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In one of the little-known and obscure cases of hidden priority in paleontology, the first name given to fossil material now universally attributed to the famous Canadian hadrosaur Lambeosaurus lambei was actually Didanodon altidens. (Click here for the complete story).
Didanodon was given its name in two parts, by different scientists in the same journal volume. Lawrence Lambe (the paleontologist who would later be honored in the name Lambeosaurus lambei) and Henry Fairfield Osborne co-edited a two-paper 1902 volume of the journal Contributions to Canadian Paleontology (part II). In his contribution, Lambe named and described a number of dinosaur species from what is now called the Dinosaur Park Formation of Alberta. One of these was a new species of hadrosaur which he classified in the genus Trachodon, as Trachodon altidens, based on a distinctive lower jaw. Lambe never considered T. altidens to be anything but a new species of Trachodon. Osborne, on the other hand, suggested in his own section of the same volume that altidens could represent a new genus, for which he proposed Didanodon. The Didanodon jaw is now usually recognized as belonging to a subadult "Lambeosaurus", but as it is the older name, it has priority unless the ICZN is petitioned to supress it.
The Didanodon altidens above is based on the specimen of a large male, ROM 794 (formerly numbered ROM 5131), shown bellowing and extending a throat sac or dewlap based on unpublished specimens of saurolophine hadrosaurids. The tree is based on the modern genus Dacrydium, a podocarp similar to the types abundant in the Dinosaur Park Formation. The restoration below depicts a juvenile D. altidens, based on the specimen AMNH 5340, previously referred to as the junior synonym Procheneosaurus praeceps. It is depicted feeding on another DPF plant, Artocarpus, similar to modern breadfruit.
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