Ceratosauria

   As I said before, I don't support the idea that the "neoceratosaurians" and the coelophysoids form a natural group, Ceratosauria.  Instead, the "neoceratosaurians" form my Ceratosauria.  Indeed, some workers are suggesting that this reduced Ceratosauria may be paraphyletic, with Ceratosaurus and the abelisauroids as basal relatives to the tetanurans.
    Ceratosaurians are most commonly found in the continents that made up Gondwana (South America, Africa, Antarctica, Australia, India, and Madagascar), in late Cretaceous-age rocks, but one of the best known members, Ceratosaurus itself, is a North American theropod from the Late Jurassic.  Ceratosaurians, while not as diverse as the tetanurans, produced many interesting taxa, including the bizarre abelisaurids and the small, large-clawed (at least in some cases) noasaurids.

<--Ceratosauria
      |--Ceratosauridae
      |    `--Ceratosaurus
      |--Elaphrosaurus
      |--Limusaurus
      |--Spinostropheus
      `--Abelisauroidea
           |--?Berberosaurus
           `--+--Noasauridae
                |    |--Genusaurus
                |    |--Laevisuchus
                |    |--Masiakasaurus
                |    |--Noasaurus
                |    `--Velocisaurus
                `-->Abelisauridae
                              
Ceratosauria and Ceratosauridae: Sereno, Wilson, and Conrad (2004)'s new analysis puts Ceratosaurus as more derived than Elaphrosaurus, but a fair amount of other analyses have suggested the opposite, so I'm not going to put one or the other closer to the abelisauroids yet.

Taxon or Taxa: Time/Place: Comments:
Ceratosaurus: Marsh, 1884 C. nasicornis (type) Marsh, 1888 Kimmeridgian (LJ) of Colorado and Utah; Kimmeridgian (LJ) of Portugal (?C. dentisulcatus)

This Morrison theropod is famous for its tall nose horn and less prominent preorbital horns.  It also possesses a row of bony nodules down the spine, which is probably a holdover from the earliest dinosaurs and their ancestors.  To go along with these ornaments, it has a moderate fin-back.  Ossified tendons are found in at least some individuals.  The hand has four metacarpals.  The skull has particularly large teeth, but is lightly-constructed.
In the past, this handsome horned beast had occasionally been considered a possible male or pathologic individual of Allosaurus, but better material and newer study show these to be very unlikely possibilities.
The two newer species C. dentisulcatus and C. magnicornis are tentatively retained for the moment, although C. magnicornis could conceivably represent a different growth stage of the type species.  C. dentisulcatus, however, has fewer teeth in a larger skull than the type (largest North American specimen of Ceratosaurus, with a femur 759 mm long, putting the living beast in the 1-metric ton range), which seems to assure specific separation.
There appears to be giant ceratosaurid-type material ("Megalosaurus" ingens) in Tanzania's famous Tendaguru beds, and the Morrison species C. dentisulcatus is apparently very large, although Ceratosaurus has usually been seen as somewhat small, and the type is certainly not Allosaurus-scale (personal observation of the skeleton at the Smithsonian).
C. dentisulcatus Madsen and Wells, 2000 
C. magnicornis Madsen and Wells, 2000
Elaphrosaurus bambergi Janensch, 1920 late Kimmeridgian-Tithonian (LJ) of Tanzania If a skull was known here, it would help measures immensely.  As it stands, Elaphrosaurus is one of the shortest of known theropods at the hip for its length.  It was once considered an ornithomimid ancestor, but I find that hypothesis hard to believe.  The hip structure, for example, is so different between Elaphrosaurus and a true ornithomimid that it casts serious doubt on such a proposition.
Material from both France and North America has been referred to this genus over the years.  The North American (Morrison Formation) material usually travels under E. sp. or "E. philtippetorum".  Among these bones are fused pubic bones which may represent Tanycolagreus, a humerus, metatarsals, and a tibia; only the pubic bones have attracted attention.
The position of Elaphrosaurus is somewhat fuzzy, but new studies find it closest to the abelisauroids, possibly related to the noasaurids.  In some ways, it is little changed from the coelophysoids.
Limusaurus inextricabilis Xu X., Clark, J. M., Choiniere, Forster, Erickson, Hone, Sullivan, Eberth, Nesbitt, Zhao Q., Hernandez, Jia C.-K, Han F.-L., and Guo Y., 2009 Oxfordian (LJ) of China Limusaurus inextricabilis, the shuvosaur-imitating toothless ceratosaur... or the ornithomimosaur-previewing toothless ceratosaur... except also with that miniscule arm thing ceratosaurs were so fond of, which also gives it a hint of alvarezsaur?  Sure, why not?
Limusaurus was floating around for a couple of years before description in various venues, known for its type specimen being mired (inextricably, one might say) at death.  The type skeleton is both mostly complete and nicely articulated, belonging to a subadult a few years old.  It was a small herbivorous biped.
The hand has been attracting the most attention.  Like all good ceratosaurs, it had four metacarpals of various sizes per hand.  What's odd is the reduction in number I (the thumb).  This has been interpreted as part of a frameshift wherein digits II, III, and IV took over the identities of I, II, and III during embryonic development.  Such a frameshift would be important because birds appear to have digits II, III, and IV, and theropods are traditionally interpreted as having digits I, II, and III. 
Spinostropheus gautieri Sereno, Wilson, and Conrad, 2004 (originally Elaphrosaurus gautieri Lapparent, 1960) sometime between the Late Triassic and Aptian, perhaps MJ of Niger Once one of the two dubious EK species of Elaphrosaurus, Spinostropheus has now been recognized as a basal ceratosaurian.  Vertebral remains in the original type have been tied to a long stretch of presacral verts found at the same horizon as Jobaria and Afrovenator.  The whole animal would have been on the order of 4 m long. 

Ceratosauria i.s.:  Among other recent discoveries, a new, fairly large ceratosaurian is known from material from the Aptian of Argentina. 

Taxon or Taxa: Time/Place: Comments:
?Bahariasaurus ingens Stromer, 1934 (?N.D.) (?Deltadromeus) ?Albian-early Cenomanian (EK-LK) of Egypt and ?Niger Bahariasaurus, like Spinosaurus and Carcharodontosaurus, had its type material destroyed in WWII.  Not all of the material assigned to it belongs to it, including some material that has since been referred to Deltadromeus, which may well be synonymous.
"Ceratosaurus" roechlingi (N.D.) Janensch, 1925 late Tithonian (LJ) of Tanzania "C." roechlingi is based on some odds and ends (quadrate, fibula, caudals, astragalus) of a theropod. Limited to a caudal, it appears to be a basal ceratosaurian, perhaps a ceratosaurid. 
?Chuandongocoelurus primitivus (?N.D.) He, 1984 Bathonian-Callovian (MJ) of China Rather obscure, Chuandongocoelurus is based on a partial skeleton, probably chimeric as the presacral verts appear to be too large for the rest of the skeleton, of a subadult individual.  It may be close to Elaphrosaurus, or a basal tetanuran.
Deltadromeus agilis Sereno, Dutheil, Iarochene, Larrson, Lyon, Magwene, Sidor, Varricchio, and Wilson, 1996 (?Bahariasaurus) early Cenomanian (LK) of Egypt and Morocco Known from a partial postcranial skeleton and other postcranial bits, Deltadromeus is considered to be one of the swiftest theropods.  It also got fairly big, as elements once assigned to the possibly closely-related Bahariasaurus that actually belong to this animal bear out.  Its coracoids (in the shoulder girdle) are unusually large.
Deltadromeus started out its public career as the most complete basal coelurosaurian.  However, new evidence suggests that, instead, it is a basal ceratosaurian (although not a noasaurid as first suggested).  It could be Elaphrosaurus-grade.
"Labrosaurus":  "L." stechowi (N.D.) Janensch, 1920 Kimmeridgian (LJ) of Tanzania This is a tooth taxon with some similarities to Ceratosaurus, and has sometimes been assigned to it.
"L." sulcatus Marsh, 1896 Kimmeridgian (LJ) of Colorado Again, this tooth may belong to Ceratosaurus.
"Megalosaurus": "M." bredai (N.D.) Seeley, 1883 Maastrichtian (LK) of the Netherlands Otherwise known as Betasuchus, this theropod, described as similar to Sarcosaurus, was once considered to be Europe's only ornithomimid.
"M." meriani (N.D.) Greppin, 1870 Tithonian (LJ) of Switzerland "M." meriani is based on a Ceratosaurus-like tooth, mostly interesting for its time and place (big theropods are rare for the LJ of Europe, except in Portugal).

Ceratosauridae i.s.:

Taxon or Taxa: Time/Place: Comments:
Genyodectes serus Woodward, 1901 ?Aptian-?Albian (?EK) of Argentina Genyodectes is based on part of the front end of some theropod jaws.  Sometimes it has been suggested that it , may be synonymous with the better-known Abelisaurus, but new study indicates that it was actually a ceratosaurid.  More surprising, given the years that it was tossed off as theropod scrap, is that when someone (Rauhut) went to look at the material, it turned out to be distinctive.  The teeth are closely packed, and the maxillary teeth are flattened side-to-side and very tall (and quite a bit longer than the pmx teeth).

Abelisauroidea: The abelisauroids were primarily a late Cretaceous Gondwanan group.  They are mostly large and some members grew exotic headgear (Carnotaurinae).  At least some members are known to have reduced their hands and arms to almost nothingness.
     Several undescribed abelisauroids have been mentioned in the literature recently, including a late Cenomanian (LK) form from Argentina.

Taxon or Taxa: Time/Place: Comments:
Berberosaurus liassicus Allain, Tykowski, Aquesbi, Jalil, Monbaron, D. Russell, and Taquet, 2007 Pliensbachian-Toarcian (EJ) of Morocco Not the same as the EJ Moroccan theropod mentioned by Gregory Paul back in 1988's Predatory Dinosaurs of the World (that's something else, under prep), Berberosaurus is based on a partial postcranial skeleton of a subadult comparable in size to Dilophosaurus or Elaphrosaurus.  Most of the remains pertain to the hindlimb or vertebrae.  It was described as the earliest known abelisauroid, and would indicate an early diversification for the group (the description of Limusaurus finds it to be a dilophosaurid instead).  Tazoudasaurus was a contemporary.

Abelisauroidea i.s.:

Taxon or Taxa: Time/Place: Comments:
Austrocheirus isasii Ezcurra, Agnolin, and Novas, 2010 Maastrichtian (LK) of Argentina Austrocheirus is known from a few postcranial bones, most importantly a hand which had not shrunk into a dangling sprig of fingers, as seen in other abelisauroids.  It was a basal abelisauroid of moderate size.
Coeluroides largus (N.D.) Huene and Matley, 1933 (?Jubbulpuria) Maastrichtian (LK) of India Originally considered a "coelurosaur", hence the name, this dinosaur is based on primitive caudals with delta-shaped transverse processes, originally described as dorsals.  Ironically, it seems to have been a large theropod, despite how its name attempts to affiliate it with Coelurus; also ironically, its caudals are said to resemble those of tiny Ligabueino.  It could be the same as Jubbulpuria, or could be an abelisaurid.
Compsosuchus solus (N.D.) Huene and Matley, 1933 (?Indosuchus or ?Rajasaurus) Maastrichtian (LK) of India The axis cervical that forms the type of this species (and is AWOL) is one of those fossils that seems to take on different affinities with every report.  It has been compared favorably with the cervicals of noasaurids (although twice the size of the same bone in Masiakasaurus), "carnotaurines", and the carnosaurian tetanuran Allosaurus.  It used to be considered a "coelurid" or compsognathid.
Ligabueino andesi Bonaparte, 1995 Barremian (EK) of Argentina One of the earliest known and smallest abelisauroids, Ligabueino is known from partial postcranial remains.
Ozraptor subotaii (?N.D.) Long and Molnar, 1998 Bajocian (MJ) of Australia As its name makes clear, this is an Australian predator.  Little else is known at this time; although some workers have suggested dromaeosaurid affinities for the type distal tibia, new research indicates that it actually was an early abelisauroid, becoming the first Australian abelisauroid and the earliest known example.
Tarascosaurus salluvicus (?N.D.) Le Loeuff and Buffetaut, 1990 early Campanian (LK) of France Tarascosaurus, a rare non-Gondwanan abelisauroid, may be related to Abelisaurus.  It is based on a femur and two dorsals, which may not belong to the same taxon.
Xenotarsosaurus bonapartei Martinez, Gimenez, Rodriguez, and Bochatey, 1987 late Cenomanian- early Turonian (LK) of Argentina This animal is based upon most of a hindlimb and some verts.  Although often tossed off as an abelisaurid, its scanty type material lacks important elements for diagnosis.

Noasauridae:  This family is composed of some of the smaller ceratosaurians (ignoring Deltadromeus and the possible member Bahariasaurus).  It was long thought that at least some of them paralleled sickle-clawed coelurosaurians like the dromaeosaurids and troodontids by developing a sickle claw, but it turns out that the "foot" claw actually went to a finger.  You know, the same thing has happened to Baryonyx, Megaraptor, Fukuiraptor (all once considered to be dromaeosaurids, however briefly), and Dryptosaurus (if I remember correctly; I'll have to check), and it probably won't be the last time; we paleontologists just like to put claws anywhere but the hands, it seems, even though the more we look, the more it seems like big manual claws aren't that uncommon among dinosaurs.  Heck, even Iguanodon's thumb spike was first interpreted as a nasal horn!  

Taxon or Taxa: Time/Place: Comments:
Genusaurus sisteronis Accarie, Beaudoin, Dejax, Fries, Michard, and Taquet, 1995 Albian (EK) of France Based on a partial skeleton, this taxon is unusual in its combination of young geologic age and conservative features, although some features suggest that it might be related to Carnotaurus.
Laevisuchus indicus Huene and Matley, 1933 Maastrichtian (LK) of India This theropod, based on three cervicals and a dorsal, was described as a "coelurid," but instead is a noasaurid.
Masiakasaurus knopfleri Sampson, Carrano, and Forster, 2001 mid Maastrichtian (LK) of Madagascar Quite possibly the first dinosaur to be described in the new millennium (preferring '01 to '00), Masiakasaurus is also garnering fame from its specific name, honoring Mark Knopfler of the band Dire Straits.  It is a rather bizarre little creature, known from several individuals, including the odd jaws: this creature had unusual forward-jutting teeth, like a fishing animal.  Anatomically, it is the best known noasaurid, although there's not much competition.  There may be two morphs ("robust" and "gracile").
Noasaurus leali Bonaparte and Powell, 1980 Maastrichtian (LK) of Argentina This small theropod was long thought to be unusual in that it seemed to independently come up with a sickle-claw system similar to that of the dromaeosaurids and troodontids, without belonging to either of those two groups by virtue of its basal skull and very different mechanism for the claw's action.  Well, there may be a good reason for why the mechanism is different: the foot claw is a hand claw. 
Velocisaurus unicus Bonaparte, 1991 Santonian (LK) of Argentina This fleet animal is known from a partial hindlimb.  The toe proportions have led some to suggest it may have fed like a chicken, through scratching at the ground.

Noasauridae i.s.:

Taxon or Taxa: Time/Place: Comments:
Jubbulpuria tenuis (N.D.) Huene and Matley, 1933 (?Coeluroides) Maastrichtian (LK) of India This theropod has been called a "coelurid" in the past simply because of its small size.  What it really is, is hard to determine from its meager remains, although its caudals appear to belong to something like Ligabueino.  It is probably a noasaurid.
"Ornithomimoides" barasimlensis (N.D.) Huene and Matley, 1933 Maastrichtian (LK) of India This dubious species is based on four dorsals (or caudals) that may pertain to a noasaurid, perhaps Laevisuchus. 

 

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