Acoelomorpha
The Acoelomorpha are a group of animals with features that were once put in the phylum Platyhelminthes (flatworms).
| Acoelomorphs | |
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| Waminoa (orange-yellow) sp. on Plerogyra sp.. | |
| Scientific classification | |
| Kingdom: | |
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| Phylum: | |
| Subphylum: | Acoelomorpha
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In 2004 molecular studies showed this was wrong.[1][2]
Now it is clear that their closest relatives are the Xenoturbellida, and the two groups make up the proposed new phylum, the Xenacoelomorpha.[3]
Most researchers believe them to be basal among the bilateria, slightly more derived than the Cnidaria. Recent results suggest that they (along with Xenoturbella) may lie near the base of the deuterostomes.[3] An ongoing collaborative research project has "the researchers ... confident that they can reach an agreement about where acoels fit in evolutionary history".[4]
- "The results show that the two groups constitute a newly classified phylum... which the authors name the ’Xenacoelomorpha’. The xenacoelomorph phylum joins the three known phyla of deuterostomes: vertebrates (including humans), echinoderms (e.g., starfish), and hemichordates (acorn worms)".[5]
Acoels are almost entirely marine, living between grains of sediment, swimming as plankton, or crawling on algae. Acoels have a statocyst, which presumably helps them orient to gravity. Their soft bodies make them difficult to classify.[6]
Acoelomorpha Media
- Acoela from Indian Ocean.gif
Various members of the Acoela class.
- Xenoturbella japonica.jpg
Xenoturbella, the sister group to acoelomorphs
- Symsagittifera roscoffensis(Jersey).jpg
References
- ↑ Lua error in Module:Citation/CS1/Identifiers at line 630: attempt to index field 'known_free_doi_registrants_t' (a nil value).
- ↑ Lua error in Module:Citation/CS1/Identifiers at line 630: attempt to index field 'known_free_doi_registrants_t' (a nil value).
- ↑ 3.0 3.1 Lua error in Module:Citation/CS1/Identifiers at line 630: attempt to index field 'known_free_doi_registrants_t' (a nil value).
- ↑ Lua error in Module:Citation/CS1/Identifiers at line 630: attempt to index field 'known_free_doi_registrants_t' (a nil value).
- ↑ "GEE: Simple marine worms distantly related to humans". University College London. 10 February 2011. Archived from the original on 14 September 2015.
- ↑ Lua error in Module:Citation/CS1/Identifiers at line 630: attempt to index field 'known_free_doi_registrants_t' (a nil value).
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