Branchiosauridae
| Branchiosauridae | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
Fossil of Branchiosaurus salamandroides , in the Museo di Storia Naturale in Venice |
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| Temporal occurrence | ||||||||||||
| Upper carbon to lower perm | ||||||||||||
| 305 to 251 million years | ||||||||||||
| Locations | ||||||||||||
| Systematics | ||||||||||||
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| Scientific name | ||||||||||||
| Branchiosauridae | ||||||||||||
| Fritsch , 1883 |
The Branchiosauridae are an extinct group of amphibian-like terrestrial vertebrates (Tetrapoda) from the Temnospondyli group . They are considered a sister group of the Micromelerpetonidae .
They were small, five to ten centimeters long animals whose fossils were mostly found in Central Europe. They had a fin hem on the top and bottom of the tail, the joints of the front and rear feet were not ossified. For a long time the Branchiosauridae was known from hundreds of finds exclusively young specimens with external gills, therefore obligatory neoteny was assumed. Finds of apparently adult specimens of Apateon with a completely ossified skull suggest, however, that at least some specimens went through a metamorphosis and had a partly land-dwelling way of life. The structure of the adult specimens' limbs suggests that they could not travel long on land. The construction of the skull in these specimens allows the assumption that larger prey was also eaten. Young animals could probably only create a negative pressure by opening their mouths quickly and thus suck in smaller prey. Branchiosaurids mostly inhabited deep lakes at high altitudes, and due to the high location the temperatures were lower than usual. There may also have been stronger seasonal fluctuations. The non-obligatory possibility of metamorphosis enabled the Branchiosauriden to delay the metamorphosis in unfavorable conditions.
Due to the unusual, leaf-like (" leaf shape ") structure of their vertebrae, they were initially classified as a basal, separate group of the Tetrapoda and compared to the Temnospondyli and Lepospondyli as "Phyllospondyli" . In 1939, Alfred Romer interpreted the branchiosaurid fossils as larvae of larger terrestrial vertebrates. Today they are generally considered to be Temnospondyles within the Dissorophoidea . In addition to the Micromelerpetonidae, their closest relatives were probably small, basal amphibamids .
Numerous, well-preserved skeletons of various stages of development have been found of branchiosaurids, which is why an ontogenetic sequence from hatchlings to adults could be reconstructed for several genera .
Earlier, an origin of the tail amphibian within the Branchiosauridae was discussed. Today, after the discovery of Gerobatrachus , who is close to the common ancestor of the Salientia and Caudata , it seems more likely that these two "modern" amphibian groups developed within the Amphibamidae.
Genera
swell
- ^ A b c d e Robert L. Carroll (2009): The rise of amphibians - 365 million years of evolution , pp. 182-185. Johns Hopkins University Press, Baltimore. ISBN 0-8018-9140-X
- ^ MJ Benton (2007): Paleontology of the vertebrates. ISBN 3-89937-072-4
- ^ RR Schoch & NB Froebisch (2006): Metamorphosis and Neoteny: Alternative Pathways in an extinct Amphibian Clade . Evolution 60 (7), pp. 1467-1475
- ↑ JS Anderson, RR Reisz, D. Scott, NB Fröbisch & SS Sumida (2008): A stem batrachian from the Early Permian of Texas and the origin of frogs and salamanders. Nature 453 pp. 515-518
