The 'Shroom:Issue LXXXVIII/Evolutionary Taxonomy of the Koopas

Evolutionary Taxonomy of the Koopas by

A couple years ago, I wrote a guest section for The 'Shroom called "Theoretical Macroevolution of Koopas", in which I discussed how the Koopas totally evolved from some sort of Tyrannosaurus-like dinosaur, and not turtles like everyone thinks. Don't believe me? Read the article - and prepared to eat your words. Anyway, in that article, I said I wouldn't go into an analysis of the diversity within the Koopa family tree, as that would involve a lot of nitty-gritty details that might bore and/or scare people off. Well, now that I've talked about the roots, there's really nowhere else for me to go but the inner working of the family tree. I had it all panned out too: I was going to teach you about data matrices, and optimization using ACCTRAN and DELTRAN, and outgroup comparison, and the Hennig's Auxiliary Principle, and the Wagner Algorithm, and it was going to be glorious. But then it took a week for me to actually break the entire bloody Koopa tree down using all of the above methods, and even then I had to fudge things, and now it's the day before this is due, and I have a billion other things to do too, and I spent all morning doodling instead of writing, soooo instead, I am going to save the phylogenetic analysis stuff for another time, and stick to good ol' classic evolutionary taxonomy. If it was good enough for Darwin it's good enough for Mario.

So what is evolutionary taxonomy?
Good question. Evolutionary taxonomy is basically the first strategy folks used to try and figure out how closely related different species are based on how similar they are. For example, cows and pigs both have cloven hooves while a horse only has one single hoof, so based on that you could argue that cows and pigs are more closely related to each other than they are to horses. Makes sense, right?

The answer is yes, it does make sense. The only problem with the method is that it's subjective: the hoof thing does work out, but other assumptions that scientists made back in the day have since been proven wrong, such as grouping birds and mammals together. Back then, they based that mainly on the fact that they were both warm-blooded, figuring that a system as complex as that could only evolve once, unlike the smaller details that birds shared with reptiles, which they dismissed as some of nature's funny little coincidences. But as we know now, they were wrong: warm-bloodedness did evolve twice, in the mammal line and the bird line, whereas all the piddly details the original scientists ignored are the real evidence of a relationship between birds and their scaly, cold-blooded brothers. Suddenly, Birdo's name's not sounding so paradoxical, isn't it?

Anyway, point is, science isn't based on gut feelings: you need to be able to test your hypotheses, and you can't do that as long as you're making judgment calls about things like the relative importance of warm-bloodedness to other similarities. It's actually a lot like how the wiki works: speculation is bad, so we try to only use the facts. Nowadays, the system used for reconstructing evolutionary relationships is known as phylogenetic systematics, with the big difference between it and oldschool evolutionary taxonomy being that the similarities aren't ranked as being more or less important: they're all given equal weight, and what's important is the number of similarities, rather than what the similarities are. Can't get much more objective, clinical and testable than raw numbers.

So if it's outdated, why are you wasting our time with it?
Well, for one thing, it makes for a snazzy name. But the main reason is because it's impossible to make a clear phylogenetic tree out of the Koopas when you stick with the raw numbers. Believe me, I tried. I probably killed a couple actual trees with all the paper I wasted scribbling down character tree after tree, only to find myself left with naught but polytomous bushes - the hated enemy of the evolutionary biologist. I was able to get a few things down the proper way, but in the end, I had to make judgment calls, otherwise this article would read "well, turns out Koopas really ARE soup, because I sure can't see any structure in there eheheheh" - which would make it a pretty sucky article, so needless to say I opted not to take that route. But while the hard science of phylogenetics was no match for the woeful lack of useful synapomorphies in the whimsical family of Koopas, there is plenty of stuff for a nice overview of Koopa diversity, and as any biologist will tell you, no taxonomic discussion works without an evolutionary perspective, and thus, evolutionary taxonomy is the name of the game today. And really, my first article was evolutionary taxonomy too, so we went down that rabbit hole a while ago anyway.

Okay fine, so where do we start?
Well, first you take a look at all the species in the group and asses their characteristics - then you can start to look for the aforementioned similarities between the characteristics that you'll need to determine who's related to whom. Including less stereotypically Koopa-ish things like Clubbas, Spinies, Buzzy Beetles and Yo Bros., the Koopa family has well over a hundred species. I grouped things like Magikoopas wearing different colours of robes, armoured Koopas like Terra Cottas and Koopatrols, and Lakitus using different hunting strageies (fishing, snorkeling, etc.) into their basic species, and I also cut out things like Mecha-Koopas and Shroobified or green things altogether since robots, aliens and mind-control aren't evolutionary relevant. I also went the opposite direction and added species designations for things we've only seen as single characters or in skeletal form (like Tolstar or even the unseen winged Spinies that produced the dreaded flying blue shells in Mario Kart). In the end, I wound up with 125 species coded in my data matrix, which looks like this:



So yeah, it's big. And complicated. And now I trust you're starting to see why doing a proper phylogenetic analysis took me the better part of a week of solid work and still didn't work out terribly well. Fortunately, evolutionary taxonomy lets us ignore a lot of the characters in favour of a few select traits. For Koopas, that means their body, shell and facial structures.

Bodies and shells!
There's three basic Koopa body plans, pictured on the left (along with a bonus sketch of what Clubbas look like). The first, on the left, is the ancestral one, seen in the earliest evolved Koopas, Bowser's species, which I call Dragon-Koopas (and so should you: let's do this, let's make this happen!). These guys have flexible shells (as adults, at any rate) and their belly scales (or, "scutes", if you will) are separated from the carapace by a region of regular body scales. The other common type of shell is the one you see in things like Koopa Troopas, Hammer Bros. and Lakitus: a totally rigid shell, complete with a plastron covering the lower levels. In between is a body plan that's only really seen in Limbo Bros. as far as the games go: it's where the scutes wrap around the entire body and connect to the upper shell, but are still soft and flexible. This body plan is a natural intermediate step between the Dragon-Koopas and regular Koopas, as the scutes would conceivably go on to become hard and form the plastron, just as the upper shell solidifies when you go from Dragon-Koopas to other species. And since this intermediate step is seen in Limbo Bros., it supports the idea that Hammer Bros. may have been the earliest of the hard-shelled Koopas.

As for the other design in that picture, Clubbas resemble Dragon-Koopas in that they have soft bellies and body scales bordering the whole shell, but instead of scutes, they just have blank white bellies (or, in the case of Spikes, body scales all the way around), and their shells are hardened and small. However, as we can see with Tubba Blubba, there's a larger breed of Clubbas that do have scutes - not to mention spiked shells like the Dragon-Koopas, and therefore we have another perfect stepping-stone species, after the shell hardened but before they lost the spikes and belly scutes. Thus we can add another branch to the family tree, rooted as it is with the Dragon-Koopas.

But wait, there's more! We also see some species removing their shells: namely, the Koopa Troopa family, with Blue Electro-Koopas and Koopa Strikers even being able to regenerate new shells after casting away the first ones (the latter instantaneously, while the former usually try to get the original one back and only regrow a shell if the first one's separated from them for long enough). As I discussed in my earlier article, this function is very specialized and would have evolved later on, which is supported by the fact that it's not seen in Hammer Bros., Magikoopas, Lakitus, Spinies or Buzzies (except Stone Buzzies when you brutally murder them, but that's not exactly a natural process, now is it). Therefore, I suggest that it evolved after Magikoopas as the lineage transitioned to the Koopa Strikers and the Koopa Troopa branch of the tree.

Faces!
The other major key to deciphering the Koopas are their facial structures - specifically, their snouts. Dragon-Koopas and the Clubba family have what I call "discernible snouts", meaning they're rounded and differently-coloured from the rest of the face. The next logical step down the line, to me, are the "discernible beaks" of the Hammer Bro. group, where the rounded snout has given rise to a pointy beak. Happily, this is in accordance with the earlier shell-based supposition that Hammer Bros. came first after the Dragon-Koopas: our tree is strengthening.

Next comes the loss of the "discernible" aspect, as we get the plain "indiscernible beaks" of Magikoopas and the Koopa Troopa group. I place Magikoopas as the more basal of the two, since they still have a bit of a nose bump, which you sorta see in Hammer Bro. but not in Koopa Troopas, whose beaks have smoothed out a bit more, it seems. And like the Dragon-Koopa → Hammer Bro. step, Magikoopa → Koopa Troopa is now supported by the facial structure progression as well as the shell development: looks like our taxonomy's on the right track here too.

Another group of species with bumpy noses are the Lakitus, and therefore, I also have them branching out of the Magikoopas - by way of Chargin' Chucks, since their nubby faces seem like another beloved intermediate step, this time between Magikoopa beaks and the relatively flat faces of the Lakitus. Another flat-faced group is the Spiny and Buzzy sect, which I have coming out of the Lakitus (represented with a classic Paper Mario design on the above chart, which I actually drew years ago and haven't bothered to update, but we're getting off-topic). I picture Spikeys as being the first to evolve of the group, as they seem to have the round head of a Lakitu under their helmets and are still bipedal like their Lakitu ancestors - with which they and Spinies still maintain a close association (a detail that shouldn't be ignored). From Spikies, this branch of Koopas dropped to all fours as Spinies and eventually started losing their thorns to become Spike Tops and then Buzzy Beetles. And with that, we have all the major groups of Koopas pretty much covered.

So, is that all?
No, there's a few other major characters that help with crafting the Koopa tree. The Spikey → Spiny → Spike Top → Buzzy Beetle progression, for example, also looked at stance and the loss of shell spikes as ways to figure out what evolved from what. We can also continue on to see that Buster Beetles are Buzzies that stood back up, while other ones grew wings as Parabuzzies and eventually ditched their legs altogether to rely on their wings alone, as Para-Beetles. It's actually pretty elegant, and the Spiny/Buzzy group is one of the few cases where I actually got a proper phylogenetic tree out of the data, but using stance and wings can also be pretty tricky...

Case in point: for the longest time, I couldn't decide whether some Koopa Troopas dropped to all fours and then those four-legged Koopas grew large separately from two-legged Koopas also turning giant, or if some Koopas grew large and then they and their smaller cousins both became quadrupedal separately, or if growing large actually forced some bipedal Koopas down to their hands and then some of those then shrunk again. I even threw in the role of wings too: perhaps there was a flying step somewhere and then the wings fell back off? And did flying evolve once in the Koopa Troopas or over and over or was there horizontal gene flow thanks to hybridization? And did that happen with Spiky Parabuzzies too, or what? So many questions, and for all of them, I ended up using the phylogenetic analyses to try and figure out the answers. Turns out that it makes the most sense for flight to simply evolve over and over, in both Koopas and Buzzies (and of course in the elusive exploding blue wingèd Spinies of doom), and while the Koopa Troopa tree did get rather messy, I found enough of a signal to determine that it works best for the small, two-legged Koopa Troopas to give rise to both small, four-legged Koopas (Shellcreepers, Koopeleons and Blue Electro-Koopas) and large, two-legged Koopas (think Big Dry Bones, but alive), with the big bipeds then dropping down themselves to become large quadrupedal Koopas (like the Gargantua Koopa Troopas of SMB3).

Another indicator that should be taken with a grain of salt are the various powers used by the Koopas, since they blink on and off all over the place in the family and create a lot of noise in the data. But you can see some patterns, such as fire being associated with both Dragon-Koopas and the Hammer Brethren (in the form of classic fire-spitting Fire Bros., and also in how both Limbo Bros. and Chomp Bros. both heal when attacked by Mario's Firebrand move). This lends even more support to the whole Dragon-Koopa → Hammer Bro. procession, although I'd go a step further here and add Fire Bros. as another intermediate step in the chain, after the Limbo Bros. and Chomp Bros. split off, but before the Hammer Bros. lose the fire for all subsequent Koopas. Another thing shared by Hammer Bros. and their Dragon-Koopa ancestors is being able to unleash constant streams of inexhaustible hammers, and Lakitus also have this same sorta hammerspace magic letting them Spinies down on the countryside. Magikoopas don't use hammerspace so much as simply conjure stuff out of thin air, but I'd imagine both strategies are rather energy-costly, and looking at power levels in general, these four groups are hands-down the strongest of the Koopas (with the Dragon-Koopas at the top of the pile, of course - as any boss battle with Bowser will attest). Even the Chargin' Chuck intermediate step between Magikoopas and Lakitus aren't too shabby on the magic front, between their ability to spontaneously clone themselves and their endless baseballs making use of hammerspace and all, although once you go further down the line, the magic seems to drop off. But who knows - maybe the exploding Mario Kart blue shells should be taken a a sign that Buzzies and Spinies actually do still have plenty of power packed in their little bodies after all.

But what of the Koopa Troopas? Well, my personal headcanon is that when they became disconnected from their shells, they had to start storing their powers in their bodies, rather than the handy reservoirs under the carapaces, and as a result, ended up with dampened powers in exchange for their removable armour. I also like to think of Koopa Strikers as being the first ones to be able to remove their shells, since their rapid regeneration isn't a sign of dampened energy levels at all, but rather, Magikoopa-level power more befitting of a basal species in the Koopa Troopa branch. Plus, I figure that when the shells first disconnected, perhaps it wasn't quite stabilized in their bodies yet: exposing raw power to the elements doesn't sound very safe, so if the shell came off, you'd probably want to replace it right away, and handily enough, you'd have the power sitting raw and ready on your back to do just that. But that's drifting into pure speculation territory, rather than something easily supported by the taxonomy, and either way, it doesn't explain how the Blue Electro-Koopas manage - although that group's the oddballs of the Koopa Troopas in more ways than one. Them and Snooze-A-Koopas. So weird. But then again, isolated islands do tend to have fun endemic species: they have a lot of time to evolve off on their own, away from their sister species, and can often go down very different paths.

Aren't we done yet?
Okay, fine, I'll leave that sort of species-level Koopa evolution for another article. Until then, I shall end this with one final summary chart, seen below. Most of the writing's probably illegible, I know, but hopefully having read the text, you can follow what it's showing. Also, please note that instead of having regular Magikoopas, Lakitus, Hammer Bros. and whatnot, I have spiked-shell variants. Since Spikeys have spikes, and random Koopa Troopa-like species like Spike Koopas have spikes, for the longest time, I thought it would make sense for all the Koopas to have spikes going right back to the spiky Dragon-Koopas, with the modern Magikoopas and Hammer Bros. and things having lost the spikes when they broke off from the central shaft of evolution. But when I started doing the ill-fated phylogenies for the Koopas, one thing did become clear all down the line: this spiked shell idea of mine made no sense. After all, why would spikes be lost half a dozen times when they could simply be lost once when going from Dragon-Koopas to Limbo Bros.? Answer: they wouldn't, and like the scientists who once said birds and mammals were closely related because of their warm blood, I must admit defeat on this one. As you'll also see in the picture, I had a similar idea for the paired head horns of the Dragon-Koopas being carried down all the way to Hammer Bros. too (because of Army Hammer Bro.), but that was proven wrong by the phylogenetic analyses as well, for the same reason as the shell spikes.

So in that case, why does the stupid chart have the spikes and the horns, you ask? Well, that's simple: like the other diagrams, I made this chart a few years back and I haven't updated it to reflect my new knowledge. Yeah, yeah, I know, I know, I'm lazy. But it's 5:00 AM and I'm tired and I have to work all day tomorrow and would like to get at least two hours of sleep to prepare for that, so I'm afraid there's really no time for me to go back and fix my pretty pictures. Terribly sorry, but please don't let that impact your viewing pleasure of the family tree, and either way, I hope you enjoyed this little discussion about evolutionary taxonomy and the diversity of the Koopas. I sure enjoyed writing it, but I'm a nerd, so yeah. Peace out!