Sunday, July 20, 2014

The generic history of dinosaur paleontology: 1990 to 2014

We come now to the end of this series (previous installments 1699 to 1869, 1870 to 1899, 1900 to 1929, 1930 to 1969, and 1970 to 1989). 1970 to 1989 was the heart of the Dinosaur Renaissance, with its "dinosaur heresies"; as you might guess, when heresies last long enough, they stop being heretical. Funnily enough, for everyone who became interested in dinosaurs after the mid-1980s, the Dinosaur Heresies are a lot closer to the Dinosaur Orthodoxies. You'd have trouble selling a book with that title, though.

I posited in the previous post that there was a transitional phase between the Renaissance and the current period, from perhaps 1990 (the year of The Dinosauria and Jurassic Park) to 1996. 1996 is significant as the year when Sinosauropteryx was published, opening up the world of feathered dinosaurs. The dinosaur–bird connection was supported by a growing number of dinosaur paleontologists before this, but Sinosauropteryx, your basic-model small theropod had it been found without its filaments, was a particularly apt vehicle to drive home the point. By 1996, most dinosaur researchers supported phylogenetics and cladistics, although they didn't always utilize them properly, and there was still an awkward echo of Linnean taxonomy as people sometimes tried to cram their new clades into the Linnean framework, ending up with infraorders and parvorders and similar, until the majority divorced themselves from the arbitrary ranking system. Computing power had greatly increased as well, permitting not only computational analyses of phylogeny, but a variety of other studies that required number crunching. The spread of the Internet led to the growth of the first crop of dinosaur websites, and to the grand old Dinosaur Mailing List. I do not think there is much left of the really early sites. The last remnants may be the Mailing List and Dinogeorge's Dinosaur Genera List. The 1997 edition of The Complete Dinosaur had a list with a few of them; if you ever yearn for those halcyon days, you can always give the addresses a whirl through Internet Archive. (If you're ever looking for one but don't remember where it originally was, drop me a line because I may have an address.) The transitional phase also saw a sorting-out of the less-likely ideas from the Dinosaur Renaissance, to be banished to the land of dated yearbook photos and retrieved occasionally for a giggle. Finally, the popularity of dinosaurs received another rocket boost with the 1993 movie adaptation of Jurassic Park.

The population of people actively engaged in dinosaur paleontology and vertebrate paleontology steadily grows through the 1990s and 2000s, which is easily appreciated by comparing the number of pages in abstract volumes for the annual meeting of the Society of Vertebrate Paleontology. In 1987, it was 32 pages. In 1997, it was 93. In 2007, it was 177. Last year's weighed in at 250. Granted, some of the increase is advertising and logistics, not abstracts, but these too show how the meeting (and field) has grown. Essentially, when adults started taking dinosaurs seriously, the kids who already loved dinosaurs were encouraged to stay interested, which led to more undergraduate and graduate students, and eventually more professionals. The modern crop of dinosaur paleontologists is the fruit of the Dinosaur Renaissance. The explosion of workers also makes it awkward to hold up specific names, which combined with the fact that this era covers the present (removing the benefit of hindsight), means I will omit a section of leading lights. "The wheel's still in spin", as they say. The biggest takeaway is that dinosaur science has spread from its little colonies of a handful of people in western Europe, eastern North America, and more recently Argentina, China, Mongolia, and Russia, to become much more cosmopolitan, which can only help.

Now, a couple of logistical matters peculiar to this this part of history. The Dinosaur Genera List gets kind of tricky in the past few years. This is because publications are frequently issued online months or even years before they appear in print, but the online versions do not officially "count". Thus, the DGL may represent certain dinosaurs as having been named one to three years before their print version. For my purposes, the DGL's early publication dates are more useful, because they represent when a publication is ready. The rest is waiting at traffic lights. The DGL also includes various early dinosaur relatives as true dinosaurs, which doesn't really become a factor until the past couple of decades when the diversity of these animals began to be revealed. Thus, this time around when I subtract non-dinosaurs from totals, near-dinosaurs are mostly what is being removed, not like the old days when people had a hard time distinguishing dinosaurs from many other types of animals.

I apologize now for the increase in technical terminology; there are just too many groups to keep it simple at this point. Here are a couple of links to help sort out groups.

There is a convenient jump in the numbers of dinosaurs described going into the 1990s. The 1980s averaged 9.5 (8.5 of which were dinosaurs), while for the 1990s every year except for 1992 and 1997 was into double digits (16.2 per year, 15.4 of which were dinosaurs). From 1990 to 1994, 68 dinosaur genera are described, 61 of which are still recognized as dinosaurs. 1990 is relatively unremarkable, although it does provide Edward Drinker Cope with the first dinosaur genus to honor his name in Drinker (a bit of a puzzling choice, because I can't see that either of the more dignified choices Edwardia or Copeia are in use for animals). He also is remembered in Anatotitan, from old Anatosaurus copei and now figured to be the same as Edmontosaurus annectens. Had he simply named the skeleton that serves as the type for A. copei (given he was happy to name everything else), instead of making a point about Diclonius and Trachodon, he would have had a more enduring memorial, but I digress. 1990 also has Richardoestesia (or is it Ricardoestesia), the most durable typo in paleontology. 1991 produces a number of notables, including: Alvarezsaurus, the first genus recognized from the strange diminutive alvarezsaurs, who got through life with but a single big claw on each hand; the high-spined sauropod Amargasaurus, at the head of a forthcoming abundance of dicraeosaurids and rebbachisaurids, specialized relatives of Diplodocus and Apatosaurus that frequented southern continents; the enigmatic Protoavis; and three names that didn't make it, Seismosaurus (now thought to be a large Diplodocus), Ultrasauros (a second try for Jim Jensen's Ultrasaurus, now thought to be Supersaurus), and Rioarribasaurus, part of a controversy about the validity of Coelophysis. 1992 is full of synonyms, dubious names, and obscurities. It is rather overshadowed by 1993, which produced among others a candidate for the biggest dinosaur (Argentinosaurus), one of the earliest dinosaurs (Eoraptor), the dinosaur that showed what alvarezsaurs were all about (Mononykus), one of the stranger Triassic dinosaur mimics (Shuvosaurus), and the ever-popular giant dromaeosaur Utahraptor. 1994 is notable for the first dinosaur named from Antarctica (Cryolophosaurus) and the first ankylosaur from the famous Morrison Formation of the American west (Mymoorapelta). Marasuchus, pulled from Lagosuchus, is one of the first in a trend to introduce new names for material that had been assigned to genera based on questionably diagnostic fossils; because determining what is diagnostic is subjective, this is not universally appreciated. Alxasaurus helps to tie Therizinosaurus and segnosaurs together as theropods. Sinornithoides is the first troodont known from most of a skeleton, which is a big deal in 1994; nowadays we get one every year or two. African carnivore Afrovenator and toothed ornithomimosaur Pelecanimimus get some press, then fade.

1995 to 1999 produce 94 new genera, only one of which has definitely ceased being a dinosaur (Eucoelophysis, which is a silesaurid, aka the next best thing). 1995 is most notable for giant theropod Giganotosaurus and second banana giant theropod Saurophaganax. We also get new ceratopsids (the truly "horned" horned dinosaurs) for the first time since the 1950s, with Achelosaurus and Einiosaurus; little did we know then we'd be swimming in them in about a decade. Also of note is Chindesaurus, finally seeing print after garnering publicity since the early 1980s under the guise of a prosauropod informally called "Gertie", after that star of stage and screen. 1996 is a bit light on star power, with the exception of Sinosauropteryx, but then again Sino's a hard act to follow. At the time, the big names are then-enigmatic theropod Deltadromeus and new "megalosaur" Neovenator. In 1997, the inevitable Jurassic Park sequel appears, a terrible movie about incompetent or actively malicious people on an island full of irritable dinosaurs. Perhaps wishing to hide, paleontologists only describe 6 new genera, although among them are notable early horned dinosaur Archaeoceratops, second feathered dinosaur Protarchaeopteryx, and Unenlagia, the first clue to a radiation of bird-like long-snouted South American theropods. When they get back to work in 1998, they make up for lost time. 29 names are introduced, a record up to then (spoiler: we've met or exceeded that number every year beginning with 2005, although 2014 might break the streak). In the end, five names stand out from this year: feathery oviraptorosaur Caudipteryx, wandering Megaraptor, "aerial dromaeosaur" Rahonavis, remarkably-preserved infant theropod Scipionyx, and spinosaur Suchomimus. I also have a soft spot for armored Gastonia. There are also dueling early hadrosaurids Eolambia and Protohadros; both later turn out to not be duckbills after all. 1999 can't quite surpass all of that, but it does come up with such additions as Beipiaosaurus (the first time we get feathers on something something really wacky, in this case an early therizinosaur), Chaoyangsaurus (cameo performer in 1980s dinosaur books as the link between bone heads and horned dinosaurs), vacuum-faced Nigersaurus, early examples of dinosaurs that couldn't make up their minds about being theropods or sauropod relatives (Guaibasaurus and Saturnalia), and Sinornithosaurus, the first feathered dromaeosaur.

'Tis not quite a Gastonia, but Gargoyleosaurus is similar, and was also named in 1998; good year for ankylosaurs.
2000 to 2004 produces 124 genera (just shy of an average of 25 a year), of which 116 or 117 are recognized as dinosaurian. Most notable for 2000 is four-winged Microraptor; it turns out that leg feathers were also present on Archaeopteryx, but their impressions were prepared away from the most famous specimen. Another genus you may know of from this year is Sauroposeidon, one of the patron dinosaurs of Sauropod Vertebra Picture of the Week. 2001 clears up a few outstanding mysteries: it has the first titanosaur to come equipped with a skull and associated skeletal material (Rapetosaurus), the first noasaurid with most of a skeleton and skull (Masiakasaurus), the first recognized basal tyrannosaur (Eotyrannus), and the first nearly complete therizinosaur (Nothronychus). We also get Eshanosaurus, either the oldest therizinosaur or some kind of odd sauropodomorph, and Megapnosaurus to replace Syntarsus, which cheeses off dinosaur paleontologists because it means "big dead lizard" and was not done with the involvement of the original describer. For whatever reason, only 17 names are published in 2002, the only time the number drops below 27 from 2001 to the present. It's a pretty good year for small theropods from China, thanks in part to the controversial Feathered Dinosaurs and the Origin of Flight volume. Epidendrosaurus and Scansoriopteryx vie to become the first described scansoriopterygid, a type of tiny theropod with extremely long third fingers. A similar duel takes place between the early bird genera Jeholornis and Shenzhouraptor. The numbers reach a new high in 2003 with 32 genera (31 classic dinosaurs; many folks like "non-avian dinosaur" when they want to make clear that they're excluding birds, but this is informal and I like "classic dinosaur"). There is a mini-flood of bone heads, part of a brief flare-up between two competing systems lasting through the middle part of the decade. The near-dinosaur Silesaurus is one of the first hints of the diversity in this direction. I personally am fond of Olorotitan, a large hollow-crested hadrosaur with the good sense to preserve the crest for once (so many new lambeosaurines, so few crests!). 2003 is also of note as roughly the beginning of a stretch of several years when the prosauropods are completely overhauled and shown to include several different groups varying by how closely related they were to the true sauropods. This ends up bringing several old genera out of storage (Eucnemesaurus, Plateosauravus, etc.). The big news out of 2004 is Prenoceratops, a—no, actually, I lied, the big news is feathered tyrannosaur Dilong, followed by "sleeping" troodontid Mei (which also establishes a new record, since tied, for shortest dinosaur genus name).

It's as if every five-year period they ratchet up the pace a little more. 2005 to 2009 has 187 new names, 180 or 181 of which are recognizable as classic dinosaurs. With roughly 30 to 40 new names each year, the years start to run together (partially because of that little quirk of the legislation of nomenclature mentioned above, the one that doesn't recognize a name until there is a print version). Each year seems to have a new feathered dromie-type thing, at least one new oviraptorosaur, heaps of new titanosaurs from South America and Asia, a couple of horned dinosaurs, a couple of hadrosaurs and near-hadrosaurs, and a new near-dinosaur. By about 2006 or 2007, with the Internet firmly established and the first group of dinosaur bloggers active, every dinosaur has its day in the online sun. The most famous get multiple press releases and write-ups in online science journals, the more obscure get a blog post or two, and everyone gets a Wikipedia article within about a day, barring other circumstances. 2005 is a good year for needle-snouted South American dromaeosaurs (Buitreraptor and Neuquenraptor) and extra-large dinosaurs (theropod Tyrannotitan and titanosaur Puertasaurus). Falcarius illustrates what therizinosaurs were like before they got eccentric. There is even a taxonomic controversy in Galvesaurus versus Galveosaurus. A series of presentations at the 2005 SVP meeting set the stage for recognizing the various dinosaur mimics and near-dinosaurs, many of which had been hiding out as supposed dinosaurs known from teeth. In 2006, the dinosaurs that catch the interest of the press include Dracorex (a spiky bone head that later gets a second look as part of the first in a series of papers intending to show that many recognized genera are immature versions of other genera, which you are probably more familiar with from Triceratops versus Torosaurus), dwarf sauropod Europasaurus, crested early tyrannosaur Guanlong, tiny Juravenator (described as featherless, but actually just being shy), giant theropod Mapusaurus (known from a bone bed), and giant sauropod Turiasaurus. Also of note is the official beginning of the detonation of Iguanodon (although the book that pulls out Mantellisaurus actually starts appearing late in 2005). Today they give newly minted PhDs a coupon for one free new genus from remains formerly referred to Iguanodon. The most publicized names announced or described in 2007 include horned Albertaceratops, near-dinosaur Dromomeron, giant sauropod Futalognkosaurus (not a typo, although it feels like one), tyrannosaur-sized oviraptorosaur Gigantoraptor, burrowing "hypsilophodont" Oryctodromeus, and the sauropod vertebra that could, Xenoposeidon. 2008 is relatively slow, with "only" 29 names announced or published. The most notable are the well-aerated theropod Aerosteon and the little arboreal Epidexipteryx. The first and so far only named genus of alvarezsaurid from North America, Albertonykus, is announced in 2008 but not in physical print until 2009. The near-bird Anchiornis shows up near the end of the year; oddly, the Dinosaur Genera List makes a point of it being from 2009, not 2008. 2009 breaks the previous record with a total of 46 genera published or announced. It is a good year for the fanged tiny basal ornithischians known as heterodontosaurids, with Fruitadens from Colorado and bristly Tianyulong from China. Australia also fares well, with two new sauropods and a theropod. Other notables include toothless Jurassic theropod Limusaurus, club-tailed sauropod Spinophorosaurus, and the beginning of the Raptorex saga.

We are now down to the most recent five years, 2010 to 2014. Even with 2014 only a little over half-complete, it's another record at 204 genera announced or described per the Dinosaur Genera List, 199 of which are classic dinosaurs. Rather than create another monster paragraph and further encourage Google to consider me a link farm, here are just a few facts. 2010 is the peak year for dinosaur taxonomic activity, and it's not even close: 69 names debut this year one way or another. No other year has exceeded 46. The number slides back down in 2011 to 45. Why the spike in 2010? I can make up a couple of stories, but I have no idea how accurate they are. Both have to do with the fact that it usually takes several years to go from discovery to preparation to drafting to print. One is that the spike traces what would have been the onset of a new increase in activity, short-circuited by the financial crises beginning in the second half of 2007. The other is that reduced funding for field work, underemployment, and unemployment left researchers with time on their hands to complete manuscripts. 2012 and 2013 hold fairly steady at 36 and 40 new genera announced or in print, respectively. 2014 indeed has been slower than typical for the past decade or so, but not beyond the year to year variation; at this point the DGL has 15 listed for the year, putting us on pace for about 28, comparable to 2004 or 2008 (and of course it's quality and not quantity that counts—but it's fun to get both). Time will tell if it's just a slow year or closer to a new normal, which would be a shame given how greatly our knowledge of dinosaur diversity has increased since 1990; about half of all known dinosaur genera have been described in the years 1994 to 2014, and we tend to do a better job picking what fossils to describe, even if the splitting impulse is still prevalent.

Final random thoughts:

  • Small theropods used to be rare. Now they're coming out of the woodwork (which is a problem if you fear small theropods). For years oviraptorosaurs were only known to be represented by Oviraptor. In 2013 there were six new genera and a renamed older genus. Practically the entire diversity of dromaeosaurids and troodontids has been described since 1990, and of course all alvarezsaur genera as well.
  • If you want press attention, be a very large theropod, a feathered theropod, or a very large sauropod. It's that easy!
  • By the same tack, never be an ornithopod that's not a hadrosaur or any kind of sauropodomorph that's not a very large sauropod, unless you've got some crazy schtick like burrowing or spikes.
  • Although 1990 to the present has been a time of plenty, not every group has benefited equally. For example, new stegosaurs should be honored with parades. Although Gallimimus got to flock in Jurassic Park, derived ornithomimosaurs have been quiet as well.
  • Antarctica has finally been added to the lists, completing the continent collection. 
  • Even after all this time, we're still coming up with unsuspected large groups of dinosaurs. This era adds the neovenatorids/megaraptorans, alvarezsaurs, scansoriopterygids, and turiasaurs, among others, and titanosaurs are still very much a large black box.
  • One wonders what oddities are lurking in museum collections and under the giant tarps labeled Omeisaurus and Mamenchisaurus.
  • Use of words from local languages beyond "[Place name]+saurus" makes the nomenclature more eclectic and can even provide some interesting cultural details.
  • A few suffixes started mostly in the previous period have become de rigueur, joining "-ceratops" for horned dinosaurs and "-mimus" for ornithomimosaurs. Ankylosaurs often get "-pelta". Bone heads get "-cephale" or occasionally "-tholus", the latter a bad omen for continued validity (ex: Majungatholus, Gravitholus, Ornatotholus, Stenotholus). Tyrannosaurs get a fair number of "-tyrannus". Dromaeosaurs get "-raptor", although sometimes other theropods try to horn in. Alvarezsaurs get "-nykus". "-dromeus" is creeping up on "hypsilophodonts". For a while, it seemed like there was a mandate to put "Sino-" in front of dinosaurs from China (we have 11 of them at this point), but that fad has been replaced with the suffix "-long", meaning "dragon".
  • The one good thing to come out of a slowdown would be a breather. Show me someone who has a good working grasp of all ~200 genera described in the past five years and I'll show you a bigger nut than myself.
  • Finished it!

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