Chesapecten

Chesapecten Temporal range: 20.4–0.7 Ma PreЄ Є O S D C P T J K Pg N Early Miocene to Early Pleistocene
Chesapecten jeffersonius (outside)
Chesapecten jeffersonius (inside)
Conservation status
Extinct
Scientific classification
Kingdom:	Animalia
Phylum:	Mollusca
Class:	Bivalvia
Order:	Ostreoida
Family:	Pectinidae
Genus:	†Chesapecten
Binomial name
Chesapecten (Ward & Blackwater, 1975)

Chesapecten is an extinct genus of fossilized scallop. Species belonging to the genus Chesapecten lived from the early Miocene period to the early Pleistocene period.^[1] Like other scallops, the shells of Chesapecten are characterized by a pattern of wide ribs which radiate outward from the apex of the shell. A distinctive feature of Chesapecten is that the radial ribs on its shell are crossed by much smaller rough concentric ribs which follow the contours of the edges of the shell. The left valve of Chesapecten is more convex than the right valve. The adductor muscle scar is large and rounded. The geographical distribution of Chesapecten is limited to the Atlantic coastal plain of North America^[2], where it can be found as far south as Florida and as far north as Delaware.^[3] One species of Chesapecten, Chesapecten jeffersonius, is the state fossil of Virginia.^[4]

Taxonomy

Chesapecten was the first genus of North American fossil to be described and illustrated, with a drawing of C. jeffersonius appearing in English naturalist Martin Lister's Historiae Conchyliorum, Liber III in 1687. However, Lister did not give Chesapecten its name.^[2] Chesapecten was formally named in 1975 by paleontologists Ward and Blackwater. In 1980, it was assigned to the family Pectinidae by Harold E. Vokes.^[1] The name Chesapecten comes from the Chesapeake Bay, where eroding cliffs and outcrops along the beaches regularly expose specimens.^[2]

Life and Lifestyle

Chesapecten lived on the seabed in coastal waters ranging in depth from a few feet to 130 feet. When not moving, it rested its flatter right valve on the seafloor. It is very likely that Chesapecten could propel itself through the water in a manner similar to that of other scallops.^[2]

Species in the genus Chesapecten

• †Chesapecten jeffersonius^[1]
• †Chesapecten coccymelus^[1]
• †Chesapecten madisonius^[1]
• †Chesapecten patagonensis^[1]
• †Chesapecten santamaria^[1]
• †Chesapecten sayanus^[1]
• †Chesapecten skiptonensis^[1]
• †Chesapecten nefrens^[5]
• †Chesapecten marylandicus^[5]
• †Chesapecten septenarius^[6]
• †Chesapecten monicae^[6]
• †Chesapecten middlesexensis^[6]
• †Chesapecten crassus^[6]

References

1. ^ ^{a b c d e f g h i} "Information on Chesapecten from The Paleobiology Database". http://paleodb.org/cgi-bin/bridge.pl?action=checkTaxonInfo&taxon_no=16548. Retrieved 2010-09-29. 
2. ^ ^{a b c d} National Audubon Society Field Guide to North American Fossils, page 465-466, Alfred A. Knopf Publishing New York, ISBN 0-394-52412-8
3. ^ "NASA ADS: Seasonal Variations Preserved in an Extinct Neogene Scallop, Chesapecten, from Florida to Delaware, USA and its Implications for Paleobiogeography". http://adsabs.harvard.edu/abs/2007AGUFMPP51E..05G. Retrieved 2010-09-29. 
4. ^ "The Geology of Virginia". http://web.wm.edu/geology/virginia/vafossils/index.php. Retrieved 2010-09-29. 
5. ^ ^{a b} "Bulletin 20: Miocene Fossils of Maryland". http://www.mgs.md.gov/esic/publications/B20/pect.html. Retrieved 2010-09-29. 
6. ^ ^{a b c d} "Chesapecten Nefrens - zipcodezoo.com". http://zipcodezoo.com/Animals/C/Chesapecten_nefrens/. Retrieved 2010-09-29. 

Further reading

Online photo gallery with several pictures of Chesapecten nefrens
Information about Chesapecten from the Global Biodiversity Information Facility
Images of Chesapecten from Google Images