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The Cartoon Guide to Vertebrate Evolution by Albertonykus The Cartoon Guide to Vertebrate Evolution by Albertonykus
In which I discover the pain of drawing non-avemetarsalian archosauriforms (so many osteoderms!) and ungulates.

I like to think that the Big Vertebrate Tree is a useful resource, but it's not very user-friendly. As such, I have produced a simplified (yes, this is simplified) and more vibrant vertebrate cladogram.

Animals that have been colored in are extant species. Age ranges represent known fossil record and do not include ghost lineages. The animals placed along the branches (instead of at the tips) are all based on real taxa that approximate the likely ancestral morphology of certain groups, but I have left them unlabeled to prevent propagation of the misconception that we can identify whether said taxa are the actual ancestors of those groups. Absolutely nothing is to scale.

My apologies if I butchered the anatomy of or left out any of your favorite lineages. There were an immense number of groups and characteristics I included in my original outline that I had to cut out for considerations of space and time. Those who desire a more in-depth depiction at vertebrate phylogeny should consult the Big Tree and the technical literature.

I am more inclined to update this image than the Big Tree. However, it is still a massive project by my standards, so major revisions (if necessary) will likely be irregular. Suggestions and corrections are welcome.

Adventure Time-style Darren Naish was designed by :iconclassicalguy:. Special thanks go to :icondracontes: for helping me visualize ear evolution in therapsids.
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:iconphoenix-the-horse:
Phoenix-the-horse Featured By Owner Mar 2, 2019  Hobbyist Traditional Artist
holy
this is great
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:iconalbertonykus:
Albertonykus Featured By Owner Mar 3, 2019
Thanks!
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:iconcatlover10192:
catlover10192 Featured By Owner Feb 28, 2019
Where do you put the likely devolopment of fur, and what do you think the upper and lower bound of that it? Crown mammalia obvoiusly has fur, and basal synapsids didn't, so how far would you narrow that down beyond that? It seems extemely likely that all or most cynodonts had fur, and I've seen reconstructions with animals as primitive as tetraceratops with it. 

Also, where do you put the devolopment of pycnofibres / proto-feathers? Do you think they're the same thing, and do how basal do you think they are? I know some people think they might be basal to all archosaurs even, so I'm wondering your position.

Personally, I don't think it's a stretch to think that insulating integument evolved in those lineages about the same time as endothermy, which seems to be pretty early for archosaurs, and somewhat of an open question for synapsids.
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:iconalbertonykus:
Albertonykus Featured By Owner Feb 28, 2019
The unsatisfying but honest answer is that we currently don't know when fur evolved in synapsids. Based on the limited evidence that we have, I'd say that fur was probably ancestral to at least prozostrodontian cynodonts. There are undescribed dicynodont specimens that suggest they lacked hair, in which case hair most likely evolved at some point within theriodonts (gorgonopsians + mammals).

As for archosaur filaments, I personally suspect that homology between pycnofibres and feathers is likely, but I wouldn't consider it a closed case. What we need is a Triassic fossil site that preserves the integument of early ornithodirans to make more confident inferences. Contrary to rampant rumors in the amateur paleo community, I've yet to see any evidence that feathers were ancestral to all archosaurs. This notion appears to be a misinterpretation of developmental studies on modern crocodylian scales, which have found that crocodylians share some of the genetic toolkit that birds also use to make feathers. However, all this shows is that birds and crocodylians use some of the same "machinery" to make their integument, not that crocodylians ancestrally had feathers. Even we have many of the genes that birds recruited for feather development, after all.
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:iconcatlover10192:
Do we have any reason to think that any evidence of fur would even be preserved under such conditions? There are many conditions I can think of where the fur of a dead animal might disperse before the skin decomposes. Also, would fur even nessacarily show up in that sort of impression. Couldn't it be matted to the body at the time of preservation? The detail certainly isn't fine enough that it'd show up in that case. I think we'd need a lot more evidence to say definitively one way or another.

This paper suggests that basal archosaurs (and most other exitinct archosaurs), and even non-archosaur archosauromorphs had a high basal metalbolic rate simmilar to that of mammals. academic.oup.com/sysbio/articl… While that doesn't nessacarily mean for ssure that they were endothermic, and the paper raises problems with the idea of the endothermy-ectothermy dichotomy, it certainly makes it a likely proposition. Because of this, in absence of evidence (which I agree the crocodile findings do not qualify as) I think it's certainly possible that basal archosaurs might have devoloped an insulated coating i.e "proto-feathers" to better take advantage of the heat generated. 

Edit: Also, when there's insifficiant evidence either way, it isn't nessacarily more parsimonious to assume a later date for "advanced" features. In fact, the assumption that "feathers" are an advanced feature in archosaurs is just that, an assumption that isn't nessacarily based on anything of worth.
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:iconalbertonykus:
Albertonykus Featured By Owner Mar 1, 2019
It is of course possible that the hair was lost during taphonomy, or that Lystrosaurus was unusual among therapsids for lacking hair. I didn't say that the specimen definitively shows that dicynodonts didn't have hair, only that it suggests it. I will say that, having seen higher-quality photos of the specimen at conferences and talked to researchers who have examined them firsthand, the details of the skin are fairly well preserved, probably enough to rule out the possibility of matted hair. From what I gather, there are also several such specimens known, which increases the likelihood that it is representative for Lystrosaurus at least.

The evidence for high metabolic rate in stem-archosaurs is interesting, but I wouldn't consider it evidence for filamentous integument on its own. As the authors of the study also point out, inferring thermal strategies from metabolic rate alone is not straightforward and there are many ways to achieve similar thermal strategies. Even if stem-archosaurs were endothermic, we know of extant endotherms that do not require filamentous integument for thermoregulation, such as various fish, leatherback sea turtles, brooding pythons, tegus during breeding season, mammals with sparse hair coverings (including some very small species), etc. (Note that I'm using "endothermic" here to refer to anything that can internally produce a body temperature significantly different from its surroundings.) I certainly wouldn't entirely dismiss the possibility that filaments evolved in stem-archosaurs, but I find it speculative at best.

There is some interesting (unpublished) research by David Lovelace and Scott Hartman modeling Triassic climates and inferring suitable environments for Triassic amniotes under different hypothetical metabolic and integumentary models. Short of finding direct evidence of integument in stem-archosaurs, if Lovelace and Hartman's methods were applied to stem-archosaurs and showed that they would not be able to survive in the climatic conditions they're known from without insulating integument, I would consider that to be more suggestive of the presence of filaments.
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:iconcatlover10192:
catlover10192 Featured By Owner Aug 9, 2018
You chose a pinniped to repersent living carnivorans. To me, that's repersenting the most asthetically pleasing group of vertibrates with its only ugly subgroup. Of course, you can't please everyone, and I'm amused rather than irritated in any way. I just thought it was a funny thing to point out. This also nicely repersents why calling raccoons rodents makes no sense. It doesn't seem like something anybody would do, but it was constan throughout Guardians of the Galaxy, so obviously some people are that ignorant. This diagram helpfully shows that humans are quite a bit closer to rodents than carnivorans like raccoons are.
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:iconalbertonykus:
Albertonykus Featured By Owner Aug 10, 2018
I picked a pinniped because I thought it would be most illustrative of the morphological and ecological diversity among carnivorans, and because they're not always acknowledged as carnivorans even in scholarly resources about the group. As you might imagine, the unpredictable aesthetic preferences of my potential audience were at best a secondary point of consideration regarding my choice of taxa, but I'm glad you took it in good humor.

And I concur, it is frustrating how often the term "rodent" is misused.
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:iconcartoonben:
CartoonBen Featured By Owner Sep 16, 2017  Student Digital Artist
Nod Very nice. Magnifying Glass I like how you sorted the animals in that picture.  
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:iconspongebobfossilpants:
SpongeBobFossilPants Featured By Owner Aug 17, 2017
Ichthyodectiforms aren't osteoglossomorphs anymore?
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:iconalbertonykus:
Albertonykus Featured By Owner Aug 17, 2017
They haven't been for some time. As far as I'm aware, all actual phylogenetic analyses that include them put them outside of crown-teleosts, and that appears to be the prevailing view.
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:iconbenuterf2:
benuterf2 Featured By Owner Jun 13, 2017
woah, it looks NEAT!
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:iconalbertonykus:
Albertonykus Featured By Owner Jun 13, 2017
Thanks!
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:iconbenuterf2:
benuterf2 Featured By Owner Jun 13, 2017
No problem
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:iconcrash-the-megaraptor:
Crash-the-Megaraptor Featured By Owner Jan 25, 2017  Hobbyist Traditional Artist
Hey, random question, have you ever heard of the video game "Evolution: The Game of Intelligent Life"?
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:icontph-original:
TPH-Original Featured By Owner Edited Mar 5, 2017  Hobbyist General Artist
I was reminded of that SNES game "EVO: The Search for Eden". Kind of a cartoony game that doesn't really have any scientific value to it, but it came to mind.
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:iconalbertonykus:
Albertonykus Featured By Owner Jan 25, 2017
Never. How is it?
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:iconcrash-the-megaraptor:
Crash-the-Megaraptor Featured By Owner Jan 25, 2017  Hobbyist Traditional Artist
I dunno, I've never played it, and it's quite old (like, 1997), but apparently it's a game that allows you to pick an early amphibian and slowly evolve it into various different types of prehistoric animal until you eventually get to intelligent life. From what few videos I've seen, it looks rather cheesy (and obviously accuracy is not entirely what they're going for) but it looks pretty cool and they have a whole lot of creatures nonetheless.

I only really asked because I was reminded of it whilst seeing this guide again.
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:iconalbertonykus:
Albertonykus Featured By Owner Jan 25, 2017
That's neat! Maybe someday we'll get a really good evolution or history of life game.
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:iconcrash-the-megaraptor:
Crash-the-Megaraptor Featured By Owner Jan 25, 2017  Hobbyist Traditional Artist
True, Especially with the myriad of cool prehistoric animals we know of now. I mean, that game was made 20 years ago, a lot has changed.
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:iconspongebobfossilpants:
SpongeBobFossilPants Featured By Owner Dec 28, 2016
Has anyone seriously challenged the (Tylopoda(Suina(Cetancodontamorpha, Ruminantiamorpha))) topology for Artiodactyla in recent years? I notice you put them in a polytomy here.
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:iconalbertonykus:
Albertonykus Featured By Owner Dec 28, 2016
I put them in a polytomy because Holtz put them in a polytomy for the class (maybe from the strict consensus of Spaulding et al., 2009?), but I concur that that looks like the best supported topology for now.
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:iconspongebobfossilpants:
SpongeBobFossilPants Featured By Owner Dec 26, 2016
Aren't brontotheres stem-perissodactyls (as per Prothero's book)?
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:iconalbertonykus:
Albertonykus Featured By Owner Dec 26, 2016
At least some analyses support the topology I have here, such as Holbrook and Lapergola (2011).
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:iconspongebobfossilpants:
SpongeBobFossilPants Featured By Owner Nov 19, 2016
Wasn't there a paper a few years ago that put turtles sister to placodonts?
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:iconalbertonykus:
Albertonykus Featured By Owner Nov 19, 2016
Do you mean Lee (2013)? One of the analyses in that study had them clading with Sinosaurosphargis and placodonts sister to that group.
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:iconcrowford210:
Crowford210 Featured By Owner Nov 6, 2016  Student Artist
Amazing that vertebrates are just a small clade in the tree of life!
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:iconraishinl:
RaishinL Featured By Owner Sep 10, 2016  Hobbyist Artist
You placed placentals going in 3 directions; Xenarthrans, Afrotheres and Boreautheres, they actually went in 2 directions with Xenarthrans and Boreautheres going the same way.
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:iconalbertonykus:
Albertonykus Featured By Owner Sep 10, 2016
That is actually an area of major debate and uncertainty in placental phylogeny! Traditionally it was thought that xenarthrans are the basalmost branch of placentals, but other studies support the topology you describe or xenarthrans and afrotheres being sister taxa of one another. For this drawing (and the course it was based on), I chose not to side with any one hypothesis by putting the three groups in a trichotomy. A couple of recent studies using different methods have strongly supported Atlantogenata (the third option), so consensus may well be starting to lean in that direction.
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:iconraishinl:
RaishinL Featured By Owner Sep 10, 2016  Hobbyist Artist
I see, so the 3 directional split may be correct
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:iconinkgink:
InkGink Featured By Owner Sep 8, 2016  Hobbyist General Artist
So what about the turtles? I'm curious.
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:iconalbertonykus:
Albertonykus Featured By Owner Sep 8, 2016
If you are asking whether the position of turtles has been resolved any better since I drew this, the answer is no. If you would like some background on the turtle problem, these two-part notes are a pretty good overview.

The long and the short of it is that both fossils and genetics now agree that turtles are diapsid reptiles that have secondarily lost their temporal fenestrae, but there is no agreement on what type of diapsid. Genetic studies strongly suggest that they are archosauromorphs (closer to crocodylians and birds than to turtles), but there is currently little solid anatomical support for that position.
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:iconcatlover10192:
catlover10192 Featured By Owner Aug 9, 2018
I think you accidently compared turltes negatively to themselves in that comment. "Genetic studies strongly suggest that they [turtles?] are archosauromorphs (closer to crocodylians and birds than to turtles)"

Unless I'm parsing that incorrectly, it seems to mean that turtles are more related to bids and crocodylians than they are to themselves. Obviously this is logically inconsistent. I'm sure this was some sort of typo where you put one wors but meant another. I am curious what you meant to so though. Of course, I could just be misunderstanding something completely logical, in which case I apologize. 
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:iconalbertonykus:
Albertonykus Featured By Owner Aug 10, 2018
Yes, that was a typo. I meant "closer to crocodylians and birds than to lizards".
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:iconinkgink:
InkGink Featured By Owner Sep 9, 2016  Hobbyist General Artist
Thanks! 
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:iconalbertonykus:
Albertonykus Featured By Owner Sep 9, 2016
Anytime!
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:iconspongebobfossilpants:
SpongeBobFossilPants Featured By Owner Aug 18, 2016
Palmer (2009) used Holotheria as a synonym of Mammaliaformes & Theriimorpha as a synonym of Mammalia sensu stricto. Is this nomenclature acceptable (if unorthodox)?
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:iconalbertonykus:
Albertonykus Featured By Owner Aug 18, 2016
I'm not familiar enough with the history of synapsid clade names to judge.
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:iconspongebobfossilpants:
SpongeBobFossilPants Featured By Owner Aug 12, 2016
Is Prototheria still used? I was under the impression that Yinotheria was preferred due to the baggage associated with Prototheria.
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:iconalbertonykus:
Albertonykus Featured By Owner Aug 12, 2016
I can find many recent references to Prototheria, whereas searching "Yinotheria" on Google Scholar returns only a handful of results. However, you may be correct that Yinotheria is preferred by paleomammalogists.
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:iconpaleosir:
paleosir Featured By Owner Jul 28, 2016  Hobbyist Traditional Artist
Oh Wow that looks like a looooooooooot of work to research! it's an awesome guide
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:iconalbertonykus:
Albertonykus Featured By Owner Jul 28, 2016
Thank you!
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:iconmarenhy:
Marenhy Featured By Owner May 27, 2016
Wow! I love this! I think evolution is extremely interesting, and I like the effort you put into the picture. Nod 
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:iconalbertonykus:
Albertonykus Featured By Owner May 27, 2016
Thank you!
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:iconspongebobfossilpants:
SpongeBobFossilPants Featured By Owner May 9, 2016
Prothero (2013) suggested that archontans, carnivorans & insectivorans form a clade and (more tentatively) that this clade is closer to glirans than to ungulates due to the presence of a baculum. What do you think?
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:iconalbertonykus:
Albertonykus Featured By Owner May 9, 2016
Wouldn't put much stock in a single character like that, especially one that we know can be lost relatively easily (as it has in us).
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:iconspongebobfossilpants:
SpongeBobFossilPants Featured By Owner May 9, 2016
What about the carnivoran-archontan thing? I vaguely remember some molecular analyses supporting that around 2007.
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:iconalbertonykus:
Albertonykus Featured By Owner May 9, 2016
I haven't read those studies, but it's fair to say they don't represent the consensus view.
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:iconspongebobfossilpants:
SpongeBobFossilPants Featured By Owner Apr 3, 2016
Would you agree with Prothero (2013) that we may actually be farther from the true mammalian tree than we were 20 years ago? We already discussed some of this on Twitter, but is such skepticism justified from a strictly paleontological perspective?
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