page_title: Basturs Poble bonebed
section_title: Size and age of the individuals
hierarchical_section_title: Basturs Poble bonebed / Size and age of the individuals
caption_attribution_description: English: Tibial circumference is used as a proxy for body size (von Bertalanffy's [22] model). Note that the trajectories are similar until age three years.
context_page_description: The Basturs Poble bonebed is a mega-bonebed of hadrosaur dinosaur fossils, discovered in Catalonia, Spain. Hundreds of hadrosaur fossils have been found at the site, which would have been on a large island during the Late Cretaceous when the animals preserved were alive. Despite the enormous amount of specimens, taxonomically informative material has been scarce at the site, leading to extensive debate as to its nature. The number of species present, age of the individuals present in the sample, and taxonomic identity of the remains have been the primary matters of debate. Previous considered to represent Koutalisaurus, Pararhabdodon, or multiple, perhaps dwarf species, it is currently thought that a single, indeterminate species of lambeosaurine was present at the site, and that individuals of many different ages were present.
context_section_description: An intertwined subject to the taxonomy which has been noted and studied has been the size and ontogeny (growth and development) of the individuals represented. Individuals of multiple sizes are represented in the sample, but overall they represent smaller animals than the hadrosaurs known from Asia and North America. Despite this, a small number of individuals falling into the adult size ranges of other hadrosaurs are indicated by isolated elements, such as femurs. Multiple hypotheses have been put forward to explain this: firstly, juvenile individuals may have been the dominant life stage living in the area where the bonebed was preserved, due to ecological differences over lifespan; secondly, it's possible they represent dwarfed animals dominating the environment relative to rare a larger species; lastly, it's possible the large individuals were comparative giants of a single dwarfed species, near the extreme end of individual variation in the species. The 2015 analysis of hadrosaur dentaries from the Pyrenees found two morphotypes to be present in the bonebed, so they favored the second hypothesis. 
  The more in-depth 2018 study used histological analysis in order to assess the age of different individuals, using tibiae. Of the several tibiae tested, four (between 390–450 millimetres (15–18 in) long)  were identified as juveniles between the ages of one and three based on comparisons to tissue patterns in other ornithopods, and three more were found to likely be juveniles based on similarities to the former four. The eighth (550 millimetres (22 in) long) and ninth (720 millimetres (28 in) long) were found to belong to an early adult and subadult individual respectively. A 720 millimetres (28 in) femur was found to share subadult growth features with the subadult tibia. Three tibiae (550 millimetres (22 in), 600 millimetres (24 in), and around 900 millimetres (35 in) respectively) were found to belong to adult individuals. Growth trajectory was found to be consistent between the tibiae, supporting the idea that the site represents a large variety of age stages of a single species.
caption: Growth trajectories of several tibiae, taken from a 2018 study of the taxonomy and ontogeny of the specimens
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