The carnosaurians, stripped of Tyrannosauroidea but still powerful, are
in a state of flux, especially considering the vast wealth of MJ and LJ dinosaur remains
coming out of China in the last twenty years that has opened large new families in
Theropoda and Sauropoda. Most pertinent for this case on this page are the sinraptorids, a
group of Chinese theropods (unless English Metriacanthosaurus proves to belong). Also, the
discovery of an EJ Antarctic predator, Cryolophosaurus, that has both funky
headgear and a pedigree that looks to be in line with Allosaurus has shed new
light on early tetanuran and carnosaurian radiation. Some workers prefer the name
Allosauria for this group. All carnosaurians have cervical
verts with a hollow
on the rear and a ball in front (opisthocoelous).
Allosauroidea, a more inclusive classification within Carnosauria, includes three main divisions: Sinraptoridae, Allosauridae, and Carcharodontosauridae. The members of Allosauroidea are very similar in overall form and epitomize the body plan of the basic big theropod: three fingers per hand, large head and teeth, small horns or ridges in front of the eye, and somewhere between seven and ten meters in length and one and two metric tons in weight.
Sinraptorids, as briefly described earlier, are primarily Chinese LJ allosauroids, sometimes with fancy cranial ornamentation. Allosaurids are pretty generic and best known from their namesake, the ubiquitous Morrison Formation theropod Allosaurus. Carcharodontosaurids are primarily a Gondwana "MK" radiation of very big theropods. They are a 1990s group, for the most part, because this decade has seen the first good remains from any member (some remains of Carcharodontosaurus were known in the 1930s, but were mostly scrappy and apparently destroyed in WWII) in the partial skeleton of Giganotosaurus and the skull of Carcharodontosaurus. They show some unusual convergences with the other main group of Gondwana theropods, the abelisaurids (some researchers put them together, in fact).
Allosauroidea, as shown here, has a triple radiation. This is by no means the only interpretation. Allosauridae and Carcharodontosauridae are sometimes regarded as closer to each other than either is to Sinraptoridae, for example.
The position of the inner ear in Acrocanthosaurus, Allosaurus, and Carcharodontosaurus indicates that instead of the traditional "jaws parallel to the ground" head pose, these theropods habitually walked with their snouts pitched down, around 25 degrees from horizontal in the case of Acrocanthosaurus.
Carnosauria: There are a number of carnosaur-type theropods that cannot yet be placed confidently into one of the three known families, or are basal to them.
|Taxon or Taxa:||Time\Place:||Comments:|
|Fukuiraptor kitadaniensis Azuma and Currie, 2000||late Hauterivian-Barremian (EK) of Japan||This smallish carnosaurian may have been known for many years under the guise of "Kitadanisaurus", supposedly a large dromaeosaurid. The type remains, from an immature individual, include a maxilla, dentary, teeth, a dorsal, a caudal, much of the forelimbs (with large claws) and a leg, and most of a hip. It is reportedly close to Sinraptor (and possibly, intriguingly, Siamotyrannus). It may be synonymous with every unofficially-named Japanese theropod starting with the letter "K".|
|Lourinhanosaurus antunesi Mateus, 1998||late Kimmeridgian-Tithonian (LJ) of Portugal||This smallish (3.5-4 meters long) carnosaurian, known from a partial skeleton including verts and most of the hips and hindlimbs, is part of a Portuguese LJ fauna that has just come out over the last couple of years and includes two sauropods and Allosaurus. Eggs, embryos, and gizzard stones are also known. It may have been a sinraptorid, or a megalosaurid.|
|Siamotyrannus isanensis Buffetaut, Suteethorn, and Tong, 1996||Barremian (EK) of Thailand||Siamotyrannus was originally described as the oldest known tyrannosaurid, but may equally well be a sinraptorid, as shown by sinraptorid-like features in the pelvis. It is known from a partial hip and some vertebrae.|
|Taxon or Taxa:||Time\Place:||Comments:|
|Erectopus superbus Huene, 1923 (originally Megalosaurus superbus Sauvage, 1882)||Albian (EK) of France||Poorly named, Erectopus appears to have been a carnosaurian of some sort. It is known from the partial skeleton of a medium-sized theropod that was thought to have a number of unusual features, but most of these appear to be in error. Part of the problem is that the original material was described fairly early in dinosaur paleontology, while another problem is that the original remains were lost in World War II, with only casts remaining.|
|?Marshosaurus bicentesimus Madsen, 1976||Kimmeridgian (LJ) of Utah and Colorado||Something of an enigma, Marshosaurus has features that are reminiscent of coelophysoids, coelurids, sinraptorids, and allosaurids, all wrapped up in a pelvis! The specific name, I assume, refers to the USA's bicentennial year 1976, the same year that this species was described. A number of other remains have been referred to this taxon, including a partial skeleton first found in 1912. This material shows a short-armed animal, probably a fairly basal carnosaur, if not closer to megalosaurids.|
|"Poekilopleuron" valens (N.D.) Leidy, 1870||late Kimmeridgian (LJ) of Colorado||This animal, better known by its later name of Antrodemus, is based on a damaged caudal vert. It may be synonymous with Allosaurus, but there is no way to be sure.|
|Sigilmassasaurus brevicollis Russell, 1996||?Albian (EK) of Morocco||Based on vertebral remains from "Spinosaurus B", and possibly including the limb material, Sigilmassasaurus is an obscure theropod. It was described as having had a long, flexible neck with a small head, a most unusual configuration for a theropod possibly weighing more than a ton. Its describer suggested that it had short arms and was adapted for a pecking-like behavior. It may be related to the spinosaurids, although new research suggests that it is a carnosaur, not synonymous with Carcharodontosaurus as had been suggested.|
Sinraptoridae: There are a number of theropods that probably belong here, but their relationships vis-à-vis Sinraptoridae's known members is not currently known. Some of this is due to poor material and some of this is due to the newness of the founding member.
|Taxon or Taxa:||Time\Place:||Comments:|
|Sinraptor dongi Currie and Zhao, 1993 (including Yangchuanosaurus hepingensis Gao, 1992)||Oxfordian (LJ) of China||Sinraptor dongi is possibly the most
boringly average large theropod now known. It doesn't even have much in the way of
cranial ornamentation, like some of its compatriots. Due to bite marks on the type's
skull, however, it can be guessed that these bland beasts got into tiffs with each other.
Having examined the figures and the characters given to differentiate S. dongi and possible second species S. hepingensis, it is my opinion that S. hepingensis, based on a skull and partial skeleton, is most likely an individual of S. dongi, instead of a separate species. S. dongi itself is not terribly different from Yangchuanosaurus.
|Yangchuanosaurus shangyouensis Dong, Chang, Li and Zhou, 1978||Oxfordian (LJ) of China||Much more interesting than its relative Sinraptor in
skull features, this theropod had a moderate finback and dual ridges running above its
nasal region and eyes. It was also larger than a lot of non-carcharodontosaurid
I have followed the practice of Predatory Dinosaurs of the World and made Y. magnus Dong, Zhou, and Zhang, 1983 a junior synonym of the type species.
Allosauridae: Like Ceratosauridae, I'm kinda fudging on the no-monogeneric families rule. A huge Morrison New Mexican theropod, based on material from the hind end, appears to be another "super-allosaur." Ankle bones from the Albian (EK) of Australia also may be allosaurid, as well as a caudal centrum from the latest Campanian-Maastrichtian (LK) of Oman.
|Taxon or Taxa:||Time\Place:||Comments:|
|Allosaurus: Marsh, 1877||A. fragilis (type) Marsh, 1877 (including Creosaurus atrox Marsh, 1878; Epanterias amplexus Cope, 1878)||Kimmeridgian (LJ) of western North America||Allosaurus has a long and fractured history, which
I will not attempt to detail here. For the record, after a challenge from the
erstwhile species Antrodemus valens (which may be seen as the name for Allosaurus
in old books), Allosaurus fragilis became the accepted name for almost any kind
of allosaurid remains from the Morrison Formation. Included
in this is a site, known as the Cleveland-Lloyd quarry, where the disarticulated remains
of over sixty individuals of Allosaurus are preserved.
It is possible that the remains assigned to A. fragilis don't all pertain to one species. A. atrox has been suggested as a second valid species, but this is unlikely. That there are at least two forms of Allosaurus is shown by the differing preorbital horns of Allosaurus skulls; there are two main configurations. Whether these show two species, two sexes, part of a spectrum of different horn forms, or something else is not clear.
Study of Allosaurus skulls suggests that it had a reinforced skull but a weak bite, and a very large gape. These have in turn led scientists to propose it attacked using its wide-open jaws like a spiky battleclub.
Epanterias is a "super-allosaur" from the early 90s. Unlike Saurophaganax, there is no reason to think that it's anything other than a really big A. fragilis.
|A. europaeus Mateus, Walen, and Telles-Antunes, 2006||late Kimmeridgian-early Tithonian (LJ) of Portugal||This species of Allosaurus is based on a partial skull that is very similar to that of A. fragilis, and may just be the same species. Other Portuguese material may also be referable to this carnosaur, including verts, ribs, and pelvic and hindlimb material.|
|Taxon or taxa:||Time\Place||Comments:|
|?"Allosaurus" tendagurensis (N.D.) Janensch, 1925||Kimmeridgian (LJ) of Tanzania||This animal cannot be proven to be a species of Allosaurus, but remains from Tendaguru indicate the presence of allosaurids. Alternatively, it could be a basal tetanuran, and/or related to the dubious EK "Elaphrosaurus" species.|
|Saurophaganax maximus Chure, 1995||Kimmeridgian (LJ) of Oklahoma||This taxon is a monstrously large allosaurid. By monstrously large, I mean an animal in the five metric ton size range. It's based on partial material from four individuals collected and prepped by WPA workers during the Depression. It was known informally as "Saurophagus" (Ray, 1941) for many years, during which it spent some time mixed up with Acrocanthosaurus because an author mistakenly thought it was from the Cretaceous.|
Carcharodontosauridae: The skulls of carcharodontosaurids are narrow, long, and in some ways resemble scissors. Several (Carcharodontosaurus, Eocarcharia, Giganotosaurus, and Mapusaurus) bear reinforced bone over the eyes, indicating a possible function in physical actions against other carcharodontosaurids. Carcharodontosaurid material is turning up all over Africa and South America, including a possible 12-13 meter long animal from the Cenomanian (LK) of Argentina known from remains of two individuals, and a Turonian (LK) specimen, also from the same country. Tyrannotitan and Mapusaurus may be united with Giganotosaurus in "Giganotosaurinae."
|Taxon or Taxa:||Time\Place:||Comments:|
|Neovenator salerii Hutt, Martill, and Barker, 1996||Barremian (EK) of England||Not much has been published on this taxon yet. It is based on a rather pathologic partial skeleton and skull including material from the main divisions of the skeleton except the forelimbs, and was originally informally called a megalosaur. It appears to have had a tall, puffin-like snout. The type individual may have been around 7 meters in length, but material from another individual suggests lengths of up to around 10 meters.|
|Acrocanthosaurus atokensis Stovall and Langston, 1950||Aptian-Albian (EK) of Oklahoma, Texas, Utah, Arizona, and Maryland||Acrocanthosaurus is one of my favorite dinosaurs. It is most famous for its tall vertebral spines, and has specimens reaching sizes like those of large tyrannosaurids. Recently, more material has turned up, including a virtually complete skull and skeleton, and shed a lot of light on this late carnosaur. An animal very similar to Acrocanthosaurus, if not one and the same, produced some of the famous Paluxy River dinosaur tracks in Texas, including a sequence where an individual appears to pursue a large Pleurocoelus (or Astrodon)-type sauropod. Although not known directly from the Cloverly, it is considered to be a contemporary of that fauna. Interestingly, its neck seems to have been straighter than most theropods, possibly as an alternative solution to holding up a large head. The skull, in gross form, appears to mostly closely resemble that of Carcharodontosaurus, but is not too different from Allosaurus as well.|
|Eocarcharia dinops Sereno and Bruasatte, 2008||Aptian-Albian (EK) of Niger||Eocarcharia is a carcharodontosaurid from the Acrocanthosaurus wing of the family, except with a strongly ornamented postorbital. It's known from skull bones, mostly the maxilla and the stuff behind the eyes. It was smallish as these things go, in the 6 to 8 m long range.|
|Tyrannotitan chubutensis Novas, de Valai, Vickers-Rich, and Rich, 2005||Aptian (EK) of Argentina||Just coming out is this carcharodontosaurid, described as being more basal than Carcharodontosaurus or Giganotosaurus. It is known from two individuals, with the type including partial dentaries, some vertebrae and ribs, partial scapulacoracoid and arm, a good chunk of the pelvis, and a femur, fibula, and metatarsal, and the other individual overlapping these remains. It seems to have been robust and at least slightly smaller than Giganotosaurus, but with a similarly squared-off dentary tip.|
|Carcharodontosaurus: Stromer, 1931||C. saharicus (type) (originally Megalosaurus saharicus Deperet and Savornin, 1927)||Albian-Cenomanian (EK-LK) of Morocco, Algeria, and Egypt||This taxon was named from some shark-like teeth. Later, skull material with such teeth in their sockets turned up. Unfortunately, the early material has either been lost or destroyed in World War II. Most recently, a very large, nearly complete skull has turned up. Carcharodontosaurus saharicus is synonymous with Megalosaurus africanus (N.D.) Huene, 1956, although apparently not with Stromer's "Spinosaurus B" material, including the holotype of Sigilmassasaurus (as has been suggested).|
|C. iguidensis Brusatte and Sereno, 2007||Cenomanian (LK) of Niger||C. iguidensis is known largely from cranial remains from a few individuals of different skeletal maturity. You may know lead author Steve Brusatte from the Official Dino Land Website.|
|Mapusaurus roseae Coria and Currie, 2006||Cenomanian (LK) of Argentina||One of the most beloved "public domain
dinosaurs," this is the famous "group carcharodontosaurid"
that has been floating around for a while. This is also, as far as I
know, the same as the "phantom spinosaur" "Mupasaurus"
created on the Internet on the basis of misinterpreted rumors of giant,
soon-to-be-published Argentine and African "MK" theropods; don't
believe everything you read on the Internet! At some points, it had
also been rumored as a second species of Giganotosaurus.
Well, here it is, so knock off the rumors.
The actual animal is known from a bonebed of at least seven individuals, maybe up to nine, of different sizes from 5 to 12 m long (the latter in Giganotosaurus's range). It was close to Giganotosaurus, but with a deeper and narrower skull. Why several individuals were found together is not known, although the paper suggests that it was intentional on the part of the animals.
|Giganotosaurus carolinii Coria and Salgado, 1995||Cenomanian-early Turonian (LK) of Argentina||Like Carcharodontosaurus a rival to Tyrannosaurus rex in size (probably longer and heavier by a shade), this taxon is known from a partial skeleton and skull, with a squared-off rostral end to the lower jaw in lateral view. It may have hunted the huge contemporary titanosaurians. New fossil remains, including that of a "family," may pertain to it or to a close relation. A new dentary suggests an individual somewhat larger than the type.|
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