Integumentary impressions on hadrosaurid specimens from the Upper Cretaceous (upper Campanian) Dinosaur Park Formation, Alberta, Canada: implications for integument patterns and hand morphology

Abstract

ABSTRACT Fossilized dinosaur skin provides information about scale morphology, scale patterns, and soft-tissue structures that are otherwise unknown from skeletal elements. Here, we describe three indeterminate hadrosaurid specimens with extensive skin impressions from the Upper Cretaceous (upper Campanian) Dinosaur Park Formation of Alberta that shed light on the diversity of integument patterns and manus soft-tissue morphology within Hadrosauridae. Skin impressions on the anterior torso of a juvenile hadrosaurid reveal a scale pattern of alternating vertical bands of small polygonal and pebbly basement scales. If these scale stripes corresponded to color stripes in life then this hadrosaur species may have preferred open habitats, as modern animals with vertical color stripes often live in such habitats. Integument preserved on the manus of two other specimens show that digits II–III–IV were of subequal length and united in a common fleshy structure, as opposed to those previously described from exceptionally preserved Edmontosaurus annectens mummies, in which digit II is apparently shorter and independent from digits III–IV. As such, the diversity of soft-tissue morphology in the manus within Hadrosauridae may be greater than previously realized.