''Yaguarasaurus'' is an extinct

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 n ...

of mosasauroid from the

Late Cretaceous The Late Cretaceous (100.5–66 Ma) is the younger of two epochs into which the Cretaceous Period is divided in the geologic time scale. Rock strata from this epoch form the Upper Cretaceous Series. The Cretaceous is named after ''creta'', ...

(

Turonian The Turonian is, in the ICS' geologic timescale, the second age in the Late Cretaceous Epoch, or a stage in the Upper Cretaceous Series. It spans the time between 93.9 ± 0.8 Ma and 89.8 ± 1 Ma (million years ago). The Turonian is preceded ...

) period of Colombia,

South America South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere at the northern tip of the continent. It can also be described as the souther ...

. The remains discovered (an articulated skull, some vertebrae and ribs) were defined as a new genus and species of mosasaurid, ''Yaguarasaurus columbianus'', by the Colombian paleontologist María Páramo, former director of the Museo de Geología José Royo y Gómez of

INGEOMINAS The Colombian Geological Survey (CGS) ( es, Servicio Geológico Colombiano; formerly known as INGEOMINAS) is a scientific agency of the Colombian government in charge of contributing to the socioeconomic development of the nation through research ...

Bogotá Bogotá (, also , , ), officially Bogotá, Distrito Capital, abbreviated Bogotá, D.C., and formerly known as Santa Fe de Bogotá (; ) during the Spanish period and between 1991 and 2000, is the capital city of Colombia, and one of the largest ...

. The first fossils remains of this animal suggested a cranial length of and a total length of ; an additional skull that measures long implies a larger size. This reptile is a member of the family of marine lizards Mosasauridae characteristic of Middle and Upper

Cretaceous The Cretaceous ( ) is a geological period that lasted from about 145 to 66 million years ago (Mya). It is the third and final period of the Mesozoic Era, as well as the longest. At around 79 million years, it is the longest geological period of ...

, with global distribution, but in South America known only through isolated remains (Price, 1957, Pierce and Welles, 1959 ; Bonaparte, 1978; Ameghino, 1918). This mosasaur discovered in Yaguará, was at the moment of discovery the most complete material known in South America.

Etymology

The remains were found in a limestone bed (Upper Turonian) of the

La Frontera Formation The La Frontera Formation ( es, Formación La Frontera, K2F, Ksf) is a geological formation, part of the Villeta Group, of the Altiplano Cundiboyacense and neighbouring areas of the Eastern Ranges of the Colombian Andes. The sequence of limeston ...

, member of the

Villeta Group The Villeta Group ( es, Grupo Villeta) is a geological group of the Eastern Ranges of the Colombian Andes, to the west of the Altiplano Cundiboyacense. The group, a sequence of shales, limestones and sandstones, is subdivided into various formatio ...

, near

Yaguará Yaguará () is a town and municipality in the Huila Department, Colombia. The urban centre is located at an elevation of in the Magdalena River Valley and the Eastern Ranges of the Colombian Andes. The municipality borders Teruel and Palermo in th ...

, Huila, in a site called Cueva Rica.''Yaguarasaurus columbianus''
at

Fossilworks Fossilworks is a portal which provides query, download, and analysis tools to facilitate access to the Paleobiology Database, a large relational database assembled by hundreds of paleontologists from around the world. History Fossilworks was cre ...

.org Its name means "Yaguará lizard of Colombia".

Phylogeny

In the initial descriptions of ''Yaguarasaurus'', it was classified as a member of the subfamily

Plioplatecarpinae Plioplatecarpinae is a subfamily of mosasaurs, a diverse group of Late Cretaceous marine squamates. Members of the subfamily are informally and collectively known as "plioplatecarpines" and have been recovered from all continents, though the occ ...

; the analysis of Polcyn and Bell (2005) showed that it was a distant relative of the advanced mosasaurids and were a close relative of '' Russellosaurus coheni'' and '' Tethysaurus nopscai'', a group that could be a basal clade to the division between

Tylosaurinae The Tylosaurinae are a subfamily of mosasaurs,Williston, S. W. 1897. Range and distribution of the mosasaurs with remarks on synonymy. ''Kansas University Quarterly'' 4(4):177-185. a diverse group of Late Cretaceous marine squamates. Members of ...

and Plioplatecarpinae subfamilies, called Russellosaurina. After the discovery of the basal mosasauroid of Hungary '' Pannoniasaurus'' by Makádi et al. 2012 it became clear that ''Yaguarasaurus'' and the rest of the "russellosaurines" form a clade of basal amphibian mosasaurs related with the

aigialosaur Aigialosauridae (from Greek, ''aigialos'' = "seashore" and ''sauros''= lizard) is a family of Late Cretaceous semiaquatic pythonomorph lizards closely related to the mosasaurs. Regarded by some paleontologists as a distinct monophyletic group an ...

s, a grouping called the subfamily

Tethysaurinae The Tethysaurinae are a subfamily of mosasaurs, a diverse group of Late Cretaceous marine squamates. Members of the subfamily are informally and collectively known as "tethysaurines" and have been recovered from North America and Africa. Only t ...

; the

cladogram A cladogram (from Greek ''clados'' "branch" and ''gramma'' "character") is a diagram used in cladistics to show relations among organisms. A cladogram is not, however, an evolutionary tree because it does not show how ancestors are related to ...

below follow the analysis of Makádi ''et al.'' de 2012: Palci et al. (2013) describe a new Russellosaurine, ''Romeosaurus'', and created subfamily Yaguarasaurinae, sister group of Tethysaurinae

References

External links

*
''Yaguarasaurus columbianus''
- Paleontología en Colombia {{Taxonbar, from=Q1027664 Russellosaurins Turonian life Mosasaurs of South America Late Cretaceous reptiles of South America Cretaceous Colombia Fossils of Colombia Fossil taxa described in 1994 Taxa named by María Páramo

Etymology

Phylogeny

See also

References

External links