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Ichthyovenator, the spinosaurid theropod with a notch in it's ridge/hump. Described in 2010 and classified as a baryonychine.



But it could have been a relative of the spinosaurines instead. Not really one of them though.



From the 2014 SVP:

New material of the theropod Ichthyovenator from Ban Kalum type locality(Laos): Implications for the synonymy of Spinosaurus and Sigilmassasaurus and the phylogeny of Spinosauridae

New excavations conducted in January 2012 at Ban Kalum, in the Savannakhet Basin, have recovered additional remains of the spinosaurid theropod Ichthyovenator laosensis. The newly discovered material includes the complete cervical skeleton and the first dorsal vertebra, as well as the left pubis, seven additional caudal vertebrae and three teeth. Thanks to this discovery, we are also able to referred isolated theropod teeth and vertebrae, previously collected in various localities of the Savannakhet basin, to Ichthyovenator. This suggests the contemporaneity of all these localities. Ichthyovenator was an important component of the late Early Cretaceous Laotian dinosaur fauna.

The first dorsal vertebra of Ichthyovenator is nearly identical to the holotypic vertebra of the enigmatic theropod Sigilmassasaurus brevicollis from the Cenomanian 'Kem Kem beds' of southeastern Morocco. Sigilmassasaurus has been recognized either as a subjective junior synonym of Carcharodontosaurus saharicus by some authors or as a valid basal tetanuran taxon by others. The two diagnostic characters used to define Sigilmassasaurus (i.e., articular surface of the "cervical" centra much wider than high, with a width/height ratio of approximately 1.5; interzygapophyseal laminae absent so that the short neural spine contacts the dorsal margin of the neural canal anteriorly and posteriorly) are present on the first dorsal vertebra of Ichthyovenator, as well as on the last two cervical vertebrae.

These characters are no longer autapomorphic of Sigilmassasaurus. The latter is here regarded as a nomen dubium, but we refer its holotypic and referred material to Spinosauridae, based on a phylogenetic analysis. The fossiliferous beds which have yielded Sigilmassasaurus material in Morocco, Egypt, and Niger have also yielded remains of Spinosaurus. It is thus very likely that Sigilmassasaurus is a subjective junior synonym of Spinosaurus.

Ichthyovenator was originally placed as the sister group to the remaining baryonychines Suchomimus and Baryonyx. In addition to the peculiar morphology of posterior cervical and anterior dorsal vertebrae, the straight unserrated crowns of the teeth of Ichthyovenator suggest it is more closely related to Spinosaurinae than previously thought.



Yet another half-arsed edit to show what Ichthyovenator may have looked like. Modified from Ibrahim et al. 's Spinosaurus skeletal.

Despite being close to the spinosaurines, Ichthyovenator is probably more compressed in the torso area than they are. There will certainly be revisions when the paper comes out, but for now, this could do. The legs and hips were scaled using ilium depth as a guide.

Unlike Spinosaurus, it's spines may have been a pure ridge/hump, rather than a hybrid "sail + ridge/hump" structure like Spinosaurus probably had, it's spines are much shorter and proportionally much wider. The spines also compare to those of bison, albeit thinner, possibly indicating a thinner, more triangular(in cross section) ridge/hump.


Ichthyovenator


Bison


Spinosaurus



Ichthyovenator being a close spinosaurine relative may have implications on the spinosaurines themselves. Does this mean that adult Spinosaurus and co. actually had decently-sized hips? Larger legs? Only time will decide about this possibility.
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:iconsekley:
Sekley Featured By Owner Jan 28, 2017
One thing I've always been skeptical about is are we sure the notches in the humps of Ichthyovenator and Concavenator aren't vertebrae that have simply been broken in half? I've never seen anything like this among tetrapods so pardon me for being misinformed.
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:iconspinoinwonderland:
SpinoInWonderland Featured By Owner Jan 28, 2017
I sometimes think that same thing myself actually. Looking at them, it really looks very plausible.

d29jd5m3t61t9.cloudfront.net/d…
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:iconsekley:
Sekley Featured By Owner Jan 28, 2017
You'd think we'd learn from Tsintaosaurus to not judge remains so quickly as they might just be broken. On an unrelated note I'm feeling better in the head.
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:iconasuma17:
Asuma17 Featured By Owner Edited Jan 27, 2017  Hobbyist General Artist
So let me get this straight. It is apart of the Baryonychidae family, but that research stated it more resembled the Spinosaurinae relatives. I don't if it's convergent evolution, but that honestly sounds fishy and I'm using it as a pun.

And it had been covered.
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:iconspinoinwonderland:
SpinoInWonderland Featured By Owner Jan 27, 2017
Actually, this means that Ichthyovenator is not really a baryonychine like it was previously thought to be.
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:iconasuma17:
Asuma17 Featured By Owner Jan 27, 2017  Hobbyist General Artist
Hmm, I don't know. The skull feature kinda strikes me more for a Baryonyx than a Spinosaurus. I mean unless these Paleontologist uncover more traits; I think I'll play it safe.
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:iconspinoinwonderland:
SpinoInWonderland Featured By Owner Jan 27, 2017
Ichthyovenator doesn't even have a known skull, where are you getting that from?
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:iconasuma17:
Asuma17 Featured By Owner Jan 27, 2017  Hobbyist General Artist
Well based on illustrations. Also it's body design is more Baryonyx-like than Spinosaurus.
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:iconspinoinwonderland:
SpinoInWonderland Featured By Owner Jan 28, 2017
Based on what illustrations? Speculative illustrations that reconstruct it after the idea of it being a baryonychine? Speculative and dated full-body reconstructions are just that, speculative and dated reconstructions, and under no circumstances should be used to infer the phylogenetic placement of anything.

Also, that half-arsed reconstruction is just that, half-arsed. I recommend :icongetawaytrike:'s skeletal reconstruction this one for now: i.imgur.com/eCB6qKK.jpg
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:iconasuma17:
Asuma17 Featured By Owner Jan 28, 2017  Hobbyist General Artist
Well first these illustrations

Ichthyovenator and the call of nature by Hyrotrioskjan    Ichthyovenator by SameerPrehistorica   Ichthyovenator recolored by Xiphactinus   Ichthyovenator by Vitor-Silva   vignette2.wikia.nocookie.net/d…

And regardless if it has Spinosaurine-like quality; I think it's more Baryonychine, cladogram doesn't put on the Spinosaurine family, the cladogram also shows that Ichythovenator branches from the Baryonyx family of dinosaurs down the line, thus far it acts as a sister group to the Baryonyx than it does Spinosaurus. So convergent evolution may have been a slight thing with this dinosaur, but despite the distinction like with Suchomimus...there would still be some traits to prove that Ichythovenator is more closely related to Baryonyx.
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:iconspinoinwonderland:
Really? REALLY? Those illustrations are speculative reconstructions that are either: a) made from the time before the new Ichthyovenator specimens were found, or b) made without awareness of the new specimens.


" the cladogram also shows that Ichythovenator branches from the Baryonyx family of dinosaurs down the line, thus far it acts as a sister group to the Baryonyx than it does Spinosaurus"

The cladogram is just an old Wikipedia one that I drew over to illustrate Ichthyovenator's old position vs it's likely new position.


"there would still be some traits to prove that Ichythovenator is more closely related to Baryonyx"

:baffled: 

What. What are those traits you speak of? Have you even read it carefully? Because:

"In addition to the peculiar morphology of posterior cervical and anterior dorsal vertebrae, the straight unserrated crowns of the teeth of Ichthyovenator suggest it is more closely related to Spinosaurinae than previously thought."
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(1 Reply)
:iconhyrotrioskjan:
Hyrotrioskjan Featured By Owner Jan 28, 2017  Professional General Artist
I can only speak for my stuff but NEVER use these illustrations as a reference, my pic was created in a short amount of time with way too
little research involved and is now a little old.
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(1 Reply)
:iconcaptainjimmbob:
captainjimmbob Featured By Owner Jan 28, 2017
What? Using artist's renditions over skeletals? Are you serious?
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(2 Replies)
:iconpcawesomeness:
PCAwesomeness Featured By Owner Jan 11, 2016
Welp, only time will decide if all spinosaurs are the same or if Spinosaurus is to the spinosaurid theropods as Acutiramus is to the pterygotid eurypterids.
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:iconzopteryx:
ZoPteryx Featured By Owner Sep 29, 2014  Hobbyist General Artist
Very interesting, thanks for sharing!
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:iconmremilable:
MREMILABLE Featured By Owner Sep 29, 2014  Hobbyist General Artist
Wonder if it's half the Way of the spinosaurus evolution.
The legs May not have been as short has spino but, not as long as the megalosaurs they Evoled form.
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:iconspinoinwonderland:
SpinoInWonderland Featured By Owner Sep 29, 2014
Ichthyovenator being a "transitional form" between low-slung spinosaurines and their longer-legged ancestors is possible, but we'll see about that on the paper's release.
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:iconmremilable:
MREMILABLE Featured By Owner Sep 29, 2014  Hobbyist General Artist
Your right
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:iconmiyess:
Miyess Featured By Owner Sep 29, 2014   Digital Artist
Good stuff. :)
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