Entoprocta

Entoprocts
Barentsia discreta
Scientific classification
Kingdom: Animalia Superphylum: Lophotrochozoa Phylum: Entoprocta Class: Entoprocta
Orders
Barentsiidae (Urnatellidae) Loxokalypodidae Loxosomatidae Pedicellinidae

Entoprocta (Gr. εντος, entos inside + προκτος, proktos anus) is a phylum of small aquatic animals, ranging in size from 0.5 mm to 5.0 mm. They have a lophophore, and as their name suggests, are distinguished from other lophophorates by the position of the anus inside the ring of cilia rather than outside. Other names include goblet worm and kamptozoan.

Entoprocts are filter feeders, their tentacles secreting a mucus that catches food particles, which is then moved towards the mouth by cilia on the tentacles. Nearly all species are sedentary, attached to the substrate by a stalk, with the body being cup-shaped. Some species are colonial, with multiple animals on branching systems of stalks.

Entoprocts can reproduce either by budding, or sexually. They are unusual in being sequential hermaphrodites.

The phylum includes about 150 species in several families. While most species are marine, the freshwater species Urnatella gracilis is widespread.

Notes

Bryozoa, also known as Ectoprocta, is a major invertebrate phyla, whose members, the bryozoans, are tiny, aquatic, and mostly sessile and colonial animals. Also known as moss animals or sea mats, bryozoans generally build stony skeletons of calcium carbonate, superficially similar to coral.

Bryozoa and Ectoprocta are generally considered synonymous, but historically Ectoprocta was considered one of two subgroups within Bryozoa, the other being Entoprocta, which most systematics now separate into its own phyla. However, some biologists still consider Ectoprocta and Entoprocta as subgroups within the larger grouping Bryozoa, whether or not they are accorded status as a sub-phyla or a phyla. The members are still known as bryozoans regardless if the phyla is known as Ectoprocta.

Bryozoans have a distinctive feeding organ called a lophophore found only in two other animal phyla, Phoronida (phoronid worms) and Brachiopoda (lamp shells). The lophophore is essentially a ciliated ribbon or string (Luria et al. 1981), which is either a horseshoe-shaped or circular extension that surrounds the mouth (Smithsonian 2007).

The Bryozoans were formerly considered to contain two subgroups: the Ectoprocta and the Entoprocta, based on the similar bodyplans and mode of life of these two groups. (Some researchers also included the Cycliophora, which are thought to be closely related to the Entoprocta.) However, the Ectoprocta are coelomate (possessing a body cavity) and their embryos undergo radial cleavage, while the Entoprocta are acoelemate and undergo spiral cleavage. Molecular studies are ambiguous about the exact position of the Entoprocta, but do not support a close relationship with the Ectoprocta. For these reasons, the Entoprocta are now considered a phylum of their own (Valentine 2004). The removal of the 150 species of Entoprocta leaves Bryozoa synonymous with Ectoprocta; some authors have adopted the latter name for the group, but the majority continue to use the former.

• Luria, S. E., S. J. Gould, and S. Singer. 1981. A View of Life. Menlo Park, CA: Benjamin/Cummings Publishing Company. ISBN 0805366482
• Ramel, G. 2005. The Phylum Ectoprocta (Bryozoa). Earth Life Web. Retrieved December 17, 2007.
• What is a bryozoan. Smithsonian Marine Station at Fort Pierce, 2007. Retrieved February 13, 2007.

• Waggoner, B., and A. G. Collins. 1999. Bryozoa: Life history and ecology. University of California Museum of Paleontology. Retrieved February 13, 2007.

Family Barentsiidae

• Genus Barentsia
• Genus Pedicellinopsis
• Genus Pseudopedicellina
• Genus Coriella
• Genus Urnatella

Family Loxokalypodidae

• Genus Loxokalypus

Family Loxosomatidae

• Genus Loxosoma
• Genus Loxosomella
• Genus Loxomitra
• Genus Loxosomespilon
• Genus Loxocore

Family Pedicellinidae

• Genus Pedicellina
• Genus Myosoma
• Genus Chitaspis
• Genus Loxosomatoides

External links

Wikimedia Commons has media related to:

Entoprocta

• Information on Entoprocta from earthlife.net

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