, including internal nostrils (to separate the breathing and feeding passages) and a large fleshy fin built on bones that could give rise to the tetrapod limb. The rhipidistian crossopterygians fulfill every requirement for this ancestry. Their palatal and jaw structures were identical to those of amphibians, and their dentition was identical too, with laby ...

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Tetrapod, Tetrapod - Evolution, Tetrapod - Devonian tetrapods, Tetrapod - Carboniferous tetrapods, Tetrapod - Permian Tetrapods, Tetrapod - Living tetrapods, Tetrapod - Classification, Tetrapod - Tetrapod groups, Tetrapod - Anatomy, Tetrapod - Anatomical features of early tetrapods, Tetrapod - Skull, Tetrapod - Dentition, Tetrapod - Sensory organs, Tetrapod - Hearing, Tetrapod - Girdles, Tetrapod - Limbs, Tetrapod - Feeding, Tetrapod - Respiration, Tetrapod - Locomotion

Read more here: » Tetrapod: Encyclopedia II - Tetrapod - Anatomy

Subclass Labyrinthodontia - extinct Subclass Lepospondyli - extinct Subclass Lissamphibia   Anura   Caudata   Gymnophiona Amphibians (class Amphibia) are a taxon of animals that include all tetrapods (four-legged vertebrates) that do not have amniotic eggs. Amphibians (from Greek αμφις "both" and βιος "life") generally spend part of their time on land, but they do not have the adaptations to an entirely terrestrial existence ...

Including:

• Amphibian - History of amphibians
• Amphibian - Classification
• Amphibian - Reproduction
• Amphibian - External references

Read more here: » Amphibian: Encyclopedia - Amphibian

Amphibians developed with the characteristics of pharyngeal slits/gills, a dorsal nerve cord, a notochord, and a post-anal tail at different stages of their life. They have persisted since the dawn of tetrapods 390 million years ago in the Devonian period, when they were the first four-legged animals to develop lungs. During the following Carboniferous period they also developed the ability to walk on land to avoid aquatic competition and predation while allowing them to travel from water source to water source. As a group they maintained th ...

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Amphibian, Amphibian - History of amphibians, Amphibian - Classification, Amphibian - Reproduction, Amphibian - External references

Read more here: » Amphibian: Encyclopedia II - Amphibian - History of amphibians

The skull of Eryops is proportionately large, being broad and flat and reaching lengths of 2 feet. It had an enormous mouth with many sharp teeth in strong jaws. Its teeth had enamel with a folded pattern, hence its classification with the Labyrinthodonts ("maze toothed"). Within the wide, gaping jaw, the fang-like palatal teeth, when coupled with the gape, suggest an inertial feeding habit. This is when the amphibian would grasp its prey and, lacking any chewing mechanism, toss its head up and backwards, throwing the prey farther bac ...

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Eryops, Eryops - Anatomy, Eryops - Respiration, Eryops - Locomotion

Read more here: » Eryops: Encyclopedia II - Eryops - Anatomy

For the purpose of reproduction most amphibians are bound to fresh water. A few tolerate brackish water, but there are no true sea water amphibians. Several hundred frog species in adaptive radiations (e.g., Eleutherodactylus, the Pacific Platymantines, the Australo-Papuan microhylids, and many other tropical frogs), however, do not need any water whatsoever. They reproduce via direct development, an ecological and evolutionary adaptation that has allowed them to be completely independent from free-standing water. Almost all of these frogs l ...

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Amphibian, Amphibian - History of amphibians, Amphibian - Classification, Amphibian - Reproduction, Amphibian - External references

Read more here: » Amphibian: Encyclopedia II - Amphibian - Reproduction

Eryops had typical amphibian posture exhibited by the upper arm and upper leg extending nearly straight out from its body, while the forearm and the lower leg extended downward from the upper segment at a near right angle. The body weight was not centered over the limbs, but was rather transferred 90 degrees outward and down through the lower limbs, which contacted the ground. Most of the animal's strength was used to just elevate its body off the ground for walking, which was probably slow and difficult. With this sort of posture, only short, broad strides could be achieved. This has been confirmed by fossilized foo ...

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Eryops, Eryops - Anatomy, Eryops - Respiration, Eryops - Locomotion

Read more here: » Eryops: Encyclopedia II - Eryops - Locomotion

Traditionally the amphibians are taken to include all tetrapods that are not amniotes. Recent amphibians all belong to a single subgroup of these, called the Lissamphibia. Recently there has been a tendency to restrict the class Amphibia to the Lissamphibia, i.e. to exclude tetrapods that are not more closely related to modern forms than they are to modern reptiles, birds, and mammals. There are two ancient, extinct, subclasses: Subclass Labyrinthodontia (paraphy ...

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Amphibian, Amphibian - History of amphibians, Amphibian - Classification, Amphibian - Reproduction, Amphibian - External references

Read more here: » Amphibian: Encyclopedia II - Amphibian - Classification

Trace fossils are found in abundance in rocks from the upper part of the Vendian period, some 550 million years ago, with the earliest occurrences in the Proterozoic (more than 1 billion years ago). One well known occurrence of trace fossils from this period is the famous 'Pipe Rock' of northwest Scotland. The 'pipes' which give the rock its name are closely packed straight tubes, which were presumably made by some kind of worm-like organism. The name given to this type of tube or burrow is Skolithos, which may be 30cm (12") in length ...

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Trace fossil, Trace fossil - Confusion with other types of fossils, Trace fossil - Information provided by ichnofossils, Trace fossil - Identification of the trackmaker, Trace fossil - Inherent bias and principle of actualism, Trace fossil - Examples

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Most trace fossils are known from marine deposits. Essentially, there are two types of traces, either exogenic ones which are on the surface of the sediment (such as tracks), or endogenic ones which are within the layers of sediment (such as burrows). Surface trails on sediment in shallow marine environments stand less chance of fossilization because they are subjected to wave and current action. Conditions in quiet, deep-water envi ...

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Trace fossil, Trace fossil - Confusion with other types of fossils, Trace fossil - Information provided by ichnofossils, Trace fossil - Identification of the trackmaker, Trace fossil - Inherent bias and principle of actualism, Trace fossil - Examples

Read more here: » Trace fossil: Encyclopedia II - Trace fossil - Inherent bias and principle of actualism

Pseudofossils are sometimes confused as being trace fossils. Trace fossils should not be confused with body casts. The Ediacara and Burgess shale fauna remains for instance primarily consist of the casts of these organisms in the sediment. Early geologists who studied the markings found on the bedding planes of sedimentary rocks gave them the name 'Fucoid', and they applied this name to a wide variety of markings and interpreted them as being the fossilized remains of seaweed. However, in more recent years these markings have been stu ...

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Trace fossil, Trace fossil - Confusion with other types of fossils, Trace fossil - Information provided by ichnofossils, Trace fossil - Identification of the trackmaker, Trace fossil - Inherent bias and principle of actualism, Trace fossil - Examples

Read more here: » Trace fossil: Encyclopedia II - Trace fossil - Confusion with other types of fossils

Trace fossils provide us with indirect evidence of life in the past, such as the footprints, tracks, burrows, borings, and droppings left behind by animals, rather than the preserved remains of the body of the actual animal itself. Unlike most other fossils which are produced only after the death of the organism concerned, trace fossils provide us with a record of the activity of an organism during its lifetime. Trace fossils are formed by organisms performing the functions of their everyday life, such as walking, crawling, burrowing, boring, or feeding. Tetrapod footprin ...

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Trace fossil, Trace fossil - Confusion with other types of fossils, Trace fossil - Information provided by ichnofossils, Trace fossil - Identification of the trackmaker, Trace fossil - Inherent bias and principle of actualism, Trace fossil - Examples

Read more here: » Trace fossil: Encyclopedia II - Trace fossil - Information provided by ichnofossils

The organisms which produce trace fossils are usually not preserved with their markings, and although it may be possible to deduce what the animal was doing at the time, it is usually impossible to determine the maker of the trace conclusively and to assign it to a given species of animal. Since different types of organisms are able to make the same types of markings, trace fossils are usually classified by their shape and their cause (such as feeding, dwelling, or ...

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Trace fossil, Trace fossil - Confusion with other types of fossils, Trace fossil - Information provided by ichnofossils, Trace fossil - Identification of the trackmaker, Trace fossil - Inherent bias and principle of actualism, Trace fossil - Examples

Read more here: » Trace fossil: Encyclopedia II - Trace fossil - Identification of the trackmaker

Early amphibians had a wide, gaping jaw with weak muscles with which to open and close it. Within the jaw were fang-like palatal teeth which, when coupled with the gape, suggests an intertial feeding habit. This is when the amphibian would grasp the prey and, lacking any chewing mechanism, toss the head up and backwards, throwing the prey farther back into the mouth. Such feeding is seen today in the crocodile and alligator. The tongue of modern adult amphibians is quite fleshy and attached to the front of the lower jaw, so it is reas ...

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Tetrapod, Tetrapod - Devonian Tetrapods, Tetrapod - Carboniferous Tetrapods, Tetrapod - Permian Tetrapods, Tetrapod - Classification of Tetrapods, Tetrapod - Anatomical features of early tetrapods, Tetrapod - Classification, Tetrapod - Skull, Tetrapod - Dentition, Tetrapod - Sensory Organs, Tetrapod - Hearing, Tetrapod - Girdles, Tetrapod - Limbs, Tetrapod - Feeding, Tetrapod - Respiration, Tetrapod - Locomotion

Read more here: » Tetrapod: Encyclopedia II - Tetrapod - Feeding

The humerus was the largest bone of the arm, its head articulating with the glenoid cavity of the pectoral girdle, distally with the radius and ulna. The radius resided on the inner side of the forearm and rested directly under the humerus, supporting much of the weight, while the ulna was located to the outside of the humerus. The ulna had a head, which muscles pulled on to extend the limb, called the olecranon that exten ...

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Tetrapod, Tetrapod - Devonian Tetrapods, Tetrapod - Carboniferous Tetrapods, Tetrapod - Permian Tetrapods, Tetrapod - Classification of Tetrapods, Tetrapod - Anatomical features of early tetrapods, Tetrapod - Classification, Tetrapod - Skull, Tetrapod - Dentition, Tetrapod - Sensory Organs, Tetrapod - Hearing, Tetrapod - Girdles, Tetrapod - Limbs, Tetrapod - Feeding, Tetrapod - Respiration, Tetrapod - Locomotion

Read more here: » Tetrapod: Encyclopedia II - Tetrapod - Limbs

Typical early amphibian posture is exhibited by the upper arm and upper leg extending nearly straight out from its body, while the forearm and the lower leg extended downward from the upper segment at a near right angle. The body weight was not centered over the limbs, but was rather transferred 90 degrees outward and down through the lower limbs, which contacted the ground. Most of the animal's strength was used to just elevate its body off the ground for walking, which was probably slow and difficult. With this sort of posture, only short, broad strides could be achieved. This has been confirmed by fossilized f ...

See also:

Tetrapod, Tetrapod - Devonian Tetrapods, Tetrapod - Carboniferous Tetrapods, Tetrapod - Permian Tetrapods, Tetrapod - Classification of Tetrapods, Tetrapod - Anatomical features of early tetrapods, Tetrapod - Classification, Tetrapod - Skull, Tetrapod - Dentition, Tetrapod - Sensory Organs, Tetrapod - Hearing, Tetrapod - Girdles, Tetrapod - Limbs, Tetrapod - Feeding, Tetrapod - Respiration, Tetrapod - Locomotion

Read more here: » Tetrapod: Encyclopedia II - Tetrapod - Locomotion

Tetrapod - Devonian tetrapods. The first tetrapods evolved in shallow and swampy freshwater habitats, towards the end of the Devonian, a little more than 360 million years ago. By the late Devonian, land plants had stabilized freshwater habitats, allowing the first wetland ecosystems to develop, with increasingly complex food webs that afforded new opportunities. [1] Primitive tetrapods developed from a lobe-finned fish (an "osteolepid Sarcopterygian"), with a two-lobed brain in a flattened skull, a wide m ...

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Tetrapod, Tetrapod - Evolution, Tetrapod - Devonian tetrapods, Tetrapod - Carboniferous tetrapods, Tetrapod - Permian Tetrapods, Tetrapod - Living tetrapods, Tetrapod - Classification, Tetrapod - Tetrapod groups, Tetrapod - Anatomy, Tetrapod - Anatomical features of early tetrapods, Tetrapod - Skull, Tetrapod - Dentition, Tetrapod - Sensory organs, Tetrapod - Hearing, Tetrapod - Girdles, Tetrapod - Limbs, Tetrapod - Feeding, Tetrapod - Respiration, Tetrapod - Locomotion

Read more here: » Tetrapod: Encyclopedia II - Tetrapod - Evolution

Labyrinthodontia Diagnostic features unique to the Labyrinthodontia are hard to find at first glance; the complex dentine infolding tooth structure was shared with crossopterygian fish. The labyrinthodonts are divided into the Temnospondyli and the Anthracosauria, the main difference between the two groups being their respective vertebral structures. The Anthracosauria had small pleurocentra, which grew and fused, becoming the true centrum in later vertebrates. In contrast, the Temnospondyli had a conservative vertebral column in whic ...

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Tetrapod, Tetrapod - Evolution, Tetrapod - Devonian tetrapods, Tetrapod - Carboniferous tetrapods, Tetrapod - Permian Tetrapods, Tetrapod - Living tetrapods, Tetrapod - Classification, Tetrapod - Tetrapod groups, Tetrapod - Anatomy, Tetrapod - Anatomical features of early tetrapods, Tetrapod - Skull, Tetrapod - Dentition, Tetrapod - Sensory organs, Tetrapod - Hearing, Tetrapod - Girdles, Tetrapod - Limbs, Tetrapod - Feeding, Tetrapod - Respiration, Tetrapod - Locomotion

Read more here: » Tetrapod: Encyclopedia II - Tetrapod - Classification

The pectoral girdle of early tetrapods such as Eryops was highly developed, with a larger size for both increased muscle attachment to it and to the limbs. Most notably, the shoulder girdle was disconnected from the skull, resulting in improved terrestrial locomotion. The crossopterygian cleithrum was retained as the clavicle, and the interclavicle was well-developed, lying on the underside of the chest. In primitive forms, the two clavicles and the interclavical could have grown ventrally in such a way as to form a broad chest ...

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Tetrapod, Tetrapod - Devonian Tetrapods, Tetrapod - Carboniferous Tetrapods, Tetrapod - Permian Tetrapods, Tetrapod - Classification of Tetrapods, Tetrapod - Anatomical features of early tetrapods, Tetrapod - Classification, Tetrapod - Skull, Tetrapod - Dentition, Tetrapod - Sensory Organs, Tetrapod - Hearing, Tetrapod - Girdles, Tetrapod - Limbs, Tetrapod - Feeding, Tetrapod - Respiration, Tetrapod - Locomotion

Read more here: » Tetrapod: Encyclopedia II - Tetrapod - Girdles

Until the 1990s, there was a 30-million year gap in the fossil record between the late Devonian tetrapods and the reappearance of tetrapod fossils in recognizable mid-Carboniferous amphibian lineages. It was referred to as "Romer's Gap", after the palaeontologist who recognized it. During the "gap", tetrapod backbones developed, as did limbs with digits and other adaptations for terrestrial life. Ears, skulls and vertebral columns all underwent changes too. The number of digits on hands and feet became standardized at five, as lineages with more digits died out. The very few tetrapod f ...

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Tetrapod, Tetrapod - Devonian Tetrapods, Tetrapod - Carboniferous Tetrapods, Tetrapod - Permian Tetrapods, Tetrapod - Classification of Tetrapods, Tetrapod - Anatomical features of early tetrapods, Tetrapod - Classification, Tetrapod - Skull, Tetrapod - Dentition, Tetrapod - Sensory Organs, Tetrapod - Hearing, Tetrapod - Girdles, Tetrapod - Limbs, Tetrapod - Feeding, Tetrapod - Respiration, Tetrapod - Locomotion

Read more here: » Tetrapod: Encyclopedia II - Tetrapod - Carboniferous Tetrapods