Limaysaurus
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''Limaysaurus'' ("Limay lizard") is a
genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...
represented by a single species of rebbachisaurid
sauropod Sauropoda (), whose members are known as sauropods (; from '' sauro-'' + '' -pod'', 'lizard-footed'), is a clade of saurischian ('lizard-hipped') dinosaurs. Sauropods had very long necks, long tails, small heads (relative to the rest of their bo ...
dinosaurs Dinosaurs are a diverse group of reptiles of the clade Dinosauria. They first appeared during the Triassic period, between 243 and 233.23 million years ago (mya), although the exact origin and timing of the evolution of dinosaurs is t ...
, which lived during the mid-
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 th ...
period, about 99.6 to 97 million years ago, in the
Cenomanian The Cenomanian is, in the ICS' geological timescale, the oldest or earliest age of the Late Cretaceous Epoch or the lowest stage of the Upper Cretaceous Series. An age is a unit of geochronology; it is a unit of time; the stage is a unit in the s ...
, in what is now
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 southe ...
(northwestern
Patagonia Patagonia () refers to a geographical region that encompasses the southern end of South America, governed by Argentina and Chile. The region comprises the southern section of the Andes Mountains with lakes, fjords, temperate rainforests, and gl ...
).


Description

''Limaysaurus'' was a medium-sized sauropod.
Gregory S. Paul Gregory Scott Paul (born December 24, 1954) is an American freelance researcher, author and illustrator who works in paleontology, and more recently has examined sociology and theology. He is best known for his work and research on theropod dino ...
in 2010 estimated its length at fifteen meters (50 ft) and its weight at seven
tonnes The tonne ( or ; symbol: t) is a unit of mass equal to 1000 kilograms. It is a non-SI unit accepted for use with SI. It is also referred to as a metric ton to distinguish it from the non-metric units of the short ton ( United States ...
.Paul, G.S., 2010, ''The Princeton Field Guide to Dinosaurs'', Princeton University Press, pp. 186 and 208. The neural spines on its back were very tall. The neural spines of the cervical and dorsal vertebrae are not V-shaped but they have a simple and straight form like an I. Its teeth were curved, unlike those of ''
Diplodocus ''Diplodocus'' (, , or ) was a genus of diplodocid sauropod dinosaurs, whose fossils were first discovered in 1877 by S. W. Williston. The generic name, coined by Othniel Charles Marsh in 1878, is a neo-Latin term derived from Greek διπΠ...
'' which were pencil-shaped. Another distinct characteristic of this sauropod is its
phylogenetic In biology, phylogenetics (; from Greek φυλή/ φῦλον [] "tribe, clan, race", and wikt:γενετικός, γενετικός [] "origin, source, birth") is the study of the evolutionary history and relationships among or within groups o ...
relationship to ''
Rebbachisaurus ''Rebbachisaurus'' (meaning " Aït Rebbach lizard") is a genus of sauropod dinosaur of the superfamily Diplodocoidea, that lived during the Late Cretaceous period in Africa and possibly also South America about 99-97 million years ago. Remains a ...
'' from
Morocco Morocco (),, ) officially the Kingdom of Morocco, is the westernmost country in the Maghreb region of North Africa. It overlooks the Mediterranean Sea to the north and the Atlantic Ocean to the west, and has land borders with Algeria to ...
. This discovery supports the theory that there was a
land bridge In biogeography, a land bridge is an isthmus or wider land connection between otherwise separate areas, over which animals and plants are able to cross and Colonisation (biology), colonize new lands. A land bridge can be created by marine regre ...
connecting South America to
Africa Africa is the world's second-largest and second-most populous continent, after Asia in both cases. At about 30.3 million km2 (11.7 million square miles) including adjacent islands, it covers 6% of Earth's total surface area ...
100 million years ago. It shared its habitat with ''
Andesaurus ''Andesaurus'' ( ; "Andes lizard") is a genus of basal titanosaurian sauropod dinosaur which existed during the middle of the Cretaceous Period in South America. Like most sauropods, belonging to one of the largest animals ever to walk the Ea ...
'' and ''
Giganotosaurus ''Giganotosaurus'' ( ) is a genus of theropod dinosaur that lived in what is now Argentina, during the early Cenomanian age of the Late Cretaceous period, approximately 99.6 to 95 million years ago. The holotype specimen was discovered in the ...
'', characterized by plains with large and shallow lagoons. The climate was mild and humid. In fossil remains of ''Limaysaurus'',
gastroliths A gastrolith, also called a stomach stone or gizzard stone, is a rock held inside a gastrointestinal tract. Gastroliths in some species are retained in the muscular gizzard and used to grind food in animals lacking suitable grinding teeth. In oth ...
have been found, which were used to help the stomach to grind food.


Discovery

''Limaysaurus'' includes a single
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 ...
, ''Limaysaurus tessonei'', which was originally referred to the genus ''Rebbachisaurus'' as ''Rebbachisaurus tessonei'', an African species, by Jorge Calvo and
Leonardo Salgado Leonardo Salgado is an Argentinean palaeontologist with a special interest in dinosaurs of the Cretaceous period and other investigations of the palaeobiology of fossil bearing geological formations. Salgado is the leading or coauthor of several t ...
in 1995.Calvo, J. O. and Salgado, L. (1995).
''Rebbachisaurus tessonei'' sp. nov. A new sauropod from the Albian-Cenomanian of Argentina; new evidence on the origin of the Diplodocidae
" ''Gaia'', 11: 13-33.
However, a generic separation was proposed by Salgado,
Alberto Garrido Alberto Rafael Garrido García (3 September 1949 – 4 December 2007) was an Argentine–Venezuelan journalist, political analyst and writer known for his works on Hugo Chávez. The focus of a better part of his career, his extensive knowledge ...
, Sergio Cocca and
Juan Cocca ''Juan'' is a given name, the Spanish and Manx versions of ''John''. It is very common in Spain and in other Spanish-speaking communities around the world and in the Philippines, and also (pronounced differently) in the Isle of Man. In Spanish, t ...
, and the genus ''Limaysaurus'' was named in 2004. The generic name is derived from
Río Limay The Limay River is an important river in the northwestern Argentine Patagonia (the region of Comahue). It originates at the eastern end of the Nahuel Huapi Lake and flows in a meandering path for about , collecting the waters of several tributar ...
which borders the region and from the specific name, ''tessonei'', in honor of Lieto Tessone, who found the first and most complete
holotype A holotype is a single physical example (or illustration) of an organism, known to have been used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of several ...
. Their discovery shed some light on the distribution of
Gondwanan Gondwana () was a large landmass, often referred to as a supercontinent, that formed during the late Neoproterozoic (about 550 million years ago) and began to break up during the Jurassic period (about 180 million years ago). The final stages ...
dinosaurs in the mid-Cretaceous period. Several specimens of ''Limaysaurus'' are known, one of which (the holotype) is 80% complete, being one of the most complete Cretaceous sauropods ever found in South America. The holotype specimen, MUCPv-205, a partial skeleton including the back of the skull, was found in 1988 by Lieto Francisco Tessone, who is honoured in the specific name. It was afterwards collected, together with MUCPv-206, a second fragmentary skeleton, by
José Bonaparte José Fernando Bonaparte (14 June 1928 – 18 February 2020) was an Argentine paleontologist who discovered a plethora of South American dinosaurs and mentored a new generation of Argentine paleontologists . One of the best-known Argentine paleo ...
. These two adult specimens likely hailed from the top of the
Candeleros Formation The Candeleros Formation (formerly known as the Candeleros Member of the "Río Limay Formation") is a geologic formation that crops out in the Río Negro, Neuquén, and Mendoza provinces of northern Patagonia, Argentina. It is the oldest formati ...
, which is dated to the early Cenomanian age. An additional smaller specimen, MUCPv-153, was found nearby, although it belonged to the base of the
Huincul Formation The Huincul Formation is a geologic formation of Late Cretaceous ( Early Cenomanian to Late Turonian) age of the Neuquén Basin that outcrops in the Mendoza, Río Negro and Neuquén Provinces of northern Patagonia, Argentina.
, from the late Cenomanian. ''Limaysaurus'' was found 15 km (9 mi) southwest of
Villa El Chocón Villa El Chocón is a village and municipality in Neuquén Province in southwestern Argentina. The village was initially created to house the workmen building the Ezequiel Ramos Mexía dam (colloquially known as El Chocón Dam) on the Limay River. ...
,
Picún Leufú Department Picún Leufú is a department located in the east of Neuquén Province, Argentina. Geography The Department limits with Confluencia Department at northeast, Rio Negro Province at southeast, Collón Curá Department at southwest, Catán Lil Dep ...
,
Neuquén Province Neuquén () is a province of Argentina, located in the west of the country, at the northern end of Patagonia. It borders Mendoza Province to the north, Rio Negro Province to the southeast, and Chile to the west. It also meets La Pampa Province a ...
, Patagonia,
Argentina Argentina (), officially the Argentine Republic ( es, link=no, República Argentina), is a country in the southern half of South America. Argentina covers an area of , making it the second-largest country in South America after Brazil, th ...
. The sediments belong to the
Río Limay Subgroup The Río Limay Subgroup is a geological unit of the Neuquén Group in the Neuquén Basin of Neuquén, Mendoza and Río Negro Provinces, northern Patagonia, Argentina. The strata date back to the Late Cretaceous ( Early Cenomanian to Early Turonia ...
, in
Lohan Cura Formation The Lohan Cura Formation is a geologic formation with outcrops in the Argentine provinces of Río Negro, Neuquén, and Mendoza. It is the second oldest Cretaceous terrestrial formation in the Neuquén Basin. The Lohan Cura Formation unconformabl ...
, at Cerro Aguada del León. These beds appear to date from the
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), a ...
-
Albian The Albian is both an age of the geologic timescale and a stage in the stratigraphic column. It is the youngest or uppermost subdivision of the Early/Lower Cretaceous Epoch/Series. Its approximate time range is 113.0 ± 1.0 Ma to 100.5 ± 0.9 M ...
interval, although these fossils were later named '' Comahuesaurus''.


Classification

The describing authors in 2004 assigned ''Limaysaurus'' to the
family Family (from la, familia) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its ...
Rebbachisauridae Rebbachisauridae is a family of sauropod dinosaurs known from fragmentary fossil remains from the Cretaceous of South America, Africa, North America, Europe and possibly Central Asia. Taxonomy In 1990 sauropod specialist Jack McIntosh included t ...
. The rebbachisaurids are a basal
clade A clade (), also known as a monophyletic group or natural group, is a group of organisms that are monophyletic – that is, composed of a common ancestor and all its lineal descendants – on a phylogenetic tree. Rather than the English term, ...
within the Diplodocimorpha, and their remains have been found in Cretaceous-age
rocks In geology, rock (or stone) is any naturally occurring solid mass or aggregate of minerals or mineraloid matter. It is categorized by the minerals included, its chemical composition, and the way in which it is formed. Rocks form the Earth's ...
in
Europe Europe is a large peninsula conventionally considered a continent in its own right because of its great physical size and the weight of its history and traditions. Europe is also considered a Continent#Subcontinents, subcontinent of Eurasia ...
, South America, and Africa. A
cladistic Cladistics (; ) is an approach to biological classification in which organisms are categorized in groups (" clades") based on hypotheses of most recent common ancestry. The evidence for hypothesized relationships is typically shared derived char ...
analysis of
macronaria Macronaria is a clade of sauropod dinosaurs. Macronarians are named after the large diameter of the nasal opening of their skull, known as the external naris, which exceeded the size of the orbit, the skull opening where the eye is located (hence ...
n sauropods (Salgado et al., 2004) demonstrated close affinities between ''Limaysaurus'', the African genera ''Rebbachisaurus'' and ''
Nigersaurus ''Nigersaurus'' is a genus of rebbachisaurid sauropod dinosaur that lived during the middle Cretaceous period, about 115 to 105 million years ago. It was discovered in the Elrhaz Formation in an area called Gadoufaoua, in Niger. Fossils of th ...
'', and the South American genera ''
Rayososaurus ''Rayososaurus'' is a genus of plant-eating sauropod dinosaur of the superfamily Diplodocoidea. It was found in the Candeleros Formation, but was named ''Rayososaurus'' after the Rayoso Member, which later has been elevated to the older Rayoso ...
'' and '' Cathartesaura''. Salgado, L., Garrido, A., Cocca, S. E., and Cocca, J. R. (2004). "Lower Cretaceous rebbachisaurid sauropods from Cerro Aguada Del León, Neuquén Province, northwestern Patagonia, Argentina." ''Journal of Vertebrate Paleontology'', 24(4): 903-912, December 2004.


References


External links


Limaysaurus (Diplodocoidea) in The Thescelsossaurus

{{Taxonbar, from=Q137252 Rebbachisaurids Cenomanian life Early Cretaceous dinosaurs of South America Cretaceous Argentina Candeleros Formation Huincul Formation Fossils of Argentina Fossil taxa described in 2004