Panarthropoda
| Panarthropoda | ||||||||||||
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a columbus |
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| Systematics | ||||||||||||
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| Scientific name | ||||||||||||
| Panarthropoda | ||||||||||||
| Nielsen , 1995 |
The Panarthropoda are a widely accepted taxon , the 1995 by Claus Nielsen were prepared and the strains of arthropods (Arthropoda), velvet worms (Onychophora) and Bärtierchen comprises (Tardigrada). They are in the About tribe of molting animals classified (ecdysozoan).
designation
Although the taxon is widely accepted in its composition, the naming is not uniform. The first proposed name for an arthropod, tardigrade, and columbus taxon was Gnathopoda Lankester , 1877; but this name is not very common. Some authors use the name Arthropoda for this group, the "real" arthropods or arthropods are then called Euarthropoda to distinguish them (also introduced by Lankester, the old name Condylopoda Bronn , 1850 has largely been forgotten). The confusion of names becomes even greater, even if extinct groups that have only survived in fossil form such as the lobopods are included in the consideration. Some editors then differentiate, within the Panarthropoda, still main groups - and crown groups - Eurarthropods, sometimes subdivided into "higher" and "lower", whereby the description of these groups can be different. The position of the (extinct) Anomalocarida is controversial .
features
They have the following features in common with other molting animals:
- Possession of legs with clawed feet
- Possession of a spinal cord
- Segmentation of the body
The relationships within the Panarthropoda are currently still controversial. In the past, colibuses and tardigrades were mostly considered to be close relatives and assigned group names such as Proarthropoda ("arising before the arthropods", Lankester 1904) or Pararthropoda ("arising alongside the arthropods", Vandel 1949). Among other things, the similar construction of the legs, which are designed as oncopodia (hence the group name Oncopoda , Weber 1954), spoke in favor of this merger . Often, however, the tardigrade are grouped together with the arthropod, as there are tardigrades with subdivided legs (the group name Tactopoda was suggested here , but also Tritocerebra , the latter referring to similarities in the structure of the brain). Molecular systematic investigations have not been able to contribute to the decision on this question, since the tardigrade group very differently depending on the investigation method and sometimes even fall out of the Panarthropoda (e.g. Dunn et al. 2008).
Sub-taxa
- Tardigrade (Tardigrada)
- Colibus (Onychophora)
- Lobopods (Lobopodia) †
- Arthropod (arthropoda)
literature
- Claus Nielsen (1995). Animal Evolution: Interrelationships of the Living Phyla. Oxford University Press. ISBN 0-19-854868-0 .
- CW Dunn et al. (2008): Broad phylogenomic sampling improves resolution of the animal tree of life. Nature 452: pp. 745-749.
- Javier Ortega-Hernández (2014): Making sense of 'lower' and 'upper' stem-group Euarthropoda, with comments on the strict use of the name Arthropoda von Siebold, 1848. Biological Reviews 91 (1): 255-273. doi: 10.1111 / brv.12168 .