Tethytheria

Tethytheria
	Caribbean manatees ( Trichechus manatus )
Systematics
without rank:	Synapsids (Synapsida)
Class :	Mammals (mammalia)
Subclass :	Higher mammals (Eutheria)
Superordinate :	Afrotheria
without rank:	Paenungulata
without rank:	Tethytheria
Scientific name
	Tethytheria
	McKenna , 1975
Orders
	Russell animals (Proboscidea); Manatees (Sirenia);

The tethytheria provide a taxon within the mammals is where the orders of mammoths (Proboscidea) and manatees (Sirenia) are summarized. In addition to them, the extinct Embrithopoda are also classified in this taxon.

features

Although the manatees and the proboscis are very different in their visible anatomy, they have a number of anatomical features that establish a sister group relationship ( apomorphies ). Particularly noteworthy are the missing sweat glands , the very specific and unique structure of the metacarpal skeleton , the enamel structure of the molars , the structure of the inner ear as well as the very high attached zygomatic arches and external auditory canals.

Tribal history

The Tethytheria probably originated in the late Cretaceous period , the oldest fossils of possible members of the trunk group are only detectable from the subsequent phase, the upper Paleocene , such as Eritherium , the earliest known member of the proboscis. In the following Eocene there was a stronger splitting of the group ( adaptive radiation ), so from this time members of the sirens with protosiren and eosiren are for the first time handed down.

As the earliest representatives of tethytheria are semi-aquatic living forms in the edge region of the Tethys accepted because both the earliest Seekuhverwandten and the ancestors of today's elephants, especially Moeritherium , a corresponding habit have. In addition, the absence of sweat glands in all representatives speaks for this origin.

Systematics

African elephant

As next of kin of Tethyteria are Hyrax discussed, this discussion is not yet complete. The common taxon from Tethytheria and snake is called Paenungulata . According to Emmanuel Gheerbrant and research colleagues 2014, the following relationships result within mammals :

Paenungulata

Hyracoidea (hyrax)

Anthracobunia (†)

Tethytheria

Proboscidea ( proboscidea )

Desmostylia (†)

Sirenia (manatees)

Minchenella (†)

	Phenocolophus (†)

	Embrithopoda (†)

literature

Martin S. Fischer: Sirenia, manatees in: W. Westheide and R. Rieger: Special Zoology. Part 2: vertebrates or skulls. Spektrum Akademischer Verlag, Munich 2004. ISBN 3-8274-0307-3

Individual evidence

↑ Emmanuel Gheerbrant: Paleocene emergence of elephant relatives and the rapid radiation of African ungulates. PNAS. 106 (6), 2009, pp. 10717-10721
^ Daryl M. Domning, Iyad S. Zalmout and Philip D. Gingerich: Sirenia. In: Lars Werdelin and William Joseph Sanders (eds.): Cenozoic Mammals of Africa. University of California Press, Berkeley, Los Angeles, London, 2010, pp. 147-160
↑ Emmanuel Gheerbrant, Mbarek Amaghzaz, Baadi Bouya, Florent Goussard and Charlene Letenneur: ocepeia (Middle Paleocene of Morocco): The Oldest Skull of an Afrotherian Mammal. PLOSone 9 (1), 2014, p. E89739 ( [1] )

[Gheerbrant_2009-1] Emmanuel Gheerbrant: Paleocene emergence of elephant relatives and the rapid radiation of African ungulates. PNAS. 106 (6), 2009, pp. 10717-10721

[Domning_et_al._2010-2] Daryl M. Domning, Iyad S. Zalmout and Philip D. Gingerich: Sirenia. In: Lars Werdelin and William Joseph Sanders (eds.): Cenozoic Mammals of Africa. University of California Press, Berkeley, Los Angeles, London, 2010, pp. 147-160

[Gheerbrant_et_al._2014-3] Emmanuel Gheerbrant, Mbarek Amaghzaz, Baadi Bouya, Florent Goussard and Charlene Letenneur: ocepeia (Middle Paleocene of Morocco): The Oldest Skull of an Afrotherian Mammal. PLOSone 9 (1), 2014, p. E89739 ( [1] )