STL Science Center

STL Science Center

26 November 2011

The Many Heads of the Lambeosaurus

©Nobu Tamura
Lambeosaurus is a genus consisting of four recognized species. These four species possess four different crests. The crests are similar, but contain enough differences that the species can be told apart by looking at the different crests as well. In part, these could and may very well be male, female, and age differences that make some of the crests so radically different and, in certain cases, this has been accepted as the standing fact of the matter.

These crests are mainly quite distinctive from other hadrosaurs. However, two of the species, L. laticaudus and L. magnicristatus, had head crests strikingly similar to the one sported by Corythosaurus. The difference in those species being the size of the crest (L. magnicristatus) and an additional spur of bone (L. laticaudus) in the Lambeosaurus crest which protrudes backwards at the bottom of the crest. Other than this one anomaly the crests of Lambeosaurus are quite unique. A Corythosaurus, for example, had forked nasal processes while the Lambeosaurus has vertically stacked nasal processes in its crest. This difference between vertical and forking nasal processes in the crest is oftentimes the only way to tell the juvenile skeletons of the two genera apart as the crests have been shown to grow into their distinctive shapes as the dinosaurs aged.

For the most part the crests are rectangular in shape with varying sizes of bone spurs jutting back over the neck of the animals. These crests, as stated before, have vertically stacked nasal processes inside of them rather than the forked passageways that are typically found in many hadrosaur crests. The sizes and other differences in crests in what appear to be identical species has led to some speculation on differences between male and female and has certainly led to the fairly universally held belief that the animals had to grow into their crests, which only makes sense really when one thinks of how little space there would be in an egg for that crest. The growth of the crest may have been fast or it may have been slow, there's no telling at this point for certain, though theories do abound.

or no fingers?

The crests, like other hadrosaurs, were almost certainly used for vocalization. This vocalization could of course be warnings, greeting, threats, and perhaps even casual conversation (I tend to hold a "fantastical" idealism for the idea that animals converse the same ways you and I do just in their own form of language). Another important aspect of life that this vocalization more than likely held was that of identification purposes. Beyond vocalizing the crests themselves in coloration and size were probably good indicators of individuality as well as the likelihood that the ones with the healthiest and prettiest looking crests were ready and willing as well as strong mates.

One healthy and eligible bachelor, coming up.

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