A new Eocene species of presbyornithid (Aves, Anseriformes) from Murgon, Australia

The taxa found in an Eocene deposit, near Murgon, Queensland, the only pre-Oligocene Paleogene site recording a terrestrial vertebrate fauna from Australia, are very significant for the insight they provide concerning the evolution of the Australian biota. Here we resolve the identity of fossils previously referred to the Graculavidae, waterbirds of then unresolved affinities. We taxonomically describe the first bird to be named from this fauna, Murgonornis archeri gen. et sp. nov., Presbyornithidae. Our findings reveal that presbyornithids were widespread globally in the earliest Eocene, and that this family had a history on Australia from at least 55 Ma until ca. 24 Ma, when they disappear from the fossil record

Tempo and Pattern of Avian Brain Size Evolution

Relative brain sizes in birds can rival those of primates, but large-scale patterns and drivers of avian brain evolution remain elusive. Here, we explore the evolution of the fundamental brain-body scaling relationship across the origin and evolution of birds. Using a comprehensive dataset sampling> 2,000 modern birds, fossil birds, and theropod dinosaurs, we infer patterns of brain-body co-variation in deep time. Our study confirms that no significant increase in relative brain size accompanied the trend toward miniaturization or evolution of flight during the theropod-bird transition. Critically, however, theropods and basal birds show weaker integration between brain size and body size, allowing for rapid changes in the brain-body relationship that set the stage for dramatic shifts in early crown birds. We infer that major shifts occurred rapidly in the aftermath of the Cretaceous-Paleogene mass extinction within Neoaves, in which multiple clades achieved higher relative brain sizes because of a reduction in body size. Parrots and corvids achieved the largest brains observed in birds via markedly different patterns. Parrots primarily reduced their body size, whereas corvids increased body and brain size simultaneously (with rates of brain size evolution outpacing rates of body size evolution). Collectively, these patterns suggest that an early adaptive radiation in brain size laid the foundation for subsequent selection and stabilization

New skeleton from the early Oligocene of Germany indicates a stem-group position of diomedeoidid birds

We report a new specimen of the extinct procellariiform species Diomedeoides brodkorbi (Aves, Diomedeoididae) from the early Oligocene (Rupelian) of Rheinweiler in southwestern Germany. The well−preserved partial skeleton allows the recognition and reassessment of new osteological details that bear on the phylogenetic affinities of diomedeoidids. The presence on the coracoid of a deeply excavated, cup−like facies articularis for the scapula suggests a stem group position of the Diomedeoididae within Procellariiformes, because this trait also occurs in stem−group representatives of several avian groups, as well as in Mesozoic non−neornithine birds, and is a plesiomorphic character. We hypothesize that the similarities of Diomedeoides to extant southern storm−petrels (Oceanitinae), such as the long mandibular symphysis, the small processus supracondylaris dorsalis and the long legs are plesiomorphic for Procellariiformes

Narrow-beaked trogons from the early Eocene London Clay of Walton-on-the-Naze (Essex, UK)

We describe multiple partial skeletons of a new trogon species from the early Eocene London Clay of Walton-on-the-Naze (Essex, UK), which are among the oldest fossils of the Trogoniformes. , gen. et sp. nov. has a much narrower and more gracile beak than extant trogons, which denotes different ecological attributes of the fossil species. already had the heterodactyl foot characterising extant trogons, even though the trochlea for the second toe is smaller than in crown group Trogoniformes. Differences to extant trogons in the wing and pectoral girdle elements suggest that was less adapted to short-term hovering, which may indicate different foraging techniques. We also report a partial tarsometatarsus from the early Miocene of France that is likely to belong to , a species previously only known from humeri. is the earliest modern-type trogon, and we show that the newly identified tarsometatarsus does not support the proposed referral of this species to the African taxon . We identify skeletal features that suggest a sister group relationship between and all other crown group Trogoniformes, but the exact affinities of remain poorly resolved. ( ). Wir beschreiben mehrere Teilskelette einer neuen Trogon-Art aus dem frühen Eozän des London Clays von Walton-on-the-Naze (Essex, UK), die zu den ältesten Fossilnachweisen der Trogoniformes zählen. , gen. et sp. nov. hat einen deutlich schmaleren und grazileren Schnabel als rezente Trogone, was darauf hindeutet, dass sich die fossile Art von ihren heutigen Verwandten in ökologischen Eigenschaften unterschied. hatte bereits den heterodactylen Fuß, der für heutige Trogone charakteristisch ist, obwohl die Trochlea für die zweite Zehe kleiner ist als bei Kronengruppen-Trogoniformes. Unterschiede zu heutigen Trogoniformes in den Flügel- und Schultergürtelelementen legen nahe, dass weniger an kurzzeitigen Rüttelflug angepasst war, was auf unterschiedliche Nahrungserwerbstechniken hinweist. Wir beschreiben auch einen unvollständigen Tarsometatarsus aus dem frühen Miozän Frankreichs, der wahrscheinlich zu gehört, einer Art, die zuvor nur von Humeri bekannt war. ist der früheste „moderne“ Trogon, und der neu identifizierte Tarsometatarsus stützt nicht die vor einiger Zeit vorgeschlagene Zuordnung dieser Art zum afrikanischen Taxon . Wir diskutieren Skelettmerkmale, die eine Schwestergruppenbeziehung zwischen und allen anderen Kronengruppen-Trogoniformes unterstützen, aber die genauen Verwandtschaftsbeziehungen von bleiben ungeklärt

A Paleocene penguin from New Zealand substantiates multiple origins of gigantism in fossil Sphenisciformes

The oldest known penguin fossils date to approximately 62 million years ago. Here, Mayr et al. describe Kumimanu biceae, an extinct penguin from approximately 55–60 million years ago, which represents an independent origin of giant size soon after the evolutionary transition from flight to diving

A swan-sized fossil anatid (Aves: Anatidae) from the early Miocene St Bathans Fauna of New Zealand

Worthy, Trevor H., Scofield, R. Paul, Hand, Suzanne J., De Pietri, Vanesa L., Archer, Michael (2022): A swan-sized fossil anatid (Aves: Anatidae) from the early Miocene St Bathans Fauna of New Zealand. Zootaxa 5168 (1): 39-50, DOI: https://doi.org/10.11646/zootaxa.5168.1.

First Complete Wing of a Stem Group Sphenisciform from the Paleocene of New Zealand Sheds Light on the Evolution of the Penguin Flipper

We describe a partial skeleton of a stem group penguin from the Waipara Greensand in New Zealand, which is tentatively assigned to Muriwaimanu tuatahi. The fossil includes the first complete wing of a Paleocene penguin and informs on previously unknown features of the mandible and tibiotarsus of small-sized Sphenisciformes from the Waipara Greensand. The wing is distinguished by important features from that of all geologically younger Sphenisciformes and documents an early stage in the evolution of wing-propelled diving in penguins. In particular, the wing of the new fossil exhibits a well-developed alular phalanx and the distal phalanges are not flattened. Because the wing phalanges resemble those of volant birds, we consider it likely that the wing feathers remained differentiated into functional categories and were not short and scale-like as they are in extant penguins. Even though the flippers of geologically younger penguins may favor survival in extremely cold climates, they are likely to have been shaped by hydrodynamic demands. Possible selective drivers include a diminished importance of the hindlimbs in subaquatic propulsion, new foraging strategies (the caudal end of the mandible of the new fossil distinctly differs from that of extant penguins), or increased predation by marine mammals