dinosaurs size and sex
The Bernissart discoveries are notable for comprising two types of Iguanodon. Animatronic dinosaur One (Iguanodon bernissartensis – quite literally ‘the Iguanodon that lived in Bernissart’) is large and robustly built, and represented by more than 35 skeletons; the other (Iguanodon atherjieldensis, formerly called I. mantelli – literally Mantell’s Iguanodon’) is smaller and more delicately built (approximately 6 metres in length) and represented by only two skeletons.
These specimens were regarded as distinct species until they were reassessed in the 1920s, by Francis Baron Nopcsa, a nobleman from Transylvania and a palaeontologist. The discovery of two quite similar types of dinosaur that evidently lived in the same place, at the same time, prompted him to ask the simple and yet obvious question: are they males and females of the same species? Nopcsa attempted to determine sexual differences in a number of fossil species. Walking dinosaur costume In the case of the Iguanodon from Bernissart he concluded that the smaller and rarer species was the male and the larger and more numerous species was the female. He observed, perfectly reasonably, that it is often the case that female reptiles are larger than males. The biological reason for this is that females often have to grow large numbers of thick-shelled eggs; these drain considerable resources from the body before they are laid.