Taxonomy, systematics och phylogeny of nematodes, especially the groups Cephaloboidea and Plectida
Sven Boström Abstract
The phylogenetic relationships within the phylum Nematoda have, beside the traditional morphological methods, during the last decades been analyzed by using molecular methods (DNA sequences).Based on these studies, the phylum is proposed to be divided into the classes:
1) Chromadorea (with one subclass and six orders)
2) Enoplea (with two subclasses and seven orders).
In the class Chromadorea, the group Cephaloboidea is included in the order Rhabditida, while Plectida is a sister group of Rhabditida.
Within the project, morphological and molecular characters of these groups are studied with the aims:
- to reveal the phylogenetic relationships within Cephaloboidea
- to reveal the phylogenetic relationships within Plectida
- to understand the role of the plectids as a sister group of Rhabditida
The studies have in recent years been focused on some interesting and crucial taxa in order to solve parts of the branches in the phylogenetic tree, like the genera Scottnema and Placodira (Cephaloboidea). In the years to come, other important taxa like Cynura and a new genus of Plectida from New Zealand, and some new genera of Cephaloboidea from California (USA) will be studied. The studies are carried out in cooperation with Oleksandr Holovachov who is also working in the Department of Invertebrate Zoology at the Swedish Museum of Natural History.
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