Cretaceous Hitchhikers: a Possible Phoretic Association between a Pseudoscorpion and Bird in Burmese Amber

Phoresy represents a non-parasitic association between animals of different taxa related to transportation. Members of several pseudoscorpion families are phoretic. In pseudoscorpions, phoresy may or may not be associated with their predatory behavior, enabling dispersal over larger distances than they could manage with their own short legs. This provides a wide distribution, and a potential food supply. Recent discoveries of mid-Cretaceous amber from Myanmar have provided new insights on the early postnatal development of primitive birds and the integumentary structures of dinosaurs. Over the last three years, Xing et al. have described two precocial Enantiornithes wings, a partial hatchling, and a partial juvenile, as well as a feathered coelurosaurian tail with primitive plumage from mid-Cretaceous Burmese amber. These new findings associate well-preserved feathers with identifiable skeletal material for the first time. In 2016–2017, the first author observed several pseudoscorpion specimens in Burmese amber with chelae clamped on to parts of feathers or preserved near feathers. These specimens indicate a possible ancient phoretic association between pseudoscorpions and birds. Herein, we describe one of the first of these specimens to enter a museum collection.