Dyslocosaurus
Encyclopedia
Dyslocosaurus is the name given in 1992 to a genus
of sauropod dinosaur
, possibly from the Late Jurassic
Period. Its fossils were found in North America
.
The holotype
or type specimen the genus is based on, AC 663, is part of the collection of the Amherst College Museum of Natural History. It was collected by professor Frederic Brewster Loomis. However, the only available information regarding its provenance is that given on the label: "Lance Creek", a county in east Wyoming
. Loomis himself thought that it stemmed from the Lance Formation
, dating from the Late Cretaceous
Maastrichtian
.
In 1963 the specimen was brought to the attention of John Stanton McIntosh, who later, together with William Coombs and Dale Russell
, decided to create a new genus and species for it. The type species
is Dyslocosaurus polyonychius. The genus name is derived from Greek dys, "bad, "poor", and Latin
locus, "place", a reference to the lack of knowledge about the exact site it was discovered in. The specific name is derived from Greek polys, "many", and onyx, "claw". The describers interpreted the remains, consisting of some limb bones, as those of a diplodocid
dinosaur. From this they concluded that it in fact dated from the Late Jurassic
Period, like most diplodocids. The species would then be unique in having four, or perhaps five, claws on the foot, whereas other diplodocids have only three — hence the specific name. A species similar to Dyslocosaurus would have made the tracks of the ichnospecies Brontopodus
birdi from the Early Cretaceous, that also features four claws.
In 1998 Paul Sereno
and Jeffrey A. Wilson
gave an alternative interpretation: the specimen would come from the Lance Formation after all but be a chimera
: in this case a mix up of titanosaur
limb bones and theropod phalanges.
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
of sauropod dinosaur
Dinosaur
Dinosaurs are a diverse group of animals of the clade and superorder Dinosauria. They were the dominant terrestrial vertebrates for over 160 million years, from the late Triassic period until the end of the Cretaceous , when the Cretaceous–Paleogene extinction event led to the extinction of...
, possibly from the Late Jurassic
Jurassic
The Jurassic is a geologic period and system that extends from about Mya to Mya, that is, from the end of the Triassic to the beginning of the Cretaceous. The Jurassic constitutes the middle period of the Mesozoic era, also known as the age of reptiles. The start of the period is marked by...
Period. Its fossils were found in North America
North America
North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...
.
The holotype
Holotype
A holotype is a single physical example of an organism, known to have been used when the species was formally described. It is either the single such physical example or one of several such, but explicitly designated as the holotype...
or type specimen the genus is based on, AC 663, is part of the collection of the Amherst College Museum of Natural History. It was collected by professor Frederic Brewster Loomis. However, the only available information regarding its provenance is that given on the label: "Lance Creek", a county in east Wyoming
Wyoming
Wyoming is a state in the mountain region of the Western United States. The western two thirds of the state is covered mostly with the mountain ranges and rangelands in the foothills of the Eastern Rocky Mountains, while the eastern third of the state is high elevation prairie known as the High...
. Loomis himself thought that it stemmed from the Lance Formation
Lance Formation
The Lance Formation is a division of Late Cretaceous rocks in the western United States. Named after Lance Creek, Wyoming, the microvertebrate fossils and dinosaurs represent important components of the latest Mesozoic vertebrate faunas...
, dating from the Late Cretaceous
Late Cretaceous
The Late Cretaceous is the younger of two epochs into which the Cretaceous period is divided in the geologic timescale. Rock strata from this epoch form the Upper Cretaceous series...
Maastrichtian
Maastrichtian
The Maastrichtian is, in the ICS' geologic timescale, the latest age or upper stage of the Late Cretaceous epoch or Upper Cretaceous series, the Cretaceous period or system, and of the Mesozoic era or erathem. It spanned from 70.6 ± 0.6 Ma to 65.5 ± 0.3 Ma...
.
In 1963 the specimen was brought to the attention of John Stanton McIntosh, who later, together with William Coombs and Dale Russell
Dale Russell
Dale A. Russell is a Canadian geologist/palaeontologist, currently Research Professor at The Department of Marine Earth and Atmospheric Sciences of North Carolina State University...
, decided to create a new genus and species for it. The type species
Type species
In biological nomenclature, a type species is both a concept and a practical system which is used in the classification and nomenclature of animals and plants. The value of a "type species" lies in the fact that it makes clear what is meant by a particular genus name. A type species is the species...
is Dyslocosaurus polyonychius. The genus name is derived from Greek dys, "bad, "poor", and Latin
Latin
Latin is an Italic language originally spoken in Latium and Ancient Rome. It, along with most European languages, is a descendant of the ancient Proto-Indo-European language. Although it is considered a dead language, a number of scholars and members of the Christian clergy speak it fluently, and...
locus, "place", a reference to the lack of knowledge about the exact site it was discovered in. The specific name is derived from Greek polys, "many", and onyx, "claw". The describers interpreted the remains, consisting of some limb bones, as those of a diplodocid
Diplodocid
Diplodocids, or members of the family Diplodocidae , are a group of sauropod dinosaurs. The family includes some of the longest creatures ever to walk the earth, including Diplodocus and Supersaurus, which may have reached lengths of up to .-Description:While still massive, when compared to the...
dinosaur. From this they concluded that it in fact dated from the Late Jurassic
Jurassic
The Jurassic is a geologic period and system that extends from about Mya to Mya, that is, from the end of the Triassic to the beginning of the Cretaceous. The Jurassic constitutes the middle period of the Mesozoic era, also known as the age of reptiles. The start of the period is marked by...
Period, like most diplodocids. The species would then be unique in having four, or perhaps five, claws on the foot, whereas other diplodocids have only three — hence the specific name. A species similar to Dyslocosaurus would have made the tracks of the ichnospecies Brontopodus
Brontopodus
Brontopodus is an ichnogenus of dinosaur footprint. The footprint has diplodocid form, but four toes when almost every diplodocid has no more than three. This leaves Dyslocosaurus as the only known genus capable of producing the footprints....
birdi from the Early Cretaceous, that also features four claws.
In 1998 Paul Sereno
Paul Sereno
Paul Callistus Sereno is an American paleontologist from the University of Chicago who discovered several new dinosaur species on several continents. He has conducted excavations at sites as varied as Inner Mongolia, Argentina, Morocco, and Niger...
and Jeffrey A. Wilson
Jeffrey A. Wilson
Jeffrey A. Wilson also known as "JAW "is a professor of geological sciences and assistant curator at the Museum of Paleontology at the University of Michigan....
gave an alternative interpretation: the specimen would come from the Lance Formation after all but be a chimera
Chimera (paleontology)
In paleontology, a chimera is a fossil which was reconstructed with elements coming from more than a single species of animal. A now classic example of chimera is Protoavis.-List of paleontological chimeras:*Brontosaurus*Lametasaurus...
: in this case a mix up of titanosaur
Titanosaur
Titanosaurs were a diverse group of sauropod dinosaurs, which included Saltasaurus and Isisaurus. It includes some of the heaviest creatures ever to walk the earth, such as Argentinosaurus and Paralititan — which some believe have weighed up to 100 tonnes...
limb bones and theropod phalanges.