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Favorite Dinosaur Reconstructions
Topic Started: Sep 28 2013, 09:05 PM (305,540 Views)
heliosphoros
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No, pure speculation. But every other detail is based on Volaticotherium, Argentoconodon and Jugulator, just as the head, so its unlikely to be wrong at large.
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Incinerox
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Āeksiot Zaldrīzoti

I thought Volaticotherium was a GLIDING animal, superficially like a sugar glider, with just stretchy skin between its limbs.

Seeing fully formed pterosaur-like wings is odd to see.
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heliosphoros
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Volaticotherium's hand is "poorly preserved", actually, according to the original paper. Specifically, four metacarpals are known, leaving the last one, as well as most of the fingers.

The wings are due to Ichthyoconodon's marine location, which could imply powered flight.

Argentoconodon shares femur characteristics with Volaticotherium that imply aerial locomotion, which suggests a long lived lineage of gliding/flying mammals. Interestingly enough, both Argentoconodon and Ichthyoconodon are the only known gondwannan triconodontids...

At any rate it can also be interpreted as as flying-squirrel-like styliform element.
Edited by heliosphoros, Jul 3 2016, 11:56 AM.
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CyborgIguana
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The notion of Mesozoic mammals as all being tiny, meek and uninteresting is dying more and more as it becomes increasingly clear that they were already doing their own thing by that point.
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heliosphoros
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True. The other option is that Ichthyoconodon was aquatic, as initially suggested, which would make it a reccord holder alongside the contemporary Dyskritodon.

However, its less likely considering that eutriconodont molars served to sheath prey, like carnassials, instead of gripping prey like seal or dolphin molars.

Combined with how Ichthyoconodon's closest relatives were gliders, it being a flyer seems like the more logical option.
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Posted Image Flish
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Assuming it is some form of bizzare "seabird" mammal, I find the lack of toe webbing and short wings unlikely, and if not, I don't see why it couldn't have been carried out to sea like theropods from the same area, swept up from a storm, which is made especially easy if this is indeed a gliding animal. I'm not saying that it's not volant, but I think, with what little evidence we have, assuming flight as the most likely conclusion to its location is a bit of a jump to conclusions.
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CyborgIguana
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I also find it somewhat unlikely that it would be THAT convergent with pterosaurs in its wing anatomy.
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heliosphoros
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Flish
Jul 3 2016, 01:48 PM
Assuming it is some form of bizzare "seabird" mammal, I find the lack of toe webbing and short wings unlikely, and if not, I don't see why it couldn't have been carried out to sea like theropods from the same area, swept up from a storm, which is made especially easy if this is indeed a gliding animal. I'm not saying that it's not volant, but I think, with what little evidence we have, assuming flight as the most likely conclusion to its location is a bit of a jump to conclusions.

As I said, its teeth are not convergent with those of piscivorous mammals. Probably a "hawk" mammal if anything, since eutriconodonts had shearing teeth specialised to deal with prey; terrestrial flyers can be preserved in marine deposits as well, since they're likely to fly overwater once in a while (see: Solnhofen anurognathids).

Again, the teeth show no erosion, implying death in situ or near, so it wasn't carried over. I believe I already explained this.
Edited by heliosphoros, Jul 3 2016, 02:48 PM.
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Posted Image Flish
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Wikipedia says there was erosion, but only some. Regardless, a small gliding mammal getting swept up in a storm and thrown out to sea is not going to experience much erosion, anyways.
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heliosphoros
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Quoting the original paper

"The cusp sharpness of these molars, combined with the preservation of
such fragile elements in littoral sediments, led us to believe that they
could not have undergone long transportation [..., justification about being piscivores]"

So no, whatever erosion there is at best is minimal, and the animal wasn't dragged to sea, especially given the littoral setting (i.e., where breaking waves and other factors greatly increase the risk of erosion).

I also haven't seen any examples of gliding mammals being dragged by storms.
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babehunter1324
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I think it's pretty safe to say that we need more fossils to figure it out...
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Posted Image Flish
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From what little I could find (which would be helped by having an actual paper to back up your sources) Ichthyoconodon's teeth match, if anything, shrew teeth moreso than anything else, and because of how small Ichthyocondon is, I don't think a similarly generalistic diet of fish, small terrestrial prey, and arthropods is unlikely. I took the time to look at the teeth of predatory bat species as well, and while there are some similarities, they do not match nearly as well as the shrew teeth.
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heliosphoros
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Flish
Jul 3 2016, 05:06 PM
From what little I could find (which would be helped by having an actual paper to back up your sources) Ichthyoconodon's teeth match, if anything, shrew teeth moreso than anything else, and because of how small Ichthyocondon is, I don't think a similarly generalistic diet of fish, small terrestrial prey, and arthropods is unlikely. I took the time to look at the teeth of predatory bat species as well, and while there are some similarities, they do not match nearly as well as the shrew teeth.

Ignoring peer-viewed papers, including one directly quoted. Lovely.*

"Triconodont" molars are well known to not have a direct analogue among insectivorous therians. Comparing them vainly to shrew teeth is almost as good as comparing them to seals and cetaceans.

In other words, inaccurate.

They do, however, have a shearing function, which has been noted as indicating carnivorous habits, as they would have served a similar role to carnassials (Mammals from the Age of Dinosaurs: origins, evolution, and structure).

Therefore, while smaller eutriconodonts like, say, Spinolestes, were likely insectivores, larger species like Ichthyoconodon (similar in size to the related Jugulator) likely ate vertebrate prey as well.

*Considering that the things I'm mentioning are listed in the wiki article, yeah, they're not hard to find at all. But regardless it is

http://www.app.pan.pl/archive/published/app40/app40-149.pdf
Edited by heliosphoros, Jul 3 2016, 05:29 PM.
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heliosphoros
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Also, twenty bucks a certain desperate contrarian person will also upvote that comment. Not naming because they know who they are.
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Posted Image Flish
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I don't care if they're easy to find or if you quoted them, as the person making the claim it's your job to provide evidence for your claims, not mine to go look for them. It's common debating etiquette.

And yes, I'm aware most Triconodont teeth are not similar to Insectivore teeth (Which shrews aren't even exclusively or in many cases, such as water shrews, primarily, particularly larger ones which would be similar in size to Ichthyoconodon), However the only thing I could find on Ichthyoconodon teeth specifically was a small paragraph from a paper talking about how its teeth are unusual compared to other Triconodont teeth. source

Edited by Flish, Jul 3 2016, 05:34 PM.
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