''Elaltitan'' is an

extinct Extinction is the termination of a kind of organism or of a group of kinds (taxon), usually a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and ...

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 ...

of large lithostrotian

titanosaur Titanosaurs (or titanosaurians; members of the group Titanosauria) were a diverse group of sauropod dinosaurs, including genera from all seven continents. The titanosaurs were the last surviving group of long-necked sauropods, with taxa still th ...

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 ...

known 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'', the ...

(mid

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 ...

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 by t ...

stage) of

Chubut Province Chubut ( es, Provincia del Chubut, ; cy, Talaith Chubut) is a province in southern Argentina, situated between the 42nd parallel south (the border with Río Negro Province), the 46th parallel south (bordering Santa Cruz Province), the Andes ra ...

, southern

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 ...

. It contains a single species, ''Elaltitan lilloi''.

Etymology

''Elaltitan'' was first described and named by Philip D. Mannion and Alejandro Otero in

2012 File:2012 Events Collage V3.png, From left, clockwise: The passenger cruise ship Costa Concordia lies capsized after the Costa Concordia disaster; Damage to Casino Pier in Seaside Heights, New Jersey as a result of Hurricane Sandy; People gather ...

and 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 ''Elaltitan lilloi''. The generic name is derived from ''Elal'' (pronounced as "ee-lal") - the god of the

Tehuelche people The Tehuelche people, also called the Aónikenk, are an indigenous people from eastern Patagonia in South America. In the 18th and 19th centuries the Tehuelche were influenced by Mapuche people, and many adopted a horseriding lifestyle. Once a ...

and ''

titan Titan most often refers to: * Titan (moon), the largest moon of Saturn * Titans, a race of deities in Greek mythology Titan or Titans may also refer to: Arts and entertainment Fictional entities Fictional locations * Titan in fiction, fictiona ...

'', giant in

Greek mythology A major branch of classical mythology, Greek mythology is the body of myths originally told by the Ancient Greece, ancient Greeks, and a genre of Ancient Greek folklore. These stories concern the Cosmogony, origin and Cosmology#Metaphysical co ...

. The

specific name Specific name may refer to: * in Database management systems, a system-assigned name that is unique within a particular database In taxonomy, either of these two meanings, each with its own set of rules: * Specific name (botany), the two-part (bino ...

, ''lilloi'', honors Miguel Lillo, for his contribution and legacy to natural sciences in Tucumán.

Discovery

''Elaltitan'' is known only from a single individual, represented by an associated partial postcranial

skeleton A skeleton is the structural frame that supports the body of an animal. There are several types of skeletons, including the exoskeleton, which is the stable outer shell of an organism, the endoskeleton, which forms the support structure inside ...

. The

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 ...

includes both PVL 4628 and MACN-CH 217 comprising three dorsal vertebrae, two

caudal vertebrae 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 ...

, left

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 ...

, left

humerus The humerus (; ) is a long bone in the arm that runs from the shoulder to the elbow. It connects the scapula and the two bones of the lower arm, the radius and ulna, and consists of three sections. The humeral upper extremity consists of a roun ...

, left

radius In classical geometry, a radius ( : radii) of a circle or sphere is any of the line segments from its center to its perimeter, and in more modern usage, it is also their length. The name comes from the latin ''radius'', meaning ray but also the ...

, both

ulnae The ulna (''pl''. ulnae or ulnas) is a long bone found in the forearm that stretches from the elbow to the smallest finger, and when in anatomical position, is found on the medial side of the forearm. That is, the ulna is on the same side of the ...

, right pubis, proximal half of right

femur The femur (; ), or thigh bone, is the proximal bone of the hindlimb in tetrapod vertebrates. The head of the femur articulates with the acetabulum in the pelvic bone forming the hip joint, while the distal part of the femur articulates with ...

, distal part of left

tibia The tibia (; ), also known as the shinbone or shankbone, is the larger, stronger, and anterior (frontal) of the two bones in the leg below the knee in vertebrates (the other being the fibula, behind and to the outside of the tibia); it connects ...

, distal two-thirds of left

fibula The fibula or calf bone is a leg bone on the lateral side of the tibia, to which it is connected above and below. It is the smaller of the two bones and, in proportion to its length, the most slender of all the long bones. Its upper extremity is ...

, right astragalus and

calcaneum In humans and many other primates, the calcaneus (; from the Latin ''calcaneus'' or ''calcaneum'', meaning heel) or heel bone is a bone of the tarsus of the foot which constitutes the heel. In some other animals, it is the point of the hock. St ...

. ''Elaltitan'' is the first titanosaur skeleton to preserve an associated calcaneum. Although all of the material was originally housed in the Colección de Paleontología de Vertebrados de la Fundación Instituto Miguel Lillo in Tucumán, Argentina and accessioned as PVL 4628, the dorsal vertebrae and complete caudal vertebra were subsequently moved to the Museo Argentino de Ciencias Naturales “Bernardino Rivadavia” in Buenos Aires, where they were accessioned as MACN-CH 217. The holotype specimen was collected by an expedition of the Fundación Miguel Lillo and the Universidad Nacional de Tucumán, led by

José Fernando Bonaparte José is a predominantly Spanish and Portuguese form of the given name Joseph. While spelled alike, this name is pronounced differently in each language: Spanish ; Portuguese (or ). In French, the name ''José'', pronounced , is an old vernacul ...

, from the right (southern) bank of the

Senguerr River The Senguerr River is a river of the Argentine province A province is almost always an administrative division within a country or state. The term derives from the ancient Roman '' provincia'', which was the major territorial and administra ...

, in the area between the bend of this river and the Pampa de María Santísima, southeast of the southernmost part of the Sierra de San Bernardo,

. It came from the lower member of the

Bajo Barreal Formation The Bajo Barreal Formation is a geological formation in the Golfo San Jorge Basin of Chubut and Santa Cruz, Argentina whose strata date back to the Middle Cenomanian to Late Turonian. The formation was first described by Teruggi & Rossetto in ...

, dating to the middle

to the

stage of the

period, about 96.5-89.3

million years ago The abbreviation Myr, "million years", is a unit of a quantity of (i.e. ) years, or 31.556926 teraseconds. Usage Myr (million years) is in common use in fields such as Earth science and cosmology. Myr is also used with Mya (million years ago). ...

Description

The

of ''Elaltitan'' was originally attributed to ''

Antarctosaurus ''Antarctosaurus'' (; meaning "southern lizard") is a genus of titanosaurian sauropod dinosaur from the Late Cretaceous Period of what is now South America. The type species, ''Antarctosaurus wichmannianus'', and a second species, ''Antarctosau ...

sp.'' by Bonaparte & Gasparini (1979), and later tentatively referred to ''

Argyrosaurus ''Argyrosaurus'' ( ) is a genus of titanosaurian sauropod dinosaur that lived about 70 million years ago, during the Late Cretaceous Period of what is now Argentina. Discovery and naming The type species, ''Argyrosaurus superbus'', was formall ...

'' by Jaime Powell (1986, 2003). Philip D. Mannion and Alejandro Otero (2012), who named the genus, diagnosed ''Elaltitan'' by a unique combination of characters, as well as one

autapomorphy In phylogenetics, an autapomorphy is a distinctive feature, known as a derived trait, that is unique to a given taxon. That is, it is found only in one taxon, but not found in any others or outgroup taxa, not even those most closely related to t ...

. The autapomorphy (unique trait) is the presence of dorsoventrally tall neural arch restricted to anterior half of centrum (excluding condylar ball) in anterior-most

. Other unusual characters include a spinopostzygapophyseal laminae in middle–posterior dorsal vertebrae bifurcate into medial and lateral branches, an astragalar ascending process that does not extend to the posterior margin of the astragalus and the presence of a calcaneum. Other potentially unusual features were also listed. These traits distinguish ''Elaltitan'' from all other titanosauriforms, including ''

'' and ''

'', as well as other sauropods from the lower member of the Bajo Barreal Formation, such as ''

Drusilasaura ''Drusilasaura'' is an extinct genus of possible lognkosaurian titanosaur sauropod dinosaur which lived during the late Cretaceous (Cenomanian-Turonian stage) of Santa Cruz Province of southern Patagonia, Argentina. ''Drusilasaura'' is known fr ...

'' and '' Epachthosaurus''. Based on comparisons with the morphologically similar

of "

''" giganteus'', which was measured as in length, the complete femur of ''Elaltitan'' would be approximately the same size. This makes it one of the largest known

s ever to have existed. Mannion & Otero (2012) also pointed out that there are currently 39 Cretaceous South American titanosauriform genera considered to be valid, the majority of which (31) are from Argentina. Its weight has been estimated at in 2014, and at in 2018. However, in 2020 Molina-Perez and Larramendi gave a smaller size of 20 meters (66 ft) and 23 tonnes (25.35 short tons).

References

{{Taxonbar, from=Q966487 Lithostrotians Monotypic dinosaur genera Cenomanian life Turonian life Late Cretaceous dinosaurs of South America Cretaceous Argentina Fossils of Argentina Bajo Barreal Formation Fossil taxa described in 2012