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Aschelminthes

(Superphylum)

Overview

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The Aschelminthes (also known as Aeschelminthes, Nemathelminthes, or Pseudocoelomata), closely associated with the , are an obsolete phylum of pseudocoelomate and other similar animals that are no longer considered closely related and have been promoted to phyla in their own right. The term Aschelminth is now generally only used as an informal name for any member of the approximately ten different invertebrate phyla formerly included within Aschelminthes.

Subdivisions

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Although invertebrate experts do not necessarily agree on these categorizations, groups that are generally incorporated into Aschelminthes include:

In addition, Priapulida, Entoprocta, and Tardigrada are sometimes included.

Photos

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Taxonomy

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The Superphylum Aschelminthes is a member of the Infrakingdom Ecdysozoa. Here is the complete "parentage" of Aschelminthes:

The Superphylum Aschelminthes is further organized into finer groupings including:

Phyla

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Kinorhyncha

Kinorhyncha (Gr. ?????, kineo 'move' + ??????, rhynchos 'snout') is a of small (1 mm or less) marine pseudocoelomate invertebrates that are widespread in mud or sand at all depths as part of the meiobenthos. They are also called mud dragons. [more]

Loricifera

[more]

Nematoda

The roundworms or nematodes ( Nematoda) are the most diverse phylum of pseudocoelomates, and one of the most diverse of all animals. Nematode species are very difficult to distinguish; over 80,000 have been described, of which over 15,000 are parasitic. It has been estimated that the total number of described and undescribed roundworms might be more than 500,000. [more]

Nematomorpha

Nematomorpha (sometimes called Gordiacea, and commonly known as Horsehair worms or Gordian worms) are a of parasitic animals which are morphologically and ecologically similar to nematode worms, hence the name. They range in size from 1cm to 1 meter long, and 1 to 3 millimetres in diameter. Horsehair worms can be discovered in damp areas such as watering troughs, streams, puddles, and cisterns. The adult worms are free living, but the larvae are parasitic on beetles, cockroaches, grasshoppers and crustaceans. About 320 species have been described. [more]

Priapulida

Priapulida (priapulid worms or penis worms, from Gr. p???p??, priapos '' + Lat. -ul-, diminutive) are a phylum of marine worms with an extensible spiny proboscis. Priapulid fossils are known at least as far back as the Middle Cambrian. Their nearest relatives are probably Kinorhyncha and Loricifera with which they constitute the taxon Scalidophora. Besides arthropods and velvet worms, it is only among Priapulida that we can find members of the Ecdysozoa which are relatively large in size. They were likely the major predators of the Cambrian period. There are 16 known species of Priapulid worms. [more]

At least 8 species and subspecies belong to the Phylum Priapulida.

More info about the Phylum Priapulida may be found here.

Sources

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Last Revised: November 18, 2008