†''Spironema'' is a

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

of extinct (

Cretaceous The Cretaceous ( ) is a geological period that lasted from about 143.1 to 66 mya (unit), million years ago (Mya). It is the third and final period of the Mesozoic Era (geology), Era, as well as the longest. At around 77.1 million years, it is the ...

)

sea snail Sea snails are slow-moving marine (ocean), marine gastropod Mollusca, molluscs, usually with visible external shells, such as whelk or abalone. They share the Taxonomic classification, taxonomic class Gastropoda with slugs, which are distinguishe ...

s, marine

gastropod Gastropods (), commonly known as slugs and snails, belong to a large Taxonomy (biology), taxonomic class of invertebrates within the phylum Mollusca called Gastropoda (). This class comprises snails and slugs from saltwater, freshwater, and fro ...

mollusk Mollusca is a phylum of protostomic invertebrate animals, whose members are known as molluscs or mollusks (). Around 76,000 extant species of molluscs are recognized, making it the second-largest animal phylum after Arthropoda. The ...

s in the

family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...

Naticidae Naticidae, common name moon snails or necklace shells, is a family (biology), family of medium to large-sized predatory sea snails, marine (ocean), marine gastropod molluscs in the clade Littorinimorpha. The shells of the species in this family a ...

, the moon snails.Siemers C. T. & King N. R. (1974). "Macroinvertebrate paleoecology of a transgressive marine sandstone, Cliff House Sandstone (Upper Cretaceous), Chaco Canyon, northwestern New Mexico". ''New Mexico Geol. Soc. Guidebook'', 25th Field Conf., Ghost Ranch (Central-Northern N.M.): 267-277
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Description

The American paleontologist

Fielding Bradford Meek Fielding Bradford Meek (December 10, 1817 – December 22, 1876) was an American geologist and a paleontologist who specialized in the invertebrates. Biography The son of a lawyer, he was born in Madison, Indiana. In early life he was in ...

firstly defined this genus in 1864. He classified the genus in the family

Littorinidae The Littorinidae are a taxonomic family of over 200 species of sea snails, marine gastropod molluscs in the clade Littorinimorpha, commonly known as periwinkles and found worldwide. Names In English-speaking countries, gastropod molluscs from ...

. He recognized two species '' Spironema bella'' and '' Spironema tenuilineata'' in 1864. These species were previously classified within the family

Trochidae The Trochidae, common name top-snails or top-shells, are a family of various sized sea snails, marine gastropod molluscs in the subclass Vetigastropoda. This family is commonly known as the top-snails because in many species the shell resembles ...

. Meek's diagnosis reads as follows:

Species

Species within the genus ''Spironema'' include: * '' Spironema bella'' (Conrad) - synonym: ''Tuba'' (?) ''bella'' Conrad, from Cretaceous of Alabama * '' Spironema tenuilineata'' (Meek & Hayden, 1856) - from Cretaceous of

Dakota Territory The Territory of Dakota was an organized incorporated territory of the United States that existed from March 2, 1861, until November 2, 1889, when the final extent of the reduced territory was split and admitted to the Union as the states of ...

, type species: ''Turbo tenuilineatus'' Meek & Hayden, 1856 - synonym: ''Turbo tenuilineata'' * '' Spironema perryi'' Stephenson - from

Maastrichtian The Maastrichtian ( ) is, in the International Commission on Stratigraphy (ICS) geologic timescale, the latest age (geology), age (uppermost stage (stratigraphy), stage) of the Late Cretaceous epoch (geology), Epoch or Upper Cretaceous series (s ...

, Texas."USGS 07545: Maastrichtian, Texas"

The Paleobiology Database The Paleobiology Database (PBDB) is an online resource for information on the distribution and classification of fossil animals, plants, and microorganisms. History The Paleobiology Database originated in the NCEAS-funded Phanerozoic Marine Pale ...

, accessed 11 August 2011. ''Spironema''

cf. The abbreviation cf. (short for either Latin or , both meaning 'compare') is generally used in writing to refer the reader to other material to make a comparison with the topic being discussed. However some sources offer differing or even contr ...

''perryi'' is also known from the Upper Cretaceous,

Cliff House Sandstone The Cliff House Sandstone is a late Campanian stratigraphic unit comprising sandstones in the western United States. Description The Cliff House Sandstone consists of fine grained white to orange calcareous sandstone. It intertongues with the ...

Chaco Canyon Chaco Culture National Historical Park is a United States National Historical Park in the American Southwest hosting a large concentration of pre-Columbian indigenous ruins of pueblos. The park is located in northwestern New Mexico, betwee ...

, northwestern New Mexico.

References

This article incorporates public domain text from the reference

Description

Species

References

Further reading