Study reveals dinosaurs had ‘belly buttons’
A 130-million-year-old early-branching ceratopsian dinosaur, has the earliest preserved umbilicus in a fossil amniote
Psittacosaurus, a 130-million-year-old early-branching ceratopsian dinosaur, has the earliest preserved umbilicus in a fossil amniote. A recent study shows the umbilicus as an elongate midline structure demarcated by a row of paired scales on the abdomen under laser-stimulated fluorescence (LSF). As shown in the image below:
A nearly complete individual of the early-branching ceratopsian Psittacosaurus from the Early Cretaceous Jehol Group of Liaoning Province, China (housed at the Senckenberg Research Institute and Natural History Museum Frankfurt, Frankfurt, Germany) is an example of the remarkable insights that well-preserved dinosaur soft tissues can reveal. In a recent study, researchers document the anatomy of the umbilical scar of a given specimen, which is newly identified based on the firsthand study under laser stimulated fluorescence (LSF) imaging and a survey of umbilical scarring in extant lepidosaurs and archosaurs.
The individual’s relatively late development stage (near sexual maturity) suggests that the umbilicus was most likely kept throughout life.