Rebbachisauridae

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Rebbachisaurids
Temporal range: Early Cretaceous
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Sauropsida
Superorder: Dinosauria
Order: Saurischia
Infraorder: Sauropoda
Superfamily: Diplodocoidea
Family: Rebbachisauridae
Bonaparte, 1997
Genera

Rebbachisauridae is a family of sauropod dinosaurs known from fragmentary fossil remains from the Cretaceous of South America, Africa, and Europe.

Taxonomy

Sauropod specialist Jack McIntosh in 1990 included the first known genus, the giant North African sauropod Rebbachisaurus in the family Diplodocidae, subfamily Dicraeosaurinae, on the basis of skeletal details. With the discovery in subsequent years of a number of additional forms, it was realised that the rebbachisaurs constitute a distinct group of dinosaurs, and in 1997 the Argentine paleontologist Jose Bonaparte named the family Rebbachisauridae.

Evolutionary relationships and characteristics

Nigersaurus taqueti teeth

Although all authorities agree that the rebbachisaurids are members of the superfamily Diplodocoidea, they lack the bifid (divided) cervical neural spines that characterise the diplodocids 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 facets and asymmetrical enamel.

Unique among sauropods, at least some rebbachisaurids (such as Nigersaurus) are characterised by the presence of tooth batteries, similar to those of hadrosaur and ceratopsian 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. Unless the nemegtosaurids are in fact diplodocoids (rather than titanosaurs), then the rebbachisaurids represent the last known representatives of this clade, and lived alongside the titanosaurs until fairly late in the Cretaceous. So far, no rebbachisaurids are known from the very end of the Cretaceous period.

References