Rebbachisauridae is a

family Family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its members and of society. Idea ...

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 ...

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 ...

s known from fragmentary

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 preserved ...

remains from the

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 ...

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 souther ...

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 ...

, North America,

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 subcontinent of Eurasia and it is located enti ...

and possibly

Central Asia Central Asia, also known as Middle Asia, is a region of Asia that stretches from the Caspian Sea in the west to western China and Mongolia in the east, and from Afghanistan and Iran in the south to Russia in the north. It includes the former ...

Taxonomy

In 1990 sauropod specialist Jack McIntosh included the first known rebbachisaurid genus, the giant North African sauropod ''

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 at ...

'', in the family

Diplodocidae 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 ...

, subfamily

Dicraeosaurinae Dicraeosauridae is a family of diplodocoid sauropods who are the sister group to Diplodocidae. Dicraeosaurids are a part of the Flagellicaudata, along with Diplodocidae. Dicraeosauridae includes genera such as '' Amargasaurus'', '' Suuwassea'' ...

, on the basis of skeletal details. With the discovery in subsequent years of a number of additional genera, it was realised that ''Rebbachisaurus'' and its relatives constituted a distinct group of dinosaurs. In 1997 the Argentine paleontologist

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 ...

described the family Rebbachisauridae, and in 2011 Whitlock defined two new subfamilies within the group:

Nigersaurinae Rebbachisaurinae is a subfamily within the family Rebbachisauridae, defined to include ''Rebbachisaurus garasbae'' and exclude '' Limaysaurus tessonei''. It was first proposed as a rank by Jose Bonaparte Jose is the English transliteration of ...

and Limaysaurinae. The

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

of the Rebbachisauridae according to Carballido ''et al.'' (2012) is shown below: Cladogram after Fanti ''et al.'', 2015.

Evolutionary relationships and characteristics

Although all authorities agree that the rebbachisaurids are members of the superfamily

Diplodocoidea Diplodocoidea is a superfamily of sauropod dinosaurs, which included some of the longest animals of all time, including slender giants like ''Supersaurus'', ''Diplodocus'', ''Apatosaurus'', and ''Amphicoelias''. Most had very long necks and long, ...

, they lack the bifid (divided)

cervical In anatomy, cervical is an adjective that has two meanings: # of or pertaining to any neck. # of or pertaining to the female cervix: i.e., the ''neck'' of the uterus. *Commonly used medical phrases involving the neck are **cervical collar **cervic ...

neural spine 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 ...

s that characterise the

diplodocids 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 ...

and dicraeosaurids, and for this reason are considered more primitive than the latter two groups. It is not yet known whether they share the distinctive whip-tail of the latter two taxa. Rebbachisaurids are distinguished from other sauropods by their distinctive teeth, which have low angle, internal

wear facet Wear is the damaging, gradual removal or deformation of material at solid surfaces. Causes of wear can be mechanical (e.g., erosion) or chemical (e.g., corrosion). The study of wear and related processes is referred to as tribology. Wear ...

s and asymmetrical enamel. Unique among sauropods, at least some rebbachisaurids (such as ''

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 t ...

'') are characterised by the presence of tooth batteries, similar to those of

hadrosaur Hadrosaurids (), 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 family, which inclu ...

and

ceratopsia Ceratopsia or Ceratopia ( or ; Greek: "horned faces") is a group of herbivorous, beaked dinosaurs that thrived in what are now North America, Europe, and Asia, during the Cretaceous Period, although ancestral forms lived earlier, in the Jurassi ...

n dinosaurs. Such a feeding adaptation has thus developed independently three times among the dinosaurs. So far, rebbachisaurids are known only from the middle and early part of the Late Cretaceous. They constitute the last known representatives of the dipldocoids, and lived alongside the

titanosaurs 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 thr ...

until fairly late in the Cretaceous.

References

* * McIntosh, J. S., 1990, "Sauropoda" in ''The Dinosauria'', Edited by

David B. Weishampel Professor David Bruce Weishampel (born November 16, 1952) is an American palaeontologist in the Center for Functional Anatomy and Evolution at Johns Hopkins University School of Medicine. Weishampel received his Ph.D. in Geology from the Univers ...

Peter Dodson Peter Dodson (born August 20, 1946) is an American paleontologist who has published many papers and written and collaborated on books about dinosaurs. An authority on Ceratopsians, he has also authored several papers and textbooks on hadrosaurs ...

, and

Halszka Osmólska Halszka Osmólska (September 15, 1930 – March 31, 2008) was a Polish paleontologist who had specialized in Mongolian dinosaurs. Biography She was born in 1930 in Poznań. In 1949, she began to study biology at Faculty of Biology and Earth Sci ...

University of California Press The University of California Press, otherwise known as UC Press, is a publishing house associated with the University of California that engages in academic publishing. It was founded in 1893 to publish scholarly and scientific works by facult ...

, pp. 345–401. * Upchurch, P., Barrett, P.M. and Dodson, P. 2004. "Sauropoda". In ''The Dinosauria'', 2nd edition. Weishampel, Dodson, and Osmólska (eds.). University of California Press, Berkeley. pp. 259–322. * * ------ (2005) "Overview of Sauropod Phylogeny and Evolution", in ''The Sauropods: Evolution and Paleobiology'' * Wilson, J. A. and Sereno, P.C. (2005) "Structure and Evolution of a Sauropod Tooth Battery" in ''The Sauropods: Evolution and Paleobiology'' in Curry Rogers and Wilson, eds, 2005, ''The Sauropods: Evolution and Paleobiology'',

, Berkeley, {{Taxonbar, from=Q132733 Prehistoric dinosaur families Diplodocimorpha