| 词条 | Phthipodochiton |
| 释义 |
|genus=Phthipodochiton |species = thraivensis |fossil_range = {{Fossil range|Upper Ordovician}} |authority = Sutton and Sigwart, 2012 |parent_authority = Sutton and Sigwart, 2012[1] }}Phthipodochiton is an extinct genus of molluscs, known from several fossils from the upper Ordovician fauna of the Lady Burn Starfish beds of Girvan, Scotland.[1] It shows a mixture of aplacophoran body plan and polyplacophoran-like valves, and it is an informative fossil in the evolution of aculiferan mollusks.[1] It was previously classified under the genus Helminthochiton,[2] but it has been reassigned to its own genus in 2012.[1] MorphologyPhthipodochiton body is worm-like, with eight polyplacophoran-like valves but no true foot.[3] Head and tail valves are slightly smaller than the intermediate ones.[1] The only ornaments on the valves appear to be growth lines.[1] The body is also covered by a sheet of spicules ; no radula has been preserved.[1]Life habitsPhthipodochiton was carnivorous, feeding on crinoids,[3] as shown by a fossil preserved with gut contents.[4] In contrast with modern chitons, Phthipodochiton probably did not creep on its foot but had a locomotion style similar to that of solenogastres.[1]TaxonomyPhthipodochiton shares similarities with genera as Alastega, Robustum and Septemchiton.[1] but it is sufficiently distinct from all of them to be considered a separate species. It is considered to belong to the aplacophoran stem lineage, along with Acaenoplax,[5] and it has also been placed close to Matthevia and the shelled aplacophoran Kulindroplax in phylogenetic analyses.[6]References1. ^1 2 3 4 5 6 7 8 {{Cite journal | last1 = Sutton | first1 = M. D. | last2 = Sigwart | first2 = J. D. | doi = 10.1111/j.1475-4983.2011.01126.x | title = A chiton without a foot | journal = Palaeontology | volume = 55 | issue = 2 | pages = 401 | year = 2012 | pmid = | pmc = }} 2. ^{{Fossil chiton catalogue}} 3. ^1 {{cite web|title=Aculifera|url=http://palaeos.com/metazoa/mollusca/aculifera/aculifera.html|work=Palaeos|publisher=Palaeos|accessdate=21 November 2012}} 4. ^{{Cite journal | last1 = Donovan | first1 = S. K. | last2 = Sutton | first2 = M. D. | last3 = Sigwart | first3 = J. D. | title = The last meal of the Late Ordovician mollusc 'Helminthochiton' thraivensis Reed, 1911, from the Lady Burn Starfish Beds, southwest Scotland | doi = 10.1002/gj.1286 | journal = Geological Journal | pages = n/a | year = 2010 | pmid = | pmc = }} 5. ^{{Cite journal| last1 = Sigwart | first1 = J. D.| last2 = Sutton | first2= M. D.| title = Deep molluscan phylogeny: synthesis of palaeontological and neontological data| journal = Proceedings of the Royal Society B: Biological Sciences| issue = 1624| volume = 274| pages = 2413–2419| date =Oct 2007| month = | pmid = 17652065| pmc = 2274978| doi = 10.1098/rspb.2007.0701}} For a summary, see {{cite web| title=The Mollusca | publisher=University of California Museum of Paleontology| url=http://www.ucmp.berkeley.edu/taxa/inverts/mollusca/mollusca.php| accessdate=2 October 2008}} 6. ^{{Cite journal | last1 = Sutton | first1 = M. D. | last2 = Briggs | first2 = D. E. G. | last3 = Siveter | first3 = D. J. | last4 = Siveter | first4 = D. J. | last5 = Sigwart | first5 = J. D. | title = A Silurian armoured aplacophoran and implications for molluscan phylogeny | doi = 10.1038/nature11328 | journal = Nature | volume = 490 | issue = 7418 | pages = 94–97 | year = 2012 | pmid = 23038472| pmc = }} 4 : Prehistoric chiton genera|Ordovician molluscs|Transitional fossils|Fossils of the United Kingdom |
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