The cranial osteology of the iguanid lizard Stenocercus guentheri (Squamata: Iguanidae) and its postembryonic development

Abstract

In spite of the great diversity of iguanid lizards, detailed descriptions of their osteocrania and postembryonic development are rare. Herein, the adult cranial osteology of the iguanid lizard Stenocercus guentheri and its postembryonic development are described based on cleared and double-stained and dry skeletal specimens from a single Ecuadorian population. The amphikinetic skull of S. guentheri is short and elevated, and bears teeth on the premaxilla, maxillae, and pterygoids. Mandibular teeth are present on the dentaries. Males having wider skulls than females, no other sexual dimorphism in the cranial osteology was found. Ossification of the articular from Meckel's cartilage, and growth of the parietal (ossification and investment of the frontoparietal fontanelle), are the most significant ontogenetic changes of the splanchnocranium and dermatocranium, respectively. The ossification of the cartilage separating the bones of the braincase is the most relevant postembryonic ontogenetic event of the neurocranium. The number of teeth does not vary ontogenetically and replacement teeth are present throughout postembryonic life. This study includes a list of the osteocranial characters of Stenocercus that have been used in systematic studies·, as well as a discussion of functional morphology and kinesis.