''Branchiosaurus'' (from , 'gill' and , 'lizard') is a

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

of small,

prehistoric amphibian This list of prehistoric amphibians is an attempt to create a comprehensive listing of all genera from the fossil record that have ever been considered to be amphibians, excluding purely vernacular terms. The list includes all commonly accepted gen ...

Fossil 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 preserve ...

s have been discovered in strata dating from the late

Pennsylvanian Pennsylvanian may refer to: * A person or thing from Pennsylvania * Pennsylvanian (geology) The Pennsylvanian ( , also known as Upper Carboniferous or Late Carboniferous) is, on the International Commission on Stratigraphy, ICS geologic timesc ...

Epoch to the

Permian The Permian ( ) is a geologic period and System (stratigraphy), stratigraphic system which spans 47 million years, from the end of the Carboniferous Period million years ago (Mya), to the beginning of the Triassic Period 251.902 Mya. It is the s ...

Period. The taxa may be invalid; the material referred to the genus may be juvenile specimens of larger amphibians. Branchiosaurus BW

This tiny amphibian was very similar to the

Rachitomi The Rachitomi were a group of extinct Palaeozoic labyrinthodont amphibians, according to an earlier classification system.Kent, G.C. & Miller, L. (1997): Comparative anatomy of the vertebrates. 8th edition. Wm. C. Brown Publishers. Dubuque. 48 ...

, differing primarily in size. Other distinguishing characteristics include a cartilaginous, less ossified skeleton and a shorter skull. Clear traces of

gill A gill () is a respiration organ, respiratory organ that many aquatic ecosystem, aquatic organisms use to extract dissolved oxygen from water and to excrete carbon dioxide. The gills of some species, such as hermit crabs, have adapted to allow r ...

s are present in many fossilized samples, hence the name. Originally thought to have

vertebrae Each vertebra (: vertebrae) is an irregular bone with a complex structure composed of bone and some hyaline cartilage, that make up the vertebral column or spine, of vertebrates. The proportions of the vertebrae differ according to their spinal ...

distinct from rhachitomous vertebrae, it was placed in a separate

order Order, ORDER or Orders may refer to: * A socio-political or established or existing order, e.g. World order, Ancien Regime, Pax Britannica * Categorization, the process in which ideas and objects are recognized, differentiated, and understood ...

named Phyllospondyli ("leaf vertebrae"). Later analysis of growth stages showed increasing ossification in larger specimens, which showed that at least some of the species was the larval stage of much larger rachitomes like ''

Eryops ''Eryops'' (; from Greek , , 'drawn-out' + , , 'face', because most of its skull was in front of its eyes) is a genus of extinct, amphibious temnospondyls. It contains the single species , the fossils of which are found mainly in early Permian (a ...

'', while others represent

paedomorphic Neoteny (), also called juvenilization,Montagu, A. (1989). Growing Young. Bergin & Garvey: CT. is the delaying or slowing of the physiological, or somatic, development of an organism, typically an animal. Neoteny in modern humans is more signi ...

species which retained the larval gills in adulthood.Boy, J.A. (1972): Die Branchiosaurier (Amphibia) des saarpfalzichen Rotliegenden (Perm, SW-Deutschland). ''Abhandlungen des Hessische Landesamt, Bodenforschung'' No 65, pp 1-137 Distribution is uncertain, though available fossils come from central Europe, most famous of which are the Permian Niederkirchen Beds around Pfalz, Germany.

References

External links

Fossil picture.''Branchiosaurus at BioLib.cz''
Branchiosaurids Permian temnospondyls of Europe Prehistoric amphibian genera Fossil taxa described in 1876 {{Temnospondyli-stub