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A skull of a new pelecaniform bird is described from the Middle Eocene of Messel (Germany). Masillastega rectirostris gen. et sp. nov. is tentatively referred to the Sulidae (boobies and gannets). If this assignment is correct, the new taxon would represent the earliest fossil record of the family, preceding Sula ronzoni Milne−Edwards, 1867 from the lowermost Oligocene of France by about 15 million years. Masillastega rectirostris most distinctly differs from extant Sulidae in the proportionally longer beak which indicates that the Eocene taxon was not adapted to plunge−diving. Contrary to extant Sulidae, which are exclusively marine birds, Masillastega rectirostris was found in a freshwater deposit. It is the first pelecaniform bird known from Messel and one of the few large birds discovered at this site.
Boobies and gannets (family Sulidae) are the most specialized plunge divers among seabirds. Their fossil record along the Pacific coast of South America extends to the early Middle Miocene. Here we describe three new species of sulids: Sula brandi sp. nov., Sula figueroae sp. nov., and Ramphastosula aguirrei sp. nov., from the early Late Miocene of the Pisco Formation (Peru). Two of them are relatives of the living genus Sula, which represents medium and large-sized boobies. A new species of the extinct genus Ramphastosula is also described, adding to the discussion of possible alternative feeding strategies among sulids. The fossil record suggests that sympatric sulids exhibit different body sizes at least since the Oligocene epoch, a strategy related with resource partitioning. Furthermore, we find current analysis and knowledge of the fossil record unsuitable to evaluate properly seabird diversity changes through time.
The fossil darter Macranhinga paranensis (Aves: Pelecaniformes) from the late Miocene of Argentina is the largest of all known extinct or living Anhingidae. Its body mass is estimated at a mean value of 5.4 kg by using a scaling model derived from the logarithmic relationship between measurements of the least shaft circumference of the femur/tibiotarsus and body masses. Predictions of body mass, as well as the analysis of anatomical evidence, are used to infer that Macranhinga paranensis would have probably had a powered flapping flight and an aquatic locomotion similar to that of cormorants. The morphology of the pelvis and the hind-limb would have allowed Macranhinga paranensis to catch fishes by means of pursuit-diving rather than stalking them in an anhinga-like manner. As determined by adaptations mainly of tarsometatarsal morphology, the species had well developed perching and climbing abilities.
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