''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 nom ...

mosasauroid Mosasaurs (from Latin ''Mosa'' meaning the 'Meuse', and Greek ' meaning 'lizard') comprise a group of extinct, large marine reptiles from the Late Cretaceous. Their first fossil remains were discovered in a limestone quarry at Maastricht on the ...

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 b ...

) 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 sout ...

. 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 in Bogotá. 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, member of the Villeta Group, near Yaguará, Huila, in a site called Cueva Rica.''Yaguarasaurus columbianus''
at Fossilworks.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 occu ...

; 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 ''Tethysaurus'' is an extinct genus of tethysaurine mosasauroid from the Early Turonian (Late Cretaceous) period. The only species is ''Tethysaurus nopcsai''. Discovery The name means "Tethys' lizard of Nopcsa", a reference to the Greek godd ...

nopscai'', a group that could be a basal clade to the division between Tylosaurinae and Plioplatecarpinae subfamilies, called Russellosaurina. After the discovery of the basal mosasauroid of Hungary ''

Pannoniasaurus ''Pannoniasaurus'' is an extinct genus of tethysaurine mosasauroid known from the Late Cretaceous Csehbánya Formation (Santonian stage) of Hungary. It contains a single species, ''Pannoniasaurus inexpectatus'', Material was copied from this sou ...

'' 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 aigialosaurs, 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 two ...

; 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