''Leurospondylus'' is a

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nom ...

plesiosaur The Plesiosauria (; Greek: πλησίος, ''plesios'', meaning "near to" and ''sauros'', meaning "lizard") or plesiosaurs are an order or clade of extinct Mesozoic marine reptiles, belonging to the Sauropterygia. Plesiosaurs first appea ...

whose

family Family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its members and of society. Idea ...

is currently disputed, but is suggested to be

Plesiosauridae The Plesiosauridae are a monophyletic group of plesiosaurs.Ketchum, H. F., and Benson, R. B. J., 2010. "Global interrelationships of Plesiosauria (Reptilia, Sauropterygia) and the pivotal role of taxon sampling in determining the outcome of phylo ...

Etymology

The name ''Leurospondylus'' comes from a fusion of two

Greek Greek may refer to: Greece Anything of, from, or related to Greece, a country in Southern Europe: *Greeks, an ethnic group. *Greek language, a branch of the Indo-European language family. **Proto-Greek language, the assumed last common ancestor ...

words, ''leuros'' (λευρός) meaning "even", "flat" or "smooth", and ''spondylos'' (σπόνδυλος) meaning "

vertebra The spinal column, a defining synapomorphy shared by nearly all vertebrates,Hagfish are believed to have secondarily lost their spinal column is a moderately flexible series of vertebrae (singular vertebra), each constituting a characteristic ...

." The name of the

type species In zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the species that contains the biological type specimen ...

''L. ultimus'' comes from the

Latin Latin (, or , ) is a classical language belonging to the Italic branch of the Indo-European languages. Latin was originally a dialect spoken in the lower Tiber area (then known as Latium) around present-day Rome, but through the power of the ...

''ultimus'' meaning "last." It was so named because this genus was the latest known occurrence of a

fossil A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved ...

plesiosaur when it was described in 1913."

Description

The first described ''Leurospondylus'' was a juvenile."A new plesiosaur, Leurospondylus, from the Edmonton Cretaceous of Alberta". ''Bulletin of the AMNH''; v. 32, article 40. The fossil included 12

e but the animal is thought to have had twice that number, and was estimated to be roughly 2 meters long as a juvenile.

Samuel Paul Welles Samuel Paul Welles (November 9, 1907 – August 6, 1997) was an American palaeontologist. Welles was a research associate at the Museum of Palaeontology, University of California, Berkeley. He took part in excavations at the Placerias Quarry in ...

noted that the vertebrae are short and similar to those of pliosaurs,Welles, S. P. 1962. A new species of elasmosaur from the Aptian of Columbia and a review of the Cretaceous plesiosaurs. University of California Publications in Geological Science 46, 96 pp. while the

scapula The scapula (plural scapulae or scapulas), also known as the shoulder blade, is the bone that connects the humerus (upper arm bone) with the clavicle (collar bone). Like their connected bones, the scapulae are paired, with each scapula on eithe ...

e and

coracoid A coracoid (from Greek κόραξ, ''koraks'', raven) is a paired bone which is part of the shoulder assembly in all vertebrates except therian mammals (marsupials and placentals). In therian mammals (including humans), a coracoid process is prese ...

s bear resemblance to those of

elasmosaurids Elasmosauridae is an extinct family of plesiosaurs, often called elasmosaurs. They had the longest necks of the plesiosaurs and existed from the Hauterivian to the Maastrichtian stages of the Cretaceous, and represented one of the two groups of p ...

, thus making it difficult to determine to which

it belongs. There is some speculation that the ''Leurospondylus'' specimen is either a juvenile of a known species, or in its own, unrecognized

taxonomic Taxonomy is the practice and science of categorization or classification. A taxonomy (or taxonomical classification) is a scheme of classification, especially a hierarchical classification, in which things are organized into groups or types. ...

group.

Distribution

The first ''Leurospondylus'' was found in the

brackish Brackish water, sometimes termed brack water, is water occurring in a natural environment that has more salinity than freshwater, but not as much as seawater. It may result from mixing seawater (salt water) and fresh water together, as in estuari ...

paleoenvironment represented by the Edmonton beds located on the present-day

Red Deer River The Red Deer River is a river in Alberta and a small portion of Saskatchewan, Canada. It is a major tributary of the South Saskatchewan River and is part of the larger Saskatchewan-Nelson system that empties into Hudson Bay. Red Deer River ...

. This area is part of the

Horseshoe Canyon Formation The Horseshoe Canyon Formation is a stratigraphic unit of the Western Canada Sedimentary Basin in southwestern Alberta. It takes its name from Horseshoe Canyon, an area of badlands near Drumheller. The Horseshoe Canyon Formation is part of the ...

Alberta Alberta ( ) is one of the thirteen provinces and territories of Canada. It is part of Western Canada and is one of the three prairie provinces. Alberta is bordered by British Columbia to the west, Saskatchewan to the east, the Northwest Ter ...

Canada Canada is a country in North America. Its ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, covering over , making it the world's second-largest country by tot ...

. The occurrence of this juvenile fossil in an identifiably brackish environment led to the conclusion that plesiosaurs spent their early lives in rivers and

estuaries An estuary is a partially enclosed coastal body of brackish water with one or more rivers or streams flowing into it, and with a free connection to the open sea. Estuaries form a transition zone between river environments and maritime environment ...

. However, some plesiosaurs spent their adult lives in fresh water also; whether ''Leurospondylus'' grew up and then left, or grew up and stayed in a fresh water

ecosystem An ecosystem (or ecological system) consists of all the organisms and the physical environment with which they interact. These biotic and abiotic components are linked together through nutrient cycles and energy flows. Energy enters the syste ...

has not been determined.

References

External links

*https://web.archive.org/web/20080703172817/http://www.plesiosaur.com/database/pdf/brown1913Leurospondylus.pdf *http://www.ppne.co.uk/index.php?m=show&id=12527 {{Taxonbar, from=Q6534633 Late Cretaceous plesiosaurs of North America Plesiosauria incertae sedis Sauropterygian genera

Etymology

Description

Distribution

See also

References

External links