Quasillites
| Quasillities Temporal range: Middle Devonian to Lower Carboniferous
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| Genus: | Quasillites Coryell & Malkin, 1936
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Quasillites is a fossil genus of ostracod from the Devonian and Carboniferous Periods.[1][2]
Description
[edit]Quasillites is distinguished from other ostracodes by the presence of a "medial spot" on each valve.[2] The surface of each valve is covered in longitudinal, bifurcating ridges, which curve and resemble a finger print.[2][3] The ribs and spines on the carapace are in front of the posterior margin, and are similar to those of other ostracods such as Bufina, Parabufina, and Healdia.[4] In fact, this comparison can also be drawn for all Quasillitids to other Healdiids.[4] The muscle scars on each valve is circular in shape, and some specimens have smaller secondary scars.[4]
Distribution
[edit]Devonian examples of Quasillites, such as Q. lobatus, Q. obliquus, Q. subobliquus, and Q. angulatus, are known from shales and claystones in northern New York, Eastern Ohio, central Pennsylvania.[2][3][5][6] Other species such as Q. fromelennensis and a second informal species can also be found in Limestones of northern France, near the city of Calais.[7] This genus has also been found in the Lower Carboniferous edge of the Illinois Basin; in central Indiana.[1]
References
[edit]- ^ a b J. J. Sepkoski Jr. 1998. Rates of speciation in the fossil record. Philosophical Transactions of the Royal Society Biological Sciences 353(1366):315-326
- ^ a b c d Moore, R., Lalicker, C., Fischer, A. 1952. Invertebrate Fossils.
- ^ a b Feldman, R. (ed.) 1996. Fossils of Ohio. Ohio Department of Natural Resources, Division of Geological Survey, Bulletin 70. pg. 115–121
- ^ a b c Moore, R. ed. Treatise on Invertebrate Paleontology. Volume Q. pp.88-94
- ^ L. E. Stover. 1956. Ostracoda from the Windom Shale (Hamilton) of Western New York. Journal of Paleontology. 30(5):1092-1142
- ^ R. L. Ellison. 1965. Stratigraphy and Paleontology of the Mahantango Formation in south-central Pennsylvania. Pennsylvania Geological Survey Bulletin.
- ^ P. Morzadec and D. Brice. 2000. The Devonian of France: a tentative tie with the GSSP of the Devonian stages. 225:115-129