Wednesday, November 5, 2014

My Opinions on the NOVA Spinosaurus Documentary.

So, I just finished watching the new Spinosaurus documentary on PBS titled "Bigger than T. rex". I decided to post a review of the documentary on Facebook from the notes I took. It ended up getting so long that it could take up a blog post. As such, here it is:

My thoughts on the NOVA Spinosaurus documentary:

-Saw an ad for the museum I work at prior to the start of the show. Tis a good sign.
-Still don't like the title. People need to be more creative with their titles. Why does everything need to be compared to T. rex for Pete sake?
-Typical promising NOVA opening. Draws you in and gets you in the mood quickly.
-CAMELS!!! I love Camels.
-Peter Dodson's comparison of Spinosaurus to Nessie immediately brought this to mind:
-They say something about flesh-eating Mesozoic birds being found in the Sahara. If somebody knows about this and cares to explain it, please do, because I have no idea what they're talking about...
-The typical NOVA animations and reenactment scenes really fit the mood. Just my personal opinion.
-I don't think I really understood exactly how crazy the re-tracking of this specific fossil hunter was until I watched this. Nizar really did have some awesome luck going for him.
-Camel playing with a coke bottle. I can't tell if this is brilliant product placement, or they were short 5 seconds of footage and decided to give a camel a coke bottle and record what happens to fill it up. Either way, I approve.
-I just noticed this, but Spinosaurus as a species has been referred to as a "he" multiple times in the documentary so far. Why? Were there no female Spinosaurus or something? Is that why they're extinct?
-Just wanted everyone to know, I called this predators in Kem Kem ate fish thing first:
-Me: Please explain your methods!
*Never explains methods.*
Me: Dammit...
-Stop saying birds are dinosaur's "closest living relatives". Just say they ARE dinosaurs! It makes us museum interpreters' lives so much easier.
-Bubba is the most calm Alligator I've ever seen. I want to hug him.
-I still don't think everyone agrees the sail looked like that, but, whatever...
-Sereno says briefly something about Spinosaurus having the most massive forearms of any dinosaur. Er, Deinocheirus? Therizinosaurus? Heck, go outside of theropods and point out Brachiosaurus! Why do they get no love?
-Again, not everyone agrees with the quadrupedal thing, but, whatever...
-The animated life-model doesn't look anything like the mount. I mean, it's got long legs, short forelimbs, etc. Doesn't look anything like what Ibrahim et. al. have stated.
-The feeding animation at the end was a disappointment. I wanted to see a Spinosaurus dive and swim after fish. Instead you saw it swim for 2 seconds, then it skipped a scene and went to heron-fishing... That's not what I signed up for!
-"Spinosaurus makes sense." Tell that to all the scientists who are still scratching their heads while waiting for the monograph!
-Ok, I get that Spinosaurus has a lot of history behind it, and this discovery is certainly a major step in our understanding of it, but they give off this vibe at the end like that this is the end of Spinosaurus' journey and we know everything we can know. I'm sorry, but no. There's certainly a lot more to learn from this, and this is going to be talked about and reviewed over for years to come. Don't tell us this is all over when we're still waiting for a proper description of these remains!

Anyways, all in all, a decent watch. It didn't teach me anything I didn't already know, but I recommend everyone watch it at least once for typical NOVA documentary goodness. Still, I would've liked to see more Spinosaurus though. Throughout the whole thing I was getting a Godzilla 2014 vibe of wanting to see more of the actual star through computer animation, but we only really got to see it in full during the last 10-ish minutes (probably less). Plus, when we finally got to the actual fishing behavior, it was incredibly dull and disappointing. Eh, at least it was 100x better than Monster's Resurrected.

Now, if you excuse me, I'm going to be waiting quietly in the corner for the Spinosaurus monograph we've been promised. Cheers!

Saturday, October 4, 2014

Short legs are in?

Spinosaurus aegypticus discusses with a certain individual of Homo sapiens about movie star traits.

So, everyone that's been keeping up with the Spinosaurus stuff these past few weeks have probably seen this post by Mark Witton by now. In it, Ibrahim and co. consulted with Mark and checked over the proportions and scaling in his model, which Mark checked a few days prior and found similar results to Scott Hartman's own numbers. They found out that the big scaling gap between their model and Scott and Witton's models was actually due to some scaling issues in the latter two's models with vertebrae D8, and when compensating for this, the short limbs become perfectly apparent. Scott later confirmed to me on Facebook that he was able to replicate their corrections, and that he was going to be talking more with the authors about things.

So, what does this mean?

Spinosaurus' comically short legs are real.

And my thoughts?


Seriously though, I was skeptical about the rear legs being that short due to all the questions and criticism being brought up about it. After all, extraordinary claims require extraordinary evidence, and when the evidence didn't seem to hold up, people should show skepticism to the idea proposed. That's what being a scientist is all about. This time however, Ibrahim and co. managed to shine through and show that their short-legged model held up to the intense scrutiny. Really great job on their part answering our questions, and their openness and willingness to talk and discuss has been a great asset to solving these problems.

Now, however, we should get onto the important bits about what the new legs actually mean. Spinosaurus being Mr. Shortstuff hasn't been too popular with people that I know (particularly a friend of mine who's a big Spino Fan), as well as many typical members "JP3 Fanboy" community on the internet. I, however, fully embrace this new model for Spinosaurus, since unlike those people, I don't care what Spinosaurus as an animal looked like. However I do care about why it looks that way, and that's where the biological questions of this new model come in.

So, how's a short-legged Spinosaurus going to function? The biggest question I and many people have is how it's going to be moving around on land easily. Ibrahim and co.'s proposed quadrupedal model still doesn't hold up in my opinion (for the reasons brought up on Headden's post as well as elsewhere), but then how is it going to be moving around? A few people have brought up some ideas on Facebook and elsewhere, but the Pangolin method of locomotion proposed by Darren Naish sounds plausible. By hunching over and sticking its tail out strait back, it might've been able to waddle around on land like a pangolin with some success. Perhaps also like a pangolin, it could've used its forelimbs to right itself occasionally while walking on rough terrain, but nothing like constant quadrupedal movement.

Pangolin waddling along... Waddle, waddle...

Moreover, as many people who've read about this already know, tail length in dinosaurs is highly varied, even on the individual level, and it's likely that many dinosaurs may have under-sized and/or over-sized tail proportions. Spinosaurus' tail could've been a good 20% longer than Ibrahim and co. proposed for all we know, if not more. It is also important to remember that dinosaurs, and particularly theropods, had massive, thick tails which would've been effective counterbalances. With the apparent presence of an extremely well-developed caudofemoralis muscle suggested by Ibrahim and co. for paddling, the tail might be extremely bulky, and this could help balance out their Spinosaurus even more while walking.

Another interesting method of locomotion that was mentioned online a few times here-and-there was the possibility of a therizinosaur-like or cormorant-like walking. That is, with a near-vertical back. This I thought was an interesting idea for the terrestrial locomotion of this animal. Normal theropods are already capable of upright movement for short periods, and considering that we think Spinosaurus wasn't spending much time on land to begin with, this could be a possible form of movement.

Behold the Crococormorant! Art by yoult of Deviantart, and name proposed by ornithischophilia.
The posture also brings back images and ideas of retrotheropods from the early and mid-1900s. In fact, wait... Possible upright posture, short legs, strong arms, aquatic habits, the largest theropod, tall extensions on the Spinosaurus a real-life Godzilla?

I'll leave you all with a third and possibly my favorite proposed method of locomotion for Spinosaurus. Stay sharp everyone! Cheers!

Obviously this method of locomotion proposed by Osmatar perfectly explains all of the bizarre proportions to the new Spinosaurus

Sunday, September 14, 2014

Spinosaurus is back!

So, if you’re a paleo-nerd like me, you’ve probably read all about the new Spinosaurus material announced by Nizar Ibrahim and Paul C. Sereno. If you’re also like me, you were probably way too ecstatic about the new material announcement to remember that the same date it was announced also happened to be the 13th Anniversary of World Trade Center Bombings. Looking back on it today, I’m seriously disappointed in myself that I forgot all about it and spent nearly the whole day running around like a giddy toddler on a sugar high about these remains. At the same time though, everybody else that I knew didn’t speak much about the anniversary either, even on Facebook posts, but I guess that shows that we’re all moving forward as a society.

Anyway, back to the topic. If you’re part of the 1% who have not kept up with the Spino News, here’s what’s going on. On September 11th in Science, Nizar Ibrahim and Paul Sereno published their long-anticipated paper on Spinosaurus material recovered from Morocco and other parts of the Sahara, and the material doesn’t just conclude that Spinosaurus was the longest theropod dinosaur, but it also reveals it has anatomy which was, well, bizarre:

OMG! What have they done to you Spiny!?
After the initial shock of the new artistic restoration and all the reports in the media, I quickly hunted down the paper and started reading. The new remains show that Spinosaurus wasn’t only a fish-eating, aquatic-dinosaur like I have talked about previously, but that it had really weird anatomy to show for it: things like a more elongate vertebral column, a more flexible tail, longer and more-developed arms (even more so than other spinosaurids), and most shocking of all, the downright shortness of the hind legs and quadrupedal movement of the animal. This was quite interesting, to say the least, because not only did it challenge a lot of things we thought we know about Spinosaurus, but it changed a lot about what we thought we knew about theropod dinosaurs in general. Let’s look over this one-by-one: starting with the very short-legged elephant in the room…

“No T.rex, please don’t take my fish and try to make me reach for it…”
- Probably no Spinosaurus aegyptiacus ever. I mean seriously, Spino and T.rex never met. I'm sure all the bullying came from the Carcharodontosaurus.
I do find it interesting that spinosaurids have been suggested as quadrupeds so many times in literature. There have been mentions of Spinosaurus as a quadruped since (I believe) the 70s, and the discovery of Baryonyx further promoted this idea with its incredibly robust forearms. Furthermore, the idea of a quadrupedal theropod isn’t impossible. Quadrupedal locomotion evolved at least four other times in the dinosauria all independently, and even living avian dinosaurs occasionally use their wings to right themselves, climb, and perform other strange 4-limbed methods of locomotion. If anything it''s kind of weird that this group of dinosaurs never seemed to evolve even one semi-quadrupedal member. So is Spinosaurus the first? I wouldn’t count on it.

The proposed evidence that Ibrahim and Sereno present in the paper is not very convincing. The primary evidence that they propose is the shortness of the hindlimbs, which are positively tiny in the reconstructions. This apparently shifts Spinosaurus’ center of mass forwards towards the front, thus making it incapable of proper terrestrial movement. They also point to things such as the strange forelimbs which have processes which correspond to powerful flexion and extension muscles. (See Jaime Headden’s post to understand why this still doesn’t work.) This is such a weird arrangement that many have suggested that the new specimen might be a chimera of two separate individuals (maybe even of different species) which were stuck together. Cau pointed out earlier today why a chimeric origin is very unlikely, but it doesn’t matter, as this limb shortness might all be untrue anyways.

Spiny! You're, well, still kinda short...
Scott Hartman was quick to point out on his blog that the skeletal given doesn’t appear to match the measurements provided by the authors in their own paper. When corrected, Spinosaurus gets a bit taller than before (though he still stays quite short), the center of mass moves back towards the legs, and the arms are no longer touching the ground. This simple change completely challenges a large number of the biological suggestions in the paper, and seems to move Spinosaurus back into bipedal territory. This also further convinces me that we should make a better effort so that discoveries like this are properly published, checked over, and peer-reviewed BEFORE major broadcasting stations latch onto them and turn them into major money-making exhibits and documentaries. (Predator X and Darwinius anyone?)

(Interestingly, the CGI Spinosaurus being used in the Nova documentary coming out next month looks like it has its leg proportions corrected. Although it still does the knuckle-walking thing…)

Despite this, the morphology of the arms and legs are still of great interest to me from a biological point of view. The large caudophemoralis muscle, the proportions of the femur and tibia, the flat and long digits and claws, the forward-facing hallux, and possible webbed feet all really suggest an aquatic lifestyle for this animal. What really seems to cement the idea, however, is the density of the long bones. The hind limbs are not hollow, are 40% more solid than other theropods, and incredibly dense. This is seen in aquatic animals to act as ballast and sink into the water easier while swimming. For a representation of this, go to 37:40 in the video below for similar limb density in the modern hippo.

The forelimbs are also interesting in that they differ from other spinosaurids in the length of the hands, and their seemingly better-developed processes for forelimb muscles. Ibrahim and Sereno suggest that these longer hands would be better at ripping and dispatching of aquatic prey, but a few people online have also suggested to me that these adaptations are what you would see in a quadrupedal animal (they’re not, for the reasons listed above). What I wonder is, if the well-developed musculature of the forelimbs and seemingly longer digits correspond at all with paddling. The powerful flexion and extension muscles could be better used for pushing it along underwater, perhaps while traversing mangroves and river bottoms in tandem with the hind legs, and the longer digits, like the hind limbs, may have been webbed to assist in underwater movement.

What’s also weird in my opinion is the vertebral column. It’s pretty long, and in fact gives Spinosaurus a swan-like neck and dachshund-like body. It is actually kind of similar to the distantly related theropod Majungasaurus, who interestingly also has an elongated body, short hind limbs, and was suggested in passing a few times to be aquatic (Does this mean anything scientists?). However Spinosaurus has it even stranger, with the tail being highly flexible. The authors actually draw similarities with the tails of bony fish, and suggest that the tail was used for propulsion via undulations.

Er, wait… So is Spinosaurus a foot-propelled paddler, or did it use tail-powered undulations to move about? Normally animals only do one or the other, not both, and for good reason. Undulating the body around can mess up the pace of the legs (and vice versa), and provides no extra acceleration. This is why not many animals alive today use both methods while swimming. I think that a better explanation for the anatomy and swimming locomotion should be provided. I propose that most of its anatomy points to Spinosaurus being a foot-propelled paddler, with the flexible tail evolving as a rudder to help this giant turn its massive body while traversing underwater environments. We don’t need two swimming methods happening simultaneously when one is good enough and makes more sense.

And then there’s the sail reconstruction, which I’m also skeptical about. Many recent sail reconstructions have the long spinuous processes continuing gradually along the spine and down the tail, but this reconstruction goes back to the early reconstructions seen throughout the 20th century and puts the sail directly over the torso and ending at the base of the hips. Like the paddling and the quadrupedal behavior, this is weird. Both Cau and Headden have stated prior that the tall backwards-sloping dorsal neural spine should instead be placed in the tail, as it’s much longer than any of the other dorsal neural spines, has a backwards slope to it similar to what we see in caudal vertebrae, and it better matches the sloping back of other spinosaurid ridges/sails. We’ll have to see in the long run who’s right about this conundrum.

Yummy, yummy, fishy, fishy...

Finally, and I just wanted to touch on this a bit, I’m surprised about how little the possibility of other semi-aquatic dinosaurs has been discussed in light of this discovery. Even Ibrahim and Sereno’s team have stated that they think that Spinosaurus was an “extreme evolutionary experiment” which went nowhere, and that dinosaurs were almost all landlubbers. While it is true that terrestrial dinosaurs represent the overwhelming majority, what about the proposed aquatic dinosaurs seen in literature occasionally as of recent? Thescelosaurus? CMN 8547? Lurdusaurus? Opisthocoelicaudia? Heck, and what about other spinosaurids? Did everyone forget about this paper?

Also, since Irritator and Oxalaia are close relatives to Spinosaurus, shouldn’t we regard them as having similar anatomy as well? Both of them are only known from skull material, and as Michael Mortimer showed, two caudals from the Alcantara Formation of Brazil were classified as Sigilmassasaurus. Since Sigilmassasaurus was just now found to be synonymous with Spinosaurus and spinosaurid in nature, it’s likely that they belong to Oxalaia. Thus, it would make much more sense for them all to have a similar anatomy and lifestyle rather than radically different anatomy, at least based on what we know. So rather than a one-off, maybe Spinosaurus was part of a much larger subfamily of semi-aquatic theropods which we’ve yet to discover?

Anyway, thanks for reading. As you can see, it has been about eight months since I last made a post on here, and I certainly regret not being able to. School has been extremely busy, and over the summer I was out doing tons of extra work to prepare for college next year. In an attempt to resurrect this blog and get back in the habit of posting (while at the same time juggling tons of other work), I’ll try posting shorter topics from now on, mixed in with occasional longer posts like this one.

As always, I’d love to hear suggestions for future topics. I’m also now on Facebook and Deviantart, so subscribe on there if you want to discuss anything science-y with me or see my wonderfully amateur artwork and other projects that I post. As always, stay sharp until next time! Cheers!