saltasauridae

Saltasauridae

    Saltasauridae is the term best employed for the most derived titanosaurians. Since Titanosauridae is pretty much defunct without a valid Titanosaurus, Saltasauridae is the next best thing. What goes for titanosaurians in general goes for saltasaurids, although they are unusual in their generally small size. Technically, Saltasauridae is defined as the smallest group including both Opisthocoelicaudia and Saltasaurus, so we'll see how the membership sorts out.
     The unusual Opisthocoelicaudia and its allies belong somewhere in the macronarians, although I confess to being very unsatisfied with the proposed positions. They show bifid neural spines with a similar morphology to those of camarasaurids, while lacking skid-like chevrons, and also are derived and titanosaurian-like in their own ways. I'm not even sure they form a family, but I've come to suspect they may be part of a heretofore-unknown (most of them were only described in the last decade) eastern Asian titanosaurian radiation.
    Nemegtosaurinae, another group of (mostly) LK east Asian sauropods, is here mostly because I didn't know what else to do with it, and it seems to be close to the saltasaurines, a small group of closely-related South American forms. It could be the same as Opisthocoelicaudiinae.

Saltasauridae i.s.: A partial skeleton from the Berriasian-Hauterivian (EK) of Japan, akin to Phuwiangosaurus, could be either a opisthocoelicaudiine or nemegtosaurine, or it might not matter since the two could be the same thing. In addition, remains from the Maastrichtian (LK) of Pakistan appear to be saltasaurid.

Taxon or Taxa:		Time\Place:	Comments:
?Adamantisaurus mezzalirai Santucci and Bartini, 2006		?Campanian-?Maastrichtian (LK) of Brazil	Based on six articulated anterior caudals and two chevrons, Adamantisaurus may be related to Aeolosaurus and the so-called "Peirópolis titanosaur" (Trigonosaurus) (which, like the "Shake-n-Bake theropod", the "carcharodontosaurid larger than Giganotosaurus," the "EK troodontid", the unnamed dromaeosaurid of Mongolia, the "Fruita Echinodon", the "Proctor Lake hypsilophodont", and the "high-spined Cedar Mountain iguanodont" sometimes identified with "Iguanodon" ottigeri, has taken on mythic stature in the literature).
Aeolosaurus Powell, 1987 (?Gondwanatitan)	A. rionegrinus (type) Powell, 1987	late Campanian-early Maastrichtian (LK) of Argentina	This is an obscure saltasaurid, with some good remains. It may be synonymous with Gondwanatitan.
	A. colhuehuapensis Casal, Martínez, Luna, Sciutto, and Lamanna, 2007	Campanian-Maastrichtian (LK) of Argentina
?Antarctosaurus: Huene, 1929a	A. wichmannianus (type) Huene, 1929	?Campanian-?Maastrichtian (LK) of Argentina, Chile, and Uruguay	This sauropod is somewhat controversial because it is not certain how much of the type material belongs in the same taxon. In particular, a square-front lower jaw included in the type material appears to have come from a rebbachisaurid (but the recent discovery of square-jawed titanosaurian Bonitasaura suggests maybe convergence in jaw style between rebbachs and titanosaurians is possible).
	?A. brasiliensis Arid and Vizotto, 1972	Santonian (LK) of Brazil
Bonatitan reigi Martinelli and Forasiepi, 2004		Campanian-Maastrichtian (LK) of Argentina	Described as a small saltasaurine, Bonatitan's material includes at least braincase and caudal remains, but little else is available to me at this time. Don't confuse it with Bonitasaura.
Maxakalisaurus topai Kellner, Campos, Azevedo, Trotta, Henriques, Craik, and Silva, 2006		Campanian-Maastrichtian (LK) of Brazil	This possible saltasaurid is based on much of a skeleton, including cranial elements and armor. So far as I can tell, it mostly specializes in being well-publicized, as Google already has 25,500 results a few weeks after it was published.
Pellegrinisaurus powelli Salgado, 1996		mid Campanian (LK) of Argentina	This saltasaurid is presently little publicized. It is based on 26 caudals, 4 dorsals, and a partial femur.
Quaesitosaurus orientalis Kurzanov and Bannikov, 1983		late Campanian (LK) of Mongolia	Possibly a close relative of Nemegtosaurus, and also based on a skull (although not quite as well-preserved), this also appears to be some sort of saltasaurid.
Rinconsaurus caudamirus Calvo and Riga, 2003		Coniacian (LK) of Argentina	Rinconsaurus is based on remains including 13 caudals and a variety of other material; at least three individuals of differing age are known. It may be close to Aeolosaurus. Its caudals include not only the expect procoelous centra, but also amphicoelous and opisthocoelous centra.
Sonidosaurus saihangaobiensis Xu, Zhang X., Tan Q., Zhao X., and Tan L., 2006		early Maastrichtian (LK) of China	This titanosaurian is based on verts including dorsals, sacrals, and caudals, ribs, a chevron, and most of the pelvis. It was one of the small titanosaurians, around 9 m long (which is in the big iguanodont-average hadrosaurid range). It appears to probably have been a saltasaurid, possibly related to Opisthocoelicaudia.

Opisthocoelicaudiinae: This is one of the few families more difficult to consistently spell than the possible Eustreptospondylidae (in fact, I had it misspelled as Opisthocoelicaudidae [back when it was a macronarian family] until a reader pointed it out!). Characters that may link the members of this family may include bifid cervical and cranial dorsal neural spines, single caudal dorsal neural spines, peglike teeth, amphicoelous to opisthocoelous caudals, caudal neural spines located on the cranial portion of the centra, long scapulae with reduced distal expansions, long ilia with prominent cranial flaring, and simple chevrons. [note: when I started this website back in 1999, I was absolutely convinced that Opisthocoelicaudia couldn't possibly be a "titanosaurid." Times change, I guess]

Taxon or Taxa:	Time\Place:	Comments:
Alamosaurus sanjuanensis Gilmore, 1922	early late Campanian-late Maastrichtian (LK) of New Mexico, Texas, and Utah	Ironically the only North American saltasaurid, but also one of the better known (although its validity has recently been challenged), Alamosaurus was likely a southern immigrant, a representative of a branch of the saltasaurids (possibly close to Neuquensaurus and some undescribed Brazilian forms) that by the end of the Maastrichtian was creeping (or stomping, or some other mode of locomotion more descriptive of a saltasaurid than creeping) steadily northward. It was one of the last sauropods, and is not named for the Alamo in San Antonio, but for a formation (Ojo Alamo). New gigantic LK Texan sauropod remains may belong to this taxon, or may simply be part of what may be better referred to as the "Alamosaurus" complex of titanosaurian remains. It may have been unarmored, which would be unusual for a saltasaurid.
Isisaurus colberti Wilson and Upchurch, 2003 (originally Titanosaurus colberti Jain and Bandyopadhyay, 1997)	Maastrichtian (LK) of India	This taxon is based on much better material, including much of the postcrania, than most titanosaurians. It looks bizarre, with a short, vertically-directed neck and long forearms.
Opisthocoelicaudia skarzynskii Borsuk-Bialynicka, 1977	early Maastrichtian (LK) of Mongolia	This sauropod may be a saltasaurid, but it also has a raft of unusual features. Among these features is the unique articulation of the tail: the caudal verts have an articulation that is opposite the regular saltasaurid condition, where a "ball" on the rear of a vert articulates with a socket on the front of the next vert (procoelous). In Opisthocoelicaudia, the verts have a "ball" on the front of each vert articulating with a socket on the rear of its predecessor (opisthocoelous, hence the name). This unique configuration makes this animal's tail both strong and apparently directed straight out behind the body. This may be related to the greatly expanded ilium; it has been suggested that the usual muscles for providing hindlimb movement in reptiles, which are attached to the tail and leg, were either not present or greatly reduced in this taxon, and the ilium then took over this attachment function. This may have been to help free up the tail for greater use as a prop in bipedal feeding (however, I have learned recently that much of the hips were restored, leaving a question as to how much is actually known). Opisthocoelicaudia also reportedly has some bifurcated presacral neural spines. It also has six sacrals, like saltasaurids, but the extra sacral appears to have come from the tail, not the back, as in other saltasaurids. These and other characters show it cannot be a mainline saltasaurid. However, a number of other characters, including form of the arm bones and sternal plates, show a strong resemblance to those of saltasaurids. Thus, it is probable Opisthocoelicaudia is an unusual saltasaurid, but it could just be converging in some characters with the saltasaurids. It is known from a headless skeleton, and some paleontologists have suggested that it represents the body of Nemegtosaurus, which is known from a partial saltasaurid skull. Originally, it was thought to be closest to Camarasaurus, which isn't a bad guess, comparing the two in general.

Opisthocoelicaudiinae i.s.:

Taxon or Taxa:	Time\Place:	Comments:
?Borealosaurus wimani You, Ji, Lamanna, Li J., and Li Y., 2004	Cenomanian-Turonian (LK) of China	This sauropod is based on an opisthocoelous mid-distal caudal from Liaoning Province, and referred to the Titanosauria. Possible remains from the same locality include a tooth crown, another caudal, and a right humerus. Given its unusual caudal morphology, I've chosen to provisionally stick it in with the opisthocoelicaudiines.
Huabeisaurus allocotus Pang and Cheng, 2000	Campanian (LK) of China	This is a new, gigantic sauropod, possibly a nemegtosaurine, referred to its own family, Huabeisauridae, but from its description it seems to be close to Opisthocoelicaudia. It has split neural spines in the cervicals, single spines in the dorsals, unforked chevrons, and amphicoelous caudals. Peglike teeth, many verts, girdles, and partial limbs are known.
?"Nurosaurus qaganensis" (N.N.) in press? described? named as something else? out to lunch?	EK of China	Known from most of a skeleton (or so we've been led to believe), this animal has been awaiting official description for a while. It is a very large animal, with bifid neural spines.

Nemegtosaurinae: Originally described as the last diplodocids, then as dicraeosaurids, these sauropods instead appear to be saltasaurids, possibly very derived saltasaurids. Other remains suggest undescribed nemegtosaurines in the ?Aptian-?Albian (EK) of China and the upper Albian (EK) of France.

Taxon or Taxa:	Time\Place:	Comments:
Trigonosaurus pricei Campos, Kellner, Bertini, and Santucci, 2005	Campanian-Maastrichtian (LK) of Brazil	This is the (comparatively) famous "Peirópolis titanosaur" (DGM Series B), about the only case I know of where a taxon was included in definitions of clades without being officially named. It is known from a good chunk of the vertebral column (5 posterior cervicals, 10 dorsals, 6 sacrals, and the left ilium), with a referred group of 10 caudals (I don't know if I necessarily trust this referral, given that the material was found in a bonebed of hundreds of titanosaur bones from at least two taxa [also Baurutitan]).
Magyarosaurus dacus Huene, 1932 (originally Titanosaurus dacus Nopcsa, 1915)	early-mid Maastrichtian (LK) of Romania	This small (possibly the smallest known adult neosauropod) titanosaurian may have remains from several different sauropods referred to it, a common problem for titanosaurians. It may be related to Ampelosaurus, and both may be armored dwarf sauropods.
Malawisaurus dixeyi Jacobs, Winkler, Downs, and Gomani, 1993 (originally Gigantosaurus dixeyi Haughton, 1928)	Aptian (EK) of Malawi	This is one of the earliest definite titanosaurian. It is based on fairly abundant remains, including muzzle bones that show it had a steep face, and armor.
Nemegtosaurus mongoliensis Nowinski, 1971	early Maastrichtian (LK) of Mongolia	Nemegtosaurus is based on a partial skull with some features similar to Brachiosaurus and others similar to Diplodocus. That it is saltasaurid is strengthened by the recent discovery of true saltasaurid skulls that closely resemble it. It may represent the skull of Opisthocoelicaudia. A second skull is reported, but I've never seen it figured.
Rapetosaurus krausei Rogers and Forster, 2001	mid Maastrichtian (LK) of Madagascar	Known from material including most of a skeleton and a very distinctive skull, Rapetosaurus (named for a mischievous giant in Malagasy folklore) is extremely important for future saltasaurid studies because of the degree of completeness and the skull. At least three individuals are known, of different ages.

Saltasaurinae: These closely-related sauropods are the most derived saltasaurids.

Taxon or Taxa:	Time\Place:	Comments:
Rocasaurus muniozi Salgado and Azpilicueta, 2000	mid Campanian (LK) of Argentina	Rocasaurus may have a good deal of referable material, including juvenile and adult remains. It is based on parts of several verts, much of the hips, and a femur, from a juvenile individual.
Saltasaurus loricatus Bonaparte and Powell, 1980	mid Campanian (LK) of Argentina	This rather small sauropod is most famous for the possession of body armor. It is known from the remains of several individuals.
Neuquensaurus australis Powell, 1992 (originally Titanosaurus australis Lydekker, 1893)	Santonian (LK) of Argentina and Uruguay	This sauropod, closely related to Saltasaurus, is also known from the remains of several individuals.

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