Comments on: The Mysterious Teeth of Ostafrikasaurus

By: Doug

Doug — Tue, 01 May 2012 17:04:53 +0000

@ Boesse: because even though mammal teeth are far more diagnostic, dinosaurs just have so much more clout in the public eye. Even though a new dinosaur is discovered, on average, every seven weeks, naming a new dinosaur is always a big deal. As such it feels like they try to name whatever they can from whatever is available. I mean, how many mammals and other cenozoic critters can you name that are based on a single specimen? Ok, now do the same for dinosaurs. Point is, it feels like dinosaurs never got out of their “butterfly collecting” phase. Even though paleontologist have been working hard these last 30 years to actually understand dinosaur biology, there still so much fanfare about finding and naming new species, as if that’s all paleontology is about.

By: Boesse

Boesse — Tue, 01 May 2012 07:33:08 +0000

Isn’t it irresponsible to designate an isolated dinosaur tooth as holotype specimen? Why not just leave it as baryonychinae indet.?

By: Paul Barrett

Paul Barrett — Tue, 01 May 2012 05:49:15 +0000

See Rauhut (2011) in Spec. Pap. Palaeontol. for a detailed discussion of the ID of many Tendaguru theropod bits.

By: W. Wolfe

W. Wolfe — Tue, 01 May 2012 01:53:53 +0000

Australia also had these giant “lizards” known as Murra-bu-garda found near Lake Eyre.

By: Chris Noto

Chris Noto — Mon, 30 Apr 2012 22:55:45 +0000

I have been working on theropod manual unguals for a while now and have presented on it at SVP (paper in the works). One thing I have seen in the distribution of claw shape among the various clades is that most, if not all, basal tetanurans have an enlarged digit I claw. This is true of allosauroids and spinosauroids and I think it may be a plesiomorphic trait for tetanurae. To say that the enlarged DI claw is definitive of spinosaurids is not evident when you look across allosaurs (think Neovenatorids) and spinosaurs. In fact I have seen some very large Allosaurus claws, as big as Baryonyx, Suchomimus, or Torvosaurus claws. Little differentiates spinosauroid from allosauroid claws, therefore saying that the BYU claw is evidence of a spinosaur is not supported. Even if it is not Torvosaurus, it is probably another allosauroid. We’ll need more diagnostic material before we can claim spinosaurs from the Morrison.

By: Doug

Doug — Mon, 30 Apr 2012 18:02:15 +0000

I’m also interested in that Torvosaurus claw. The carnivores of the American Jurassic are mind numbingly frustrating. We’ve been plumbing the Morrison for over 100 years and yet most are known from such fragmentary remains. They are barely known while allosaurus dominates the fossil record. I once saw someone suggest on here that Saurophaganax may be a carcharodontosaurid (citing that one is known from the Jurassic of, you guessed it, Tanzania. However, i don’t know if it too is based on just teeth). So if that claw turns out to be from a spinosaur, and Saurophaganax turns out to be it’s own entity, then that’s two more theropods known from jack squat. Plus they would just add to the enigma: the carnivore guild in the late Jurassic of North America was extremely diverse and yet (practically) all we find is Allosaurus. Hopefully this will get cleared up somewhat in the coming decades.

By: Denver Fowler

Denver Fowler — Mon, 30 Apr 2012 17:45:46 +0000

It’s worth noting that only the premaxillary and anterior dentary teeth of Ceratosaurus bear the fluting seen on these teeth. Back before my 2007 poster, Dr. Oliver Rauhut told me that ‘ceratosaur’ lateral teeth had not been found at Tendaguru. This is fairly surprising, although we are dealing with small sample sizes, and I do not know if this fact still stands. The potential ceratosaur link was really just put out as a ‘what-if’ scenario, and wasn’t the main emphasis of the poster.

Also, the closeup photo (Fig 2) in Buffetaut’s new paper seems to show the granular enamel that you see in baryonychines (which he notes), supporting his conclusion.

So its still interesting to pose the question I asked in my poster; what would ancestral baryonychine teeth look like? Which features ‘typical’ of baryonychines would be absent / less developed?

By: 220mya

220mya — Mon, 30 Apr 2012 17:40:54 +0000

Chris – the claw is mentioned in the Ichthyovenator paper itself.

By: Chris Noto

Chris Noto — Mon, 30 Apr 2012 17:30:23 +0000

Your link to the Late Jurassic claw attributed to Torvosaurus goes to your post on Ichthyovenator. Is this correct? There is no mention of the Torvosaur claw in your post, unless it is mentioned in the paper itself. I’m very interested in learning more about this isolated claw. Thanks.

By: Jaime Headden

Jaime Headden — Mon, 30 Apr 2012 17:22:33 +0000

Such is the fault of so-called definitive morphologies. The weight of the material seems deliberately more ceratosaurian with some spinosaur micro-features. Is he correct? Can the material be localized within the jaw and not evidenced for general dental morphology? Something to investigate.

By: Paul Barrett

Paul Barrett — Mon, 30 Apr 2012 16:56:20 +0000

I’d be surprised if we don’t find some latest Jurassic spinosaurids one day given that spinosauroids like Eustreptospondylus were around in the Middle Jurassic. Sadly the teeth of Eustreptospondylus are lost so we don’t know if they possessed the combination of features seen in Ostafrikasaurus.