Rebbachisauridae

Rebbachisaurids Temporal range: Early Cretaceous, 130–93 Ma PreЄ Є O S D C P T J K Pg N
Limaysaurus tessonei skeleton restoration
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Order:	Saurischia
Suborder:	†Sauropodomorpha
Superfamily:	†Diplodocoidea
Family:	†Rebbachisauridae Bonaparte, 1997
Genera
Amazonsaurus Comahuesaurus Histriasaurus[1] Nopcsaspondylus Zapalasaurus Khebbashia Limaysaurinae Rebbachisaurinae

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 José Bonaparte named the family Rebbachisauridae. Whitlock, 2011 defined two new subfamilies Nigersaurinae and Limaysaurinae within Rebbachisauridae. Cladogram of the Rebbachisauridae after Fanti et al., 2013, which is based on Carballido et al., 2012:^[2]

Cladogram after Fanti et al., 2015.^[3]

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

• Bonaparte J.F. (1997). "Rayososaurus grioensis Bonaparte 1995". Ameghiniana 34 (1): 116. 
• McIntosh, J. S., 1990, "Sauropoda" in The Dinosauria, Edited by David B. Weishampel, Peter Dodson, and Halszka Osmólska. University of California Press, 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.
• Wilson J.A. (2002). "Sauropod dinosaur phylogeny: critique and cladistic analysis". Zoological Journal of the Linnean Society 136 (2): 215–275. doi:10.1046/j.1096-3642.2002.00029.x. 
• ------ (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, University of California Press, Berkeley, ISBN 0-520-24623-3