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March 8, 2014
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Megalosaur interrupted by ScottHartman Megalosaur interrupted by ScottHartman
As a general rule most books sort of gloss over the transition from basal coelophysoid or ceratosaurian grade theropods to allosaurids, but megalosaurs are actually a fascinating bunch. They not only rose to prominence during the Middle Jurassic, but they continued to compete in the Northern Hemisphere alongside sophisticated allosauroids, and managed an impressive Cretaceous radiation (as spinosaurids). Sadly a lot of these specimens are not terribly complete, so if we want to restore them we need to do a lot of gap filling.

Torvosaurus is actually surprisingly complete once all of the referred specimens are accounted for (mercifully they also have quite a bit of overlap between material, so cross-scaling isn't such a challenge). So perhaps not surprisingly that's what was used to help fill out Megalosaurus and the new T. gurneyi.

Marshosaurus is too far from Torvosaurus to use it, so instead Condorraptor and Piatnitzkysaurus stood in. Also, to be fair to the megalosaurs and the completeness issue some of the more basal taxa like Eustreptospondylus and Piatnitzkysaurus are more complete, but I haven't got to them (yet!).
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:iconladymedusa218:
Ladymedusa218 Featured By Owner Jul 28, 2014  Hobbyist General Artist
megalosaurs descended into spinosaurs??? wow ive never heard of that!!!what "links" would be between these two?? also is it thought that maybe the bones of megalosaurus may actually be juvenile torvos??? well i guess actually it would be megalosaurus that would be the correct genus name since it was named first. id love to know the details about all of this :) 
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:iconscotthartman:
ScottHartman Featured By Owner Jul 29, 2014  Professional Digital Artist
Since I'm sort of swamped atm I'll point you to the appropriate Wikipedia page: en.wikipedia.org/wiki/Megalosa… Not only does it have some fairly recent family trees, but if you meander down towards the works cited at least one paper is available to download (and it has all the characters).

The easiest not-so-technical characters to see are a very large thumb claw, and an elongated head (sure, it's taken further in spinosaurids, but megalosaurs also have long heads).
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:iconasuma17:
Asuma17 Featured By Owner Jul 17, 2014  Hobbyist General Artist
Come to pass the Torvosaurus seems to pretty well complete though I still can't see why it is so rare and plus on that Marshosaurus too and I wish they'd find more fossils of Megalosaurus it's been incomplete for so long and it was the first dinosaur ever discovered!
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:iconjeda45:
Jeda45 Featured By Owner Jul 1, 2014
What do you think of nasal crests/ridges in megalosauroids? Dennonyx says that it's parsimonious to assume that they had them, since most basal members of "carnosaur-grade" (Ceratosauria, Allosauroidea, Tyrannosauroidea) lineages had them. I'm especially interested in piatnitzkysaurids, so I can make my Marshosaurus reconstruction as accurate as possible.
On a related note, did they have lacrimal horns?
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:iconthediremoose:
thediremoose Featured By Owner Mar 14, 2014
I'm curious. The specimen of Marshosaurus from the Carnegie Quarry included the back of the skull, the cervicals, and the first five dorsals (which are shown) but also a scapula and partial humerus (which are not). Is the forelimb material no longer considered part of that specimen?
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:icondennonyx:
Dennonyx Featured By Owner Mar 23, 2014  Student General Artist
^agree
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:iconezekiel-black:
Ezekiel-Black Featured By Owner Mar 11, 2014
Awesome, I love Torvosaurus. Maybe this is a sign for me to do more dino drawings.
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:iconscotthartman:
ScottHartman Featured By Owner Mar 12, 2014  Professional Digital Artist
It's definitely a sign.
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:iconasacquaf:
asacquaf Featured By Owner Mar 10, 2014
Where does Edmarka come in on this scale?
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:iconscotthartman:
ScottHartman Featured By Owner Mar 10, 2014  Professional Digital Artist
Edmarka is just another specimen of Torvosaurus, so its remains have been included already (and the skeletals are not to scale).
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:iconkazuma27:
Kazuma27 Featured By Owner Mar 10, 2014  Hobbyist General Artist
What?!
And i thought we had at least one complete megalosauridd arm :P
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:iconscotthartman:
ScottHartman Featured By Owner Mar 10, 2014  Professional Digital Artist
Well we have the arm of Torvosaurus, just not all of the wrist and hand.
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:iconthedinorocker:
thedinorocker Featured By Owner Mar 10, 2014
I recently saw your (modified) skeletal of T.gurneyi on the paper!
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:iconscotthartman:
ScottHartman Featured By Owner Mar 10, 2014  Professional Digital Artist
Indeed :)
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:icongojira5000:
Gojira5000 Featured By Owner Mar 9, 2014  Hobbyist Digital Artist
Torvosaurus probably wasn't the most amazing at running, judging from comparisons of it's upper-lower leg ratio to more high-speed animals like a cheetah or Carnotaurus; it's lower legs are almost laughably puny in comparison to a cheetah's.

In fact, it looks like a running Torvosaurus might just go at a "whopping" 20 miles an hour, I can't see it possibly running much faster unless it had the most freakin' roided-up drumstick legs in the animal kingdom.

Even still, 20 mph is enough to kill most people (and sauropods), so maybe I shouldn't mock it's speed.
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:iconzegh8578:
ZEGH8578 Featured By Owner Mar 9, 2014
Had I come across this 10 years ago, I woulda fallen into a happy spasm. This is amazingly cool, über obscure critters together. Afrovenator and Dubreuillosaurus, how closely related are they?
All of them have this long, narrow snout, that I like to imagine as being dead-sauropod-stomach-content-scoops. Such a specialization possibly explaining their departure from more standard hunting body shapes (as in Allosaurus), and also their relation to Spinosaurids, whos elongated snout allready forms the basis around their specialization. Mid and especially late jurassic would be a time when dead, rotting sauropods would exist in quantities, here and there, not only sauropods, of course, but there would be a lot of sauropods around! A whole niche of long snouted, expert-sniffing prowlers wouldn't be too unlikely.

It also puzzled me before, how narrow Torvosaurus belly is. Is it unusually wide, to compensate for the seemingly diminished stomach size? If not, that too could reflect a specialization in Torvosaurus' life.
Lots of speculation on my part now, but someone's gotta do that too :D
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:iconscotthartman:
ScottHartman Featured By Owner Mar 9, 2014  Professional Digital Artist
Torvosaurus does not have a particularly wide abdomen (no megalosaurs do to my knowledge). I'm not sure if the ribcage itself is unusually short as much as the pelvic girdle is. It's clearly a derived condition (and we have complete pelvic remains, so it's not a matter of mis-scaling something) but I have to admit I don't know what exactly they are doing with them. Maybe they can more easily crawl into a sauropod rib cage to get at the entrails? Or maybe it has something to do with respiration. One thing I can say (and hope to blog about) is that the legs of Torvosaurus are much more splayed than you see in carnosaurs (let alone coelurosaurs), so maybe that has an impact on the pelvic musculature.
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:iconeriorguez:
Eriorguez Featured By Owner Mar 9, 2014
Mmm, Megalosaurus being ancestral to Torvosaurus, or at least quite similar to the animal Torvosaurus evolved from, is something that shouldn't be rule out, right?

Still, neat to see more of those animals, they tend to be labeled as generic and left forgotten, so they deserve a bit of attention.
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:iconscotthartman:
ScottHartman Featured By Owner Mar 9, 2014  Professional Digital Artist
It absolutely shouldn't be ruled out. Megalosaurus clades with Torvosaurus, and existed sufficiently early relative to it. Of course we don't test literal ancestor-descendant relationships in modern phylogenetics, we test shared common ancestry, so currently there's no easy way to test the idea.
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:iconolofmoleman:
olofmoleman Featured By Owner Mar 9, 2014  Student Digital Artist
Nice to see some love for Megalosaurs.
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:iconzopteryx:
ZoPteryx Featured By Owner Mar 8, 2014  Hobbyist General Artist
Shame there's not more remains to go on.  I never realized they had a small notch at the end of the upper jaw.  Any particular reason for the longer arms on Marshosaurus?
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:iconscotthartman:
ScottHartman Featured By Owner Mar 9, 2014  Professional Digital Artist
It's based on the arms of Piatnitzkysaurus, which seem to be similarly large (and is closer related to Marshosaurus). FWIW Eustreptospondylus seems to have a somewhat intermediate arm length. I think the take-home message is that megalosaurs dominated a lot of niches during the Middle Jurassic, so they evolved a bunch of sizes and proportions in response to those environments.
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:iconblade-of-the-moon:
Blade-of-the-Moon Featured By Owner Mar 8, 2014  Professional Traditional Artist
It's interesting out 4 species now how little we have..reminds of a similar issue spinosaurs face. 

I've always wanted to create a 1:1 Megalosaurus and Iguanodon.. but I generally shy away from species with such incomplete skeletons as Megalosaurus...though your reconstructions here make me think it might just work out.
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:iconfloyatoy:
Floyatoy Featured By Owner Mar 8, 2014
Thanks Scott.  I'd love to see them to scale. 
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:iconscotthartman:
ScottHartman Featured By Owner Mar 8, 2014  Professional Digital Artist
That was my original intent, but I have to decide how to scale Megalosaurus, since the shotgun-style of referred specimens by Benton has lead to more than one size class of individuals.
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:iconangrydinobirds:
Angrydinobirds Featured By Owner Mar 8, 2014  Hobbyist
So when might you get to the other megalosaurs like Eustreptospondylus?
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:iconscotthartman:
ScottHartman Featured By Owner Mar 8, 2014  Professional Digital Artist
I really have no idea. I have Eustreptospondylus AND Piatnitzkysaurus totally scaled and ready to go, but precious little time for anything but research, course work, and teaching right now.
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:iconangrydinobirds:
Angrydinobirds Featured By Owner Mar 10, 2014  Hobbyist
All right. Guess I could wait. ;) (Wink) 
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:iconkitwhitham:
KitWhitham Featured By Owner Mar 8, 2014
So is it starting to be a more accepted view that magalosaurs/torvosaurs evolved into spinosaurs?
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:iconscotthartman:
ScottHartman Featured By Owner Mar 8, 2014  Professional Digital Artist
It seems pretty settled that spinosaurs are megalosauroids. They probably didn't literally evolve from the Megalosaurus/Torvosaurus clade though.
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:iconkitwhitham:
KitWhitham Featured By Owner Mar 8, 2014
 I see. When I was looking at the arms of Torvosaurus and Baryonyx, I did notice that they were similar. Hopefully we'll find a transitional Megalo-to-spinosaurid in 2014!
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:iconthediremoose:
thediremoose Featured By Owner Mar 12, 2014
Actually, we may already have one. Monolophosaurus has shown up as immediately basal to the meg+spin clade, and it has a prominent midline crest on its skull and sort of "rosette" of teeth on its lower jaw like spinosaurs do.
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:iconkitwhitham:
KitWhitham Featured By Owner Mar 13, 2014
Huh, of all the times I've looked at his skeletals I've failed to notice that.
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:iconjeda45:
Jeda45 Featured By Owner Mar 8, 2014
How big were Megalosaurus and Marshosaurus? Gregory Paul has all of the piatnitzkysaurs as being 4.5 meters long, and Megalosaurus at 6 meters, is that right?
Also, did megalosaurs have lacrimal horns? It looks to me like Marshosaurus has some, but I see that the lacrimals aren't preserved and I could be misinterpreting them.

Thanks.
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:iconspinodontosaur4:
Spinodontosaur4 Featured By Owner Mar 8, 2014
If I recall correctly the largest material referred to Megalosaurus is an 83 cm illium, so based on the skeletal above that would indicate a tip-to-tip length of something like 8.3 meters, for over the curves I'm not sure, I lack the means to measure it atm, but something like 8.5 - 9 meters is probably in the ballpark.
Doing the same for Marshosaurus (largest remain is, I believe, a 37.5 cm illium) gives a tip-to-tip length of 4.1 meters.

So I think Paul is probably close to the money with Marshosaurus, but not Megalosaurus.
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:iconjeda45:
Jeda45 Featured By Owner Mar 8, 2014
Wow, Marshosaurus was hardly bigger than a big Deinonychus. Surprisingly tiny for something so stock-"carnosaur"-y. Is this true of Piatnitzkysaurus too?
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:iconscotthartman:
ScottHartman Featured By Owner Mar 9, 2014  Professional Digital Artist
Yeah, Piatnitzkysaurus isn't very large either.
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:iconscotthartman:
ScottHartman Featured By Owner Mar 8, 2014  Professional Digital Artist
Marshosaurus isn't terribly large, but Megalosaurus is something of an enigma - most of the composite material seems to come from a ~7m long theropod, but one of the isolated ilia looks like it could scale up to a 10m long animal to me.
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:iconblazze92:
bLAZZE92 Featured By Owner Mar 8, 2014
That femur in Torvosaurus tanneri (Britt (1991) says the femur is unknown) is part of the unpublished specimen you mentioned before right? or is it something you can't say?
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:iconscotthartman:
ScottHartman Featured By Owner Mar 8, 2014  Professional Digital Artist
There is a complete leg with the "Brontoraptor" specimen.
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:iconblazze92:
bLAZZE92 Featured By Owner Aug 26, 2014
Looking at the supplemental material of Benson et al. (2014) I'm seeing that the Brontoraptor specimen is comparable in size to the subadult from dry mesa, is that correct? I always thought that it was supposed to be gigantic.
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:iconscotthartman:
ScottHartman Featured By Owner Aug 27, 2014  Professional Digital Artist
That's about right. It was supposed to be robust (and it is), but it's not special in size. Nor in morphology...
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:iconblazze92:
bLAZZE92 Featured By Owner Mar 8, 2014
Oh, thanks.
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:icontomholtzpaleo:
TomHoltzPaleo Featured By Owner Mar 8, 2014
Tyrannosaurs did not come from megalosaurs: they are coelurosaurs, related to smaller theropods like compsognathids, Ornitholestes, and ornithomimosaurs. The oldest tyrannosaurs (Proceratosaurus & Kileskus) are about as old as the oldest megalosaurs.
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:iconscotthartman:
ScottHartman Featured By Owner Mar 8, 2014  Professional Digital Artist
Tom, is that really you on DA?
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:iconjonagold2000:
JonaGold2000 Featured By Owner Mar 8, 2014  Hobbyist
Didnt Tyrannosaurs come from earlier Megalosaurs?
I didnt know they evolved into Spinosaurs though
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:iconguilmon182:
guilmon182 Featured By Owner Mar 8, 2014  Hobbyist Traditional Artist
Actually tyrannosaurs are coelurosaurs, the same group as dromaeosaurs, ornithomimids, and the like.
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:iconjonagold2000:
JonaGold2000 Featured By Owner Mar 8, 2014  Hobbyist
oh ok. I got a lil confused there.
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:iconguilmon182:
guilmon182 Featured By Owner Mar 8, 2014  Hobbyist Traditional Artist
That's alright. I do admit that Torvosaurus does look quite a bit like a tyrannosaur in the skull.
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:iconjonagold2000:
JonaGold2000 Featured By Owner Mar 8, 2014  Hobbyist
Im not the biggest expert out there thoug :P
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