Adelobasileus cromptoni is a species of an extinct genus of proto-mammals from the middle Triassic, about 225 million years ago. It is poorly represented in the fossil record and is known only from a partial skull recovered from the Tecovas Formation in western Texas. The Triassic is a geologic period that extends from about 245 to 202 Ma (million years ago). ... Scientific classification or biological classification is how biologists group and categorize extinct and living species of organisms. ... Phyla Porifera (sponges) Ctenophora (comb jellies) Cnidaria (coral, jellyfish, anemones) Placozoa (trichoplax) Subregnum Bilateria (bilateral symmetry) Acoelomorpha (basal) Orthonectida (parasitic to flatworms, echinoderms, etc. ... Typical Classes Subphylum Urochordata - Tunicatas Ascidiacea Thaliacea Larvacea Subphylum Cephalochordata - Lancelets Subphylum Myxini - Hagfishes Subphylum Vertebrata - Vertebrates Petromyzontida - Lampreys Placodermi (extinct) Chondrichthyes - Cartilaginous fishes Acanthodii (extinct) Actinopterygii - Ray-finned fishes Actinistia - Coelacanths Dipnoi - Lungfishes Amphibia - Amphibians Reptilia - Reptiles Aves - Birds Mammalia - Mammals Chordates (phylum Chordata) include the vertebrates, together with... Clades Adelobasileus Sinoconodon Morganucodonta Docodonta Hadrocodium Mammalia Mammaliaformes is an extinct class of pre-mammals from which all modern mammals are descended. ... Incertae sedis—of uncertain position (seat)—is a term used to define a taxonomic group where its broader relationships are unknown or undefined. ... Incertae sedis—of uncertain position (seat)—is a term used to define a taxonomic group where its broader relationships are unknown or undefined. ... In biology, binomial nomenclature is the formal method of naming species. ... This article is about the year. ... Orders Subclass Multituberculata (extinct) Plagiaulacida Cimolodonta Subclass Palaeoryctoides (extinct) Subclass Triconodonta (extinct) Subclass Eutheria (includes extinct ancestors)/Placentalia (excludes extinct ancestors) Afrosoricida Artiodactyla Carnivora Cetacea Chiroptera Cimolesta (extinct) Creodonta (extinct) Condylarthra (extinct) Dermoptera Desmostylia (extinct) Embrithopoda (extinct) Hyracoidea Insectivora Lagomorpha Litopterna (extinct) Macroscelidea Mesonychia (extinct) Notoungulata (extinct) Perissodactyla Pholidota Plesiadapiformes... The Triassic is a geologic period that extends from about 245 to 202 Ma (million years ago). ... Ever since recorded history began, and probably before, people have found pieces of rock and other hard material with indentations from the remains of dead organisms. ... Official language(s) None. ...
Adelobasileus predates the most advanced non-mammalian cynodonts (tritylodonta and trithelodonta) and all other known Mammaliaformes by 10 million years. In fact, distinct cranial features, especially the housing of the cochlea, suggest that Adelobasileus is a transitional form in the character transformation from cynodonts to Triassic mammals. For this reason, it is thought to be the common ancestor of all modern mammals or a close relative of the common ancestor. Clades Procynosuchidae Epicynodontia Galesauridae Eucynodontia Cynognathia Cynognathidae Tritylodontidae Probainognathia Trithelodontidae Mammaliformes Cynodonta is the suborder that contains the most mammal-like of the non-mammalian therapsids, which are sometimes termed mammal-like reptiles. The most derived cynodonts are found within Eucynodontia clade, which also contains the members of Mammalia. ... Clades Adelobasileus Sinoconodon Morganucodonta Docodonta Hadrocodium Mammalia Mammaliaformes is an extinct class of pre-mammals from which all modern mammals are descended. ... A hippopotamus skull A skull, or cranium, is a bony structure of Craniates which serves as the general framework for a head. ... Cross section of the cochlea. ... A transitional fossil is the fossil remains of a creature that exhibits primitive traits in comparison with the more derived life-forms it is related to. ... A group of organisms is said to have common descent if they have a common ancestor. ...
References
S.G. Lucas and Z. Lou, Adelobasileus from the upper Triassic of west Texas: the oldest mammal, J. Vert. Paleont, 1993.
Adelobasileus cromptoni (late Triassic; 225 Ma, west Texas)...Also note that this fossil dates from slightly before the known tritylodonts and trithelodonts, though it has long been suspected that tritilodonts and trithelodonts were already around by then.
Adelobasileus is thought to have split off from either a trityl.
This is the case with Adelobasileus cromptoni of the "late Triassic gap".
However, Adelobasileus cromptoni, a fairly "new" species, has been discovered; its age is 225, putting it squarely in the middle of the triassic gap.
The proto-mammal Adelobasileus is thought to be either (1) the common ancestor of all mammals, or (2) a very close relative of that common ancestor [Hunt, 1997].
S.G. Lucas and Z. Lou, Adelobasileus from the upper Triassic of west Texas: the oldest mammal, J. Vert.
Feeds |
Contact