As we noted at the beginning of the year, we decided we were going to do some dinosaur baraminology in 2020. This month, we decided to look at the Hadrosaurs. As always, we will emphasize upfront that we do not have access to the fossils involved, nor do we have access to all the papers involved. As such, these studies should be considered highly preliminary. They are meant more to give a general framework for dinosaur baraminology than as a definite answer for dinosaur baramins. With that in mind, lets have a look at the Hadrosaurs.
Hadrosaurs, better known in common parlance as the duckbilled dinosaurs, are characterized in the public mind by showy crests atop their head. However, most actually lacked the showiest crests and some had no crests at all, at least that was preserved in the fossil record. They were medium to large dinosaurs, with some rivaling the larger Tyranosaurids in size. Thought to walk alternatively on four or two legs, Hadrosaurs are some of the most well-known dinosaurs at all stages of life. Eggs and hatchlings are much more common than in most other dinosaurs, allowing scientists to piece together a general idea of what the Hadrosaur lifecycle was like. Hadrosaur skin impressions have been found. They are uniformly scaly and reptilian, rather than feathered as evolutionists claim some dinosaurs were.
While there are some taxonomic controversies surrounding the Hadrosaurs (as there almost always are), as best I can tell, there are around fifty-nine species currently considered valid. A couple of these are considered either dubious or synonymous with other species. They fall into four roughly distinct groups, based mostly on head ornamentation (which is how Hadrosaurs tend to be classified in modern systematics). The largest group is the one with minimal head ornamentation, consisting of fourteen different genera. The genera included in this grouping are: Aquilarhinus, Lapampasaurus, Willinakaqe, Prosaurolophus, Brachylophosaurus, Maiasaura, Shantungosaurus, Eotrachodon, Acristavus, Bactrosaurus, Claosaurus, Nanyangosaurus, Tethyshadros, and the family and clade namesake Hadrosaurus. The second group is small and contains some of the more ornate head crests among the Hadrosaurs, Olorotitan, Corythosaurus, and Saurolophus. The third group is even smaller, consisting of just two taxa, Parasaurolophus and Charonosaurus. Given the similarities between the two, it is possible they are the same genus. The fourth group is the second largest group including Hypacrosaurus, Latirhinus, Edmontosaurus, Amurosaurus, Gryposaurus, and Lambeosaurus. As usual, there is a group of fragmentary taxa. In this case, it constitutes a clear majority of taxa, with thirty-six genera in this group.
As usual, the classification has been heavily influenced by evolutionary ideas. There are a proliferation of fragmentary taxa. Fragmentary taxa make up a clear majority of the Hadrosaurs, with some consisting of mere skull fragments. Further, since the evolutionists hypothesize that the Hadrosaurs share ancestry with the Iguanadon dinosaurs, some taxa, such as Nanyangosaurus appear to have been dropped into the Hadrosauromopha clade to facilitate such a relationship. Superficially, these species do resemble the Hadrosaurs but, from pictures, it is difficult to distinguish the two if the characteristic traits of the groups are absent from the skeleton. Thus Nanyangosaurus is included in this analysis, though it could equally be considered with the iguanodons.
The groups within the Hadrosaur clade are interesting to consider. The easy way to resolve them would be to either consider them all the same or all separate. However, this seems overly simplistic. Grouping the Hadrosaur and Edmontosaur groups could be seen as reasonable as the structures on their skulls are either absent or minimal in most cases. It is the larger, more flamboyant structures that characterize the Corynthosaur and Parasaurolophus groups that are harder to justify. While the argument could be made that the Corynthosaur group could have developed from an original created Hadrosaur which resembled the Edmontosaur group, Parasaurolophus seems much less clear. Ultimately, we have elected to group the Edmontosaurus’ and Corynthosaurs in one group and place the Hadrosaurs and Parasaurolophus’ in their own groups. The specialized head structures of Parasaurolophus really seem to set them apart from the rest of the Hadrosaurs. Putting the Hadrosaur group with the Edmontosaurus’ and Corynthosaurs could work as well and is something we strongly considered but elected not to, on a very preliminary basis. We would, of course, be open to changing this as it is preliminary at best.
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