Lithostrotia

    With Titanosauridae left as hors de combat, a variety of subdivisions have been deployed to organize Titanosauria. The most successful have been Lithostrotia and Saltasauridae. As mentioned on the lead-in page, Lithostrotia is composed of Saltasaurus, Malawisaurus, and all descendents of their most recent common ancestor. Similarly, Saltasauridae is Saltasaurus, Opisthocoelicaudia, and all descendents of their most recent common ancestor. Lithostrotia includes "armored" titanosaurs, although the armor is not necessarily that impressive. Rapetosaurus is known to sometimes have one chunk of hollow "armor", perhaps for mineral storage and exchange in a strongly seasonal setting.

<--Lithostrotia
      |--Malawisaurus
      `--+--Epachthosaurus
           |--Narambuenatitan
           `--Eutitanosauria
                |--Diamantinasaurus
                |--Isisaurus 
                |--Lirainosaurus
                |--Aeolosauridae
                |    |--"Aeolosaurinae"
                |    |     |--Adamantisaurus
                |    |     |--Aeolosaurus
                |    |     |--Gondwanatitan
                |    |     |--Maxakalisaurus
                |    |     |--Panamericansaurus
                |    |     `--Pitekunsaurus
                |    `--Rinconsauria
                |         |--Muyelensaurus
                |         |--Overosaurus
                |         `--Rinconsaurus
                |--Nemegtosauridae
                |    |--Nemegtosaurus
                |    |--Rapetosaurus
                |    `--Tapuiasaurus
    
           `--Saltasauridae
                     |--+--Alamosaurus
                     |    `--+--Opisthocoelicaudia
                     |         `--?Yongjinglong
                     `--+--Neuquensaurus
                          |--Rocasaurus
                          `--Saltasaurus 

Lithostrotia:

Taxon or Taxa: Time/Place: Comments:
Malawisaurus dixeyi Jacobs, Winkler, Downs, and Gomani, 1993 (originally Gigantosaurus dixeyi Haughton, 1928) Aptian (EK) of Malawi This is one of the earliest definite titanosaurians. It is known from fairly abundant remains, including muzzle bones that show it had a steep face, and armor.
Epachthosaurus sciuttoi Powell, 1990 late Cenomanian-early Turonian (LK) of Argentina Epachthosaurus is not as well known as some of the others, but new finds including most of a skeleton should change that. It might prove to be an unarmored titanosaurian, or more basal than Lithostrotia.
Narambuenatitan palomoi Filippi, García, and Garrido, 2011 early-middle Campanian (LK) of Argentina Narambuenatitan is known from a partial skeleton including that precious rarity, associated cranial material. Postcranial bones include a handful of vertebrae and representatives of the other major skeletal segments, with a general lack of distal limb bones.
Diamantinasaurus matildae Hocknull, White, Tischler, Cook, Calleja, Sloan, and Elliott, 2009 Cenomanian-Turonian (LK) of Australia Diamantinasaurus is a robust derived titanosaurian, known principally from forelimb, hindlimb (minus the foot), and pelvic and pectoral girdle bones. It is unusual in retaining a thumb claw (titanosaurians are known for not even having phalanges on their hands). The species name is a reference to "Waltzing Matilda", which was written in the part of the country where this dinosaur was found. It may be a relative of Tapuiasaurus or Opisthocoelicaudia.
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.
Lirainosaurus astibiae Sanz, Powell, Le Loeuff, Martinez, and Pereda-Suberbiola, 1999 late Campanian-?early Maastrichtian (LK) of Spain This saltasaurid appears to be somewhat less derived than Saltasaurus, possibly as the sister group to Saltasauridae. It is known from the remains of several individuals, including skull material and armor.

Lithostrotia i.s.:

Taxon or Taxa: Time/Place: Comments:
Antarctosaurus wichmannianus Huene, 1929 early-middle Campanian (LK) of Argentina 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 is sometimes suspected 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).
Atacamatitan chilensis Kellner, Rubilar-Rogers, Vargas, and Suárez, 2011 LK of Chile Atacamatitan is known from a partial skeleton including two dorsals, caudals, ribs, part of the humerus, a possible sternal, the right femur, and lithostrotian debris. It is described as more derived than Malawisaurus but less than saltasaurids. 
Bonatitan reigi Martinelli and Forasiepi, 2004 late Campanian-?Maastrichtian (LK) of Argentina Described as a small saltasaurid, Bonatitan's material includes braincase, vertebral, and limb remains. It is known from a group of remains first thought to pertain to two individuals, but now known to include five. Don't confuse it with Bonitasaura.
Brasilotitan nemophagus Machado, Avilla, Nava, Campos, and Kellner, 2013 Turonian-Santonian (LK) of Brazil Brasilotitan is represented by cervicals, sacrals, pelvic bones, an ungual, and a lower jaw with an L shape. It is thought to be close to Antarctosaurus and Bonatitan.
Elaltitan lilloi Mannion and Otero, 2012 middle Cenomanian-Turonian (LK) of Argentina Among the abundance of remains shuffled off as Argyrosaurus or Antarctosaurus over the years was a partial skeleton, including three dorsals, two caudals, the left scapula and arm above the wrist, the right ulna and pubis, and most of a leg (if you combine the right and left elements). Further review showed that it did not belong to either of these two South American titanosaurian stooges (to make three stooges, just add Laplatasaurus; if you want Shemp, there's always Titanosaurus itself). The name refers to the Tehuelche creator god Elal.  
Loricosaurus scutatus (N.D.) Huene, 1929 (?Saltasaurus or Neuquensaurus) early Campanian (LK) of Argentina At one time considered an ankylosaurian, this armored sauropod may instead be a synonym of Saltasaurus or Neuquensaurus.
Magyarosaurus: Huene, 1932 M. dacus (Nopcsa, 1915 [originally Titanosaurus]) (type) early-middle 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.
Of the two other species assigned to Magyarosaurus (both Huene, 1932), M. hungaricus may represent a new genus, and M. transsylvanicus may be a synonym of M. dacus.
?M. hungaricus Huene, 1932
Pellegrinisaurus powelli Salgado, 1996 early-middle Campanian (LK) of Argentina This lithostrotian 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 lithostrotian.
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 lithostrotian, possibly related to Opisthocoelicaudia.
Trigonosaurus pricei Campos, Kellner, Bertini, and Santucci, 2005 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]). 

Aeolosauridae: Aeolosaurids (or aeolosaurins, if you use Aeolosaurini under Saltasauridae) includes a variety of South American sauropods, with two subclades: an unnamed group identified as "Aeolosaurinae" for our purposes, its members in the immediately succeeding table; and Rinconsauria, below.

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" [Mapusaurus, if I recall correctly] the "EK troodontid", the unnamed dromaeosaurid of Mongolia, the "Fruita Echinodon" [now Fruitadens], the "Proctor Lake hypsilophodont", and the "high-spined Cedar Mountain iguanodont" sometimes identified with "Iguanodon" ottigeri, had 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 lithostrotian, with some good remains. It may be synonymous with GondwanatitanA. rionegrinus is based on caudal vertebrae, some limb elements, fragmentary scapulae, and ischia; A. colhuehuapensis is known from caudals; and A. maximus is known from partial  vertebrae (cervicals, dorsals, and caudals), ribs, limb bones, and a couple of girdle bones.
A. colhuehuapensis Casal, Martínez, Luna, Sciutto, and Lamanna, 2007 Campanian-Maastrichtian (LK) of Argentina
A. maximus Santucci and Arruda-Campos, 2011 Campanian-Maastrichtian (LK) of Brazil
Gondwanatitan faustoi Kellner and de Azevedo, 1999 (?Aeolosaurus) Santonian (LK) of Brazil This is a recently described titanosaurian (although not particularly large, despite the name). It may be synonymous with Aeolosaurus, and is known from material including two cervicals, seven dorsals, six sacrals, 24 caudals, part of a scapula, much of the hips, humeri, and tibiae.
Maxakalisaurus topai Kellner, Campos, Azevedo, Trotta, Henriques, Craik, and Silva, 2006 Campanian-Maastrichtian (LK) of Brazil  This possible lithostrotian 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 had 25,500 results a few weeks after it was published. 
Panamericansaurus schroederi Calvo and Porfiri, 2010 late Campanian-?Maastrichtian (LK) of Argentina Panamericansaurus is based on five caudals, a sacral, the left humerus, a couple of chevrons, and some fragments of ribs. It is thought to be a close relative of Aeolosaurus, perhaps in a clade with it and Gondwanatitan (Aeolosaurini).
Pitekunsaurus macayai Filippi and Garrido, 2008 early-middle Campanian (LK) of Argentina Pitekunsaurus is another possible relative of Rinconsaurus, and is apparently from the same area (formational ages are clashing, though, so I'll have to reconcile those). Presacrals, a scapula, a femur, and cranial material are known; odd that it hasn't attracted more attention on that basis. Speaking of which, when will there be a description of that Argentine titanosaur skull that was in a National Geographic article around the turn of the century?

Rinconsauria:

Taxon or Taxa: Time/Place: Comments:
Muyelensaurus pecheni Calvo, González-Riga, and Porfiri, 2007 late Coniacian-Santonian (LK) of Argentina Described as a slender titanosaur, Muyelensaurus is known from a braincase, verts from throughout the column, and various appendicular bones. It may be closest to Rinconsaurus.
Overosaurus paradasorum Coria, Filippi, Chiappe, García, and Arcucci, 2013 Campanian (LK) of Argentina Overosaurus is a small lithostrotian known mostly from vertebrae (posterior cervicals, dorsals, sacrals, and anterior caudals), some ribs, and partial ilia.
Rinconsaurus caudamirus Calvo and Riga, 2003 early-middle Campanian (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.

Nemegtosauridae: Originally described as the last diplodocids, then as dicraeosaurids, these sauropods instead appear to be titanosaurians, possibly very derived lithostrotians. 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:
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 a titanosaurian was strengthened by the recent discovery of other titanosaurian 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 middle 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 titanosaurian studies because of the degree of completeness and the skull. Multiple individuals are known, of different ages. Rapetosaurus was armored, at least as an adult.
Tapuiasaurus macedoi Zaher, Pol, Carvalho, Nascimento, Riccomini, Larson, Juarez-Valieri, Pires-Domingues, Silva, and Campos, 2011 Aptian (EK) of Brazil Tapuiasaurus is known from much of the front end and limbs of a titanosaur, including a skull (interesting, isn't it, that the titanosaurs with skulls end up in Nemegtosauridae). Other bones include seven cervicals, five dorsals, ribs, a sternal, a coracoid, a humerus, a radius, both ulnae, metacarpals, both femurs, a fibula, and most of a foot. The skull is like that of the other nemegtosaurids; if I had to describe it briefly, I'd say in between the other two skulls, without the curved Nemegtosaurus profile, and without as enormous an antorbital fenestra as Rapetosaurus.

Saltasauridae:

Taxon or Taxa: Time/Place: Comments:
Alamosaurus sanjuanensis Gilmore, 1922 middle late Campanian-late Maastrichtian (LK) of New Mexico, Texas, and Utah The only (named) North American lithostrotian, but also oddly enough 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 lithostrotians (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 lithostrotian 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 lithostrotian.
Opisthocoelicaudia skarzynskii Borsuk-Bialynicka, 1977 early Maastrichtian (LK) of Mongolia This sauropod may be a lithostrotian, but it also has a raft of unusual features (although this may just be a result of having more complete remains than most lithostrotians). Among these features is the unique articulation of the tail: the caudal verts have an articulation that is opposite the regular lithostrotian 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, 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 lithostrotians, but the extra sacral appears to have come from the tail, not the back, as in other lithostrotians. However, a number of other characters, including form of the arm bones and sternal plates, show a strong resemblance to those of lithostrotians.
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 lithostrotian skull. Originally, it was thought to be closest to Camarasaurus, which isn't a bad guess, comparing the two in general.
?Yongjinglong datangi Li L.-G., Li D.-Q., You H.-L., and Dodson, 2014 EK of China Yongjinglong is based on a partial skeleton of what is interpreted as possibly a subadult, including three spatulate teeth, a cervical, four loose and three articulated dorsals (the restoration's a bit misleading, making it look like some of the dorsals are in the neck), a rib, a radius and ulna, and an enormous scapulocoracoid, nearly two meters long, with a strap-like blade. The ulna is only 59 cm long, and the dorsals are relatively short compared to the scapulocoracoid, suggesting unusual proportions for this animal. (I'm imagining fairly stubby limbs) The presacral neural spines are not split. In phylogenetic analyses, it tends to come out closest to Opisthocoelicaudia. Oddly enough, it is the first dinosaur to begin with "Yo-"
Neuquensaurus: Powell, 1992 N. australis (Lydekker, 1893 [originally Titanosaurus]) (type) Santonian-Maastrichtian (LK) of Argentina and Uruguay This sauropod, closely related to Saltasaurus, is also known from the remains of several individuals.
The specimens assigned to N. australis and N. robustus are a bit of a problem (it was one of those cases where Huene took a bunch of intermixed specimens and parceled them out). Some of the robustus bones look like they should go to australis, and vice-versa. Be that as it may, it does appear that there is more than one taxon in the pot of material originally assigned to South American species of Titanosaurus.
N. robustus (?N.D.) (Huene, 1929 [originally Titanosaurus]) early Campanian (LK) of Argentina
Rocasaurus muniozi Salgado and Azpilicueta, 2000 late Campanian-early Maastrichtian (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 late Campanian-?Maastrichtian (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.

 

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