''Bonitasaura'' 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 ...

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 ...

hailing from uppermost layers of 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 ...

(

Santonian The Santonian is an age in the geologic timescale or a chronostratigraphic stage. It is a subdivision of the Late Cretaceous Epoch or Upper Cretaceous Series. It spans the time between 86.3 ± 0.7 mya ( million years ago) and 83.6 ± 0.7 m ...

)

Bajo de la Carpa Formation The Bajo de la Carpa Formation is a geologic formation of the Neuquén Basin that outcrop, crops out in northern Patagonia, in the provinces of Río Negro Province, Río Negro and Neuquén Province, Neuquén, Argentina. It is the oldest of two for ...

Neuquén Group The Neuquén Group is a geologic unit, group of geologic formations found in Argentina. Rocks in the Neuquén Group fall within the Cenomanian to early Campanian stages of the Late Cretaceous Period. It overlies the older Lohan Cura Formation and ...

of the eastern

Neuquén Basin Neuquén Basin () is a sedimentary basin covering most of Neuquén Province in Argentina. The basin originated in the Jurassic and developed through alternating continental and marine conditions well into the Tertiary. The basin bounds to the wes ...

, located in

Río Negro Province Río Negro (, ''Black River'') is a province of Argentina, located in northern Patagonia. Neighboring provinces are from the south clockwise Chubut, Neuquén, Mendoza, La Pampa and Buenos Aires. To the east lies the Atlantic Ocean. Its cap ...

, Northwestern

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 ...

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 ...

. The remains, consisting of a partial sub-adult skeleton jumbled in a small area of

fluvial A river is a natural stream of fresh water that flows on land or inside caves towards another body of water at a lower elevation, such as an ocean, lake, or another river. A river may run dry before reaching the end of its course if it ru ...

sandstone Sandstone is a Clastic rock#Sedimentary clastic rocks, clastic sedimentary rock composed mainly of grain size, sand-sized (0.0625 to 2 mm) silicate mineral, silicate grains, Cementation (geology), cemented together by another mineral. Sand ...

, including a

lower jaw In jawed vertebrates, the mandible (from the Latin ''mandibula'', 'for chewing'), lower jaw, or jawbone is a bone that makes up the lowerand typically more mobilecomponent of the mouth (the upper jaw being known as the maxilla). The jawbone i ...

with teeth, a partial vertebrae series, and limb bones, were described by Sebastian Apesteguía in 2004. The genus name ''Bonitasaura'' refers to the

fossil A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserve ...

quarry's name, "La Bonita", while the name of the

type species In International_Code_of_Zoological_Nomenclature, 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 spe ...

, ''B. salgadoi'', pays homage to Leonardo Salgado, a renowned 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 ...

.Gallina, P. A. (2011)
Notes on the axial skeleton of the titanosaur Bonitasaura salgadoi (Dinosauria-Sauropoda).
''Anais da Academia Brasileira de Ciências'', ''83''(1), 235-246.

Description

''Bonitasaura'' measured in length, and had a skull similar to another group of

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 ...

s, the

diplodocid Diplodocids, or members of the family Diplodocidae ("double beams"), are a group of sauropod dinosaurs. The family includes some of the longest creatures ever to walk the Earth, including '' Diplodocus'' and '' Supersaurus'', some of which may ha ...

s. The lower jaw had a distinctive, sharp ridge immediately behind a reduced set of teeth. This ridge supported in life a sharp, beak-like

keratin Keratin () is one of a family of structural fibrous proteins also known as ''scleroproteins''. It is the key structural material making up Scale (anatomy), scales, hair, Nail (anatomy), nails, feathers, horn (anatomy), horns, claws, Hoof, hoove ...

sheath that probably paired with a similar structure in the upper jaw. The keratin sheath worked much like a

guillotine A guillotine ( ) is an apparatus designed for effectively carrying out executions by Decapitation, beheading. The device consists of a tall, upright frame with a weighted and angled blade suspended at the top. The condemned person is secur ...

to crop vegetation raked into the mouth by the peg-like front teeth. This animal also had a rather short neck and robust projections of the back vertebrae for muscle attachment, indicating that the neck was used in vigorous exertions, probably during feeding. Bonitasaura salgadoi Skeletal

''Bonitasaura'' also shows that some lines of titanosaurian evolution converged with diplodocids, namely low long skulls without the characteristic nasal arches of other

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 ...

ns (such as ''

Brachiosaurus ''Brachiosaurus'' () is a genus of sauropod dinosaur that lived in North America during the Late Jurassic, about . It was first Species description, described by American paleontologist Elmer S. Riggs in 1903 in paleontology, 1903 from fossi ...

'' or ''

Camarasaurus ''Camarasaurus'' ( ) is a genus of sauropod dinosaur that lived in North America during the Late Jurassic period. Its fossil remains have been found in the Morrison Formation, dating to the Kimmeridgian and Tithonian ages of the Jurassic, betwe ...

'') and lower jaws that were squared off and contained comb-like teeth (as in

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 ...

), reversed limb proportions (the front limbs shorter than the hind limbs, unlike the condition in most other macronarians) and rudimentary whiplash tails. It also made the suggestion that the titanosaur ''

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

'' is a

chimera Chimera, Chimaera, or Chimaira (Greek for " she-goat") originally referred to: * Chimera (mythology), a fire-breathing monster of ancient Lycia said to combine parts from multiple animals * Mount Chimaera, a fire-spewing region of Lycia or Cilicia ...

made up of a titanosaurian skull and body and a diplodocoid jaw, as proposed by some authors (McIntosh 1990; Jacobs et al. 1993; Upchurch 1999) less likely.Apesteguía, S. (2004). Bonitasaura salgadoi gen. et sp. nov.: a beaked sauropod from the Late Cretaceous of Patagonia. ''Naturwissenschaften'', ''91''(10), 493-497.

Palaeopathologies

Multiple

palaeopathologies Paleopathology, also spelled palaeopathology, is the study of ancient diseases and injuries in organisms through the examination of fossils, mummified tissue, skeletal remains, and analysis of coprolites. Specific sources in the study of ancient ...

have been identified from the holotype of ''B. salgadoi''. These include a femoral osteoblastic tumour, an

enthesophyte Enthesophytes are abnormal bony projections at the attachment of a tendon or ligament. They are not to be confused with osteophytes, which are abnormal bony projections in joint spaces. Enthesophytes and osteophytes are bone responses for stress. ...

on metatarsal III, and abnormal tissue in a caudal

prezygapophysis The articular process or zygapophysis ( + apophysis) of a vertebra is a projection of the vertebra that serves the purpose of fitting with an adjacent vertebra. The actual region of contact is called the ''articular facet''.Moore, Keith L. et al. ...

caused by an infection.

Classification

''Bonitasaura'' was originally classified as a member of

Nemegtosauridae Nemegtosauridae is a family of titanosaurian sauropod dinosaurs based on their diplodocid-like skulls. Only three species are known: '' Nemegtosaurus'', '' Quaesitosaurus'' and possibly '' Tapuiasaurus'', each from the Cretaceous. History of cla ...

in the original description, but subsequent cladistic analyses and description found it to be nested among the titanosaur clade that includes

Lognkosauria Lognkosauria is a clade of giant long-necked sauropod dinosaurs within the clade Titanosauria. It includes some of the largest and heaviest dinosaurs known. They lived in South America and likely Asia during the Late Cretaceous period. Descripti ...

and

Rinconsauria Rinconsauria is an extinct clade of titanosaurian sauropods known from the late Cretaceous period of Argentina. All members of this clade are fairly small compared to the largest titanosaurs, at less than around long. The membership of Rinconsau ...

.Gallina & Apesteguí, 2015Carballido, J. L., Pol, D., Otero, A., Cerda, I. A., Salgado, L., Garrido, A. C., ... & Krause, J. M. (2017). A new giant titanosaur sheds light on body mass evolution among sauropod dinosaurs. ''Proceedings of the Royal Society B: Biological Sciences'', ''284''(1860), 20171219. In the description of '' Chucarosaurus'' in 2023, Agnolin ''et al''. recovered ''Bonitasaura'' as a colossosaurian member of the Titanosauria, as the

sister taxon In phylogenetics, a sister group or sister taxon, also called an adelphotaxon, comprises the closest relative(s) of another given unit in an evolutionary tree. Definition The expression is most easily illustrated by a cladogram: Taxon A and ...

to a clade formed by ''Chucarosaurus'', '' Notocolossus'' and the

. The results of their

phylogenetic analyses In biology, phylogenetics () is the study of the evolutionary history of life using observable characteristics of organisms (or genes), which is known as Computational phylogenetics, phylogenetic inference. It infers the relationship among organ ...

are shown in the

cladogram A cladogram (from Greek language, Greek ''clados'' "branch" and ''gramma'' "character") is a diagram used in cladistics to show relations among organisms. A cladogram is not, however, an Phylogenetic tree, evolutionary tree because it does not s ...

below:

References

* {{Portal bar, Dinosaurs, Argentina Lithostrotia Dinosaur genera Santonian dinosaurs Bajo de la Carpa Formation Fossil taxa described in 2004 Dinosaurs of Argentina