Quasillites

Quasillites is a fossil genus of ostracod from the Devonian and Carboniferous Periods.[1][2]

Quasillities
Temporal range: Middle Devonian to Lower Carboniferous 388.1โ€“342.8 Ma
Scientific classification
Kingdom:
Animalia
Phylum:
Arthropoda
Subphylum:
Crustacea
Class:
Ostracoda
Order:
Podocopida
Family:
Quasillitidae
Genus:
Quasillites

Coryell & Malkin, 1936
Species
  • Q. angulatus
  • Q. lobatus (Schwartz & Oriel)
  • Q. subobliquus
  • Q. obliquus (Coryell & Malkin, 1936)
  • Q. fromelennensis

Description

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

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
  1. J. J. Sepkoski Jr. 1998. Rates of speciation in the fossil record. Philosophical Transactions of the Royal Society Biological Sciences 353(1366):315-326
  2. Moore, R., Lalicker, C., Fischer, A. 1952. Invertebrate Fossils.
  3. Feldman, R. (ed.) 1996. Fossils of Ohio. Ohio Department of Natural Resources, Division of Geological Survey, Bulletin 70. pg. 115-121
  4. Moore, R. ed. Treatise on Invertebrate Paleontology. Volume Q. pp.88-94
  5. L. E. Stover. 1956. Ostracoda from the Windom Shale (Hamilton) of Western New York. Journal of Paleontology. 30(5):1092-1142
  6. R. L. Ellison. 1965. Stratigraphy and Paleontology of the Mahantango Formation in south-central Pennsylvania. Pennsylvania Geological Survey Bulletin.
  7. P. Morzadec and D. Brice. 2000. The Devonian of France: a tentative tie with the GSSP of the Devonian stages. 225:115-129
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