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Ayla Tierney Isabelle Deregnaucourt John M. Anderson Paul Tierney Torsten Wappler 《Alcheringa: An Australasian Journal of Paleontology》2020,44(2):279-285
AbstractTwo new, subcomplete forewings belonging to the ‘triassolestid assemblage’, a group of Triassic stem-relatives of dragon- and damselflies (Odonata), are described. One, recovered from Australia (Aranbanga Volcanic Group), belongs to Mesophlebia antinodalis Tillyard, 1916, previously documented on the basis of two very incomplete wings. The other, recovered from South Africa (Molteno Formation), is assigned to a new species, Mesophlebia elegans sp. nov. The new data allow a reconsideration of the diagnosis of the genus Mesophlebia Tillyard, 1916 and a re-instatement of the family Mesophlebiidae Tillyard, 1916. Notably, the new specimens possess, near the wing base, a posterior lobe absent in most ‘triassolestid’ genera, but present in crown-Odonata and a number of their stem-relatives. Lobodonata tax. nov. is erected to accommodate odonates possessing this lobe. The nature of the ‘vein-like’ element anteriorly delimiting this lobe is discussed. We submit that it might have been initially composed of an invagination of the posterior wing-margin (‘fibula’), which was later captured by AA, imposing its course on CuP.Ayla Tierney [ayla.
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Aldo Manzuetti Daniel Perea Washington Jones Martín Ubilla Andrés Rinderknecht 《Alcheringa: An Australasian Journal of Paleontology》2020,44(2):332-339
AbstractAmong the three recognized species of Smilodon, S. populator is the largest in size and has the widest distribution across South America. The present contribution describes an almost complete skull assigned to the aforementioned felid. The material was recovered from sediments of the Dolores Formation (Lujanian Stage/Age) from the southern part of Uruguay. This specimen is remarkable for its unusual craniodental measurements, indicating that it is one of the largest known specimens of the genus. Estimates of body mass indicate that this individual weighed over 400?kg. In addition, maximum prey size estimation greatly surpasses 1 t and approach nearly 3 t. Based on this, aspects of the paleobiology and paleoecology of S. populator are discussed. Undoubtedly, this kind of carnivorous mammal was at the top of the food chain, with clear adaptations for feeding upon the largest available herbivores, which potentially includes several megafaunal mammal species found in South America during the late Pleistocene.Aldo Manzuetti [aldomanzuetti@adinet.
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Ana Andruchow-Colombo Ignacio H. Escapa Raymond J. Carpenter Robert S. Hill Ari Iglesias Ana M. Abarzua 《Alcheringa: An Australasian Journal of Paleontology》2019,43(1):127-145
A new podocarpaceous conifer is described from the early Danian Salamanca Formation (southern Chubut, Patagonia, Argentina) based on compressions of leafy branches with cuticular remains. Kirketapel salamanquensis gen. et sp. nov. has amphistomatic, scale-like leaves with marginal frills distinguishable at the apex; stomata oriented randomly in relation to the major axis of the leaf with four to five subsidiary cells and extremely reduced Florin rings; and irregularly shaped epidermal cells. We compare K. salamanquensis with extant and extinct members of the imbricate-leaved podocarps, among which it closely resembles Florin’s Dacrydium group C genera (i.e., Lagarostrobos, Manoao, Lepidothamnus and Halocarpus). Among these genera, only Lepidothamnus has a living representative in South America, the Chilean L. fonkii, whose leaf macro- and micromorphological characters are described in detail for comparison. Overall, the Patagonian fossil species is most similar to the extant and extinct members of Lagarostrobos in its cuticular micromorphology; however, macromorphological characters, such as the leaf size, apex curvature and mode of flattening, clearly differentiate it from all four genera of Dacrydium group C. We include Kirketapel salamanquensis in a combined molecular and morphological phylogenetic analysis conducted under the maximum parsimony criterion. The new, early Paleocene fossil taxon is confidently recovered as part of the scale-leaved clade as defined herein, which also includes Halocarpus, Phyllocladus, Lepidothamnus, Parasitaxus, Lagarostrobos and Manoao, and it constitutes the oldest record known for the group by at least 17 million years as well as its first fossil occurrence outside Australasia, establishing a widespread Gondwanan history. Furthermore, based on its oldest locality of occurrence, K. salamanquensis shows that the divergence of the total group of the scale-leaved podocarps occurred by at least 65 million years ago, adding to the growing systematic knowledge of earliest Cenozoic macrofloras in the Southern Hemisphere.
Ana Andruchow-Colombo [aandruchow@mef.