The enigmatic arthropod Duraznovis gallegoi from the Late Triassic of Argentina is a cicadomorphan head (Insecta: Hemiptera: Auchenorrhyncha)

Recently, Lara et al. (2020a, b) described a new fossil taxon, Duraznovis gallegoi, based on two specimens from the Upper Triassic Potrerillos Formation at Quebrada del Durazno, Cuyana Basin of Argentina. This fossil is considered to be an enigmatic arthropod closely resembling the living and fossil representatives of xiphosurans (Chelicerata) and notostracans (Branchiopoda), two completely different arthropod groups with convergent body plans. Some distinctive combination of features, however, makes the systematic position of these specimens indeterminate (Lara et al., 2020a, b).

An enigmatic Arthropoda from the Upper Triassic (Carnian) southwestern Gondwana (Argentina)

The presence of a new taxon, Duraznovis gallegoi new genus new species is reported and described from an early Late Triassic (Carnian) deposit in Argentina. Two specimens, recovered from the Quebrada del Durazno locality, uppermost levels of the Potrerillos Formation, Cuyana Basin (Mendoza), are represented by the molds of their shield and imprints of soft parts. The identity of these specimens appears enigmatic but closely resembles in the possession of a generalized arthropod morphology and a distinctive combination of characters, to living and fossil representatives of xiphosurans (Chelicerata) and notostracans (Branchiopoda). The new fossils are associated with a rich biota comprising abundant insects, spinicaudatans, plants, and scarce fish remains living in semipermanent swamps and/or ponds within a delta plain environment with intermittent episodes of flooding, in a warm temperate and humid megamonsoonal climate during Triassic times. In this context, we analyze the taphonomic and ecological implications of their presence. Lastly, these unique specimens at the Quebrada del Durazno locality adds to the diversity of the biota, revealing the importance of this site as an exceptional paleontological Triassic deposit.UUID: http://zoobank.org/8d1194c2-170c-4b7a-b0c6-5c08b0974d95

New species of osmundaceous fertile leaves from the upper Triassic of Argentina

A new species of Osmundopsis Harris is described based on several impression-compression fossils from the upper section of the Potrerillos Formation (Uspallata Group) at Cerro Cacheuta Hill, Mendoza Province, Argentina. Osmundopsis zunigai sp. nov. is characterized by having fertile pinnae with a slender striate rachis, bearing widely separate, opposite to subopposite short falcate pinnules with an entire margin, rounded apex, and a partially reduced lamina. The pinnules bear sporangia loosely disposed in clusters of four or five on the abaxial side. The sporangia are wedge- to heart-shaped, shortly stalked, with cells of the apical region thickened, and have a vertical dehiscence slit. The spores are trilete and laevigate. This is the first record of Osmundopsis in the Triassic of Argentina. The mutual occurrence or co-preservation of Osmundopsis zunigai sp. nov. with sterile fronds of Cladophlebis kurtzi suggests the possibility that these species formed part of a dimorphic bipinnate frond. The diversity and geographic extent of fertile leaves of the Osmunda lineage in the early Late Triassic, with records in South Africa and Antarctica and now with this new taxon, support the idea of a moist mesothermal climatic belt in southern Gondwana.