Two halves make a holotype: Two hundred years between discoveries

Abstract

The holotype specimen of Atlantochelys mortoni, a large sea turtle of Cretaceous age, consisted of only the proximal half of a humerus. Remarkably, the distal half of the same bone has now been recovered, 163 years after the holotype was first described. Besides clarification of the type locality, the size of the complete humerus suggests that this is among the largest turtles known. Circumstances of the discovery suggest that multiple periods of deposition and erosion took place at the discovery site.