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105697 — Creatures of Albian-Cenomanian North Africa: P.T 2
#spinosaurs #cenomanian #spinosaurusaegyptiacus #kemkembeds #northafricanspinosaurcomplex
Published: 2017-04-09 23:02:49 +0000 UTC; Views: 4060; Favourites: 68; Downloads: 32
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Description
The spinosaurs continue.Here we have Spinosaurus aegyptiacus, probably the most famous resident of Africa during this time period.
Spinosaurus aegyptiacus was a very large theropod (more on that later). It has material from across the Sahara Desert, suggesting it was very widespread. It probably managed to distribute so far because of it swimming abilities. Unlike S. maroccanus/S. brevicollis, this species was more suited to swimming and punting around on the bottom. This is seen in its foot claws, which are much flatter than that of Sigil, its thigh bones, which have bigger muscle attachments, its legs, which proportionally thinner and shorter, and its massive sail, which would have added a lot of weight onto the animal proportionally than that of Sigil.
Now, a lot of people think that Spinosaurus aegyptiacus is the largest theropod dinosaur to ever walk the Earth. This was true for some time, as the giant skull fragment, MSNM V4047, was attributed to this species. This suggests an animal around 15 meters in length, making it the longest theropod yet discovered. However, not too long ago, in the olden days of 2016, (our scale lord and savior) GDI'd Ibrahim's Spinosaurus skeletal, which to this day still stands as the most accurate skeletal of this genus yet, despite what you may have heard.
franoys.deviantart.com/journal…
According to his GDI matlab script, a 15 meter S. aegyptiacus would only weigh in at around 7.5 tonnes, which is still heavy, but not as heavy as some of the largest T.rex specimens. However, as I said before, the MSNM V4047 skull might not actually belong to S. aegyptiacus (more on that in a later deviation). If we take MSNM V4047 from the pile of spinosaur remains that are labeled under S. aegyptiacus, than we get something interesting: Several, mature individuals that are possibly the largest S. aegyptiacus specimens known. They are IPHG 1912 (the Holotype), NHMUK 16665, and MNHM.KK378. All these specimens are mature adults, but the thing is they probably weren't 15 meters in length. According to , all these specimens fall into the 11.5-12 meter range (Holotype: 11.52 meters; MNHM.KK378: 11.6 meters; NHMUK 16665: 12 meters). Now, does this mean that S. aegyptiacus never got to 15 meters in length? Of course not. It is totally possible that it could have reached 15 meters in length since even adult animals grow quite a bit after they reached sexual maturity. It's just that we don't have that many specimens fitting the 15 meter range (in fact, none at all). So while I have interpreted this S. aegyptiacus at around the 11.5-12 meter adult, the 15 meter estimates still remain possible.
Also, while MSNM V4047 probably isn't S. aegyptiacus proper anymore, that doesn't mean we don't have any upper jaw bones from this species. May I introduce you to NHMUK 16665, probably the most complete S. aegyptiacus upper jaw we found yet.
www.researchgate.net/profile/E…
This specimen shows some interesting characteristics about the species. For example, the jaws are thinner than those of MSNM V4047. Even when you scale them to the same size, NHMUK 16665 has slender jaws compared to the other, very complete Spinosaurus upper jaw. It also has a slight concave curve on the top of its skull. This probably means this species was probably tackling "small" prey (will be explained in depth in the ecology section).
ECOLOGY: S. aegyptiacus is the largest predator in what will one day be North Central and North East Africa. It's greatly suited to life in the water, with webbed feet, heavy bones, powerful legs, nostrils high up on the snout, and a long steering tail. It could distribute so freely from the three separate landmasses that make up Cenomanian Africa because they can swim from one place to another easily. S. aegyptiacus hunts down medium-sized fish, such as giant bichirs and youn individuals of Mawsonia and Onchopristis. They can come onto land, but they don't need to. Males spend most of their life in the water, with females coming out of the water to lay their eggs. They are usually free from competition in most of their range, but on the North West side of Africa, they have to compete with large crocodilians and other types of spinosaurs.
Oh, and the dude on the other side of the paper? That will be our next creature.
BTW, I'll probably start only drawing on one side cause then my art looks more refined and I don't give away the next animal I'll be drawing. Also because forced me to XD.
NOTE: The references I used to make this drawing are not mine. The full body reconstruction of S. aegyptiacus is based of 's higher quality version of Ibrahim's skeletal.
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Comments: 28
Wait...
I just read the diet section again...
Welp, it's time to start having Spinosaurus eat small fry such as Bawitius, Retodus, Asteracanthus, and Lepidotes!
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S. aegyptiacus anyway.
Not to mention, that doesn't mean that it couldn't kill large prey like adult Mawsonia and Onchopristis. Many modern semi-aquatic predators go after prey that can be swallowed whole, but they can take down prey that is larger than their mouth from time to time.
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Dammit, I thought this thing was going to be settled for a while xD
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Spinosaurus didn't eat adult Mawsonia and onchopristis? Considering that it's twice as large as those giant fish, it probably still could happen.
And for those who doubt a predator with thin jaws can kill large prey: false gharials.
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I'm not saying Spinosaurus didn't eat adult Mawsonia and Onchopristis, I'm saying that Spinosaurus aegyptiacus probably didn't go after the adults of the two regularly, and probably went after somewhat smaller, but still large prey.
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That doesn't really make much sense, seeing false gharials will eat prey half their size on a regular basis.
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Why are false gharials all of a sudden good analogues to spinosaurs?
Sure, they do have some things in common in their head, but the snout shape is different, the teeth are different, and the whole body build is completely different.
"false gharials regularly eat prey half their size on a regular basis"
An average False Gharial is around 200 kg in mass, while some of the biggest prey that it lives with (two species of Rusa deer) are around 50 kg in mass, which is about 1/4 of its mass. There are cases of False Gharials hunting and killing larger animals (one was observed attacking a cow, but not killing it, and there were a few encounters where adult humans fell prey to Tomistoma), but those aren't taken on a daily basis.
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False gharial jaws are the closest living animals we have to spinosaur jaws, however.
No aquatic crocodilian attacks large, land-living prey on a daily basis anyways. If you take that into account, false gharials aren't really that different from salties.
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No. Pike congers are the closest living analouges we have to spinosaur jaws.
c1.staticflickr.com/3/2808/122…
upload.wikimedia.org/wikipedia…
Pike Congers eat anything they grab swallow into their mouths.
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And it's not like these eels don't eat prey too large to eat whole
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Pike Congers hunt prey they can swallow whole. I've never heard of them taking down prey larger than they can swallow.
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But pretty much all other eels do, including morays with relatively thin jaws
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Moray Eels have a different jaw structure than Pike Congers.
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LOVE THE ART. Although there are a few things. I don't believe their's evidence for NHMUK 16665 being an adult and I kind of doubt that it is one. In fact I don't even think their's any evidence for any of these specimens (except msnm v4047) for being adults. The rostrum of NHMUK 16665 is incredibly small in comparison to these other specimens. In fact I'm pretty sure it's even smaller then the rostrum of the drouot spinosaurs, both of which are juveniles of about 8 meters in length. As for the others, although they are larger then the drouot spinosaurus, they still are rather small in comparison to msnm v4047. I think the difference we see in these rostrums are not due to them being different species, but rather different ages. But of course this cannot be proven until we find more of this species. That's the hard part about spinosaurus, such an interesting animal but we have next to nothing of it (and the best stuff we do have, the drouot spinosaurus, have been sold at a private auction).
And of course it could be argued that MSNM v4047 isn't a spinosaurus,but I highly doubt it isn't because it is still remarkibly similar to all other S.aegyptiacus specimens (especially to MNHM KK378).
Also do you know how the 12 meter length was aquirred for NHMUK 16665??? the rostrum is only about 50-ish centimeters long (the three black dots under the rostrum in the picture represents 5cm) I doubt a spinosaurus with a 2.7-ish foot skull would be 12 meters long.....
But still don't get me wrong I am IN LOVE WITH THE ART!!
Also, I may have mistaken MNHM KK378 for MNHN SAM 124, sorry about that, forget what I said up top
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well the smallest adult spinosaurus specimen seems to be FSAC-KK 11888 seeing as its basically an adult at the age of 17.
www.deviantart.com/art/Spinosa…
seeing as both the 'adult' spinosaurus specimens (other than MSNM v 4047) are in the ~11-12 meter range perhaps the MSNM v 4047 specimen is just a big headed adult considering that a big head would help with hunting fish.
then again we need more specimens to confirm or disprove this.
but yeah scaled from smaller specimens, MSNM v 4047 seems to be 14.88 meters long and 7.56 tonnes.
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How do we know that its an adult though? I would go and look at the paper but unfortunatly it seems like you have to log in for the paper. And i dont want to do that XD
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normally by counting growth rings or seeing fused bone elements i guess.
by the age of 17 an animal like that is basically an adult its close in size to most of the other adult Spinosaurus specimens anyway.
T.rex for example mostly stops growing by the age of 20 (or rapidly slows down growth) so i guess its possible for this to apply for other large theropods.
(i don't actually know if this is unique to T.rex or not though)
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From on the 11.5-12 meter spinosaur individuals.
"Citing Hendrickx et al 2016:
MHNM.KK378 is the largest quadrate and most likely belongs to a fully grown individual. The quadrate is much larger than the other ones, and the entocondyle is strongly prominent, suggesting that the intercondylar sulcus of the mandibular articulation was particularly deep (Fig 10J–10L ). The squamosal capitulum is also globular and an additional quadrate ridge appears ventral to it (Fig 10K ).
These ontogenetic transformations result from the fusion between the quadrate and quadratojugal, the reinforcement of the quadrate shaft, and the stabilization and tightening of the articulation of the squamosal capitulum and mandibular condyles with the squamosal and lower jaw, respectively.
(This is the study, it is open access: journals.plos.org/plosone/arti… )"
MHNM.KK378 is around the same size as the Holotype, suggesting that both are mature adults.
"And of course it could be argued that MSNM v4047 isn't a spinosaurus, but I highly doubt it isn't because it is still remarkibly similar to all other S. aegyptiacus specimens (especially to MNHM KK378)."
MNHM.KK378 is only known from five pieces of the back of the skull, so there is no overlapping material between the two specimens. Also, Jaime Headden has wrote down several posts as to why MSNM V4047 is probably not S. aegyptiacus that will be elaborated in the next deviation, not to mention that MSNM V4047 actually has more in common with the "Oxalaia" material from South America (I'll also elaborate that on the next post as well with an image). All this suggests to me that MSNM V4047 probably wasn't S. aegyptiacus, but a different species of Spinosaurus.
I showed the skull and the scale bar, and he came up with a 77.8 cm long snout, suggesting a 12 meter animal.
Also, there are adult specimens of dinosaurs which show MUCH bigger variation in size. Plateosaurus adults range from 4.8 meters to 10 meters in length and 600 kg to 4 tonnes in mass.
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I've been playing around a little bit more with NHMUK 16665. I keep getting a range of different sizes between 8-13m. At first I thought it looked so different from MSNM v4047 because of ontogeny, but now I'm starting to suspect that it may be a different genus now that i've realized its similarity to one of the drouot spinosaurus (that, and the fact that both the rostrum and one of the drouot spinosaurs looks different from the other drouot spinosaurus)
"MNHM.KK378 is only known from five pieces of the back of the skull, so there is no overlapping material between the two specimens. Also, Jaime Headden has wrote down several posts as to why MSNM V4047 is probably not S. aegyptiacus that will be elaborated in the next deviation, not to mention that MSNM V4047 actually has more in common with the "Oxalaia" material from South America (I'll also elaborate that on the next post as well with an image). All this suggests to me that MSNM V4047 probably wasn't S. aegyptiacus, but a different species of Spinosaurus."
I don't think you saw my edit on my last comment but I had mistaken MNHM.KK378 for a different specimen (I thought you had been talking about a rostrum not a quadrate) So apologies for that, forget what I said about that individual.
I have seen other people disagree with his opinion on MSNM v4047 not being a s. aegyptiacus, and I do think these people have a good standing (i haven't seen that post in awhile though). Last I checked, he argued that msnm was from a different species because it was too thin in comparison to the holotype. However, this difference could be due to individual difference (since both individuals are of different sizes). But honestly, for two different sized individuals, their jaws due seem to still fit together rather well. But, going back to the other rostrum, NHMUK is much thinner then msnm, which actually makes me think it may not be a spinosaurus. Although I do think oxalaia will one day be found to be synonymous with Spinosaurus, I don't think msnm is all too different from other spinosaurus specimens in Africa. Just look at the drouot spinosaurus (skeleton) and MNHN SAM 124, they are incredibly similar.
But going back to NHMUK, there actually has been arguments against the idea of NHMUK being a spinosaurus, and i'm actually finding myself starting to agree with these people....
Also, i didn't think we had a quadrate from the holotype? is it in one of the photographs/ drawings of it?
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You seem to keep bringing up the Drouot Spinosaurus. The thing is that "specimen" was a hoax that failed to sell at an auction.
Here is a comparison of MSNM V4047 and NHMUK 16665 trying to fit into the Holotype dentary.
cdn.discordapp.com/attachments…
The snout of MSNM V4047 isn't a good fit and there is an obvious overbite and slight concave depression in MSNM's snout doesn't match that of the Holotype dentary's slight convex jaw. Meanwhile, NHMUK is an almost perfect fit with the Holotype dentary.
We don't have any from what I'm aware of.
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How was it a hoax? Sure it was reconstructed poorly (more specifically the lower jaw) but if you compare that skull to NHMUK they are almost completely identical.
Also the link didn't seem to work
Although when ever I compare NHMUK to the holotype the maxilla does fit into the dentary, however the premaxilla overarches the dentary more so then MSNM v4047. But when compared to the other drouot specimen its almost a perfect fit.
And it's also good to note that, although NHMUK may fit the holotype somewhat laterally, it won't fit it very well dorsally. The reason why MSNM v 4047 was thought to be from a different genus/species was because it was thinner then the holotype, and NHMUK is even thinner the MSNM v4047
lh5.googleusercontent.com/-2w2…
Wait so what's the evidence then for the holotype being an adult?
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