Ogallala opaline sandstone with Cremnoceramus deformis fragments 20201115 143032

''Cremnoceramus'' ("cremno-" = ''kremnos''

reek Reek may refer to: Places * Reek, Netherlands, a village in the Dutch province of North Brabant * Croagh Patrick, a mountain in the west of Ireland nicknamed "The Reek" People * Nikolai Reek (1890-1942), Estonian military commander * Salme Reek ...

precipice or over hanging wall or bank; "ceramus" = ''keramos''

clay pot) is an extinct

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nom ...

of fossil marine

pteriomorphia The Pteriomorphia comprise a subclass of saltwater clams, marine bivalve molluscs. It contains several major orders, including the Arcida, Ostreida, Pectinida, Limida, Mytilida, and Pteriida. It also contains some extinct and probably basa ...

n bivalves that superficially resembled the related winged pearly oysters of the extant genus '' Pteria''. They lived from the

Turonian The Turonian is, in the ICS' geologic timescale, the second age in the Late Cretaceous Epoch, or a stage in the Upper Cretaceous Series. It spans the time between 93.9 ± 0.8 Ma and 89.8 ± 1 Ma (million years ago). The Turonian is preceded b ...

to the

Maastrichtian The Maastrichtian () is, in the ICS geologic timescale, the latest age (uppermost stage) of the Late Cretaceous Epoch or Upper Cretaceous Series, the Cretaceous Period or System, and of the Mesozoic Era or Erathem. It spanned the interval ...

of the

Late Cretaceous The Late Cretaceous (100.5–66 Ma) is the younger of two epochs into which the Cretaceous Period is divided in the geologic time scale. Rock strata from this epoch form the Upper Cretaceous Series. The Cretaceous is named after ''creta'', ...

Description

''Cremnoceramus'' were facultatively mobile, blind,

suspension feeding Filter feeders are a sub-group of suspension feeding animals that feed by straining suspended matter and food particles from water, typically by passing the water over a specialized filtering structure. Some animals that use this method of feedin ...

bivalves with low-magnesium calcite shells. ''Inoceramids'', like the ''Cremnoceramus'' in particular, had thick shells composed of particular "prisms" of calcite deposited perpendicular to the surface, and unweathered fossils commonly preserve the mother-of-pearl luster the shells had in life. Compared to the many examples of broad and flattened ''Inoceramidae'', ''Cremnoceramus'' shells are rather "high-walled", deep bowl-shaped. The top shell is commonly encrusted with oysters.

Species

The following species are recognized: * ''C. crassus'' * ''C. deformis'' * ''C. inconstans'' * ''C. rotundatus'' * ''C. waltersdorfensis''

Biostratigraphic significance

The first appearance of the species '' Cremnoceramus rotundatus'' marks the beginning of the Coniacian stage.

Distribution

Fossils of the genus have been found in:''Cremnoceramus''
at Fossilworks.org *

Gosau Formation The Gosau Group (German: ''Gosau-Gruppe'') is a geological stratigraphic group in Austria, Germany and western Slovakia whose strata date back to the Late Cretaceous to Eocene.Höfling, 1985McCann, 2008 It is exposed in numerous sporadic isolated ...

, Austria * Cotinguiba Formation, Brazil * Pointe-Noire, Congo-Brazzaville * Jicin, the Czech Republic * Arnager Limestone Formation, Denmark * Craie de Villedieu Formation, France * Germany * Anaipadi Formation, India * Tongobury, Madagascar *

Austin Group The Austin Group or the Austin Common Standards Revision Group is a joint technical working group formed to develop and maintain a common revision of POSIX.1 and parts of the Single UNIX Specification. It is named after the location of the first ...

, Mexico * Sant Corneli and El Zadorra Formation, Spain * Lewes Nodular Chalk Formation, the United Kingdom *

Niobrara Formation The Niobrara Formation , also called the Niobrara Chalk, is a geologic formation in North America that was deposited between 87 and 82 million years ago during the Coniacian, Santonian, and Campanian stages of the Late Cretaceous. It is com ...

, New Mexico, United States

Gallery

Note the oyster encrustation of the top shells: File:Fort Hays Limestone, Cremnoceramus deformis 20181124 153914.jpg, Anterior section of articulated ''C. deformis'' (Fort Hays ls.) File:Fort Hays Limestone, Cremnoceramus deformis (Ft. Hays Blockhouse) 20160619 081653.jpg, Anterior section of articulated ''C. deformis'' (Fort Hays ls.) File:Fort Hays Limestone, Cremnoceramus deformis (FUMC) 20160619 071549.jpg, Vental section of articulated ''C. deformis'' (Fort Hays ls.) File:Fort Hays Limestone, Cremnoceramus deformis (FUMC) 20160619 071713.jpg, Vental section of articulated ''C. deformis'' (Fort Hays ls.)

References

{{Reflist, 3 {{Taxonbar, from=Q104822798 Inoceramidae Prehistoric bivalve genera Index fossils Cretaceous Austria Fossils of Austria Cretaceous Brazil Fossils of Brazil Fossils of the Czech Republic Cretaceous Denmark Fossils of Denmark Cretaceous France Fossils of France Cretaceous Germany Fossils of Germany Cretaceous India Fossils of India Cretaceous Madagascar Fossils of Madagascar Cretaceous Mexico Fossils of Mexico Cretaceous Spain Fossils of Spain Cretaceous England Fossils of England Cretaceous geology of New Mexico Fossils of the United States Fossil taxa described in 1969 {{Cretaceous-animal-stub, Add information on diagnostic features, indexing use, citations, and global distribution. {{paleo-bivalve-stub