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Aschelminthes

(Superphylum)

Overview

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Previously a single phylum containing all the pseudocoelomate animals including the nematodes and rotifers. Used as a collective term for the variety of pseudocoelomate phyla now recognised.

Taxonomy

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

The Superphylum Aschelminthes is further organized into finer groupings including:

Phyla

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Chordata

Chordates (phylum Chordata) are animals which are either vertebrates or one of several closely related invertebrates. They are united by having, for at least some period of their life cycle, a notochord, a hollow dorsal nerve cord, pharyngeal slits, an endostyle, and a post-anal tail. The phylum Chordata consists of three subphyla: Tunicata, represented by tunicates; Cephalochordata, represented by lancelets; and Craniata, which includes Vertebrata. The Hemichordata have been presented as a fourth chordate subphylum, but they are now usually treated as a separate phylum. Tunicate larvae have both a notochord and a nerve cord which are lost in adulthood. Cephalochordates have a notochord and a nerve cord (but no brain or specialist sensory organs) and a very simple circulatory system. Craniates are the only sub-phylum whose members have skulls. In all craniates except for hagfish, the dorsal hollow nerve cord is surrounded with cartilaginous or bony vertebrae and the notochord is generally reduced; hence, hagfish are not regarded as vertebrates. The chordates and three sister phyla, the Hemichordata, the Echinodermata and the Xenoturbellida, make up the deuterostomes, one of the two superphyla that encompass all fairly complex animals. [more]

Kinorhyncha

Kinorhyncha (Gr. ?????, kineo 'move' + ??????, rhynchos 'snout') is a phylum 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 nematodes () or roundworms (phylum 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 28,000 have been described, of which over 16,000 are parasitic. The total number of nematode species has been estimated to be about 1,000,000. Unlike cnidarians or flatworms, roundworms have tubular digestive systems with openings at both ends. [more]

Nematomorpha

Nematomorpha (sometimes called Gordiacea, and commonly known as horsehair worms or Gordian worms) is a phylum of parasitic animals that are superficially morphologically similar to nematode worms, hence the name. They range in size in most species from 50 to 100 centimetres (20 to 39 in) long and can reach in extreme cases up to 2 metres, and 1 to 3 millimetres (0.039 to 0.12 in) 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, orthopterans, and crustaceans. About 351 species are known and a conservative estimate suggests that there may be about 2000 species worldwide. The name "Gordian" stems from the legendary Gordian knot. This relates to the fact that nematomorpha often tie themselves in knots. [more]

Priapulida

Priapulida (priapulid worms or penis worms, from Gr. p???p??, priapos 'Priapus' + Lat. -ul-, diminutive) is a phylum of marine worms. They are named for their extensible spiny proboscis, which, in some species, may have a shape like that of a human penis. They live in the mud, which they eat, in comparatively shallow waters up to 90 metres (300 ft). [more]

Radiozoa

Radiolarians (also radiolaria) are amoeboid protozoa (diameter 0.1-0.2 mm) that produce intricate mineral skeletons, typically with a central capsule dividing the cell into inner and outer portions, called endoplasm and ectoplasm. They are found as zooplankton throughout the ocean, and their skeletal remains cover large portions of the ocean bottom as radiolarian ooze. Due to their rapid turn-over of species, they represent an important diagnostic fossil found from the Cambrian onwards. Some common radiolarian fossils include , Heliosphaera and Hexadoridium. [more]

At least 709 species and subspecies belong to the Phylum Radiozoa.

More info about the Phylum Radiozoa may be found here.

Sources

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Last Revised: August 24, 2012
2012/08/24 19:59:09