First evidence of globuli ossei in bird (Aves, Spheniciformes). Implications on paleohistology and bird behaviour

Globuli ossei are subspherical structures of endochondral origin that are inserted in the hypertrophic cartilage of long bones, and are related to paedomorphic phenomena. These structures are here described for the first time in Aves, concretely in a postcranial bone of an extinct Spheniciformes from Antarctica (Delphinornis arctowskii). Although it is difficult to infer the significance of the presence of these structures, they appear not to be related to adaptations to aquatic life or depend on the small size or ontogenetic stage of the specimen. A pathological origin for these structures lacks evidence sustaining this hypothesis. The data provided in this contribution reveals that the presence of globuli ossei in vertebrate long bones is not always linked with adaptations to aquatic life and/or paedomorphic processes.