New Applications for Constrained Ordination: Reconstructing Feeding Behaviors in Fossil Remingtonocetinae (Cetacea: Mammalia)

Abstract

During the Eocene epoch, archaic cetaceans made the land-to-sea transition, giving rise to modem whales, dolphins, and porpoises. During this transition, the feeding apparatus of fossil remingtonocetines displayed morphologies that are distinct from other cetaceans, confounding straightforward interpretations of their feeding behaviors. This study utilized a novel combined ordination of morphology and feeding strategy, while accounting for phylogeny, in a sample of2 remingtonocetines and 18 extant cetartiodactylans, to assess the morphological signal of feeding behaviors. Results showed that differences between prey acquisition in extant taxa were driven by a suite of mandibular characters and width of the palatal arch, providing a behaviorally constrained morphospace. Remingtonocetinae clustered closest to the snap-feeding river dolphins, suggesting that they too were snap feeders. The methods presented here represent a novel application for constrained ordination that links morphology with performance, and may be widely applied in the fossil record.