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Information about Mammaliaformes

Mammaliaformes
Fossil range: Late Triassic - Recent

Scientific classification
Kingdom:Animalia
Phylum:Chordata
Subphylum:Vertebrata
(unranked)Amniota
Class:Synapsida
(unranked)Mammaliaformes
Rowe, 1988
Clades


See text
Mammaliaformes ("mammal-shaped") is a clade that contains the mammals and their closest extinct relatives. The precise phylogeny is disputed due to the scantness of evidence in the fossil record. However, it is thought that the Mammaliaformes were of three major groups: Allotheria, the longest extinct lineage of pre-mammals; Docodonta, including close relatives such as Morganucodonta; and Symmetrodonta, the most basal of modern mammals. Mammaliaformes radiated from Cynodontia. Probainognathia of the Eucynodonts probably evolved into the early mammaliaformes, but the branch Allotheria was so different that they may have come from an entirely different group of cynodonts.

Early mammaliforms were generally rodent-like in appearance and size, and most of their distinguishing characteristics were internal. In particular, the structure of the mammaliform (and mammal) jaw and arrangement of teeth is nearly unique. Instead of having many teeth that are frequently replaced, mammals have one set of baby teeth and later one set of adult teeth which fit together precisely. This is thought to aid in the grinding of food to make it quicker to digest. Being warm-blooded requires more calories than "cold-blooded" animals, so quickening the pace of digestion is a necessity. Early mammaliaformes were probably nocturnal.

Mammaliforms have several common structures. Most importantly, mammaliforms have highly specialized molars, with cusps and flat regions for grinding food. This system is also unique to mammals, although it seems to have evolved convergently in pre-mammals multiple times.

Lactation and fur, along with other characteristically mammalian features, are also thought to characterize the Mammaliaformes, but these traits are difficult to study in the fossil record. The fossilized remains of Castorocauda lutrasimilis are a unique exception.

Some non-mammal mammaliformes still retain reptile-like traits. Some mammaliformes had reptile-like locomotion. Furthermore, these mammaliformes still had some bones on their lower jaw seen in reptiles.

Taxonomy

External links

See also

The Triassic is a geologic period that extends from about 251 to 199 Ma (million years ago). As the first period of the Mesozoic Era, the Triassic follows the Permian and is followed by the Jurassic. Both the start and end of the Triassic are marked by major extinction events.
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Scientific classification or biological classification is a method by which biologists group and categorize species of organisms. Scientific classification also can be called scientific taxonomy, but should be distinguished from folk taxonomy, which lacks scientific basis.
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Chordata
Bateson, 1885

Typical Classes

See below

Chordates (phylum Chordata) are a group of animals that includes the vertebrates, together with several closely related invertebrates.
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Vertebrata
Cuvier, 1812

Classes and Clades

See below
Vertebrates are members of the subphylum Vertebrata (within the phylum Chordata), specifically, those chordates with backbones or spinal columns.
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Amniota
Haeckel, 1866

Living subgroups

See text

The amniotes are a group of tetrapod vertebrates that include the Synapsida (mammals and mammal-like reptiles) and Sauropsida (reptiles and dinosaurs, including birds).
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Synapsida *
Osborn, 1903

Orders & Suborders
  • '''Order Pelycosauria *
  • Suborder Caseasauria
  • Suborder Eupelycosauria *
  • Order Therapsida

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Mammalia
Linnaeus, 1758

Subclasses & Infraclasses
  • Subclass †Allotheria*
  • Subclass Prototheria
  • Subclass Theria

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extinction is the cessation of existence of a species or group of taxa, reducing biodiversity. The moment of extinction is generally considered to be the death of the last individual of that species (although the capacity to breed and recover may have been lost before this point).
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phylogenetics (Greek: phyle = tribe, race and genetikos = relative to birth, from genesis = birth) is the study of evolutionary relatedness among various groups of organisms (e.g., species, populations).
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For other uses of the term, see Fossil (disambiguation)


FOSSIL is a standard for allowing serial communication for telecommunications programs under the DOS operating system.
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Multituberculata
Cope, 1884

Suborders of Allotheria
  • Order †Multituberculata 
  • Order †Volaticotheria


The Multituberculata
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Docodonta
Kretzoi, 1946

Docodonta is an order of extinct mammals that lived during the mid- to late-Mesozoic era. Their most distinguishing physical features were their relatively sophisticated set of molars, from which the order gets its name.
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Morganucodon
Kühne, 1949

species
  • M. watsoni
  • M. oehleri
Morganucodon is an early mammalian genus which lived during the Upper Triassic. It first appeared about 205 million years ago.
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Symmetrodonta

Families
  • Kuehneotheriidae
  • Shuotheriidae
  • Spalacolestidae
  • Spalacotheriidae
  • Tinodontidae
Symmetrodonta is a basal group of Mesozoic mammals characterized by the triangular aspect of the molars when viewed from
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In phylogenetics, basal members of a group diverged earlier than a subgroup of others (or vice versa). It is often used in opposition to the word derived. The following are example usages of the term basal:....
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Adaptive radiation describes the rapid speciation of a single or a few species to fill many ecological niches. This is an evolutionary process driven by natural selection, successful and novel adaptation, and sometimes by mutation (heritable/genetic variation).
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Cynodontia
Owen, 1861

Families

See text

Cynodonts, or 'dog teeth', are a taxon of Therapsids, traditionally called mammal-like reptiles. They were one of the most diverse groups of therapsids. They are named after their dog-like teeth.
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Probainognathia

Families and Clades

See "taxonomy"
Probainognathia is a taxon of mostly carnivorous cynodonts, and are one of the two main branches of the Eucynodontia infraorder, with the other being the mainly herbivorous Cynognathia.
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Eucynodontia

Families by diet
  • Carnivores
  • Cynognathidae
  • Probainognathidae

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Multituberculata
Cope, 1884

Suborders of Allotheria
  • Order †Multituberculata 
  • Order †Volaticotheria


The Multituberculata
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Rodentia
Bowdich, 1821

Suborders

Sciuromorpha
Castorimorpha
Myomorpha
Anomaluromorpha
Hystricomorpha
Rodentia is an order of mammals also known as rodents
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jaw is either of the two opposable structures forming, or near the entrance to, the mouth.

The term jaws is also broadly applied to the whole of the structures constituting the vault of the mouth and serving to open and close it.
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Teeth (singular, tooth) are structures found in the jaws (or mouths) of many vertebrates that are used to tear, scrape, and chew food. Some animals, particularly carnivores, also use teeth for hunting or defense. The roots of teeth are covered by gums.
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Molars are the rearmost and most complicated kind of tooth in most mammals. In many mammals they grind food; hence the Latin name mola, "millstone".

Human molars

Adult humans have twelve molars, in four groups of three at the back of the mouth.
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Cusp may refer to:
  • Cusp (singularity), a singular point of a curve
  • Cusp form in modular form theory
  • Cuspidal representation, a generalization of cusp forms in the theory of automorphic representations

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In evolutionary biology, convergent evolution is the process whereby organisms not closely related (not monophyletic), independently evolve similar traits as a result of having to adapt to similar environments or ecological niches[1].
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Lactation describes the secretion of milk from the mammary glands, the process of providing that milk to the young, and the period of time that a mother lactates to feed her young.
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