Oldest preserved umbilical scar reveals dinosaurs had 'belly buttons'.

ABSTRACT:

Background

In egg-laying amniotes, the developing embryo is tethered to a number of the extraembryonic membranes including the yolk sac and allantois that deliver oxygen and nutrients and remove metabolic waste products throughout embryonic development. Prior to, or soon after hatching, these membranes detach from the animal leaving a temporary or permanent umbilical scar (umbilicus) equivalent to the navel or 'belly button' in some placental mammals, including humans. Although ubiquitous in modern mammals and reptiles (including birds), at least early in their ontogeny, the umbilicus has not been identified in any pre-Cenozoic amniote.

Results

We report the oldest preserved umbilicus in a fossil amniote from a ~130-million-year-old early-branching ceratopsian dinosaur, Psit

SUBMITTER: Bell PR 

PROVIDER: S-EPMC9172161 | biostudies-literature | 2022 Jun

REPOSITORIES: biostudies-literature