Pancrustacea
As Pancrustacea or Tetraconata is a group of arthropods called, in which insects are combined with the crustaceans to a group. This is the subject of several phylogenetic theories.
System
The systematics within the Euarthropoden ( Arthropod in the narrower sense without Onychophora and Tardigrada ), as their relationship affiliation with outside groups, is still controversial.
Traditional outline
Traditionally, the chelicerates (arrow tails and arachnids ) the Mandibeltieren ( Mandibulata ) are compared ( millipedes, crabs and insects). Within the taxon Mandibulata is an open question whether the insects with the centipedes as Tracheata ( Antennata ) should be summarized. Arguments for this are common, such as the reduction of the second antenna and the possession of specific tracheae:
Crustaceans (Crustacea )
Sechsfüßer ( Hexapoda, including insects)
Millipedes ( Myriapoda )
Jaw jaw carrier ( Chelicerata ) (arrow tails and arachnids )
Tetraconatahypothese
According to various studies is often represented in the literature, the hypothesis that insects classified within the Mandibeltiere closer to the crustaceans (Crustacea ) and compare against the centipedes as a common taxon Tetraconata. The main argument for this is the construction of the compound eyes in crustaceans and insects. You agree in their construction agreement in detail and have two Corneagenzellen, four Semper cells and eight Retinulazellen.
Millipedes ( Myriapoda )
Sechsfüßer ( Hexapoda, including insects)
Crustaceans (Crustacea )
Jaw jaw carrier ( Chelicerata ) (arrow tails and arachnids )
Pancrustaceahypothese
Some authors assume that the insects have developed within the crustaceans. This would " Crustacea " a Paraphylum unless the insects were included. This thesis is expressed by the term Pancrustacea. Arguments for this are supplied by developmental biology.
Millipedes ( Myriapoda )
Crustaceans (Crustacea ) incl Sechsfüßer ( Hexapoda ) (including insects)
Jaw jaw carrier ( Chelicerata ) (arrow tails and arachnids )
Myriochelatahypothese
Is also held by some authors, the Myriochelata hypothesis. Hereafter are the millipedes with the jaw -mouth -makers the monophyletic Myriochelata, which is compared with the Tetraconaten. The main argument for the relationship of spiders to centipedes is the matching number of neural immigration centers in the ganglion formation.
Crustaceans (Crustacea )
Sechsfüßer ( Hexapoda ) (including insects)
Millipedes ( Myriapoda )
Jaw jaw carrier ( Chelicerata ) (arrow tails and arachnids )
Source
- H. Paul Euarthropoda, Arthropod ieS In W. West Heath and R. Rieger (eds.): Systematic Zoology Part 1: protozoa and invertebrates. Spectrum Verlag, Heidelberg 2006; S.463 - 473
- J. Regier, J. Shultz, A. Zwick, A. Hussey, B. Ball, R. Wetzer, J. Martin, & C. Cunningham: Arthropod relationships revealed by phylogenomic analysis of nuclear protein -coding sequences. Nature, 2010, doi: 10.1038/nature08742