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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.

The Cenozoic Pelagornithidae, or pseudotoothed birds, are characterized by unique bony projections along the cutting edges of the beak. These birds were previously known from late Paleocene to Pliocene fossil sites and some species reached wingspans up to 6.4 m. Here we describe a partial skeleton of a small‐sized pelagornithid from the early Paleocene of New Zealand. Protodontopteryx ruthae gen. et sp. nov. is the oldest record of the clade, the smallest known species, and the first pre‐Eocene pelagornithid from the Southern Hemisphere. The skull of the new species exhibits the characteristic pelagornithid morphology, but the postcranial skeleton distinctly differs from other pelagornithids, and various plesiomorphic features indicate that it is the earliest‐diverging representative of the Pelagornithidae. The much stouter humerus suggests that the new species was less adapted to sustained soaring than previously known pelagornithids. Pseudoteeth therefore evolved before pelagornithids became highly specialized gliders. Unlike the giant Neogene pelagornithid species, which presumably were skimmers, early Paleocene pelagornithids are likely to have targeted selected prey items and may have been predominantly piscivorous. The new species furthermore suggests that pelagornithids evolved in the Southern Hemisphere and documents a very early radiation of neornithine seabirds, which may have been triggered by changes in marine ecosystems around the K–Pg boundary.

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The North American endemic genus Penstemon (Mitchell) has a recent geologic origin of ca. 3.6 million years ago (MYA) during the Pliocene/Pleistocene transition and has undergone a rapid adaptive evolutionary radiation with ca. 285 species of perennial forbs and sub-shrubs. Penstemon is divided into six subgenera occupying all North American habitats including the Arctic tundra, Central American tropical forests, alpine meadows, arid deserts, and temperate grasslands. Due to the rapid rate of diversification and speciation, previous phylogenetic studies using individual and concatenated chloroplast sequences have failed to resolve many polytomic clades. We investigated the efficacy of utilizing the plastid genomes (plastomes) of 29 species in the Lamiales order, including five newly sequenced Penstemon plastomes, for analyzing phylogenetic relationships and resolving problematic clades. We compared whole-plastome based phylogenies to phylogenies based on individual gene sequences (matK, ndhF, psaA, psbA, rbcL, rpoC2, and rps2) and concatenated sequences. We also We found that our whole-plastome based phylogeny had higher nodal support than all other phylogenies, which suggests that it provides greater accuracy in describing the hierarchal relationships among taxa as compared to other methods. We found that the genus Penstemon forms a monophyletic clade sister to, but separate from, the Old World taxa of the Plantaginaceae family included in our study. Our whole-plastome based phylogeny also supports the rearrangement of the Scrophulariaceae family and improves resolution of major clades and genera of the Lamiales.