''Glyptops'' (Greek for "grooved face") is an extinct genus of
pleurosternid freshwater turtle known from the Late Jurassic of North America.
Taxonomy
The type species, ''Glyptops plicatulus'', was first described as ''Compsemys plicatulus'' by
Edward Drinker Cope
Edward Drinker Cope (July 28, 1840 – April 12, 1897) was an American zoologist, paleontologist, comparative anatomist, herpetologist, and ichthyologist. Born to a wealthy Quaker family, Cope distinguished himself as a child prodigy interested ...
on the basis of AMNH 6099, a partial shell from the
Late Jurassic
The Late Jurassic is the third epoch of the Jurassic Period, and it spans the geologic time from 163.5 ± 1.0 to 145.0 ± 0.8 million years ago (Ma), which is preserved in Upper Jurassic strata.Owen 1987.
In European lithostratigraphy, the name ...
(
Tithonian
In the geological timescale, the Tithonian is the latest age of the Late Jurassic Epoch and the uppermost stage of the Upper Jurassic Series. It spans the time between 152.1 ± 4 Ma and 145.0 ± 4 Ma (million years ago). It is preceded by the Ki ...
) aged
Morrison Formation
The Morrison Formation is a distinctive sequence of Upper Jurassic sedimentary rock found in the western United States which has been the most fertile source of dinosaur fossils in North America. It is composed of mudstone, sandstone, siltstone, ...
of
Colorado
Colorado (, other variants) is a state in the Mountain West subregion of the Western United States. It encompasses most of the Southern Rocky Mountains, as well as the northeastern portion of the Colorado Plateau and the western edge of the ...
. In 1890, a partial skull, YPM 1784 (described from
Como Bluff
Como Bluff is a long ridge extending east–west, located between the towns of Rock River and Medicine Bow, Wyoming. The ridge is an anticline, formed as a result of compressional geological folding. Three geological formations, the Sundance, ...
,
Wyoming), was named ''Glyptops ornatus'' by
Othniel Charles Marsh
Othniel Charles Marsh (October 29, 1831 – March 18, 1899) was an American professor of Paleontology in Yale College and President of the National Academy of Sciences. He was one of the preeminent scientists in the field of paleontology. Among h ...
. Later,
Oliver Perry Hay
Oliver Perry Hay (May 22, 1846 – November 2, 1930) was an American herpetologist, ichthyologist, and paleontologist.
Hay was born in Jefferson County, Indiana, to Robert and Margaret Hay. In 1870, Hay graduated with a bachelor of arts from ...
recognized ''Compsemys plicatulus'' and ''Glyptops ornatus'' as being from the same species, hence the new combination ''G. plicatulus''. Another Morrison species of ''Glyptops'', ''G. utahensis'', was described from a complete shell (CM 3412) found at
Dinosaur National Monument
Dinosaur National Monument is an American national monument located on the southeast flank of the Uinta Mountains on the border between Colorado and Utah at the confluence of the Green and Yampa rivers. Although most of the monument area is i ...
in
Utah
Utah ( , ) is a state in the Mountain West subregion of the Western United States. Utah is a landlocked U.S. state bordered to its east by Colorado, to its northeast by Wyoming, to its north by Idaho, to its south by Arizona, and to it ...
. ''Glyptops'' later became a
wastebasket taxon
Wastebasket taxon (also called a wastebin taxon, dustbin taxon or catch-all taxon) is a term used by some taxonomists to refer to a taxon that has the sole purpose of classifying organisms that do not fit anywhere else. They are typically defined ...
to refer to isolated shell fragments with a finely sculpted surface texture. The type of ''Glyptops plicatulus'' was later judged to be a ''
nomen dubium
In binomial nomenclature, a ''nomen dubium'' (Latin for "doubtful name", plural ''nomina dubia'') is a scientific name that is of unknown or doubtful application.
Zoology
In case of a ''nomen dubium'' it may be impossible to determine whether a s ...
'', due to it lacking any diagnostic characters, and ''Glyptops ornatus'' was made to be the only valid species.
The species ''Glytops caelatus'' Hay, 1908 was described from the middle Cretaceous (late
Aptian
The Aptian is an age in the geologic timescale or a stage in the stratigraphic column. It is a subdivision of the Early or Lower Cretaceous Epoch or Series and encompasses the time from 121.4 ± 1.0 Ma to 113.0 ± 1.0 Ma (million years ago) ...
-early
Albian
The Albian is both an age (geology), age of the geologic timescale and a stage (stratigraphy), stage in the stratigraphic column. It is the youngest or uppermost subdivision of the Early Cretaceous, Early/Lower Cretaceous epoch (geology), Epoch/s ...
)
Arundel Formation of
Maryland
Maryland ( ) is a state in the Mid-Atlantic region of the United States. It shares borders with Virginia, West Virginia, and the District of Columbia to its south and west; Pennsylvania to its north; and Delaware and the Atlantic Ocean to it ...
. However, it was later dismissed as a ''nomen dubium'' based on non-diagnostic remains.
[E. S. Gaffney. 1979. The Jurassic turtles of North America. Bulletin of the American Museum of Natural History 162(3):95-135]
Description
The skull of ''Glyptops ornatus'' exhibit adaptions likely for
suction feeding
Aquatic feeding mechanisms face a special difficulty as compared to feeding on land, because the density of water is about the same as that of the prey, so the prey tends to be pushed away when the mouth is closed. This problem was first identifi ...
.
References
''Glyptops''at The Paleobiology Database
Pleurosternidae
Prehistoric turtle genera
Tithonian genera
Late Jurassic turtles
Late Jurassic reptiles of North America
Morrison fauna
Fossil taxa described in 1890
Taxa named by Othniel Charles Marsh
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