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Tomozaurus — Hell Creek Deinonychosauria revision sketch dump
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Published: 2012-06-09 06:29:51 +0000 UTC; Views: 4432; Favourites: 40; Downloads: 114
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Description
A revision of the Deinonychosaur species, or tooth types at least, known from Hell Creek.I am aware that there are apparently a wealth of undescribed, indeterminate troodontid teeth as well, but I can't really find any data on them. Zapsilis may not technically count as it seems to be known only from Lance and Scollard.
Anything anyone knows on the subject is welcome.
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Comments: 33
With the new discovery of Acheroraptor, and the notion that there might not be as much deinonychosaurian diversity as known before, which species are crossed from the image?
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At the moment Acheroraptor and Pectinodon will be all that remain. It is possible that cf. Richardoestesia gilmorei is still separate and Paronychodon may represent the teeth of birds, but both are awaiting further data.
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That's crazy ._.
Well, at least Richardoestesia has a good chance of being a piscivorous microraptorine... Whilst Paronychodon... Isn't it more of a form taxon?
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This actually adds to a point I've found about the Hell Creek ecosystem. Look at how many small Theropds there are compared to the mid-sized Nanotyrannus and the large Tyrannosaurus, then look at fauna from ecosystems around the same time. Something just seems to be mussing, and that something is other mid-sized and large Theropods.
By the way, nice work 
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So (maybe) there was a Deinonychus-sized dromie living alongside Tyrannosaurus Rex afterall?
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Yes, that's what the rumours suggest; and the tooth I saw was certainly large enough.
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I can't believe this, the fact that richardo is a microraptoriine....
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Greg Paul mentioned a single tooth known from Hell Creek that corresponded to a raptor that was at least as large as deinonychus, in "Predatory Dinosaurs of the World".
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Yes, you'll see I've listed the dromaeosaurine as probably the Deinonychus sized species. I have also seen photos of a dromaeosaurine tooth alongside a tyrannosaur tooth for scale that appears to be around that size.
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And to believe that none of these are large enough to regularly provide large enough meals for a scavenging T. rex.
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No, certainly not. Tyrannosaurus and deinonychosaurs were in a completely different prey range.
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And the only creatures that filled in the "medium sized" predator role would be younger Tyrannosaurus.
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What a nice set of little beauties. Trying to decide whether this is too "spec evo" for #Deinonychosauria, lol.
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Thanks! Yeah, your call on that one. They are all technically real species, but I completely made up their appearance outside of tooth shape.
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I bet you can lump those six into three.
I didn't know that Richardoestestia was a microraptorine. Very interesting.
...
citations?
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RE Richardoestesia: The actual cite was Mickey Mortimer's theropod phylogeny, but it's been thrown around all over based on the size and shape of the teeth. I don't think it's in any actual published literature though.
RE: Lumping: I certainly don't know about three over-all. I need to see the actual teeth, but I'm pretty sure I'll be lumping Zapsilis into "Dromaeosaurus". Carpenter's animal does seem like it's a Saurornitholestine, while the Richardoestesia speces are possible Microraptorans, and the other two are derived dromaeosaurines. That's 3 minimum for dromaeosaurs. Then there are the troodontids, seemingly at least two plus the apparent multiple types of undescribed troodontid teeth. Mortimer's phylogeny had Pectinodon ("Troodon") as a derived troodontid sister and Paronychodon as a possible basal troodont. Again, I really wish I could see the teeth for myself; I have a niggling feeling that the latter could just be juvenile examples of the former. I need to see how different they really are.
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I would tend to agree in part. From what I've read (very little) it seems like "Zapsalis" teeth are probably juvenile Dromaeosaurus (and the holotype is from Judith River fmtn. so Zap should also be in quotes) and Paronychodon (ditto) are probably juvenile troodontids. So most conservatively I'd have 4 deinonychosaurs in the Lance/Hell Creek: an unnamed dromaeosaurine, and unnamed saurornitholestine, Richardoestesia, and Pectinodon.
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Thanks for the info. I had pretty much assumed that "Paronychodon" were juvenile troodonts, but nice to know about "Zapsalis", so cheers.
Know anything about weather the two Richardoestesia are legitimately different species?
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Not really, but I suspect not. IMO until we have a full set of teeth in a jaw, it's most conservative to assume the variation is within the jaw as seen in other species, or even ontogenetic.
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I was thinking three:
small diurnal arboreal predators (i.e. Richardoestesia)
medium nocturnal ground predators (i.e. Troodon)
medium-large diurnal ground predators (i.e. Dromaeosaurus)
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The saurornitholestine teeth are really far too different to be lumped with anything else.
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Oh right. Hm. Maybe fox-coyote-wolf would make a good Troodon-Sauronitholestes-Dromaeosaur comparison. What do you think?
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That sounds alright to me.
Though, I was thinking of having 'Troodon' and the saurornitholestine fill the same niche (mammals, lizards, turtles, eggs, etc.), but the former at night and the latter at day. While dromaeosaurus was going to be somewhat of a pachycephalosaur specialist restricted to the highlands.
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I'm sure we're reinventing the wheel here. Maybe I should ask the DML for some paleo-ecology references.
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Yeah, good idea. Could probably do with some outside opinions too.
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"Dromaeosaurus sp." is probably Deinonychus -sized?!?!
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It's just rumoured undescribed data.
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