Overview
The lophophore () is a characteristic feeding organ possessed by four major groups of animals: the Brachiopoda, Bryozoa, Entoprocta, and Phoronida.[1] All lophophores are found in aquatic organisms.
Characteristics
It can most easily be described as a ring of ciliated tentacles surrounding the mouth, but it is often horseshoe-shaped or coiled. Phoronids have their lophophores in plain view, but the valves of brachiopods must be opened wide to get a good view of their lophophore.
The lophophore surrounds the mouth and is an upstream collecting system for suspension feeding. Its tentacles are hollow with extensions of a coelomic space thought to be a mesocoel. The gut is U-shaped with the anterior mouth at the center of the lophophore. The anus, where present, is also anterior, but is dorsal to the mouth. In the Bryozoa it is outside the ring of the lophophore; in the Entoprocta the anus is within the ring of the lophophore. Some brachiopods do not have an anus.
Classification of lophophorates
Groups with lophophores are called lophophorates. In the old view of metazoan phylogeny, the lophophorates were placed within the Deuterostomia. Now they have been reassessed and placed within a new Superphylum known as the Lophotrochozoa[2] (located within the Protostomia) which includes the Mollusca and Annelida.
The extinct hederelloids, microconchids, cornulitids and tentaculitids were likely lophophorates based on their biomineralization.[3]
Etymology
Lophophore is derived from the Greek lophos (crest, tuft) and -phore, -phoros (f????) (bearing), a derivative of ph?rein (f??e??) (to bear); thus crest-bearing.
oids, microconchids, cornulitids and tentaculitids were likely lophophorates based on their biomineralization.[3]Etymology
Lophophore is derived from the Greek lophos (crest, tuft) and -phore, -phoros (f????) (bearing), a derivative of ph?rein (f??e??) (to bear); thus crest-bearing.
References
- ^ Introduction to the Lophotrochozoa - accessed 03 May 2010
- ^ Giribet, G. (2008). "Assembling the lophotrochozoan (=spiralian) tree of life". Philosophical transactions of the Royal Society of London. Series B, Biological sciences 363 (1496): 1513?1522. doi:10.1098/rstb.2007.2241. PMC 2614230. PMID 18192183. http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2614230. edit
- ^ Taylor, P.D.; Vinn, O., Wilson, M. (2010). "Evolution of biomineralization in 'lophophorates'". Special Papers in Palaeontology 84: 317?333.
Taxonomy
The Superphylum Lophophorata is a member of the Infrakingdom Lophotrochozoa. Here is the complete "parentage" of Lophophorata:
- Domain: Eukaryota
Whittaker & Margulis,1978 - eukaryotes
- Kingdom: Animalia
C. Linnaeus, 1758 - animals
- Subkingdom: Bilateria
(Hatschek, 1888) Cavalier-Smith, 1983 - bilaterians
- Branch: Protostomia
Grobben, 1908 - protostomes
- Infrakingdom: Lophotrochozoa
- Lophotrochozoans
- Superphylum: Lophophorata
- Infrakingdom: Lophotrochozoa
- Lophotrochozoans
- Branch: Protostomia
Grobben, 1908 - protostomes
- Subkingdom: Bilateria
(Hatschek, 1888) Cavalier-Smith, 1983 - bilaterians
- Kingdom: Animalia
C. Linnaeus, 1758 - animals
The Superphylum Lophophorata is further organized into finer groupings including:
- Phylum (1): Brachiopoda
Phyla
Brachiopoda
Brachiopods, phylum Brachiopoda, are marine animals that have hard "valves" (shells) on the upper and lower surfaces, unlike the left and right arrangement in bivalve molluscs. Brachiopod valves are hinged at the rear end, while the front can be opened for feeding or closed for protection. Two major groups are recognized, articulate and inarticulate. Articulate brachiopods have toothed hinges and simple opening and closing muscles, while inarticulate brachiopods have untoothed hinges and a more complex system of muscles used to keep the two halves aligned. In a typical brachiopod a stalk-like pedicle projects from an opening in one of the valves, known as the pedicle valve, attaching the animal to the seabed but clear of silt that would obstruct the opening. [more]
At least 6,533 species and subspecies belong to the Phylum Brachiopoda.
More info about the Phylum Brachiopoda may be found here.
References
- ^ Introduction to the Lophotrochozoa - accessed 03 May 2010
- ^ Giribet, G. (2008). "Assembling the lophotrochozoan (=spiralian) tree of life". Philosophical transactions of the Royal Society of London. Series B, Biological sciences 363 (1496): 1513?1522. doi:10.1098/rstb.2007.2241. PMC 2614230. PMID 18192183. http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2614230. edit
- ^ Taylor, P.D.; Vinn, O., Wilson, M. (2010). "Evolution of biomineralization in 'lophophorates'". Special Papers in Palaeontology 84: 317?333.
Sources
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