Cotylacrinna Sample 1 Burr Oak (Ordovician of the United States)

Where: Winneshiek County, Iowa (43.5° N, 91.9° W: paleocoordinates 19.1° S, 60.6° W)

• coordinate based on nearby landmark

• outcrop-level geographic resolution

When: Ischadites iowensis other zone, Sherwood Member (Dunleith Formation), Katian (453.0 - 445.2 Ma)

• Unit 1 of section.

• bed-level stratigraphic resolution

Environment/lithology: wackestone

• During the Upper Ordovician, the Galena Group of northeast Iowa and southeast Minnesota lay in warm shallow tropical water at about 10 to 15° south latitude. Productivity was probably low inasmuch as lower Paleozoic oceans are generally visualized as oligotrophic (e.g., Bambach, 1993; Martin, 1998, p. 164–173). At this time, the Sebree Trough lay at about 18° south and was connected to the Iapetus Ocean in present-day Oklahoma, Arkansas, and Missouri (Kolata, et al., 2001). Sediments in the trough consist of dark graptolitic shales with ostracodes, orbiculoid brachiopods, and the trilobites Triarthrus and Cryptolithus. Periodically, cool phosphate-rich water from the Iapetus Ocean and Sebree Trough invaded the craton and mixed with the tropical water mass, and these invasions were probably important in maintaining the faunas on the Galena Platform (Kolata, et al., 2001)
• Cotylacrinna sandra and Praecupulocrinus conjugans common in micrite at top of micritic to calcarenitic wackestone bed, which varies from 3 cm to 4 cm thick; weathered top surface indicates hardground.

Size class: macrofossils

Preservation: original calcite

Collected by J. C. Brower

• University of Iowa

Primary reference: J. C. Brower. 2013. Paleoecology of Echinoderm Assemblages from the Upper Ordovician (Katian) Dunleith Formation of Northern Iowa and Southern Minnesota. Journal of Paleontology 87(1):16-43 [P. Wagner/P. Wagner]more details

Purpose of describing collection: paleoecologic analysis

PaleoDB collection 138446: authorized by Pete Wagner, entered by Pete Wagner on 19.01.2013

Creative Commons license: CC BY (attribution)

Taxonomic list

 Dichoporita - Glyptocystidae
Tanaocystis "n. sp." Sprinkle 1982
 Glyptocystitoida - Pleurocystitidae
Edrioasteroidea indet. Billings 1858
  - Hemicystitidae
Hemicystites sp. Hall 1852
 Calceocrinida - Calceocrinidae
Cremacrinus "n. sp." Ulrich 1886 Sea lily
C. n. sp. aff. C. arctus
 Cladida -
 Porocrinida -
Porocrinus sp. Billings 1857 Sea lily
Carabocrinus sp. Billings 1857 Sea lily
 Cyathocrinida - Euspirocrinidae
 Dendrocrinida - Cupulocrinidae
Quienquecaudex springeri Kolata 1975 Sea lily
 Dendrocrinida - Merocrinidae
Praecupulocrinus conjugans Billings 1857 Sea lily
 Hybocrinida - Hybocrinidae
Hybocrinus conicus Billings 1857 Sea lily
 Camerata -
Camerata indet. Wachsmuth and Springer 1885 Sea lily
 Diplobathrida - Dimerocrinitidae
 Diplobathrida - Rhodocrinitidae
"Cotylacrinna sandra" = Cotylacrina
"Cotylacrinna sandra" = Cotylacrina Sea lily
 Diplobathrida - Cleiocrinidae
Cleiocrinus regius Billings 1857 Sea lily