File:Promopalaeaster fossil starfish (hexaradial variant) (Richmondian Stage, Upper Ordovician; Caesar Creek Lake's emergency spillway, northeastern Warren County, southwestern Ohio, USA) 3.jpg
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editDescriptionPromopalaeaster fossil starfish (hexaradial variant) (Richmondian Stage, Upper Ordovician; Caesar Creek Lake's emergency spillway, northeastern Warren County, southwestern Ohio, USA) 3.jpg |
Promopalaeaster fossil starfish (hexaradial variant) (field of view ~2.2 cm across) from the Ordovician of Ohio, USA. A nice 6-armed fossil starfish specimen was found in the Upper Ordovician of southwestern Ohio, USA during an geology class field trip from Ohio State University at Newark. The starfish specimen is moderately large, aboral side up, and sitting on a hard, bioturbated wackestone. The surface on which the starfish sits was likely a firmground on the original ocean floor. Daniel Blake, a fossil starfish researcher at University of Illinois at Urbana-Champaign, has tentatively identified the specimen as a hexaradial variant (mutation) of Promopalaeaster sp. Because features of the oral side are hidden from examination, a more precise determination is difficult at present. This photo shows the madreporite (radiating structure at center) on the central disc. The specimen was donated to Orton Geology Museum (Ohio State University, Columbus, Ohio, USA), and has been prepared. Stratigraphy: float piece, likely derived from the top meter of the Liberty Formation or possibly from the lower 1-2 meters of the Whitewater Formation (a known fossil starfish horizon occurs 0.8 meters below the Liberty-Whitewater contact at this locality), Richmondian Stage, upper Cincinnatian Series, upper Upper Ordovician. Locality: loose talus along cut wall of Caesar Creek Lake’s emergency spillway, northeastern side of Clarksville Road, northeastern Warren County, southwestern Ohio, USA. |
Date | |
Source | Promopalaeaster fossil starfish (hexaradial variant) (Richmondian Stage, Upper Ordovician; Caesar Creek Lake's emergency spillway, northeastern Warren County, southwestern Ohio, USA) 3 |
Author | James St. John |
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This image was originally posted to Flickr by James St. John at https://flickr.com/photos/47445767@N05/15302389265 (archive). It was reviewed on 9 November 2017 by FlickreviewR 2 and was confirmed to be licensed under the terms of the cc-by-2.0. |
9 November 2017
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current | 02:09, 9 November 2017 | 3,072 × 2,016 (6.26 MB) | Sw0 (talk | contribs) | =={{int:filedesc}}== {{Information |Description=Promopalaeaster fossil starfish (hexaradial variant) (field of view ~2.2 cm across) from the Ordovician of Ohio, USA. A nice 6-armed fossil starfish specimen was found in the Upper Ordovician of southwes... |
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Orientation | Normal |
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Horizontal resolution | 96 dpi |
Vertical resolution | 96 dpi |
Software used | Adobe Photoshop CS2 Macintosh |
File change date and time | 19:16, 20 September 2014 |
Color space | Uncalibrated |
Image width | 3,072 px |
Image height | 2,016 px |
Date and time of digitizing | 15:13, 20 September 2014 |
Date metadata was last modified | 15:16, 20 September 2014 |