Scenella is an extinctgenus of fossil invertebrate animal which is generally considered to be a mollusc; at various times it has been suggested that this genus belongs with the gastropods, the monoplacophorans, or the helcionellids, although no firm association with any of these classes has been established.[4] An affinity with the hydrozoa (as a flotation device) has been considered,[1] although some authors oppose this hypothesis.[5] A gastropod affinity is defended on the basis of six pairs of internal muscle scars,[6] whilst the serially-repeated nature of these scars suggests to other authors a monoplacophoran affinity.[1] However the specimens showing this scarring have not been convincingly shown to belong to the genus Scenella.[1] A similarity to the Ediacaran Ovatoscutum has also been drawn.[7]
The shell of Scenella is elongated along its anterior-posterior axis, and comprises concentric rings around a conical central peak. Radial and concentric corrugations exist in some species.[7] Some specimens are preserved as organic films, others appear to have been infilled with calcite.[1] They are usually preserved point-upwards, with their long axes consistently oriented; this probably represents their most stable position under their depositional current.[1] Soft parts have never been reported in association with Scenella, suggesting that the preserved fragments separated quickly from the associated tissue prior to burial.[1]
Fossil occurrenceedit
Scenella lived from the Cambrian to the Ordovician. Its remains have been found in Antarctica, Asia, Europe, and North America. Individual fossils are common throughout the Burgess shale, where they often occur in dense aggregations.[1] Where they overlap, specimens deform as by draping.[1] Specimens are sometimes cracked or torn, with margins often damaged by folding or "tattering".[1] 1206 specimens of Scenella are known from the Greater Phyllopod bed, where they comprise 2.29% of the community.[8]
Taxonomyedit
Scenella from the Burgess Shale, Middle Cambrian, Walcott Quarry, near Field, British Columbia
Scenella is the only genus in the family Scenellidae. This family has no subfamilies and Scenella is the type genus of the family Scenellidae.
^ abcdefghijBabcock, L. E.; Robison, R. A. (1988). "Taxonomy and paleobiology of some Middle Cambrian Scenella (Cnidaria) and Hyolithids (Mollusca) from western North America" (PDF). University of Kansas Paleontological Contributions. 121: 1–22. hdl:1808/3638.
^Miller S. A. (after October 1889). North American geology and palaeontology: 389.
^ abBouchet P. & Rocroi J.-P. (Ed.); Frýda J., Hausdorf B., Ponder W., Valdés Á. & Warén A. 2005. Classification and nomenclator of gastropod families. Malacologia: International Journal of Malacology, 47(1-2). ConchBooks: Hackenheim, Germany. ISBN3-925919-72-4. ISSN 0076-2997. 397 pp.
^Yochelson, E. L.; Cid, D. G. L. (1984). "Reevaluation of the systematic position of Scenella". Lethaia. 17 (4): 331–340. doi:10.1111/j.1502-3931.1984.tb00679.x.[dead link]
^Landing; Narbonne (1992). "Scenella and "A Chondrophorine (Medusoid Hydrozoan) from the Basal Cambrian (Placentian) of Newfoundland"". Journal of Paleontology. 66 (2): 338. Bibcode:1992JPal...66..338L. doi:10.1017/s0022336000033837. JSTOR 1305918. S2CID 132296800.
^Rasetti (1954). "Internal Shell Structures in the Middle Cambrian Gastropod Scenella and the Problematic Genus Stenothecoides". Journal of Paleontology. 28 (1): 59–66. JSTOR 1300208.
^ abBenjamin M. Waggoner; Allen G. Collins (March 1995). "A new chondrophorine (Cnidaria, Hydrozoa) from the Cadiz Formation (Middle Cambrian) of California". Paläontologische Zeitschrift. 69 (1–2): 7–17. doi:10.1007/BF02985970. ISSN 0031-0220. S2CID 128662109.
^ abCaron, Jean-Bernard; Jackson, Donald A. (October 2006). "Taphonomy of the Greater Phyllopod Bed community, Burgess Shale". PALAIOS. 21 (5): 451–65. Bibcode:2006Palai..21..451C. doi:10.2110/palo.2003.P05-070R. JSTOR 20173022. S2CID 53646959.
^BERGERG-MADSEN V, PEEL JS (1986). "Scenella barrandei (Mollusca) from the Middle Cambrian of Baltoscandia". Norsk Geologisk Tidsskrift. 66 (1): 81–86.
^Billings (1872). "On some fossils from the primordial rocks of Newfoundland". Nat. Can. 2nd series. vi: 465–479.
^Ford (1873). "On some new species of fossils from the Primordial or Potsdam group of Rensselaer County, New York (lower Potsdam)". American Journal of Science. 3. 5 (27): 211–215. Bibcode:1873AmJS....5..211F. doi:10.2475/ajs.s3-5.27.211. S2CID 130771815.
^Chapman F. (1911). "New or Little Known Victorian Fossils in the National Museum". Proceedings of the Royal Society of Victoria, Melbourne 23: 305-324. plate 58-61.; Scenella tenuistriata at 313-314, plate LIX. figure 18 a,b.
External linksedit
Wikimedia Commons has media related to Scenella.
"Scenella amii". Burgess Shale Fossil Gallery. Virtual Museum of Canada. 2011. Archived from the original on 2020-11-12.
scenella, extinct, genus, fossil, invertebrate, animal, which, generally, considered, mollusc, various, times, been, suggested, that, this, genus, belongs, with, gastropods, monoplacophorans, helcionellids, although, firm, association, with, these, classes, be. Scenella is an extinct genus of fossil invertebrate animal which is generally considered to be a mollusc at various times it has been suggested that this genus belongs with the gastropods the monoplacophorans or the helcionellids although no firm association with any of these classes has been established 4 An affinity with the hydrozoa as a flotation device has been considered 1 although some authors oppose this hypothesis 5 A gastropod affinity is defended on the basis of six pairs of internal muscle scars 6 whilst the serially repeated nature of these scars suggests to other authors a monoplacophoran affinity 1 However the specimens showing this scarring have not been convincingly shown to belong to the genus Scenella 1 A similarity to the Ediacaran Ovatoscutum has also been drawn 7 ScenellaTemporal range Cambrian Stage 3 Late Ordovician 1 PreꞒ Ꞓ O S D C P T J K Pg N Dorsal view of the shell of Scenella tenuistriata lateral view of the shell of Scenella tenuistriata Scientific classification Kingdom Animalia Phylum Mollusca Superfamily Scenelloidea Family ScenellidaeS A Miller 1889 2 Genus ScenellaBillings 1872 Synonyms 3 Helcionellinae Wenz 1938 Hampilinae Kobayashi 1958 Securiconidae Missarzhevsky 1989 Contents 1 Description 2 Fossil occurrence 3 Taxonomy 4 Species 5 References 6 External linksDescription editThe shell of Scenella is elongated along its anterior posterior axis and comprises concentric rings around a conical central peak Radial and concentric corrugations exist in some species 7 Some specimens are preserved as organic films others appear to have been infilled with calcite 1 They are usually preserved point upwards with their long axes consistently oriented this probably represents their most stable position under their depositional current 1 Soft parts have never been reported in association with Scenella suggesting that the preserved fragments separated quickly from the associated tissue prior to burial 1 Fossil occurrence editScenella lived from the Cambrian to the Ordovician Its remains have been found in Antarctica Asia Europe and North America Individual fossils are common throughout the Burgess shale where they often occur in dense aggregations 1 Where they overlap specimens deform as by draping 1 Specimens are sometimes cracked or torn with margins often damaged by folding or tattering 1 1206 specimens of Scenella are known from the Greater Phyllopod bed where they comprise 2 29 of the community 8 Taxonomy edit nbsp Scenella from the Burgess Shale Middle Cambrian Walcott Quarry near Field British Columbia Scenella is the only genus in the family Scenellidae This family has no subfamilies and Scenella is the type genus of the family Scenellidae The taxonomy of the Gastropoda by Bouchet amp Rocroi 2005 3 categorizes Scenellidae in the superfamilia Scenelloidea within the Paleozoic molluscs of uncertain systematic position Species editSpecies in the genus Scenella include 9 Species Authority Range Scenella affinis Ulrich and Schfield 1897 Scenella amii Matthew 1902 Babcock and Robinson 1988 Burgess Shale Mid Cambrian 508 million years ago 8 Scenella anomala Billings 1865 Wagner 2008 Scenella augusta Billings 1865 Wagner 2008 Scenella barrandei Linnarsson 1879 Bergerg Madsen and Peel 1986 10 Scenella beloitensis Ulrich and Scofield 1897 Scenella clotho Walcott 1936 Scenella compressa Ulrich and Scofield 1897 Scenella conica Whiteaves 1884 Scenella conula Walcott 1884 Scenella conicum Whitfield 1886 Ulrich and Scofield 1897 Scenella hujingtanensis Yu 1979 Scenella magnifica Ulrich and Scofield 1897 S mira Vasil yeva 1994 Scenella montrealensis Billings 1865 Scenella obtusa Sardeson 1892 Ulrich and Scofield 1897 Scenella orithyia Billings 1865 Ulrich and Scofield 1897 Scenella pretensa Raymond 1905 Scenella radialis Ulrich and Scofield 1897 Scenella radians Babcock amp Robinson Scenella radiata Yu 1979 Scenella reticulata Billings 1872 type 11 Scenella retusa Ford 1873 12 Scenella unicarinata Kobayashi 1934 Wagner 2008 Scenella varians Walcott 1908 Scenella venillia Billings 1865 Wagner 2008 Scenella tenuistriata Chapman 1911 Mid Cambrian 13 References edit a b c d e f g h i j Babcock L E Robison R A 1988 Taxonomy and paleobiology of some Middle CambrianScenella Cnidaria and Hyolithids Mollusca from western North America PDF University of Kansas Paleontological Contributions 121 1 22 hdl 1808 3638 Miller S A after October 1889 North American geology and palaeontology 389 a b Bouchet P amp Rocroi J P Ed Fryda J Hausdorf B Ponder W Valdes A amp Waren A 2005 Classification and nomenclator of gastropod families Malacologia International Journal of Malacology 47 1 2 ConchBooks Hackenheim Germany ISBN 3 925919 72 4 ISSN 0076 2997 397 pp Yochelson E L Cid D G L 1984 Reevaluation of the systematic position of Scenella Lethaia 17 4 331 340 doi 10 1111 j 1502 3931 1984 tb00679 x dead link Landing Narbonne 1992 Scenella and A Chondrophorine Medusoid Hydrozoan from the Basal Cambrian Placentian of Newfoundland Journal of Paleontology 66 2 338 Bibcode 1992JPal 66 338L doi 10 1017 s0022336000033837 JSTOR 1305918 S2CID 132296800 Rasetti 1954 Internal Shell Structures in the Middle Cambrian Gastropod Scenella and the Problematic Genus Stenothecoides Journal of Paleontology 28 1 59 66 JSTOR 1300208 a b Benjamin M Waggoner Allen G Collins March 1995 A new chondrophorine Cnidaria Hydrozoa from the Cadiz Formation Middle Cambrian of California Palaontologische Zeitschrift 69 1 2 7 17 doi 10 1007 BF02985970 ISSN 0031 0220 S2CID 128662109 a b Caron Jean Bernard Jackson Donald A October 2006 Taphonomy of the Greater Phyllopod Bed community Burgess Shale PALAIOS 21 5 451 65 Bibcode 2006Palai 21 451C doi 10 2110 palo 2003 P05 070R JSTOR 20173022 S2CID 53646959 Scenella Paleobiology Database accessed 16 August 2009 BERGERG MADSEN V PEEL JS 1986 Scenella barrandei Mollusca from the Middle Cambrian of Baltoscandia Norsk Geologisk Tidsskrift 66 1 81 86 Billings 1872 On some fossils from the primordial rocks of Newfoundland Nat Can 2nd series vi 465 479 Ford 1873 On some new species of fossils from the Primordial or Potsdam group of Rensselaer County New York lower Potsdam American Journal of Science 3 5 27 211 215 Bibcode 1873AmJS 5 211F doi 10 2475 ajs s3 5 27 211 S2CID 130771815 Chapman F 1911 New or Little Known Victorian Fossils in the National Museum Proceedings of the Royal Society of Victoria Melbourne 23 305 324 plate 58 61 Scenella tenuistriata at 313 314 plate LIX figure 18 a b External links edit nbsp Wikimedia Commons has media related to Scenella Scenella amii Burgess Shale Fossil Gallery Virtual Museum of Canada 2011 Archived from the original on 2020 11 12 Scenella at the Field Museum s Evolving Planet Retrieved from https en wikipedia org w index php title Scenella amp oldid 1192905625, wikipedia, wiki, book, books, library,
