Spironema (gastropod)

†Spironema is a genus of extinct (Cretaceous) sea snails, marine gastropod mollusks in the family Naticidae, the moon snails.[1]

Spironema Temporal range: Cretaceous PreꞒ Ꞓ O S D C P T J K Pg N
Scientific classification
Kingdom:	Animalia
Phylum:	Mollusca
Class:	Gastropoda
(unranked):	clade Caenogastropoda clade Hypsogastropoda clade Littorinimorpha
Superfamily:	Naticoidea
Family:	Naticidae[1]
Genus:	†Spironema Meek, 1876[2]

Description

The American paleontologist Fielding Bradford Meek firstly defined this genus in 1864.[2] He classified the genus in the family Littorinidae.[2] He recognized two species Spironema bella and Spironema tenuilineata in 1864.[2] These species were previously classified within the family Trochidae.[2] Meek's diagnosis reads as follows:[2]

Shell ovate; whorls rounded, and separated by a rather deep

suture; aperture ovate, lip thin, continuous; columella not thickened, perforated by a very small umbilicus; surface with revolving lines and furrows. The non-perlaceous texture of the interior layer, as well as the other characters of such Cretaceous

shells, remove them from the Trochidae.

Species

Species within the genus Spironema include:

• Spironema bella (Conrad) - synonym: Tuba (?) bella Conrad, from Cretaceous of Alabama[2]
• Spironema tenuilineata (Meek & Hayden, 1856) - from Cretaceous of Dakota Territory, type species: Turbo tenuilineatus Meek & Hayden, 1856[2][3] - synonym: Turbo tenuilineata
• Spironema perryi Stephenson - from Maastrichtian, Texas.[4] Spironema cf. perryi is also known from the Upper Cretaceous, Cliff House Sandstone, Chaco Canyon, northwestern New Mexico.[1]

References

This article incorporates public domain text from the reference[2]

1. 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. PDF.
2. Meek F. B. (1864). "Check list of the invertebrate fossils of North America. Cretaceous and Jurassic". Smithsonian Miscellaneous Collections 7(177): 1-40. page 19, page 35.
3. Meek F. B. & Hayden F. V. (1856). "Descriptions of new species of Gastropoda from the Cretaceous formations of Nebraska Territory". Proceedings of the Academy of Natural Sciences of Philadelphia 8: 63-69. page 64.
4. "USGS 07545: Maastrichtian, Texas". The Paleobiology Database, accessed 11 August 2011.

Further reading

• Meek F. B. (1876). "A report on the Invertebrate Cretaceous and Tertiary Fossils of the Upper Missouri Country". Report of the United States Geological Survey of the territories, Washington, volume ix: i-ixv, 1-629, plates i-xlv. Spironema is on pages 341-343. Plate 32, figure 9a-c.
• Stephenson L. W. (1941). The larger invertebrate fossils of the Navarro group of Texas. The University of Texas Publication 4101: 1-625.