Gluteus minimus (fossil)
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| Davis & Semken Jr., 1975 |
Gluteus minimus is anUpper Devonian fossil foundin Iowa . The fossils were first found in 1902, but were not examined and described until 1975. Each of the animals consists of a two-legged lens that is up to 11 mm × 8 mm in size. Virtually all fossils have the same slight asymmetry. Viewed from above, the fossil has an incision; the top has rough growth rings, the bottom is smooth but has one or two furrows.
Finds and collections
The first finds were made by Stuart Weller , who looked for fossils near Maple Hill on the English River , Washington County , Iowa in 1902 . The layers of the upper Devonian there are rich in conodonts , sporocarps , gastropods , arm pods , bivalves and scolecodonts (jaws of segmented worms).
During a similar period, Charles Rochester Eastman was out in Iowa and collected the same fossils in the Kinderhook Beds in Burlington , Des Moines County . Thirty years later, CH Belanski found specimens in the Lime Creek Formation in Floyd County , Iowa.
Since then, the collections have contained several thousand copies.
Description and classification
Gluteus minimus was formally described in Science by Richard Arnold Davis and Holmes A. Semken Jr. in 1975 ; they did research at the universities of Cincinnati and Iowa, respectively . Their work was based on more than 3,200 copies, most of which are in the possession of the two universities. University employees informally called these finds horse collars (German: horse collars, kumt ).
The classification of the fossils has been a mystery from the beginning. Weller's findings from 1902 are labeled fish remains? (German: fish remains?). Burlington suspected cone scales? (cone: cone, scale: scales, shell), and Belanski finally classified them as apparently dermal ossifications of some fish (German: apparently ossified skin of a fish).
Since then, gluteus minimus has been interpreted as a fish tooth or an arm pod. So far, however, the fossils could not be classified with any certainty in any tribe and are therefore considered incertae sedis .
literature
- Richard Arnold Davis & Holmes A. Semken Jr .: Fossils of uncertain affinity from the Upper Devonian of Iowa. In: Science. Retrieved October 11, 2019 .