Inoceramus

Inoceramus Temporal range: Early Jurassic-Maastrichtian ~189–66  Ma PreꞒ Ꞓ O S D C P T J K Pg N
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Mollusca
Class:	Bivalvia
Order:	Pteriida
Family:	† Inoceramidae
Genus:	† Inoceramus Sowerby, 1814
Species
See text

Inoceramus (Greek: translation "fibrous shell" for the fibrous structure of the mineral crystals in the shell) is an extinct genus of fossil marine pteriomorphian bivalves that superficially resembled the related winged pearly oysters of the extant genus Pteria . They lived from the Early Jurassic to latest Cretaceous. ^{[1] [2]}

The English naturalist James Sowerby proposed the name Inoceramus at a meeting of the Linnean Society in London in 1814 but a text version was not published until 1822. He gave the etymology from Greek with Latin translation as: ἴς fibra [fiber] et κέραμος testa [shell]. The fibrous-appearing mineral structure of the shell inspired the name choice: "[I]t consists entirely of a substance composed of parallel perpendicular fibres, and much more conspicuously so than Pinna or any other genus". ^{[3] [4]}

Taxonomy

The taxonomy of the inoceramids is disputed, with genera such as Platyceramus sometimes classified as subgenus within Inoceramus. Also the number of valid species in this genus is disputed.

Description

Halves of a gigantic specimen of I. steenstrupi 187 cm (74 in) across, found on the Nuussuaq Peninsula, Greenland

Weathered shell fragment of the closely related Cremnoceramus difformis, highlighting the orientation and texture of the calcite prisms of the Inoceramids.

Inoceramids had thick shells composed of "prisms" of calcite deposited perpendicular to the surface, and unweathered fossils commonly preserve the mother-of-pearl luster the shells had in life. ^[5] Most species have prominent growth lines which appear as raised semicircles concentric to the growing edge of the shell. ^[5]

In 1952, the huge specimen of Inoceramus steenstrupi 187 cm long, was found in Qilakitsoq, the Nuussuaq Peninsula, Greenland. This fossil is 83 Ma old, the Upper Santonian or Lower Campanian stage. ^[6] Paleontologists suggest that the giant size of some species was an adaptation for life in the murky bottom waters, with a correspondingly large gill area that would have allowed the animal to survive in oxygen-deficient waters. ^[5]

Selected species

• †I. aequicostatusVoronetz, 1937
• †I. albertensisMcLearn, 1926
• †I. altifluminisMcLearn, 1943
• †I. americanusWalaszczyk & Cobban, 2006
• †I. andinusWilckens, 1907
• †I. anglicusWoods, 1911
• †I. anilisPcelinceva, 1962
• †I. anomalusHeine, 1929
• †I. anomiaeformisFeruglio, 1936
• †I. apicalisWoods, 1912
• †I. arvanusStephenson, 1953
• †I. bellvuensis
• †I. biformisTuomey, 1854
• †I. browneiMarwick, 1953
• †I. carsoniMcCoy, 1865
• †I. comancheanus
• †I. confertim Roemer, 1849 ^[7]
• †I. constellatusWoods, 1904
• †I. corpulentusMcLearn, 1926
• †I. coulthardiMcLearn, 1926
• † I. cuvieri Sowerby, 1814
• †I. dakotensis
• †I. dominguesiMaury, 1930
• †I. dowlingiMcLearn, 1931
• †I. dunveganensisMcLearn, 1926
• †I. elburzensisFantini, 1966
• †I. everestiOppel, 1862
• †I. fibrosusMeek & Hayden, 1857
• †I. formosulusVoronetz, 1937
• †I. fragilisHaal & Meek, 1856
• †I. frechiFlegel, 1905
• †I. galoiBoehm, 1907
• †I. gibbosus
• †I. ginterensisPergament, 1966
• †I. glacierensisWalaszczyk & Cobban, 2006
• †I. haastHochstetter, 1863
• †I. howelliWhite, 1876
• †I. incelebratusPergament, 1966
• †I. inconditusMarwick, 1953
• †I. kystatymensisKoschelkina, 1960
• †I. lamarckiParkinson, 1819
• †I. laterisRossi de Gargia & Camacho, 1965
• †I. mesabiensisBergquist, 1944
• †I. moriiHayami, 1959
• †I. multiformisPergament, 1971
• †I. mytiliformisFantini, 1966
• †I. nipponicusNagao & Matsumoto, 1939
• †I. perplexus
• †I. pictus
• †I. pontoniMcLearn, 1926
• †I. porrectusVoronetz, 1937
• †I. prefragilisStephenson, 1952
• †I. proximus''Tuomey, 1854
• †I. pseudoluciferAfitsky, 1967
• †I. quenstedtiPcelinceva, 1933
• †I. robertsoniWalaszczyk & Cobban, 2006
• †I. saskatchewanensisWarren, 1934
• †I. selwyniMcLearn, 1926
• †I. sokoloviWalaszczyk & Cobban, 2006
• †I. steenstrupide Loriol, 1883
• †I. steinmanniWilckens, 1907
• †I. subdepressusMeek & Hayden, 1861
• †I. tenuirostratusMeek & Hayden, 1862
• †I. triangularis''Tuomey, 1854
• †I. undabundusMeek & Hayden, 1862
• †I. undulatoRoemer, 1849
• †I. ussuriensisVoronetz, 1937

Distribution

The Western Interior Seaway that covered North America during the Cretaceous

Species of Inoceramus had a worldwide distribution during the Cretaceous and Jurassic periods (from 189.6 to 66.043 Ma). ^[1] Many examples are found in the Pierre Shale of the Western Interior Seaway in North America. Inoceramus can also be found abundantly in the Cretaceous Gault Clay that underlies London. Other locations for this fossil include Vancouver Island, ^[5] British Columbia, Colombia (Hiló Formation, Tolima and La Frontera Formation, Boyacá, Cundinamarca and Huila), ^[8] Spain, France, Germany, Afghanistan, Albania, Algeria, Angola, Antarctica, Argentina, Australia, Austria, Brazil, Bulgaria, Canada (Alberta, Northwest Territories, Nunavut, Saskatchewan, Yukon), Chile, China, Cuba, the Czech Republic, Denmark, Ecuador, Egypt, Hungary, India, Indian Ocean, Iran, Italy, Jamaica, Japan, Jordan, Kenya, Libya, Madagascar, Mexico, Morocco, Mozambique, Nepal, New Caledonia, New Zealand, Nigeria, Papua New Guinea, Peru, Poland, the Russian Federation, Saudi Arabia, Serbia and Montenegro, South Africa, Sweden, Switzerland, Tunisia, Turkey, Turkmenistan, the United Kingdom, United States (Alabama, Alaska, Arizona, Arkansas, California, Colorado, Delaware, Idaho, Iowa, Kansas, Maryland, Minnesota, Mississippi, Montana, Nebraska, New Jersey, New Mexico, North Carolina, North Dakota, Oregon, South Carolina, South Dakota, Tennessee, Texas, Utah, Washington, Wyoming), and Venezuela. ^[1]

Gallery

• 
  Inoceramus from the Cretaceous of South Dakota
• 
  Inoceramus proximus
• 
  Inoceramus cuvieri
• 
  Inoceramus vancouverensis
• 
  Inoceramus hobetsensis

References

1. Inoceramus at Fossilworks.org
2. Ward et al., "Ammonite and inoceramid bivalve extinction patterns in Cretaceous/Tertiary boundary sections of the Biscay region (southwestern France, northern Spain)", Geology , 1991
3. Sowerby, J. (1822). "On a fossil shell of a fibrous structure, the fragments of which occur abundantly in the chalk strata and in the flints accompanying it". Transactions of the Linnean Society of London. 13: 453–458.
4. "Inoceramids" Oceans of Kansas website: http://oceansofkansas.com/Inoceramids.html
5. Ludvigsen & Beard, 1997, pp. 102–103
6. "Verdens største musling". 5 March 2020. Archived from the original on 18 August 2022.
7. Roemer, F. (1849). Texas : mit besonderer Rücksicht auf deutsche Auswanderung und die physischen Verhältnisse des Landes nach eigener Beobachtung. A. Marcus.
8. Acosta & Ulloa, 2001, p. 41

Bibliography

• Ludvigsen, Rolf; Beard, Graham (1997). West Coast Fossils: A Guide to the Ancient Life of Vancouver Island . Harbour Pub. pp.  102–103. ISBN   9781550171792.
• Acosta Garay, Jorge; Ulloa Melo, Carlos E (2001). Geología de la Plancha 208 Villeta - 1:100,000 (PDF). INGEOMINAS. pp. 1–84. Archived from the original (PDF) on 24 March 2017. Retrieved 4 April 2017.

Further reading

• Paleontology portal

• Kennedy, W.J.; Kauffman, E.G.; Klinger, H.C. (1973). "Upper Cretaceous Invertebrate Faunas from Durban, South Africa". Geological Society of South Africa Transactions. 76 (2): 95–111.
• Klinger, H.C.; Kennedy, W.J. (1980). "Upper Cretaceous ammonites and inoceramids from the off-shore Alphard Group of South Africa". South African Museum . 82 (7): 293–320.
• Gebhardt, H. (2001). "Inoceramids, Didymotis and ammonites from the Nkalagu Formation type locakity (late Turonian to Coniacian, southern Nigeria): biostratigraphy and palaeoecologic implications". Neues Jahrbuch für Geologie und Paläontologie, Monatshefte. 2001 (4): 193–212. doi:10.1127/njgpm/2001/2001/193.
• El Qot, G.M. (2006). "Late Cretaceous macrofossils from Sinai, Egypt". Beringeria. 36: 3–163.
• Wild, T. J.; Stilwell, J. D. (2016). "First Cretaceous (Albian) invertebrate fossil assemblage from Batavia Knoll, Perth Abyssal Plain, eastern Indian Ocean: taxonomy and paleoecological significance". Journal of Paleontology. 90 (5): 959–980. Bibcode:2016JPal...90..959W. doi:10.1017/jpa.2016.76.

External links

• "Upper Cretaceous Bivalvia of Alabama". Geological Survey of Alabama. Archived from the original on 16 September 2019.