''Aeolosaurus'' (; "Aeolus' lizard") is a

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

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

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 b ...

dinosaur Dinosaurs are a diverse group of reptiles of the clade Dinosauria. They first appeared during the Triassic Geological period, period, between 243 and 233.23 million years ago (mya), although the exact origin and timing of the #Evolutio ...

from the

Late Cretaceous The Late Cretaceous (100.5–66 Ma) is the more recent 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 ''cre ...

Period Period may refer to: Common uses * Period (punctuation) * Era, a length or span of time *Menstruation, commonly referred to as a "period" Arts, entertainment, and media * Period (music), a concept in musical composition * Periodic sentence (o ...

of what is now

South America South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a considerably smaller portion in the Northern Hemisphere. It can also be described as the southern Subregion#Americas, subregion o ...

. Like most sauropods, it would have been a

quadrupedal Quadrupedalism is a form of Animal locomotion, locomotion in which animals have four legs that are used to weight-bearing, bear weight and move around. An animal or machine that usually maintains a four-legged posture and moves using all four l ...

herbivore A herbivore is an animal anatomically and physiologically evolved to feed on plants, especially upon vascular tissues such as foliage, fruits or seeds, as the main component of its diet. These more broadly also encompass animals that eat ...

with a long neck and tail. ''Aeolosaurus'' is well known for a titanosaur, as it is represented by the remains of several individuals belonging to at least two species. However, like most titanosaurs, no remains of the skull are known. The

holotype A holotype (Latin: ''holotypus'') is a single physical example (or illustration) of an organism used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of s ...

of ''Aeolosaurus rionegrinus'' consists of a series of seven tail

vertebra Each vertebra (: vertebrae) is an irregular bone with a complex structure composed of bone and some hyaline cartilage, that make up the vertebral column or spine, of vertebrates. The proportions of the vertebrae differ according to their spina ...

e, as well as parts of both forelimbs and the right hindlimb. It was discovered in the

Angostura Colorada Formation The Angostura Colorada Formation is a Campanian to Maastrichtian geologic formation of the Neuquén Basin and North Patagonian Massif in the Río Negro Province of Argentina. Dinosaur remains diagnostic to the genus level are among the fossils ...

in Argentina, which dates from the

Campanian The Campanian is the fifth of six ages of the Late Cretaceous epoch on the geologic timescale of the International Commission on Stratigraphy (ICS). In chronostratigraphy, it is the fifth of six stages in the Upper Cretaceous Series. Campa ...

stage of the Late Cretaceous, about 83 to 74

million years ago Million years ago, abbreviated as Mya, Myr (megayear) or Ma (megaannum), is a unit of time equal to (i.e. years), or approximately 31.6 teraseconds. Usage Myr is in common use in fields such as Earth science and cosmology. Myr is also used w ...

. The species ''A. maximus'' was transferred over to the new genus '' Arrudatitan'' in 2021.

Etymology

This dinosaur is named after the

Greek mythological Greek mythology is the body of myths originally told by the ancient Greeks, and a genre of ancient Greek folklore, today absorbed alongside Roman mythology into the broader designation of classical mythology. These stories concern the ancient ...

figure

Aeolus In Greek mythology, Aiolos, transcribed as Aeolus (; ; ) refers to three characters. These three are often difficult to tell apart, and even the ancient mythographers appear to have been perplexed about which Aeolus was which. Diodorus Siculus m ...

, Keeper of the

Wind Wind is the natural movement of atmosphere of Earth, air or other gases relative to a planetary surface, planet's surface. Winds occur on a range of scales, from thunderstorm flows lasting tens of minutes, to local breezes generated by heatin ...

s in

Homer Homer (; , ; possibly born ) was an Ancient Greece, Ancient Greek poet who is credited as the author of the ''Iliad'' and the ''Odyssey'', two epic poems that are foundational works of ancient Greek literature. Despite doubts about his autho ...

Odyssey The ''Odyssey'' (; ) is one of two major epics of ancient Greek literature attributed to Homer. It is one of the oldest surviving works of literature and remains popular with modern audiences. Like the ''Iliad'', the ''Odyssey'' is divi ...

, because of the frequent winds that blow across

Patagonia Patagonia () is a geographical region that includes parts of Argentina and Chile at the southern end of South America. The region includes the southern section of the Andes mountain chain with lakes, fjords, temperate rainforests, and glaciers ...

, where the remains were found. The generic name also includes the

Greek Greek may refer to: Anything of, from, or related to Greece, a country in Southern Europe: *Greeks, an ethnic group *Greek language, a branch of the Indo-European language family **Proto-Greek language, the assumed last common ancestor of all kno ...

''sauros'' ('lizard'), the traditional suffix used in dinosaur names. The

specific Specific may refer to: * Specificity (disambiguation) * Specific, a cure or therapy for a specific illness Law * Specific deterrence, focussed on an individual * Specific finding, intermediate verdict used by a jury in determining the final ...

name (''A. rionegrinus''), refers to its location, in the

Rio Negro Province Rio or Río is the Portuguese and Spanish word for "river". The word also exists in Italian, but is largely obsolete and used in a poetical or literary context to mean "stream". Rio, RIO or Río may also refer to: Places United States * Rio, Fl ...

Argentina Argentina, officially the Argentine Republic, is a country in the southern half of South America. It covers an area of , making it the List of South American countries by area, second-largest country in South America after Brazil, the fourt ...

. Both genus and species were named and described by Argentine

paleontologist Paleontology, also spelled as palaeontology or palæontology, is the scientific study of the life of the past, mainly but not exclusively through the study of fossils. Paleontologists use fossils as a means to classify organisms, measure geolo ...

Jaime Powell Jaime Eduardo Powell (January 13, 1953 – February 1, 2016) was an Argentine paleontologist who described the titanosaur sauropod dinosaur taxa ''Aeolosaurus'' and found evidence that titanosaurs have osteoderms. Research Powell described the f ...

in 1987.

Provenance

''Aeolosaurus'' is a widespread genus of titanosaur known from the

. Fossils have been collected from the

Allen Allen, Allen's or Allens may refer to: Buildings * Allen Arena, an indoor arena at Lipscomb University in Nashville, Tennessee * Allen Center, a skyscraper complex in downtown Houston, Texas * Allen Fieldhouse, an indoor sports arena on the Univ ...

, Angostura Colorada, Lago Colhué Huapí, and Los Alamitos Formations of

and the

Serra da Galga Formation The Serra da Galga Formation is a geological formation in Minas Gerais state of southeastern Brazil. Its strata date back to the Maastrichtian, and are part of the Bauru Group. It was originally considered a member of the Marília Formation. Di ...

Brazil Brazil, officially the Federative Republic of Brazil, is the largest country in South America. It is the world's List of countries and dependencies by area, fifth-largest country by area and the List of countries and dependencies by population ...

. All ''Aeolosaurus'' fossils are from the

and

Maastrichtian The Maastrichtian ( ) is, in the International Commission on Stratigraphy (ICS) geologic timescale, the latest age (geology), age (uppermost stage (stratigraphy), stage) of the Late Cretaceous epoch (geology), Epoch or Upper Cretaceous series (s ...

ages of the

Cretaceous The Cretaceous ( ) is a geological period that lasted from about 143.1 to 66 mya (unit), million years ago (Mya). It is the third and final period of the Mesozoic Era (geology), Era, as well as the longest. At around 77.1 million years, it is the ...

period.

History

The type species of ''Aeolosaurus'', ''Aeolosaurus rionegrinus'', was originally named along with the genus in the doctoral thesis of Jaime E. Powell. However, according to the ICZN, names from dissertations are not valid, so it was not formally named until it was published the following year. Powell's thesis was ultimately published in 2003, which is sometimes incorrectly cited as having named the genus. In 2004, ''Aeolosaurus'' and ''Gondwanatitan'' were recognized as forming a new group of titanosaurs, which was named

Aeolosaurini Aeolosaurini is an extinct clade of titanosaurian dinosaurs known from the Cretaceous period of Argentina and Brazil. Rodrigo M. Santucci and Antonio C. de Arruda-Campos (2011) in their cladistic analysis found ''Aeolosaurus'', '' Gondwanatitan'' ...

. In 2007, a second species, ''A. colhuehuapensis'' was named, also from Patagonia. A third species, ''A. maximus'', was named in 2011. ''A. maximus'' was moved to the genus '' Arrudatitan'' in 2021.

Description

Like all sauropods, ''Aeolosaurus'' was a large, long-necked, quadrupedal herbivore. ''A. rionegrinus'' was roughly 14 meters (46 ft) long and 6 tonnes (6.6 short tons) in weight according to

Gregory S. Paul Gregory Scott Paul (born December 24, 1954) is an American freelance researcher, author and illustrator who works in paleontology. He is best known for his work and research on theropoda, theropod dinosaurs and his detailed illustrations, both l ...

. In 2020 Molina-Pérez and Larramendi gave a larger estimation of 18.1 meters (60 ft) and 14.7 tonnes (16.2 short tons). ''A. rionegrinus'' was heavily built for a titanosaur, with limb bones similar in robustness to those of ''

Saltasaurus ''Saltasaurus'' (which means "lizard from Salta") is a genus of saltasaurid dinosaur of the Late Cretaceous Period (geology), period of Argentina. Small among sauropods, though still heavy by the standards of modern creatures, ''Saltasaurus'' was ...

.'' Aeolosaurs, ''Aeolosaurus'' in particular, have very distinctive caudal vertebrae. The genus ''Aeolosaurus'' is diagnosed by the shared presence of down-curved prezygapophyses on its anterior caudal vertebrae and chevrons from the anterior and middle portions of the tail with concave posterodorsal surfaces that contain double articular facets. The caudal vertebrae of ''Aeolosaurus'' and the related genus ''Gondwanatitan'' share anteriorly-inclined neural spines in the anterior caudal vertebrae. The vertebrae from the middle part of its tail had elongated

centra Centra is a convenience shop chain that operates throughout Ireland. The chain operates as a symbol group owned by Musgrave Group, the food wholesaler, meaning the individual shops are all owned by individual franchisees. The chain has three ...

. ''Aeolosaurus'' had vertebral lateral fossae that resembled shallow depressions. Fossae that similarly resemble shallow depressions are known from ''

'', ''

Alamosaurus ''Alamosaurus'' (; meaning "Ojo Alamo lizard") is a genus of titanosaurian sauropod dinosaurs containing a single known species, ''Alamosaurus sanjuanensis'', from the Maastrichtian age of the Late Cretaceous period in what is now southwestern ...

'', ''

Malawisaurus ''Malawisaurus'' (meaning "Malawi lizard") is an extinct genus of titanosaurian sauropod dinosaur. It is known from the Dinosaur Beds of northern Malawi, which probably date to the Aptian stage of the Early Cretaceous. The type species is ''M. di ...

'', and '' Gondwanatitan''. Its middle tail vertebrae's

neural spines Each vertebra (: vertebrae) is an irregular bone with a complex structure composed of bone and some hyaline cartilage, that make up the vertebral column or spine, of vertebrates. The proportions of the vertebrae differ according to their spinal ...

angled anteriorly when the vertebrae are aligned. These vertebrae resemble those of ''

Cedarosaurus ''Cedarosaurus'' (meaning "Cedar lizard" - named after the Cedar Mountain Formation, in which it was discovered) is a genus of nasal-crested macronarian dinosaur from the Early Cretaceous Period (Valanginian). It was a sauropod which lived in wha ...

'', ''

Venenosaurus ''Venenosaurus'' ( ) is a genus of sauropod dinosaur that lived in what is now Utah during the Early Cretaceous. Its type and only species is ''Venenosaurus dicrocei''. Fossils of ''Venenosaurus'' were first discovered in 1998, by Denver Museum o ...

'', and ''Gondwanatitan''. The tail of ''Aeolosaurus'' was apparently curved strongly downward, a trait likely shared with other members of Aeolosaurini. This curvature would likely have led to the posterior portion of the tail being very low to the ground, though likely not touching it. The curved base of the tail may have enabled the m. caudofemoralis longus, which extended from the femur to the tail vertebrae, to exert more force while retracting the hindlimb. ''Aeolosaurus'', like many lithostrotian titanosaurs, bore osteoderms. However, its osteoderms were unusual and most closely resemble those of '' Mendozasaurus''. As in all osteoderm-bearing titanosaurs, the osteoderms were probably arranged in one or two rows along the flanks.

Classification

''Aeolosaurus'' is most closely related to the genera '' Gondwanatitan'' and ''

Panamericansaurus ''Panamericansaurus'' (meaning " Pan American Energy lizard") is a genus of titanosaurian sauropod dinosaur from the Late Cretaceous Period of Argentina. The holotype is very similar to known fossil material of ''Aeolosaurus'', which ''Panamerica ...

''. Together with ''Gondwanatitan'', it defines the clade

. The two ''Aeolosaurus'' species from

, ''A. rionegrinus'' and ''A. colhuehuapensis'', appear to be more closely related to each other than to the Brazilian species ''A. maximus''.

The classification of ''Aeolosaurus'' and its relatives is heavily based on features of the tail vertebrae, which are the only bones preserved in most aeolosaurs. ''Aeolosaurus'' has been included in several cladistic analyses. The phylogeny of Aeolosaurini here is based on Gallina and Otero 2015, with the application of clade names according to their phylogenetic definitions.

Species

There are currently two named valid species of ''Aeolosaurus'', as well as several specimens that have been referred to the genus but not given a species. In addition, ''Gondwanatitan faustoi,'' the closest known relative of the genus, has been proposed to represent an additional species of ''Aeolosaurus'', as ''Aeolosaurus faustoi''. However, ''Gondwanatitan'' is typically considered a distinct genus. *''Aeolosaurus rionegrinus'' is the type species of ''Aeolosaurus''. It is known from a single specimen, MJG-R 1, that consists of seven caudal vertebrae and many appendicular elements. Its limb bones suggest that it was heavily built, similar to ''

''. It is found in the

. *''Aeolosaurus colhuehuapensis'' is known only from 21 caudal vertebrae. It is found in the Lago Colhue Huapi Formation of

.Casal GA, Allard JO and Foix N (2015) Análisis estratigráfico y paleontológico del Cretácico Superior en la Cuenca del Golfo San Jorge: nueva unidad litoestratigráfica para el Grupo Chubut. Revista de la Asociación Geológica Argentina 72: 77–95. Aeolosaurus forelimb

Another specimen, described in 1993, consists of five tail vertebrae, and some bones from the forelimb and

pelvis The pelvis (: pelves or pelvises) is the lower part of an Anatomy, anatomical Trunk (anatomy), trunk, between the human abdomen, abdomen and the thighs (sometimes also called pelvic region), together with its embedded skeleton (sometimes also c ...

. Since there are two right

ulna The ulna or ulnar bone (: ulnae or ulnas) is a long bone in the forearm stretching from the elbow to the wrist. It is on the same side of the forearm as the little finger, running parallel to the Radius (bone), radius, the forearm's other long ...

(forearm) bones, the specimen must consist of at least two individuals. These bones were also associated with two

osteoderms Osteoderms are bony deposits forming scales, plates, or other structures based in the dermis. Osteoderms are found in many groups of Extant taxon, extant and extinct reptiles and amphibians, including lizards, crocodilians, frogs, Temnospondyli, ...

, or bony

armor Armour (Commonwealth English) or armor (American English; see American and British English spelling differences#-our, -or, spelling differences) is a covering used to protect an object, individual, or vehicle from physical injury or damage, e ...

plates, providing evidence that this dinosaur was armored. This specimen is from the

Allen Formation The Allen Formation is a geological formation in Argentina whose strata date back to the Late Cretaceous (middle Campanian to early Maastrichtian.Salgado et al., 2007 Dinosaur remains are among the fossils that have been recovered from the forma ...

of Rio Negro, dating back about 70 to 68 million years ago to the middle

stage. While this specimen bears features that characterize the genus ''Aeolosaurus'', it is from a younger time period and shows enough differences that the authors recognized it as a possible second species. Additional material from the same quarry, described in 2013, shows that the quarry contained the remains at least three individuals of ''Aeolosaurus''. Another partial skeleton, including four more tail vertebrae and material from both limbs on the left side of the body, was described in 1997. This was recovered from the

Los Alamitos Formation The Los Alamitos Formation is a geological Formation (geology), formation of the North Patagonian Massif in Rio Negro Province, northwestern Patagonia, Argentina, whose strata date back to the Late Cretaceous (Campanian, Late Campanian to Maastri ...

of Rio Negro, which falls between the other two dates. This specimen was also referred to the genus ''Aeolosaurus'', but not to the species ''A. rionegrinus'', and may represent a third species. However, since the genus ''Aeolosaurus'' is not well known, the authors chose not to formally name either of these possible new species. For now, they are both simply known as "''Aeolosaurus'' sp." Future discoveries may give scientists more information on variation within the genus, and show that all of the above specimens belong to ''A. rionegrinus'', or that they merit being formally named. A middle caudal vertebra from the

, CPP 248, cannot be evaluated for any diagnostic features of the genus ''Aeolosaurus''. However, because it clearly does not belong to '' Gondwanatitan'', it is most likely that this vertebra represents ''Aeolosaurus'', a genus otherwise unknown from the

. Another series of 15 tail vertebrae was assigned to ''Aeolosaurus'' in the original description, but it was later determined that the series does not belong to this genus, as it lacks several features found in the other specimens of ''Aeolosaurus''.

Paleoecology

''Aeolosaurus'' lived during the

and

ages of the

and shared its environment with

hadrosaurs Hadrosaurids (), also hadrosaurs or duck-billed dinosaurs, are members of the ornithischian family Hadrosauridae. This group is known as the duck-billed dinosaurs for the flat duck-bill appearance of the bones in their snouts. The ornithopod fami ...

. The unnamed

species of ''Aeolosaurus'' inhabited an environment that it shared with five other species of titanosaur, including '' Rocasaurus muniozi'', as well as hadrosaurs and ankylosaurs.

References

{{Taxonbar, from=Q131766 Lithostrotia Dinosaur genera Campanian dinosaurs Dinosaurs of Argentina Fossil taxa described in 1987 Taxa named by Jaime Powell