the Therapsiden, also mammal-similar reptiles mentioned,is a group of land vertebrate animals, which rank as descendants of the Pelycosaurier among the Synapsiden. The Therapsiden has their meaning in the fact that among them the ancestors of the mammals are to be found. They lived from the middle Permian into the upper Trias and belongedover 400 kinds and far over 1000 kinds to the most successful groups of reptiles, which lived ever.
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1838 in Russia and 1845 in South Africa were found to discovery the first Therapsiden. To thatTo discoverers smelling pool of broadcasting corporations Owen belongs.
ancestors of the mammals
the subordination of the Theriodontier the ancestors contain of the mammals. Were these polyphyletisch (vielstämmig), i.e. several groups of the Theriodonta lead to the mammals. The progressive characteristics leading to the mammals are:
- Differentiation of the Dentures.
- Tooth change (only with some kinds).
- Hinterhaupt becomes larger and broader (larger brain area).
- Separation of the primary Kiefergelenks by the secondary.
- Formation of the auditory ossicles.
- 7 Halswirbel.
- Separation of the thorax from the remaining trunk.
- Legs are associated under the trunk and do not stand any longer laterallyoff.
- Number of the finger and toe members as with the suction animals.
- Short tail.
- Körperbehaarung (only the higher Theriodontier).
- Warm bloodyness (only the higher Theriodontier).
the Therapsiden are divided into three sub-groups.
The Theriodontier, i.e. „Raubtierzähner “are the most primitive group of the Therapsiden. Nevertheless are it the group, from which the mammals came out. They are rather small Raubtiere, fast runners. The legs are direct under the body. They remind of today's robbery mammals like e.g. Wolves. The Bezahnung is already differentiated, in front Schneidezähne, Eckzähne, in the back molars, with the primitive formsprovide pointedly, with the higher with höckrigen chewing surfaces.
The Dinokephalier, i.e. „Animals with large head “. Members itself in two groups, the karnivoren Titanosuchia and the herbivoren Tapinocephalia. In both groups are rather large and awkward animals, which became extinct to leave without descendants.
The Anomodontier, i.e. „Animals with unusual teeth “were a group large, awkward Therapsiden, which worked like today's river horses. They were planting or Allesfresser. Some kinds did not have teeth up to two large Hauer.
One knows fossils of the Therapsiden e.g. in the museum for natural history inBerlin see.
- Oskar bold: The mammal-similar reptiles. A. Ziemsen publishing house, 2003, ISBN 3-89432-797-9