Friday, August 31, 2018

The Many Crests of Pterodactylus

Little Pterodactylus,  from the late Jurassic period of Bavaria, was one of the first pterosaurs ever discovered (a story you can read all about in my book Beasts of Antiquity). Represented by numerous juvenile and subadult specimens, it's among the better understood pterosaurs as well, especially if you include a few controversial specimens that have recently been argued to represent distinct genera such as Aerodactylus (a conclusion many pterosaur specialists remain skeptical of, but that's a topic for another post).

Although many Pterodactylus specimens preserve soft tissue, one pretty important aspect of their biology is NOT so well understood - their crests. In the past few decades, it has become apparent that crests of one kind or another are a hallmark of most pterodactyloid pterosaurs (and even a good number of non-pterodactyloids). Crests were first reported for Pterodactylus itself by Doderlein in 1929, but it was almost never depicted with a crest in art afterwards. The first-ever crested Pterodactylus was probably a toy. In 1988, Tyco released a crested Pterodactylus toy as part of their "Dino-Riders" line. Though produced under the supervision of Bob Bakker, it's unclear whether or not the crest was based on Bakker's inside knowledge of pterosaurs or was just a lucky guess added to give a fairly plain pterosaur toy more flair. Bakker himself had illustrated Pterodactylus without any crests in The Dinosaur Heresies several years earlier. Despite the fact that Peter Wellnhofer described a lappet "crest" (see below) for Pterodactylus in 1970, and even figured this specimen in his popular 1996 book The Illustrated Encyclopedia of Prehistoric Flying Reptiles, illustrations in that same book depicted Pterodactylus as crestless.

Photo of Pterodactylus specimen BSP 1929 I 18, from Wellnhofer 1996. You can see a thin occipital lappet extending diagonally up from the back of the skull.

The dubious Tyco example aside, the concept of a crested Pterodactylus didn't really reach the popular consciousness (and had apparently been forgotten by science, much like several other "modern" ideas about pterosaurs that were really discovered by 19th and early 20th century German paleontologists) until the first ultraviolet florescence studies done by Eberhard Frey and Helmut Tischlinger in the late 1990s and early 2000s. They produced what, at the time, seemed like a very bizarre reconstruction of a pterosaur, especially one like Pterodactylus which was somewhat famous for being the 'crestless one' (as opposed to its more famous, crested cousin, the giant Pteranodon). The illustration that was sent out in press materials about the early UV studies showed a shaggy mane of filaments on the neck, big, floppy webbed feet, a throat pouch, and a big, teardrop-shaped crest that extended above and behind the eyes. Clearly, the UV analysis had totally overhauled our image of Pterodactylus.

Frey and Tischlinger's reconstruction of Pterodactylus based on UV studies.

Or did it? The actual UV papers are still difficult to come by online, so early on it was difficult if not impossible for many paleoartists to examine the source material themselves. In the mean time, Frey's Pterodactylus became the gold standard for accuracy, with savvy artists beginning to incorporate the mane, webbed feet, and distinctive crest into their own work, all based not on any photos or diagrams of fossils, but simply on Frey's pencil drawing. Here's my own early take on the "new" Pterodactylus. Note that, in order to try and be a little different, I applied the UV soft tissue findings to a different specimen, the holotype of Pterodactylus brevirostris (which may actually be a juvenile Ctenochasma!).

Note that this was done in June 2002, shortly after the publication of Frey's English-language work summarizing the UV findings of the past few years. I later sketched out a version based more directly on Frey's original drawing:

A couple of things turned out to be... maybe not wrong, per se, but definitely speculative and not directly evidence-based, about the Frey-style Pterodactylus.

For one, that shaggy mane. Pterodactylus did indeed have a coat of unusually long pycnofibres on its neck. And by "unusually long", I mean that they are nearly half a centimeter long (compared to a ~10 cm long neck), unlike most of the incredibly tiny fibers coating the rest of the body. The "mane", therefore, would probably have appeared as a particularly fuzzy, bristly section of a short, dense coat.

As for the crest, none of the specimens show an oval shaped crest extending above and behind the eyes. What the few specimens we have of the crest show is actually two discrete crests or crest-like structures. The main crest, as preserved, is roughly triangular, with its peak just in front of the eyes. A second structure protrudes behind the skull. This has been called the "occipital lappet", and was first noticed by Wellnhofer in 1970. Superficially, the lappet resembles a small version of the crest of Pteranodon. Or, maybe more appropriately, the rear spar of the crest of Tupandactylus. In that tapejarid, the crest is comprised of two bony supports. One, roughly triangular in shape, above the snout. The other, a long horizontal spike, extends behind the skull. In between was an enormous, rounded crest composed of keratin or some other rigid soft tissue. The two "obvious" crests are merely the support struts for these larger structures. Frey imagined that in life, the triangular crest above the eyes and the occipital lappet may have been joined together into this kind of single structure, the apparent shape of the crests as preserved being an artifact of decomposition or post-mortem breakage. This interpretation has been followed by a majority of artists since, as a Google Image search will show.

You can see that an image search for "Pterodactylus crest" brings up some fossils and diagrams, 2 reconstructions of Pteranodon (of course), 1 of an ornithocheirid (somebody got confused?), 1 old-fashioned reconstruction with no crest, 3 different reconstructions with a triangular crest and separate lappet (one of which is my own), and 9 reconstructions with a Frey-style joined crest (again including one of my own!). 
Mark Witton, in his 2013 book Pterosaurs, was influential in popularizing an even larger tapejarid-like crest, which he included both in his reconstructions and skeletal diagrams. His reasoning for taking the Frey-style crest to the next level was based mainly on the general rule that pterosaur crests tend to be larger than they appear.

There are some important differences, though, that we should consider before speculating too much about a tapejarid-style crest in Pterodactylus. First, the two are not particularly close relatives, and tapejarid-like crests have not yet been found in any other pterodactyloid groups. Given the enormous crest diversity among pterosaurs, I'm not sure it's appropriate to assume they were all basically big ovals and differences are just preservational. Some other pterosaurs unrelated to Tupandactylus did have big, rounded crests, but these were more like semicircles erupting from the skull, not extending behind it or significantly above it (like wukongopterids and even some ctenochasmatoids closer to Pterodactylus itself). One other example of "enormous crest supported by bony struts" has been proposed in the form of Nyctosaurus, but despite some spectacular looking restorations out there, it's unlikely those enormous spars supported any soft tissue.

The huge, oval-shaped crest of Tupandactylus was supported by long bony crests that graded into soft tissue, unlike the totally soft crests of Pterodactylus. Photo from the AMNH pterosaur exhibit by Lisa Brormann.
Second, the supposed spars of the Pterodactylus crest are not made of bone! The reason Tupandactylus and other tapejarids can have those huge oval crests sitting on their heads is because they have bony supports. Even the smaller species like Tapejara wellnhoferi has a significant hard, bone-based component to its (possibly) large oval crest. In Pterodactylus, not only is the main crest comprised entirely of soft tissue with an unusually minimal amount of bone as an underlying base, the occipital lappet is not made of keratin at all. Upon close examination of the internal structure of the lappet, it seems to be supported internally by twisted fibers similar to those that make up the pycnofibre coat. The lappet would not have been flat in life, like the crest of Pteranodon, but conical. The fact that it is composed internally of fibers may imply that it was flexible, a result that would explain why it is preserved in different positions in different specimens (some curving upward, some straight). The lappet seems to have been more an extension of the skin integument than a typical crest, sort of like the wattles and caruncles of a turkey.

Possible crest reconstructions for Pterodactylus (based on specimen BSP 1929 I 18). Clockwise from top: Crest and lappet as preserved; joined crest after Frey 2002; joined crest after Witton 2013; minimally extended unjoined crest.
Diagram by M. Martyniuk 2018, all rights reserved. 
It's entirely possible that future specimens will show that we have Pterodactylus crest shapes wrong, or that the main crest was in some way attached to the lappet. But given the evidence right now, that interpretation is one of the less likely possibilities. A few prominent paleoartists who helped popularize the tapejarid-style crest have since produced lappeted ones, including Mark Witton and John Conway, both of whom, intriguingly, depicted the lappet as just part of the larger pycnofiber assemblage - Conway as an extension of the "mane", Witton as part of a larger set of display fibers). You can read more about Witton's new Pterodactylus reconstruction on his blog.

All of these reconstructions still go a bit beyond the known evidence by depicting large, flamboyant crests. As they probably should - Witton was correct when he pointed out that pterosaur crests were probably larger, in general, than traditionally thought. All of our crested Pterodactylus specimens are also sub-adult, so even though the soft tissue crests we have preserved seem to be pretty small, it's likely the crest would have gotten at least a little bigger with maturity. We just don't know how much bigger.

Reconstruction of a subadult Pterodactylus by M. Martyniuk.

Sunday, June 10, 2018

Review: "Beasts of the Mesozoic" Tsaagan by Creative Beast Studios

Quick Facts
2018 Beasts of the Mesozoic Raptor Series Tsaagan mangas action figure
Size: 20cm long
Scale: 1:6
Sculpted by: David Silva
Produced by: Creative Beast Studios

Back in April 2016, toy industry veteran David Silva launched a Kickstarter campaign to produce scientifically accurate "raptor" (eudromaeosaur) figures. Unlike the vast majority of static PVC dinosaur figures on the market, these would be super articulated, with up to 24 joints allowing significant posability. Now, over two years later, the project has become a reality, and my selection of a Wave 2 Tsaagan mangas figure has finally arrived. So, how does it stack up to the high expectations and lofty claims that these are the most scientifically correct dinosaur action figures on the market?

Friday, May 4, 2018

The Step-wise Bird: Andrea Cau on Bird Evolution

Above: WIP reconstrcution of one potential Connecticut River Valley trackmaker, the bird-like reptile Anchisaurus polyzelus. By M. Martyniuk, all rights reserved.
This morning saw the publication of a new paper by Andrea Cau, titled Assembly of the Avian Body Plan, and what a mammoth (dinosaurian?) work it is! Cau does an amazing job of synthesizing the step-wise nature of bird evolution that is so often hidden behind imprecise or muddy nomenclature. Far from a dichotomy between "non-avian" and "avian" dinosaurs, the important features we associate with modern birds gradually accumulated in a particular lineage of stem-birds ever since the early Triassic period. I should have a lot more to say on the nitty-gritty of this paper this weekend after I've had a chance to fully digest this important work on avian origins. In the mean time, I wanted to share a brief excerpt from (one of) my upcoming book(s), this one dealing with the struggles to interpret some of the earliest known dinosaur remains in an era before the nature of dinosaurs as weird transitional members of the bird lineage was fully understood. The chapter this comes from is discussing Edward Hitchcock's work in the early-mid 1800s on bird-like footprints found in the Connecticut River Valley. The footprints date to the early Jurassic (Cau's "Huxleyan stage" of bird evolution).

Several, more prominent, scientists of the time criticized Hitchcock’s interpretation of the footprints as having been made by birds. He was ridiculed for imagining huge birds that must have been many times the size of the largest living bird, the ostrich. Soon, the rediscovery of giant extinct birds like the moa granted him some level of vindication. But more serious criticisms followed. The sandstone of the Connecticut River Valley was simply too old, other scientists argued. Birds, being “higher” life forms in the ranked scheme of life most believed in at the time, must have also been newer, having developed fully only after the so-called “age of reptiles”. Some scientists went so far as to argue that the three-toed tracks belonged to giant frogs, and that only the large, strong hind limbs left impressions while the lighter forelimbs often did not. And, indeed, one fact which was very inconvenient to Hitchcock’s explanation was that some of the tracks preserved light forelimb impressions, and some were found along with tail drag marks.

What could Hitchcock do to save his bird hypothesis from the facts? By 1861, the discovery of an archaic proto-bird named Archaeopteryx lithographica provided the answer. Here was an example of a “bird” with primitive, reptilian features and a long tail. Perhaps, Hitchcock suggested, his sandstone prints were not made by giant moa-like birds, but giant Archaeopteryx-like birds. And what of the occasional forelimb impressions? Hitchcock actually suggested that, along with its primitive skeletal anatomy, the Archaeopteryx may have been a facultative quadruped! In his view, the Archaeopteryx was halfway between birds and reptiles in both anatomy and gait. Hitchcock had, rather unscientifically, crafted his hypothesis to be immune to all criticism. His peers weren’t buying it.

By the time of Hitchcock’s death in 1864, the bipedal, bird-like nature of many Mesozoic reptiles like Hadrosaurus and Compsognathus had been discovered. For most scientists, these creatures provided a more plausible explanation for Hitchcock’s “sandstone bird” tracks than actual birds. By the late 1800s, the tracks were universally accepted as having been made by prehistoric reptiles, though intriguingly bird-like ones. Today, we know that these ancestrally bipedal reptiles, the dinosaurs and their kin, did indeed have more in common with modern birds than with any of the modern reptile groups, and in fact included the evolutionary ancestors of true birds.

In the end, it turns out that Hitchcock was half-right. His sandstone bird tracks were made by creatures in many ways more like Archaeopteryx than any modern bird or reptile, some of which were partly or fully quadrupedal, with great sweeping tails and enormous body sizes compared to any birds alive today. Many of them even had feathers and feather-like filaments covering parts of their bodies. What Hitchcock had actually discovered were the bird-like reptiles, creatures descended from the same ancestors as crocodiles and turtles, but which had evolved a wide array of uniquely avian features. At a time when most mainstream scientists envisioned dinosaurs as huge, quadrupedal, mammal-like reptiles (in appearance and gait if not lineage), Hitchcock was able to use the traces they made in life to arrive at a conclusion that was actually much closer to the truth in many ways. The Mesozoic was not an “age of reptiles”, at least not on land. It was an age dominated by the bizarre, archaic relatives of birds.

I think the above is a good example of Cau's thesis that a false, dichotomous paradigm, like "bird" vs. "reptile", or "non-avian dinosaur" vs. "bird", and focusing mainly on "key" specimens like Archaeopteryx, can actively mask the reality behind fossil evidence. What do you think?

Sunday, April 30, 2017

Review: Dino-Riders Struthiomimus by TycOMG IT HAS FEATHERS

Quick Facts
1988 Dino-Riders Struthiomimus action figure WITH FEATHERS. IN 1988.
Size: 20cm of feathered glory.
Scale: Scales on the feet, feathers up top. Also, 1:12.
Sculpted by: The wokest of all 1980s dinosaur toy sculptors.
Produced by: Tyco (obviously with a lot of help from Bob Bakker).

No need to adjust your TV sets folks, this is a mass-produced dinosaur toy made in 1988 that is covered in feathers. Not like lame, Primal Carnage, Jurassic Park 3, cool-guy dragon with a mohawk. Natural looking feathers.

This is why Dino-Riders was the best thing about the '80s (sorry, He-Man). Dino-Riders gave us aliens from the future riding armored mind-controlled dinosaurs blasting a thousand lasers at other armored dinosaurs who were not mind controlled but who were just in it because they cared about justice, and the toy versions of these things looked more naturalistic and scientifically accurate (for the time) than anything in Jurassic World.

I'm going to use this particular review to drop some history.

Wednesday, April 12, 2017

You're Doing It Wrong: Pteranodon Bills

Your bill's looking a little puny, there, buddy.
(Painting by Heinrich Harder, 1912, public domain).
Everybody knows Pteranodon. Quick, stop to imagine it! It's easy, because it's the most often-illustrated and well known pterosaur to the general public (though today's marketing departments often call it a pterodactyl, following it's original, century-out-of-date classification).

But hold on. That image you have in your head right now, of a big pterosaur with a long crest and a mid-length pointy beak? That's likely wrong, and may be just as much a hybrid as those Flintstones-style creatures with pteranodont crests and Rhamphorhynchus tails.

How do we know? Let's talk about Dawndraco.

Wednesday, April 5, 2017

Review: Dino-Riders Pterodactyl by Tyco

Quick Facts
1987 Dino-Riders Pterodactyl action figure
Size: 20cm (wingspan)
Scale: 1:3 or 1:4
Sculpted by: unknown
Produced by: Tyco

Pterodactylus antiquus has a special place in history as one of the first ever prehistoric reptiles to be subjected to scientific study. It's one of the best known pterosaurs, with many complete specimens known to science, and it ended up lending its name to the entire group of pterosaurs to which it belongs (Pterodactyloidea). In fact, "pterodactyl" has become a common nickname for all pterosaurs, thanks in part to the fact that nearly all pterosaurs were considered species of Pterodactylus during the 19th century.

Despite the importance of pterodactyls, very few toy versions of them have been produced (in fact I don't know of any other than this one and one made by Starlux - if you know of more, let me know in the comments!). Sure, there are lots and lots (and LOTS) of toys out there claiming to be "pterodactyls", but the vast majority of these are actually other species of pterosaur, most often Pteranodon. A lot of older "pterodactyl" toys from the 1950s - 1980s are weird hybrids of the Pterosaurs' Greatest Hits, like pteranodonts with teeth, or with Rhamphorhynchus tails. But almost none of them are the classic, the original, the one and only pterodactyl. That's probably not a coincidence or a mistake - like the "velociraptors" in Jurassic Park that were really Deinonychus, pterodactyls have a cool name attached to a somewhat wimpy animal. Most pterodactyl fossils are tiny, with wingspans of only a few feet. Larger specimens do exist, but these skin-winged critters don't seem to have grown any bigger than a large seagull. Personally, I think that's part of their charm - I can't help but picture flocks of them squabbling over dead squids any time I watch gulls at the beach. But in terms of raw awesomeness, they certainly can't compete with 20 foot beasts like Pteranodon.

One of the very few pterodactyl toys that's actually a REAL pterodactyl is this one from Tyco. Produced in 1987 and released in 1988 at part of the Dino-Riders line, this pterodactyl came with a 2" action figure and a little hang glider accessory, but I won't be worrying about those here. Despite it's age, this is still one of my favorite pterosaur toys and holds up reasonably well even today. Let's get into some details...

Monday, July 18, 2016

Playing with Saurian's Genericometer

There's a dinosaur game in development called Saurian. Have you heard of it? You should really check out! It's shaping up to be super cool and extremely rigorous when it comes to science and coming up with accurate portrayals of an extinct ecosystem. Check out their page!*

*Full disclosure: I may be involved in this game's development in some small capacity. There will be birds.

The Saurian developers have made a somewhat controversial choice when it comes to the name of the Hell Creek Formation hadrosaurid. Yes, boys and girls, a video game company has dipped its toe into the boiling caldera that is dinosaur nomenclature.  Many fans (and keep in mind these are people who know enough to be early backers of a game priding itself on scientific accuracy and technical minutiae) were a little shocked to see the announcement of the Saurian hadrosaurid. Not just at the unbelievably painstaking level the devs went to in order to research and create the character - everything from life history and growth trajectories to mapping out the actual pattern of scales found on an infamous fossil mummy. People were also a little put off by the fact it was named Anatosaurus annectens rather than Edmontosaurus annectens.

I'm not going to re-hash the long and convoluted history of everybody's favorite "trachodont" (Wikipedia does a pretty good job of that). For the purposes of this post, it's enough to understand that these two species of dinosaurs, Anatosaurus annectens and Edomontosaurus regalis, are fairly similar. So similar that for the past 25 years or so, most scientists have "lumped" them together under the same group of species, the genus Edmontosaurus, making the binomial of the Hell Creek Formation species Edmontosaurus annectens and relegating the name Anatosaurus to the trash heap of history.

But, a few years ago something changed. See, there was a second Hell Creek hadrosaurid, a bigger and much more different looking beast named Anatotitan copei. During the same 25 year period, mostly everybody has agreed this dinosaur was different enough from its relatives to deserve its own genus name. Recently, studies have demonstrated that those differences aren't necessarily due to being more distantly related, but just being... older. Anatotitan, it turns out, is just a mature version of Anatosaurus/Edmontosaurus annectens that had built up more unique features with age. It's not just a similar species to annectens, like Edmontosaurus reglais is, it's the same species. So onto the trash heap with Anatotitan.

But wait! Anatosaurus was thrown out because it was too similar to Edmontosaurus. Now, it turns out, it was actually different--different enough that its adult form was given its own genus for all those years. So shouldn't Anatosaurus be a genus again?

Well, that depends on what you mean by "genus". There is no universally recognized rationale for what makes something "different enough" to be a genus, and the concept varies wildly between fields of biology. Each scientist has their own opinion, their own gut feeling based on tradition and intuition, not science, of what a genus should be. If you asked an entomologist to re-classify all dinosaurs based on her own personal "genericometer" settings, we'd end up with one single genus of dinosaur, and it would include every bird that ever lived. Probably crocodiles too. We'd be left arguing, based on page priority or something, if the star of Jurassic Park should be called Passer rex, Vultur rex, or Crocodylus rex. On the flip side, if you had a ceratopsian worker reclassify the beetles, we'd end up with a hundred billion new genera of beetle.*

*I'm not 100% sure that's the correct number, but it'd be something with a lot of zeroes.

Some people have attempted to bring some science to the art of taxonomy, and quantify genera. Recently and most famously, Emanuel Tschopp and colleagues published their precise genericometer settings, and used those settings to reclassify the diplodocid sauropods. This resulted in bringing back the old, previously-junked genus name Brontosaurus (you may have heard of it). This is a great thing to try, but the method was only designed to apply to diplodocids. It might wreak havoc with names in other dinosaur groups, and would certainly result in an entomologist revolt if anybody ever tried to use it on bugs.

To their credit, the Saurian team have been up front with their genericometer settings used in the game. Rather than base their concept of genus completely on anatomical similarity, they've made the very intriguing choice of combining evolutionary relationships with a chronological component. Basically, if species B is the closest relative of species A, and if species B is known from fossils that can be dated to within one million years of species A fossils, then species A and B are to be classified in the same genus.

I thought it would be fun to try out these genericometer settings and see how it compares to the current traditional consensus, and to some other more widely criticized attempts to re-genericize dinosaurs, like the classification used by Greg Paul in his Princeton Field Guide to Dinosaurs.

Edmontosaurus vs. Anatosaurus.

We'll start with Anatosaurus. If we take Anatotitan to be its synonym, then according to most recent phylogenies, its closest relative is Edmontosaurus regalis, which lived more than a million years earlier. This is why Saurian chose to split Anatosaurus back off into its own genus. But right here, we immediately need to note how highly dependent on the vagaries of phylogenetic analysis this method is. Ugrunaaluk is a very similar hadrosaurid that actually lived in between Edmontosaurus and Anatosaurus, and was originally thought to represent specimens of Edmontosaurus. According to the (very few) phylogenetic analysis on its relationships, Ugrunaaluk is actually outside the Anatosaurus+Edmontosaurus clade. But, given its chronological position, it's always possible more analysis will show that it is transitional between them. Ugrunaaluk is still too old to connect Anatosaurus to Edmontosaurus by a million years or less, but only slightly. Ugrunaaluk lived about 69 Ma ago, and the earliest Anatosaurus fossils are about 67 Ma old. All it would take would be one slightly younger Ugrunaaluk specimen, in that case, to pull the whole shebang back into Edmontosaurus.

Following this cladogram for the sake of argument, let's look at the next outgrip to Edmontosaurus, which is the clade Saurolophini. Now we reach the sticky question of what counts as the next closest relative of Edmontosaurus, moving down the tree. So lets start at the tip of the next branch, with Saurolophus. S. osborni lived between about 69-68 Ma ago, slightly later than the last Edmontosaurus, but still within a million years. S. angustirostris lived about 70 Ma ago, during the time Edmontosaurus was alive. Prosaurolophus lived up until around 74 Ma ago, which predates Saurolophus but sits just barely within a million years of the lower range of Edmontosaurus. Since both Saurolophus and Prosaurolophus lived within a million years of the upper and lower range of Edmontosaurus, following these genricometer settings, they should all be lumped into a single genus. Because of the rules of priority, that means Edmontosaurus itself goes on the trash heap and Saurolophus regalis becomes the correct name for that species. Same for the next closest relative to the Saurolophus + Edmontosaurus group, Gryposaurus, which is within a million years of Prosaurolophus. Ditto Kritosaurus. It's not until the Brachylophosaurini clade that we finally get a break from all this lumping, but already, half of the short-crested hadrosaurids are now Saurolophus.

Obviously, I'm taking this a little far on purpose, just to test it out as a general-use genericometer for dinosaurs. You could easily tweak these settings to produce more traditional genera, like adding a rule against paraphyly (both Anatosaurus and Kerberosaurus would fall within a clade formed by members of Saurolophus in the above example; though in my opinion this is a feature rather than a bug, since some genera had to have evolved from others anyway, it's a little silly trying to rigidly keep them monophyletic). We could also add a stipulation that the time component is relative to the type species or, even better, type specimen, to allow for inevitable evolutionary grades from one form to another. This would, in effect, place a sort of million-year "radius" around a species that is not ever-expanding. So anything up-tree or down-tree of E. regalis, like Ugrunaaluk, gets caught in its gravity well, but we don't then jump to anything within a million years of Ugrunaluuk, too. I have to think this is probably the real intent of the Saurian team's method.

A variety of ceratopsid genera, by Danny Cicchetti (CC-By-SA).
"These are all different GENERA? That's hilarious," --Entomologists.

Using this type-restricted genericometer method could still do some fun things in the one part of the dinosaur tree that everybody sort of secretly thinks is horribly over-split but doesn't say so out loud because nobody really wants to rain on those guys' big ol' naming party: the ceratopsids.

The Saurian team stated that, if they were to include Torosaurus as a distinct species in the game, it would be as a species of Triceratops, per the genericometer settings described above. Following this cladogram and a type-restricted interpretation of Saurian's method, Torosaurus does become a species of Triceratops, the holotype of which is from about 67 million years ago. Nedoceratops has to go as well. Now, the Triceratops party ends there based on this particular cladogram, but I find the placement of the Titanoceratops a little er... iffy. Titanoceratops is really, really similar to Pentaceratops from almost the same time and place, so finding it in between a bunch of species that look basically identical to Triceratops is odd. I'm not saying it's wrong, but let's just ignore it for the moment. If we do, then Ojoceratops, Eotriceratops, and Regaliceratops all become species of Triceratops, too. So the entire clade Triceratopsini = Triceratops.

Further down the tree, we have Anchiceratops and Arrhinoceratops becoming synonyms. Kosmoceratops and Vagaceratops, too. Chasmosaurus subsumes Mojoceratops, Agujaceratops, Utahceratops, and Pentaceratops. Coahuiloceratops and Bravoceratops are both safe, and form the sister clade to the big Chasmosaurus complex.

On the centrosaurine side of the tree, Achelousaurus becomes Einiosaurus, unless paraphyly is invoked. Centrosaurus gobbles up Coronosaurus, Spinops, and Styracosaurus (again, unless paraphyly is invoked, in which case Styracosaurus remains valid but includes Rubeosaurus ovatus; this was the plan for one of the unmet Saurian Kickstarter stretch goals that would have included Styracosaurus ovatus).

Overall, this system produces a classification that is similar to, but not nearly as extensively lumped, as the one used by Greg Paul. I kind of like it, especially with the type species stipulation in play. I think that if you are going to use genera, and not just convert all genus names to species praenomen as some people have suggested, it's a good idea to have some kind of standard metric. The problem is, of course, that nobody will ever agree to one standard. Even within dinosaurs. Nobody specializes in all dinosaur groups. We have ceratopsian workers, tyrannosaur workers, avialan workers, sauropod workers, etc., all with their own traditions and personal metrics. This is why it tends to be the science popularizers, like the Saurian devs or Greg Paul or even Bob Bakker, who are the ones coming up with what all the professionals view as highly idiosyncratic classifications. They're attempting to take all these disparate fields within dinosaur paleontology and apply a single metric to all of them, which is bound to change a few things away from the consensus.

At the end of the day, the consensus is what it is. I'm glad people are exploring ways to apply consistency and standards to science-related minutiae like taxonomy. But it's equally important that those efforts be transparent, so we can compare each metric to the others and see which produces the results we like the best. Because at the end of the day, all of this splitting and lumping of genera comes down to just that: a matter of opinion.