Anyone who frequents the Pittsburgh area is familiar with ‘Pittsburghese,’ the regional dialect given full voice in what was once voted America’s ugliest accent (a fact that does not diminish our pride for it). One of my personal favorite Pittsburghese words is “nebby,” which translates to “nosy” for any non-local readers. “Nebby” can be used in a variety of contexts: the distant relative asking prying questions about your love life at Thanksgiving dinner is nebby, the pet cat trying to crawl under the bathroom door to see what you’re doing is nebby, and even the statue of Carnegie Museum of Natural History mascot Dippy the Diplodocus, silently judging your driving on Forbes Avenue, is nebby. We can assume other dinosaurs were nebby too, since so many had huge noses to stick into things. One of the biggest noses in the fossil record belongs to Gryposaurus notabilis, the star of this edition of Mesozoic Monthly.
Gryposaurus belongs to a group of dinosaurs called hadrosaurs, which are commonly referred to as duck-billed dinosaurs. Hadrosaurs were herbivores that got their nickname from the flat, toothless, somewhat duck-like beaks at the tips of their jaws. These beaks were used to bite through tough vegetation so that it could be ground up by the numerous teeth embedded in the rear half of the jaws. There are two main groups of hadrosaurs, both of which are featured in CMNH’s Dinosaurs in Their Time exhibition. Probably the more famous group is the Lambeosaurinae, known for their distinctive head crests that housed extra-long nasal passages. Virtually everyone can recognize the incredible backward-curving crest of Parasaurolophus (featured multiple times in the Jurassic Park franchise), and visitors to CMNH will also know the helmet-like crest of Corythosaurus. The second group is the Saurolophinae (traditionally known as the Hadrosaurinae), which typically lack bony crests. You can find a simulated carcass of the saurolophine Edmontosaurus (lovingly known to those of us in CMNH’s Section of Vertebrate Paleontology as “Dead Ed”) between the two imposing Tyrannosaurus skeletons in Dinosaurs in Their Time.
As a crestless hadrosaur, Gryposaurus was a saurolophine. Despite its lack of crest, its skull still had pizzazz: its nasal bone arched dramatically, giving the impression of a ‘Roman nose’ (which is very noticeable if you compare the skulls of Edmontosaurus and Gryposaurus in the image above). The name Gryposaurus notabilis means “notable hooked-nose lizard” in homage to this feature. G. notabilis is the type species of Gryposaurus; type species are typically the first ones to be named in a genus, and therefore become the reference to which all new specimens that may belong to that genus are compared. The other species (such as G. monumentensis, shown in the photo montage above) are similar enough to the type species that they can be referred to the genus Gryposaurus, but they differ in too many ways to be assigned to G. notabilis itself.
Occasionally, paleontologists will revisit a fossil species or genus and decide that it is either too similar to another to justify its own name or that certain specimens are too different to be grouped under the same name. Kritosaurus, another saurolophine with a ‘Roman nose,’ has fallen victim to both of these circumstances. It was originally considered its own genus, but was subsequently revisited by paleontologists who decided that it was so similar to Gryposaurus that the two genera were lumped together under the name Gryposaurus (when combining taxonomic groups, the first name that was published is the one that gets used). However, later paleontologists reviewed the evidence again and split a single species of Kritosaurus back out of Gryposaurus. The famous sauropod (giant long-necked herbivorous dinosaur) Brontosaurus underwent a similar series of changes over the years: originally, it and Apatosaurus were considered different animals, but after a review they were lumped together under Apatosaurus. Recently, the two were split apart again and the name Brontosaurus was revived (to the delight of fans of that name around the world).
It is not uncommon in paleontology for species to be lumped or split based on new or revisited evidence. When you consider that the decision to name new fossil species is often based on fragmentary, highly incomplete skeletons, you can see why it might be difficult to get things right the first time! These changes sometimes give people the impression that paleontologists “can’t make up their minds” or “contradict themselves,” but we must remember two things. First, that science is meant to change based on new evidence. Second, there have been thousands of paleontologists over the course of history, and every one of them is an individual person who can draw their own conclusions based on the same evidence. Although the resulting changes can disappoint fans of a specific animal or hypothesis, revision is normal and beneficial for the field as a whole. Scientists are supposed to be nebby – it’s how we make new discoveries!
Lindsay Kastroll is a volunteer and paleontology student working in the Section of Vertebrate Paleontology at Carnegie Museum of Natural History. Museum staff, volunteers, and interns are encouraged to blog about their unique experiences and knowledge gained from working at the museum.