Friday, October 10, 2014

Top Twelve Worst Name Changes for prehistoric taxa.

Sometimes animals get very evocative names in scientific description. Tyrannosaurus the tyrant, Hyaenodon the Hyena tooth, Stegosaurus the roofed, Styracosaurus the spiked, Megalosaurus and Megatherium, the big animals. Sadly, not all such names survive. The rule of priority is vital here; if we could arbitrarily change the names of taxa, it’d be a mess. Paleontological taxonomy is complicated and deceptive enough that many animals are given different names by different people, or assumed to be a new species when they aren’t. Sadly, this happens all too often, and many classic, evocative names are cast aside for more generic (pardon the pun), dull names.

12. Indricotherium and Baluchitherium.

The history of this species starts with awful names, superceding far better names. This gigantic rhino, famous among prehistoric mammals for its size, was first discovered in 1907 by Anglo-Indian paleontologist Guy Ellcock Pilgrim. In the Balukistan region of Pakistan (then part of the Raj), Pilgrim discovered a big rhinoceros jaw and teeth. This was still the period of wastebasket taxa, when all theropods were assumed Megalosaurus and all ornithopods Iguanodon. For rhinoceros, it was Aceratherium, a common, long lived genus of big, hornless rhinoceros. Pilgrim, not wanting to rock the boat by claiming a new taxon, simply put it down as Aceratherium bugtiense, the hornless beast of the Bugti hills.

The next name it was given was by a British paleontologist from Cambridge, Sir Clive F Cooper. Cooper underwent his own expedition to Balocistan, and found more of the rhinoceros. He realized that it was not Aceratherium itself, but a relative. Showing only slightly more imagination, he named it Paraceratherium in 1911. He looked for more in 1913, and believed he discovered two similar, seemingly larger genera with a far more impressive names, first Thaumastotherium (Marvelous Beast), then Baluchitherium osborni (Osborn’s Beast of Balukistan, named after his former boss Henry Osborn of New York) It was too late to change Paraceratherium, but at least the other names implied either an exotic eastern origin or a type of uniqueness.

Meanwhile, The Russian empire was trying to expand west and south, not only in industry, but in science as well. Alexander Borrissak, an experienced geologist, came back from Afghanistan with a rhinoceros of his own, where it became the centerpiece of the St Petersburg (then the Leningrad) museum. Borrissak managed to keep his head down and survived the revolution, along with his fossil which he called Indricotherium, Indrik Beast. The Indrik was the king of the beasts in ancient Russian mythology-part horse, part bull, and armed with a giant horn, this huge god-beast ruled the Holy Mountain of the gods (later of Yaweh himself), creating earthquakes and thunder and protecting the lush slopes from human invasion.

Finally, the People’s Republic of China found their own, even larger specimen in 1973. Of course, not wanting to be shadowed by the American and Russian rivals, Wu and Xang named their specimen Dzungariotherium after the Chinese name for the region in Xinjiang province. So, for a time, many names were used. The Russian name gained currency in the West, and was used interchangeably with Baluchitherium and Paraceratherium for most of the 20th century.

Alas, the dull, nondescriptive name of Paraceratherium won out in 1989. The opening of the Communist PRC and USSR to the Western nations allowed for interchange of scientific papers. So in 1989 Jay C Sorbus and Spencer G Lucas, two Americans who took advantage of this new openness, compiled the data and came to the conclusion that all these animals were of the same genus. Sadly, the oldest name is still Paraceratherium. So while Indricotherium and Baluchitherium are still popular, Paraceratherium remains the legitimate scientific name. The best we can do is refer to it as an Indrik or Indricothere as a common name.

11. Anatosaurus and Trachodon. The classic Duckbill dinosaur, one of the pantheon of great American dinosaurs featured in the American Museum. If you’re old enough, you immediately associate the big, flat-headed duckbill with the name Trachodon or Anatosaurus. What happened is a confusing taxonomic mixup that should definitely be addressed by a paleontologist.

The story begins with a collection of teeth. In 1856, Joseph Leidy of Philadelphia received bags of fossil remains found in Montana, mostly teeth. He classified them into several species-big carnivore teeth became Deinodon (Terrible tooth), small herbivore teeth became Palaeoscincus (ancient skink), small carnivore teeth Troodon (wounding tooth), and larger herbivore teeth became Trachodon (rough tooth). He compared it to his earlier find, Hadrosaurus, and found Trachodon very similar in form. Logically enough, he concluded that Trachodon was a descendant or Western counterpart to New Jersey’s Hadrosaurus.

Soon after, Leidy’s student and former friend turned rival, Edward Cope, found similar teeth. Cope, like his rivals Leidy and Othniel Marsh, refused to consider that his specimens could be of a species discovered by his rivals, and so called it Diclonius (two stems). When Cope found a complete skull of the teeth’s owner in 1882, he smugly argued that Trachodon, being a tooth taxon and thus of dubious worth, should be reassigned to Diclonius. Marsh found a specimen in 1889, and, seeing a chance to one-up Cope and align himself with Cope’s old mentor Leidy, named it Trachodon and placed it in his headquarters at Yale.

The real winner, however, was Barnum Brown of the American Museum. The Museum had bought Cope’s specimen from rapidly impoverished scientist at the same time Marsh found his, and Brown found another complete specimen as well as a spinal column of another Trachodon in 1906. Brown and his successor Henry Osborn would mount both specimens from a composite of fossils, and they joined the great American Museum pantheon, where they reside today.

Meanwhile, in 1892, Marsh found a complete specimen of his very own from Wyoming. He called it Claosaurus after his 1972 duckbill despite being larger, found in younger strata, and more advanced. So, as of 1906, there were two very similar duckbills in Eastern Museums-Trachodon in New York and Claosaurus in New Haven.

Enter the great Canadian paleontologist Lawrence Lambe. On the Red Deer river in Alberta, Lambe discovered more material in one of his last expeditions. He saw it as similar to Diclonius but seemingly ignored Marsh and Leidy’s classifications, calling it Edmontosaurus after the province’s growing capitol in 1917. Lambe’s successor at the National Museum (now the Canadian Museum of Nature) was Charles Sternberg from Kansas, whose father (a surgeon for the USA in the Civil War) worked for Marsh and brothers George and Levi were paleontologists in their own right. In 1926, Sternberg found a smaller, but almost complete specimen in Saskatchewan , and since it was found later than Edmontosaurus, called it Thespius.

For the next two decades, the names battled it out in a state of confusion. Philadelphia, New York, New Haven, and Ottawa all had their own duckbills, and no one knew if they were all the same animal, and if so what should they be called. Trachodon, having the New York honor, became the most popular, although Thespius and Edmontosaurus held their own across the border.

A resolution happened in 1942 when Osborn’s successor Richard Lull and his assistant Nelda Wright wrote a paper synthesizing the perspectives. Neither the Yale or American specimens could be assigned to Diclonius, Claosaurus or Trachodon, as so each was its own species but both belonged to a new genus, Anatosaurus. Problem solved, right?

Nope. In the 1970s and 80s, Michael K. Brett-Surman of the National Museum (part of the Smithsonian Institution) finally incorporated the Canadian specimens. Anatosaurus, he argued, was invalid. Instead, the Yale specimen was a new species of Edmontosaurus and coined the name Anatotitan copei for the New York specimens. So, as of 1990, there was a division of three species-Lambe’s Edmontosaurus regalis, Marsh’s E. annectens, and Sternberg’s E. Saskatchewanensis. The final lumping came in the 2000s; 2004 saw Jack Horner of the Museum of the Rockies, David Weishampel of the John Hopkins School of Medicine, and Catherine Forster of George Washington University arguing that Anatotitan was an Edmontosaurus with a skull modified by taphonomy. In 2011, a morphological study was made by Nicolás Campione of the University of Toronto (currently at Uppsala University) and David Evans of the Royal Ontario Museum. They concluded that the four species of the mess were two; E. copei (the New York specimens) was an older E. annectens and E. regalis was an older E. Saskatchewanensis. Of course, you could still argue the two species were so separated by 5 million years so that the younger species could still remain Trachodon/Anatosaurus/Anatotitan, but the splitters have not made much of a fight for it and so the lumpers currently hold sway and the unimaginative, nondescriptive Edmontosaurus holds sway. The best we can do is use Anatotitan/Anatosaurus/Trachodon as a subgenus or a common name.

10. Dinohyus. A less obscure Miocene animal today is the Terminator Pig. Distant relative of hippos, these giant omnivores ruled the early Miocene of the American west. You can certainly find it in Washington, Pittsburg, Denver, New York, or Harrison, Nebraska. The founder of the species is our friend Edward Cope. In 1878, he found big ungulate teeth in a jaw fragments from Oregon, assumed they were of a late Menodont (more on that confusion later), and named them Daeodon or destructive tooth as he imagined the huge teeth were used for defoliating environments.

Enter Elotherium. 1847 saw the legendary French paleontologist August Pomel erect a new species of what he determined to be a giant pig. His college M. Aymard discovered Entelodon, a similar genus. So, when Leidy discovered similar specimens in the USA, he assigned them to Elotherium, and reconstructed them according to the French perspective of gigantic warty boars. Marsh, naturally, refused to cooperate. When he found similar teeth, he called them Ammodon (thinking them first sheeplike, then rhinolike).

The plot thickened in 1905, when Olof August Peterson, a young paleontologist from Pittssburg, found more in Agate Springs (see my Moropus writeup for more). He found a huge piglike animal, clearly entelodont, and named it Dinohyus Hollandi or Holland’s terrible pig (this could be considered a veiled insult, as Peterson was oppressed by Holland’s boorish or rather boarish command at Agate Springs). The specimen was excellent, and took it to the Carnegie Museum where it remains. For most of the century, Daeodon fell by the wayside as Dinohyus, a far more complete specimen and supported by many more, became the great American killer pig. Charles Knight and Rudolph Zallinger illustrated them as Dinohyus, a giant boar of the Miocene, part of the strange menagerie of their tableaus. Daeodon, as a poorly known Oregon animal, was relegated to just another entelodont.

Alas, it was not to last. Dinohyus and Daeodon were suggested to be the same animal by the great American paleontologist George Gaylord Simpson. While beginning his long tenure at the American museum, he set about classifying the museum’s treasure trove of fossils, arguing that that Dinohyus was simply the complete specimen of Daeodon. The next 40 years, however, saw Dinohyus hold its own. Finally in 1998, a team of veteran paleontologists Spencer G Lucas of New Mexico (who would lose credibility in 2008 when it was discovered that he plagiarized from his students), Robert J Emry of the Smithsonian (apparently the headquarters for lumpers), and Scott E Foss (the premier authority on entelodonts) did a taxonomic revision of the entelodonts, arguing convincingly that Dinohyus belonged to Daeodon. Fortunately, Foss and other entelodont workers have come up with a good common name we can use- Terminator Pig. To put a coda on this affair, Michelle Spaulding, Maureen A. O'Leary, and John Gatesy have done molecular DNA and anatomical analysis of Cetoarirtodactyla (the group containing whales, most hoofed mammals except horses, rhinos and tapirs, and their ancestors), classifying the entelodonts as further from pigs and closer to hippos, and hippos closer to whales than pigs. Frankly, considering how dangerous hippopotami are, this only makes the Entelodonts look even more frightening

9.Huxleysaurus (and Darwinosaurus, Mantellisaurus,and Owenodon) This next name change is more straightforward. In 1881, Richard Lyddeker of the Natural History Museum of London found Iguanodon limbs and vertebrae at Hollington, East Sussex. Fast forward to 2012, when Gregory S Paul, despite a tendency to lump theropods, ornithopods, and ceratopsians, came across it during his ongoing splitting of Iguanodon. He argued that this specimen was far more basal than the classic Iguanodon or its gracile sister genus Mantellisaurus, and named it Huxleysaurus. I’m usually against naming fossils after people like Efraasia or Magnapaulina or god help you Lenina, but it can work like Arthurdactylus or Lambeosaurus or Darwinius. In this case, it honors one of the great scientists of the 19th century, Thomas Henry Huxley. Huxley has been described as a hands-on nercrologist, studying dead bodies and fossils as to learn everything about their anatomy. He supported Darwin being one of the first to agree with the scientific principle of Natural Selection, and would debate Darwin’s critics that the sickly, mild-mannered Darwin refused to face despite Huxley’s criticism of demands for a physical mechanism for evolution. Huxley was the first to argue for the origin of birds from dinosaurs, doing a personal examination on Archaeopteryx. He classified archaic animals into Cnidaria (the name is not his, but the classification is) and discovered that the turnicates were invertebrate chordates. He even coined the term agnostic and defined it, unifying the existentialist perspectives of Kierkegaard, Kant, and Hume (and myself, as a follower of Hume).

Here’s the bad news- all splitting must be done with some sort of restraint, and like its relative Dollodon, Huxleysaurus proved to be within the variation of another one of Lyddeker’s Iguanodonts. David Norman of Cambridge, authority on Iguanodon, argued that the specific traits of Huxleysaurus were not diagnostic, and that they fell within the physical range of Norman’s Hypselospinus. Hypselospinus is a rather generic name, descriptive but lacks the dignity of Huxleysaurus. The same fate happened to Paul’s Darwinosaurus-Norman shut it down as a chimera, and likewise Owenodon is too fragmentary to be a legitimate species as of yet. In this case, there still might be hope. Norman and Paul aren’t done yet, and further Iguanodon finds could restore Huxley’s, Darwin’s, and Owen’s dinosaurs to legitimate status. I suppose it could be worse. Could be Planicoxa or Delapparentia.

8. Diatryma. If there’s ever a book or TV program on prehistoric mammals before the Ice Age, you can bet Diatryma will be in it. It’s the giant killer bird that ate the first horses. In 1855, French scientist and inventor of the Rheostatic Machine Gaston Plante found bird bones near Meudon. The bones were huge, and from the hips and legs. More bones were found in the 1860s and 1880s, and in 1881 Victor Lemoine drew a reconstruction of Gastornis parisiensis(named after its discoverer). It was based on ostriches, naturally, the only large flightless birds the French knew-a giant herbivore that could reach above any of the contemporary mammals. In 1874, Edward Drinker Cope found similar bird bones in New Mexico, again of the feet and legs, and named it Diatryma giganteous (Naturally, when Marsh found similar fossils, he invented a new taxon, Barornis). Diatryma sound great as a name, but the meaning is awful-it simply means “perforated”, roughly, because Cope found toe bones riddled with small holes, an artifact of preservation. Still the similarity was found early on, but the French and Americans dueled over which genus had priority.

Things changed, however, in 1917. The American Museum found a complete specimen, including the head, and it transformed the ostrichlike version based on Gastornis into a true terror. Scientists realized this animal was a predator with a giant beak, unlike any living bird today. Gastornis was dismissed as being the prior name, as everyone interpreted Lemoine’s restoration as accurate. So for years, Diatryma ruled the primordial jungles of Knight, Zallinger, and Zdenek Burian as the Tyrannosaurus of its time.

All good things come to an end-in this case it was in 1990s. In 1992, Allison Andors argued for Diatryma’s herbivory and in 1997 Buffetaut and Burrrraur found out that Lemoine’s restoration of Gastornis was mostly conjecture and that it indeed was the same species as Diatryma. So the reign of Diatryma came to an end. I’ve already dealt with the herbivory argument previously, but you can’t fight taxonomy. Diatryma and Gastornis, despite living on different continents, were the same animal. Again, common names come to the rescue-diatryma in the lowercase is still a popular common name despite the family and genus.

7. Jenghizkhan. This one’s a lot more recent. 1946’s Soviet-Mongolian expedition to Omnogovi brought back a wealth of fossils, including three giant theropod. In 1955 Evgyny Maleev named the largest Tyrannosaurus bataar (tyrant lizard warrior) and the other two Gorgosaurus lanicinator and novojilovi. However, ten years later, Anatoly Rozhdestvensky re-examined the fossils, correctly identifying them as growth stages of the same species. He also distinguished it from the American genera, creating a new genera Tarbosaurus (alarming lizard). This remained until the fall of the USSR. Kenneth Carpenter, an American Tyrannosaur expert, examined the fossils and argued that one of the ex-Gorgosaurus was a distinct species that he named Maleevosaurus. Paleontologist George Olshevsky did his own reclassifying in 1995, splitting it Tarbosaurus into three genera-Tarbosaurus efremovi, Maleevosaurus novojilovi, and Jenghizkhan bataar. Jenghizkhan is a brilliant name for a tyrannosaur-equating the ferocious predator with the equally ferocious conqueror of Asia.

Genghizkhan, however, didn’t last as long as his namesake. Another Tyrannosaur expert, Thomas Carr, did a study on ontogeny and growth of known tyrannosaurs. While Nanotyrannus still has its supporters and legitimate arguments, Jenghiskhan wasn’t as lucky. Carr restored Rozhdestvensky’s scheme, re-aligning them as Tarbosaurus. I guess we’re lucky he didn’t sink the genus altogether into Tyrannosaurus. Jenghizkhan is still a good name, and while the tiny oviraptorid Khaan isn’t exactly worthy of the name, it’s better than nothing.

6. Grendelius. This species lasted 23 years before being slain, not bad at all. This story begins in 1904, when the prolific Belgian-British zoologist George Boulenger found a front fin of an ichthyosaur near Bath. Ichthyosaurus was then a wastebasket taxon, where all similar species were assigned, so he named this animal Ichthyosaurus extremus for its very large size. However, in the 20s, renamings began as more and more scientists learned and became skilled at taxonomy. The legendary Fredrich von Huene of Württemberg began to examine the ichthyosaurs, comparing the specimens to the type specimen. He realized that this later, giant fossil could not possibly be Ichthyosaurus itself. He decided to categorize the large late Jurassic ichthyosaurs into taxa based on the shape of the fin-the small finned type was Nannopterygius, the narrow finned type was Platypterygius, and the wide finned type was Brachypterygius.

Fast forward to 1976. A three-foot skull is found in Norfolk by the Sedgewick Museum. Contacting the Royal Ontario Museum, they have the ichthyosaur expert Christ McGowan analyze it. He pronounces it a new species, calling it Grendelius mordax. This name is superb: Grendel, Beowulf’s ogre enemy is a good analogy for this large predator, and the species name mordax refers to the powerful bites this animal could take. No doubt it hunted fish and even smaller reptiles.

Alas for Grendelius; in 1997, the Bristol Museum found an excellent specimen: the head and torso of a large ichthyosaur found in Kimmeridge Bay. The head was similar to Grendelius, and the fin from Brachypterygius. In took them 6 years. To McGowan’s chagrin, the animal proved to be identical to both his Grendelius and Von Huene’s Brachypterygius. Older names have priority, so he was resigned to mark off his old species. Too bad; Grendelius is an evocative, poetic name. Grendel’s been slain again.

5. Dromiceimimus. Back to the Canadian dinosaurs. Let’s go back to our friend Charles Marsh. 1890 saw his description of a new form of smaller, birdlike dinosaur. The long hollow limbs were like a bird’s so Marsh named it Ornithomimus velox “Swift bird mimic”. At first he thought they were relatives of Dryosaurus or Hypsilophodon, but more material made him realize it was a slender theropod dinosaur unlike any before. Two years later saw the discovery the similar Struthiomimus or Ostrich Mimic. Indeed, the similarity is such that the two were often confused. Decades of taxonomic confusion continued as more and more specimens were assigned to one, the other, or both.

It took until 1972 to figure things out, as the great Canadian scientist Dale Russell undertook an examination of the ostrich dinosaur material. He managed to organize the specimens into four genera with two species each: Ornithomimus velox and edmontonicus, Struthiomimus altus and sedens, Dromiceimimus brevitertius and samueli, and Archaeornithomimus asiaticus and affinis. Simple and elegant. Plus, two new species with good names-Archaeornithomius precedes Ornithomimus, and might have been an ancestor, while Dromiceimimus (Emu-Mimic) was the emu to Struthiomimus’ostrich.

So things stood for the next 32 years. Then the next generation of theropod workers decided to take another look. This time it was a team- Yoshitsugu Kobayashi of Hokkaido University, Peter Mackovicky of Chicago’s Field Museum, and Russell’s friend Phillip Currie of the Royal Tyrrell Museum in Drumheller. Archaeornithomimus had already lost A. affinus due to it being a bad fragment, so it escaped unscathed. Poor Dromiceimimus, however, was sunk into Ornithomimus as its anatomical features all fell within the range of Ornithimuus’ many specimens. Fortunately, Struthiomimus survived the shearing. Interestingly, it seems as if Ornithomimus and Struthiomimus coexisted in the last 10 million years of the Mesozoic. The emu-mimic is dead (although I saw its specimen) but the ostrich mimic survives.

4. Mastodon.I’ve talked about it before, so I’ll recap it here:

So, in 1792, Robert Kerr, a Scottish anatomist, looked at specimens brought over from the recently established United States by his fellow fossil enthusiast Thomas Jefferson. Kerr, agreeing with Jefferson’s slaves, identified the bones as those of a prehistoric elephant, calling it Elephas americanum. However, later that year, Kerr erected a new species since the teeth were far different from Elephas (then containing species of living elephants and mammoths), and called it Mammut for the ancient Siberian underground monster. Apparently, Jefferson was fond of the name Mammoth, and wanted to use it for the American “elephant”, so he might have had some influence on Kerr’s reclassification. In 1817, however, Cuvier ignored Kerr’s name and dubbed the animal Mastodon. While Cuvier’s name became popular in media and the popular culture, Brookes acknowledged his colleague Kerr’s name and called the new genus of mammoths Mammuthus instead of Mammut. There’s also the fact that Jefferson considered the Mammut and the Mammuthus to be the same animal, arguing that the teeth Cuvier described were from his carnivorous Megalonyx (described based on giant claws, and later turning out to be a ground sloth).

3. Gigantosaurus. The very name Gigantosaurus sounds awesome. I’m sure everyone’s used it for Giganotosaurus by mistake at one point or another. In fact, you would think there would be one called Giganotosaurus. There was.

The eminent British paleontologist in 1869 was Harry Seeley, who would go on to invent the terms Saurichia and Ornithichia. Finding an assortment of unarticulated giant bones, Seeley dubbed them Gigantosaurus. Problem is, they were never really diagnosable, so they wound up in wastebasket taxons. First was Ornithopsis, another of Seeley’s Taxa, then Pelorosaurus, one dating back to Mantell. Right now it’s a nomen dubium-the finds are currently such scrap they can’t be assigned to any taxon, even their own.

The story isn’t over yet-in 1907, Eberhard Fraas of the Stuttgart museum discovered sauropod material at Tendaguru. Two were skeletons, each of a distinct new species. So Fraas named them Gigantosaurus africana and Gigantosaurus robustus. Neither one lasted that long-both were renamed Tornieria (yuck) by Richard Sternfeld (a herpetologist that was murdered in Auschwitz) then africana was renamed by Werner Janensch (another Tendaguru paleontologist and curator of the Humboldt Museum) as a species of Barosaurus. In 1991, robustus was established as a titanosaurus and renamed Janenschia. In 2006, Kristian Remes of the Deutsche Forschungsgemeinschaft took a second look and managed to restablish Barosaurus africanus it as Torneria. Whew!

So, alas, Gigantosaurus is too poor to be a real species, and the two African specimens with really ugly names are certainly not the same animal as Seeley’s. The only hope for Gigantosaurus is that a good specimen is found that can definitely be connected to the holotype.

2. Brontotherium, Brontops, Titanotherium. This one’s another product of the Bone Wars and a pretty classic prehistoric mammal. If you ever see what looks like a rhino with a slingshot on its snout, you’ve seen it.

Let’s go back to 1849, when Auguste Pomel finds a large jaw of a herbivore in Wyoming. He calls it Menodus “Strong tooth”, a name he used for large herbivore material in Europe. It’s not diagnostic of anything other than that, so he assumes it’s a giant version of the big primitive mammal Paleotherium.

1852. Joseph Leidy takes fossils from Wyoming belonging to what looks like a rhinoceros. Careful study shows that they’re not rhino bones, but of some large relative, a giant pachyderm mammal from the late Eocene. Leidy calls the bones Titanotherium.

Fast forward to 1870. This time Leidy finds a skull. It’s both familiar and different-it’s clearly a relative of a tapir or rhinoceros, but the teeth are different, the brain is smaller, and instead of a nasal opening for a tapir trunk or a bone pad for a horn, there is a bony nose horn similar in structure to the ossicones (bone knobs) on a giraffe. The size of the skull is impressive-he calls it Megacerops coloradensis “giant horned face of Colorado”).

Then in 1873, both Cope and Marsh find more bones of similar animals. Cope names his Megaceratops (basically ripping off his former Philadelphia friend but current rival). Marsh calls his Brontotherium “Thunder Beast” (trying to outshine both). Marsh finds four more in 1887, naming them Menops “Strong Face”, Allops “Strange face” (both at Yale), Brontops “Thunder Face” (which would find its way to New York) and Titanops “Giant Face”. It’s not over-Cope fired back with 1889’s less poetic name Haplacodon. The following year, Marsh describes another titanothere (as they are now called in a nod to Leidy) called Teleodus “Final Face”.

In 1929 Henry Fairfield Osborn of the American Museum wrote a two-volume magnum opus on all these Brontotheres. He was fascinated by them for years, commissioning sculptor Erwin S. Christman to make a series of busts showing Brontothere evolution. In his decades of work, Osborn identified Pomel’s Menodus as specimen, sank Haplacodon and Brontops into Megacerops, and sank Menops, Teleodus and Titanops into Titanotherium. Soon after, his student Erich Schalikjer found a new species, naming it as the new genus Atelodon (pointless tooth).

In 1967 Clark and Beerbower took a crack at the taxonomic mess, arguing that all brontothere species belonged to Menodus as the oldest specimen. So, that’s it for all those evocative names, right? We all get thoroughly robbed by a broken jaw with a lousy name?

Not quite. R.L. Carrol revived Brontops and Megacerops in 1988. Ten years later, B.J. Mader defended Menops, Megacerops and Brontops but condemned the other species.

Finally, ten years ago, 2004, Matthew C. Mihlbachler of the AMNH, Spencer G Lucas of the New Mexico Museum of Natural History, and Robert J. Emry of the Smithsonian Institution collaborated on one more Brontothere paper.

The final verdict: Menodus was not diagnostic and was already used for another prehistoric mammal. OUT. Every single genus since Leidy’s Megacerops falls within variation-they use Giraffes to establish range of variation in skull shape. While I do think there were more species, considering the sheer range of variation in horn shape and skull size, his arguments are very convincing. I do hope more paleontologists touch on the brontothere mess, but for now Mihlbachler holds the key.

So this leaves Megacerops as the one and only at the moment. Brontotherium, Brontops and Titanotherium are sadly lost. Still, I’m glad that among the two, Megacerops wins over Menodus. Menodus is a truly horrible name in my view while Megacerops is still descriptive and a good name. It’s just not the same as Brontotherium or Titanotherium, though. The names live on in taxonomy as the names of the family (Brontitheriidae) and the suborder (Titanotheromorpha)

1. Brontosaurus. The last, and most famous of name changes happened to one of the most iconic dinosaurs ever. You’ve probably heard this one, so this will be quick. 1877-Marsh finds vertebrae from a juvenile sauropod. It’s hard to classify, so he calls it Apatosaurus ajax“deceptive lizard, Greek hero”. 1879-Marsh finds an older, far more complete specimen that only lacks a head and feet. Impressed, he calls it Brontosaurus excelsus “superlative thunder lizard”. The mount is still the centerpiece of the Yale Peabody’s dinosaur hall. Nearby, a Camarosaurus skull and feet are found, and Marsh assumes they belong to the brontosaurus. In 1903, Elmer Riggs of the Field Museum finds his own specimen, and compares it to the existing material. He concludes that Brontosaurus excelsus is a species of Apatosaurus, and so the older name should have priority. Friedrich von Huene argued that Brontosaurus was a species of Camarosaurus. Charles Gilmore in the 1930s and Alfred Romer in the 1950s supported Rigg’s opinion. However, the name stuck for decades until the Dinosaur Renaissance.

The head, by the way, was finally discovered in 1976 but the reconstructions didn’t change until the dinosaur renaissance of the 80s. Ironically, the main figures of the dinosaur renaissance, Robert Bakker and the late, great Steven Jay Gould argue for the return of Brontosaurus. The main problem with the classification is the fact that Apatosaurus ajax just isn’t as well represented in the fossil record as Brontosaurus excelsus. Things haven’t changed much since Riggs’ time. So, unlike most of these animals, Brontosaurus has a small chance. Perhaps it will beat the odds. Right now, however, Apatosaurus is the status quo. Brontosaurus is still a fine common name or subgenus, though, and again things can change and Brontosaurus will make its return again. I for one will keep my fingers crossed.


  1. This comment has been removed by a blog administrator.

  2. This comment has been removed by a blog administrator.