| 词条 | Stenothecoida |
| 释义 |
| fossil_range = Early–mid-Cambrian, {{Fossil range | 525|500|refs=[1][2] }} | taxon = Stenothecoida | authority = Yochelson, 1968[3] | subdivision_ranks = Genera | subdivision = {{Genus list | Stenothecoides |Resser | Bagenovia |Radugin |Cambridium| Horny | Bagenoviella |Aksarina | Sulcocarina |Aksarina |Kaschkadakia |Aksarina |Makarakia |Aksarin }} (given in {{jstor|1739764}}) }} Stenothecoida is a taxon of bivalved fossils from the Early to middle Cambrian period. They look a bit like brachiopods or bivalve molluscs. AffinityTheir affinity is uncertain. They were considered by E. L. Yochelson 1968{{citation needed|date=November 2016}} to belong to Mollusca, whereas Runnegar and Pojeta (1974) suggested that they might be 'bivalved monoplacophorans'. This said, the morphology of the shell does not resemble the shell of any other class of molluscs; they also look a little like brachiopods[1] It's not clear whether their two valves are each other's mirror images, as in bivalve molluscs, though they aren't identical to one another [?].[1] It's more likely that the valves each have a single plane of symmetry (as in brachiopods), suggesting a brachiopod affiliation.[1] As with many other Cambrian taxa,[4][5] it has been suggested that they arise through reduction of a Halkieria-like ancestor.[1] MineralogyThought to be low-Mg calcite.[6] OccurrenceThe earliest occurrence dates to 525 Ma.[2] These fossil shells have been found in Canada, China, Greenland, Kazakhstan, Kyrgyzstan, and the USA. References1. ^1 2 3 4 {{cite book|title=Molluscs, hyoliths, stenothecoids, and coeloscleritiphorans|chapter-url=https://www.researchgate.net/publication/264808572|doi=10.7312/zhur10612-015|chapter=15. Mollusks, Hyoliths, Stenothecoids, and Coeloscleritophorans|year=2000|last1=Kouchinsky|first1=Artem V.|isbn=9780231505161}} 2. ^1 Kouchinsky, A. V., Bengtson, S., Runnegar, B.N., Skovsted, C.B., Steiner, M., and Vendrasco, M.J. (2012). Chronology of early Cambrian biomineralization. Geol. Mag. 149, 221–251. 3. ^{{Cite journal | doi = 10.1111/j.1502-3931.1969.tb01250.x| title = Stenothecoida, A Proposed New Class of Cambrian Mollusca| journal = Lethaia| volume = 2| pages = 49–62| year = 1969| last1 = Yochelson| first1 = Ellis L.}} 4. ^1. Cohen, B.L., Holmer, L.E., and Lüter, C. (2003). The brachiopod fold: a neglected body plan hypothesis. Palaeontology 46, 59–65. 5. ^Skovsted, C.B., Betts, M.J., Topper, T.P., and Brock, G.A. (2015). The early Cambrian tommotiid genus Dailyatia from South Australia. Mem. Assoc. Australas. Palaeontol. 48, 1–117. 6. ^Kouchinsky, A. V. et al. Chronology of early Cambrian biomineralization. Geol. Mag. 149, 221–251 (2012).
3 : Prehistoric mollusc taxonomy|Mollusc classes|Prehistoric protostome classes |
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