Phylogeny, natural groups and nemertean classification.

Contemporary practice in the classification of nemerteans (phylum Nemertea) is critically discussed. It is argued that basing higher taxa on the existence of a unique combination of characters in a species (or genus) is unlikely to lead to monophyletic taxa, and that this approach should be abandoned in favour of a classification based on explicit hypotheses of phylogeny.

Thirty-Five Years of Nemertean (Nemertea) Research—Past.

Nemertea is a phylum of invertebrate animals also known as ribbon worms or proboscis worms. Alternative names for the phylum have included Nemertini, Nemertinea and Rhynchocoela. (1) Most are very slim, usually only a few millimeters wide, although a few have relatively short but wide bodies.What classification is a worm? Home. Uncategorized. What classification is a worm? April 16, 2018.. others are nonparasitic and just live elsewhere like the Nemertea phylum which contains marine worms such as the marine nemertean worm the longest worm at up to 55 meters. Post navigation. Previous Previous post: What are nucleotides?Global Biodiversity Information Facility. Free and Open Access to Biodiversity Data.

The classification of nemerteans has been in constant flux, both at the intra-phylum level and with respect to the position of the phylum among the metazoans. Relations between higher taxa are not steadily positioned within a phylogenetic framework and some taxonomic groups within Nemertea are clearly not monophyletic.The higher classification of nemerteans is still based on Stiasny-Wijnhoff’s (1936) arrangement of the nemerteans into the subclasses Palaeonemertea, Heteronemertea, Hoplonemertea, and Bdellonemertea.

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ADVERTISEMENTS: In this article we will discuss about Phylum Annelida:- 1. Taxonomic Retrospect of Phylum Annelida 2. Definition and Fossil Record of Phylum Annelida 3. Habit and Habitat 4. Generalised Characters 5. Specialised Characters 6. Features 7. Trend in Classification 8. Phylogenetic Relationship 9. Locomotion 10. Circulatory System 11.

The classification into genera and families proposed by Stiasny-Wijnhoff is the one still in use, with only a few new species and genera being added since.

In any scientific discipline, meetings with presented papers and discussions are the most effective stimulus to the advancement of knowledge. Nemerteans have long been largely neglected because their taxonomy is difficult: the need for histological study of serial sections has proved inhibiting.

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Bdellonemertea (represented by Malacobdella) is found to be a part of Monostilifera, and Polystilifera is the monophyletic sister group to Monostilifera. Cratenemertidae is the sister group to the remaining monostiliferans (including Malacobdella), a group to which we apply the new name Distromatonemertea.

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The statistical analysis showed that different nemertean species harbor distinct bacterial communities, while members of the same species mostly share more similar microbiomes. The bacterial species historically associated with TTX production were found in all studied samples but predominated in TTX-bearing nemertean species.

Phylum Annelida: Habitat, Features and Classification.

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ADVERTISEMENTS: In this article we will discuss about Phylum Entoprocta:- 1. Characters of Phylum Entoprocta 2. Classification of Phylum Entoprocta 3. Affinities 4. Phylogenetic Relationship. Characters of Phylum Entoprocta: This group includes a number of minute sedentaric animals. They are either solitary or colonial forms (Fig. 14.34A). Superficially they resemble the Hydroidea and Bryozoa.

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Phylogeny, natural groups and nemertean classification.

Thirty-Five Years of Nemertean (Nemertea) Research—Past.

Disentangling ribbon worm relationships: multi-locus.

Phylum Annelida: Habitat, Features and Classification.