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 Extinction is the termination of a kind of organism or of a group of kinds (taxon), usually a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and ...

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

of fossil

marine Marine is an adjective meaning of or pertaining to the sea or ocean. Marine or marines may refer to: Ocean * Maritime (disambiguation) * Marine art * Marine biology * Marine debris * Marine habitats * Marine life * Marine pollution Military * ...

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 basal ...

bivalve Bivalvia (), in previous centuries referred to as the Lamellibranchiata and Pelecypoda, is a class of marine and freshwater molluscs that have laterally compressed bodies enclosed by a shell consisting of two hinged parts. As a group, bival ...

s that superficially resembled the related winged pearly oysters of the

extant Extant is the opposite of the word extinct. It may refer to: * Extant hereditary titles * Extant literature, surviving literature, such as ''Beowulf'', the oldest extant manuscript written in English * Extant taxon, a taxon which is not extinct, ...

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 by t ...

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 from ...

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'', the ...

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 Calcite is a Carbonate minerals, carbonate mineral and the most stable Polymorphism (materials science), polymorph of calcium carbonate (CaCO3). It is a very common mineral, particularly as a component of limestone. Calcite defines hardness 3 on ...

shells. ''Inoceramids'', like the ''Cremnoceramus'' in particular, had thick shells composed of particular "prisms" of

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 The Coniacian is an age or stage in the geologic timescale. It is a subdivision of the Late Cretaceous Epoch or Upper Cretaceous Series and spans the time between 89.8 ± 1 Ma and 86.3 ± 0.7 Ma (million years ago). The Coniacian is preceded by t ...

stage.

Distribution

Fossils of the genus have been found in:''Cremnoceramus''
at

Fossilworks Fossilworks is a portal which provides query, download, and analysis tools to facilitate access to the Paleobiology Database The Paleobiology Database is an online resource for information on the distribution and classification of fossil animals ...

.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 Pointe-Noire (; kg, Njinji, french: Ndjindji with the letter d following French spelling standards) is the second largest city in the Republic of the Congo, following the capital of Brazzaville, and an autonomous department since 2004. Before t ...

, 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 Lewes () is the county town of East Sussex, England. It is the police and judicial centre for all of Sussex and is home to Sussex Police, East Sussex Fire & Rescue Service, Lewes Crown Court and HMP Lewes. The civil parishes in England, civil p ...

, 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 compose ...

, 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