At the root of the early penguin neck: a study of the only two cervicodorsal spines recovered from the Eocene of Antarctica

The spinal column of early Antarctic penguins is poorly known, mainly due to the scarcity of articulated vertebrae in the fossil record. One of the most interesting segments of this part of the skeleton is the transitional series located at the root of the neck. Here, two such cervicodorsal series, comprising reinterpreted known material and a new specimen from the Eocene of Seymour Island (Antarctic Peninsula), were investigated and contrasted with those of modern penguins and some fossil bones. The new specimen is smaller than the counterpart elements in recent king penguins, whereas the second series belonged to a large-bodied penguin from the genus Palaeeudyptes. It had been assigned by earlier researchers to P. gunnari (a species of “giant” penguins) and a Bayesian analysis—a Bayes factor approach based on size of an associated tarsometatarsus—strongly supported such an assignment. Morphological and functional studies revealed that mobility within the aforementioned segment probably did not differ substantially between extant and studied fossil penguins. There were, however, intriguing morphological differences between the smaller fossil specimen and the comparative material related to the condition of the lateral excavation in the first cervicodorsal vertebra and the extremely small size of the intervertebral foramen located just prior to the first “true” thoracic vertebra. The former feature could have resulted from discrepancy in severity of external pneumatization. Both fossils provided valuable insights into the morphology and functioning of the axial skeleton in early penguins

The first fossil owls (Aves: Strigiformes) from the Paleogene of Asia and a review of the fossil record of Strigiformes

e fossil record of owls (Strigiformes) is one of the most extensive among the neornithine birds, yet at the same time largely restricted geographically to Europe and North America. Various fossil owls are known from the Paleocene (ca. 60 Ma) to Recent. Here we present the first taxonomic description of new species of Paleogene owls from Asia, two new taxa from the Eocene and Oligocene of Mongolia. The anatomy of Heterostrix tatsinensis gen. et sp. nov., represented by a complete Early Oligocene tarsometatarsus, sheds light on the evolution of perching adaptations in these birds and expands the family diversity of this order. Eostrix tsaganica sp. nov. from the Early Eocene extend the known range of the protostrigid genus Eostrix into Asia (the other known species come from Europe and western North America). The paper also provides a review of the fossil record of owls, which gives evidence for the Late Cretaceous evolutionary radiation of this lineage. In spite of the absence of specimens from the Mesozoic, fossil owl collector-effort (since the 1860s) suggests that, in contrast to many other avian clades, the fossil record of these birds is complete enough for biological signal to be extracted