The oldest modern spearer-type mantis shrimp dactyli - fossils from the Maastrichtian (Cretaceous) of the Peedee Formation, North Carolina, USA

摘要

We describe here new fragmentary remains of mantis shrimps (Stomatopoda) from the Late Cretaceous of Rocky Point, Pender County, North Carolina, USA. The specimens represent two forms of isolated dactyli of the large raptorial appendages. Type 1 is a typical spearer-type form with median spines (9 or 10). Each spine (besides the terminal one) is flanked by a distinct serration. This type cannot be ascribed to a specific ingroup of Stomatopoda easily. It resembles certain species of the modern stomatopod ingroups Lysiosquilloidae and Squillidae. Type 2 is less completely known and differs from type 1 by a lack of spines and a distinct shallow concavity on the lateral edge of the dactylus. An ascription is more difficu it could be a representative of the modern stomatopod ingroups Hemisquillidae or Pseudosquillidae, but could also be a representative of a non-verunipeltatan group (i.e., branching off before the monophyletic group including all modern forms of stomatopods), e.g., of Sculdidae, or a larval form of a verunipeltatan species. Type 1 represents our first direct evidence of a spearer-type mantis shrimp from Cretaceous sediments, with this it is the oldest modern spearer-type mantis shrimp. These findings demonstrate the importance also of fragmentary material for enlightening the evolutionary history of Stomatopoda.