Deuterostome
The Neumündern the blastopore ( blastopore ) becomes the anus, the mouth opening is newly formed.
- Chordates ( Chordata )
- Gill hole Animals ( Hemichrodata )
- Echinoderms ( Echinodermata )
- Xenacoelomorpha
As a new mouths ( Deuterostomia AltGr. Δεύτερο deutero, second - ' and Στόμα stoma, mouth ') or second mouths applies to those animals bilaterally symmetrical addition ( bilaterian ) where in embryonic development of the intestine of the primitive mouth ( blastopore ) to after will and the mouth secondarily from the primitive gut ( archenteron ) breaks through ( the process is called Deuterostomie ).
Scientific Importance
Deuterostomie was traditional morphologically an important feature to bring together various groups such as the Chordata, Echinodermata Hemichrodata, as a community of descent (see section systematics). How many Bilateriergruppen in deuterostome taxon are to be classified, but a long time has been controversial since Deuterostomie for example, at the arrow worms and some Lophophorata occurs further in some strings worms and arthropods.
Using molecular biological relationship research has been made on this issue some clarity. Thus, Chordata, Echinodermata Hemichrodata, form indeed a monophyletic group, but the remaining groups with Deuterostomie are not included.
System
The Neumündern include four recent and extinct animals tribe:
- Xenacoelomorpha
- Echinoderms ( Echinodermata ), among others, the starfish and sea urchins
- Gill hole Animals ( Hemichrodata ) with the Flügelkiemern ( Pterobranchia ) and acorn worms ( Enteropneusta )
- † Vetulicolia. Only known from the Lower and Middle Cambrian.
- Chordates ( Chordata ) with the tunicates ( Tunicata ), amphioxus ( Acrania ) and vertebrates ( Vertebrata, syn. Craniata )
Recent phylogenomic work yield the following scheme:
- Deuterostomia Xenacoelomorpha
- Ambulacraria Echinoderms ( Echinodermata )
- Gill hole Animals ( Hemichrodata )
- Acrania
- Olfactores tunicata
- Craniata
Conspicuous above all the new clade Olfactores, the Tunicata and Craniata is summarized in this system. For this, the Acrania form the sister group. This contradicts the traditional view of comparative morphology, should be grouped according to the Acrania and Craniata for monophyletic Notochordata. In the illustrated current system some common group names are different reasons no longer used:
- Ambulacrals - Synonym to Ambulacraria
- Cephalochordata - Synonym to Acrania
- Chordonia - Synonym to Chordata
- Coelomorpha - Synonym to Ambulacraria
- Craniata - Synonym to Craniata
- Euchordata - Synonym to Notochordata
- Myomerozoa - Synonym to Notochordata
- Notochordata - Paraphylum from Acrania and Craniata
- Notoneuralia - Synonym to Deuterostomia
- Urochordata - Synonym to Tunicata
- Vertebrata - Synonym to Craniata