STL Science Center

STL Science Center

30 March 2016

Crest Conundrum

Adapted from Nobu Tamura
Crests (and sails) are perplexing in a vast array of taxa. In dinosaurs the existence of any kind of crest divides and destroys goodwill toward other scientists in some cricles but thankfully that is not a typically common occurrence. Crests tend to be a haven for so-called "arm-waving science" in which people speculate (often wildly) about scientific conclusions that require a significant suspension of disbelief with rather little evidence to infer from. In discussing the crests of Lambeosaurus, speculation and ridicule of speculators should be kept to a minimum, and will be done here. Bear in mind, though, that many strange assertions have been made regarding these crests, their functions, and why there are different shapes represented in the genus. Shape variation can be explained by differences in species within the genus as well as ontogeny; shapes of crests have been shown to change in individuals over the course of their lives in many different animals, living and fossil. Variations in shape that cannot be explained by ontogeny or species differences entirely may be explained by many other purposes. These include dimorphism where males and females exhibit different shapes and styles of crest. These could be indicative of vocal differences between the sexes as well as differences in visual signalling that requires the use of the crest. These purposes are all often cited as fact and are commonly accepted as such in documentaries and other popular outlets. In general, the shape of the crests is vaguely similar across species and ontogeny within lambeosaurines, including Lambeosaurus. The general shape includes  high vaulted anterior/rostral portion of the crest and, later in ontogeny it appears, that there is a longer posterior/caudal part of the crest that extends over the back portion of the skull. A few recreations and illustrations have made the back end of the crest appear to be flush with the posterior portion of the skull. Most of the ontogeny series abandons this flush look after juveniles grew into adulthood

No comments:

Post a Comment