''Comahuesaurus'' (meaning "Comahue 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 ...

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 ...

dinosaur 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 ...

of the family

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 ...

. It was found in the

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 ...

, in

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 ...

and lived during the Early

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 ...

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 ...

. 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 ...

is ''C. windhauseni'', named by Carballido and colleagues in 2012. It had originally been assigned to ''

Limaysaurus ''Limaysaurus'' ("Limay lizard") is a genus represented by a single species of rebbachisaurid sauropod dinosaurs, which lived during the mid-Cretaceous period, about 99.6 to 97 million years ago, in the Cenomanian, in what is now South America ( ...

'' by Salgado ''et al.'' (2004), but was later assigned its own genus based on the presence of diagnostic characters in the caudal centra, pubis and ischium. ''Comahuesaurus'' is known from abundant material compared to other rebbachisaurids; 37 caudal vertebrae, three fragmentary dorsal vertebrae and multiple appendicular elements, including a right humerus, pubis, ischium and a 113 cm long left femur. In their phylogenetic analysis, Carballido ''et al.'' (2012) placed ''Comahuesaurus'' in an intermediate position between basal rebbachisaurids such as '' Histriasaurus'' and the derived clade formed by subfamilies Rebbachisaurinae and

Limaysaurinae Khebbashia is a clade of herbivorous sauropod dinosaurs belonging to the Rebbachisauridae. P. D. Mannion, P. Upchurch, D. Schwarz and O. Wings. (2019). Taxonomic affinities of the putative titanosaurs from the Late Jurassic Tendaguru Formation ...

. It shares with more derived rebbachisaurids a reduced hyposphene-hypantrum system, but hadn't yet completely lost said structure; that change would happen at some further point in the evolution of the clade, as it is so far only known to be fully absent in limaysaurines.

References

Rebbachisaurids Albian life Aptian life Early Cretaceous dinosaurs of South America Cretaceous Argentina Fossils of Argentina Neuquén Basin Fossil taxa described in 2012 {{Sauropodomorph-stub