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Goeppertella has been postulated as a monophyletic group, whose precise position within the Gleichenoid families Dipteriaceae and Matoniaceae, remains poorly understood. Previously described Goeppertella specimens are based on frond fragments and its fertile morphology is represented by a few, poorly preserved specimens. We describe a new species based on the largest collection of fertile specimens known to date and discuss the evolutionary history of the genus based on the additional reproductive characters provided by the fossils described. Plant impressions were collected in Early Jurassic sediments of Patagonia, Argentina. The specimens were described, and silicone rubber casts were developed to examine in detail vegetative and reproductive features. The new species was compared with other Goeppertella species. Finally, a backbone analysis was performed in the context of a previously published combined matrix of Dipteridaceae, using the maximum parsimony criterion. The new species is described based on a combination of features that have not been previously reported. The vegetative morphology shows affinities with most fossil and extant Dipteriaceae, contrasting with the reproductive morphology which is more comparable with the scarce number of fossil dipteridaceous forms and it is more spread in the sister family, Matoniaceae. The backbone analysis indicates that the position of the new species vary among different positions among Dipteridaceae and Matoniaceae. Additional analyses, discriminating the signal of reproductive and vegetative character, are provided to discuss the base of this uncertainty. We consider Goeppertella as a member of the family Dipteridaceae since we interpret most shared features with Matoniaceae as plesiomorphic conditions for the family. In contrast, most shared features with Dipteridaceae represent apomorphies for the group. Thus, Goeppertella would represent an early diverging genus in Dipteridaceae, considering the venation characters as the most important in order to define the family. [ABSTRACT FROM AUTHOR]

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Premise: The sooty molds are a globally distributed ecological group of ascomycetes with epiphyllous, saprotrophic habit, comprising several phylogenetically distant taxa (i.e., members of the classes Dothideomycetes and Eurotiomycetes). Their fossil record extends almost continuously back to the early Cretaceous; however, they are hypothesized to have originated in the early Mesozoic. Here, we describe new specimens of sooty molds associated with conifer leaves from Jurassic hot spring deposits of Patagonia, Argentina. Methods: Thin sections of chert samples from the La Matilde Formation, Deseado Massif (Santa Cruz, Argentina) were observed using light microscopy. Results: The fungi occur on the surface and axils of leafy twigs with podocarpaceous affinities, forming dense subicula comprised by opaque moniliform hyphae. Additionally, several asexual and sexual reproductive structures are observed. On the basis of vegetative (i.e., dense subicula composed of moniliform hyphae; hyphae composed of opaque cells deeply constricted at the septa) and reproductive characters (i.e., poroconidial and sympodioconidial asexual stages and diverse spores), two morphotypes were identified with affinities within lineages of the subphylum Pezizomycotina that encompass the ecological group of sooty molds, and a third morphotype was within the phylum Ascomycota. Conclusions: This finding extends the fossil record of sooty molds to the Jurassic and their geographic fossil range to the South American continent. In particular, their association with podocarpaceous conifers is shown to be ancient, dating back to the Jurassic. This new record provides an additional reference point on the diversity of interactions that characterized Jurassic forests in Patagonia. [ABSTRACT FROM AUTHOR]

Premise of research. A new Early Jurassic species of Cupressaceae is reconstructed from the Cañadón Asfalto Formation in Argentina, based on impressions of foliage and attached and dispersed seed and pollen cones. Methodology. Over 230 specimens were examined using reflected-light microscopy and epifluorescence. Relevant extant taxa were studied for structural comparisons using herbarium specimens and living material from botanical gardens. Relationships of the new conifer were assessed in the context of currently known fossil and living taxa and used to evaluate morphological trends in the early evolution of Cupressaceae. Pivotal results. The new species, Austrohamia asfaltensis D.L. Contreras, I.H. Escapa, R.C. Iribarren, & N.R. Cúneo, has helically arranged, dorsiventrally flattened leaves that are rotated into semiplanar orientation, seed cones consisting of helically arranged coriaceous ovuliferous complexes that each bear two seeds and have a distinct abaxial keel and acuminate apex, and pollen cones that occur in clusters subtended by keeled bracts. Specimens show evidence that normal vegetative shoot growth continues from the pollen cone clusters, a condition that appears to characterize living Cunninghamia and some extinct conifers but not Taiwania. The new species is assignable to the genus Austrohamia , which shares a combination of characteristics consistent with the Cunninhamioideae and Taiwanioideae subfamilies of the Cupressaceae. It is distinct from other Austrohamia species, most notably by having seed cones that are twice as large and with many more ovuliferous complexes. Conclusions. The new species expands the known morphological diversity of Austrohamia , which is the oldest recorded genus of Cupressaceae based on reproductive material, and provides a new early occurrence of the family in the Southern Hemisphere. The development of a whole-plant concept enabled morphological comparisons over a broad range of traits and with taxa known from different combinations of organs, which has provided additional insights into the early evolution of Cupressaceae. [ABSTRACT FROM AUTHOR]

Macrofossil impressions of caytonialean leaves and micro- and megasporangiate organs from the Early Jurassic Taquetrén locality in Patagonia, Argentina, are described based on more than 300 hand specimens. Leaves of the organ-genus Sagenopteris are described using both discrete and continuous features allowing us to erect the species Sagenopteris trapialensis sp. nov. Associated microsporangiate organs of Caytonanthus type are the first recorded for South America and are characterized by a unique combination of architecture, size and type of dehiscence. Two specimens, one resembling an isolated Caytonia cupule, and the other a Caytonia axis, are also described. The availability of a collection with numerous specimens has proven to be an important tool in order to fully understand the intraspecific morphological plasticity of the studied species. The striking morphological resemblance of both vegetative and reproductive organ-genera with their Northern Hemisphere counterparts suggests that they were part of the same lineage, which was widely distributed during the Jurassic. Well-defined whole-plant concepts are still needed to advance the goal of deciphering the internal relationships of caytonialeans in particular, and their relationships with other groups of seed-plants in general, and thorough macro-morphological characterization of the organs that compose them, as we present here, may be of valuable use in achieving it. [ABSTRACT FROM AUTHOR]

Premise of research. The Río Genoa Formation of Argentine Patagonia hosts Early Permian fossil assemblages that document levels of plant diversity rare among coeval floras. Ongoing work to exhaustively characterize the diversity of these assemblages is key to understanding Permian vegetation and plant evolution. A new fern type identified in the Río Genoa Formation exhibits a novel combination of characters that required taxonomic assessment. Methodology. Observations and measurements of vegetative and reproductive morphology of compression fossils were used in a comparative framework to address the taxonomic placement of the fossils. Pivotal results. The new fern, Floratheca apokalyptika gen. et sp. nov., is characterized by small pinnules with a free base, weakly lobed margin, highly decurrent midvein, and rarely branched lateral veins, as well as radially symmetrical synangia with stellate dehiscence, consisting of six spindle-shaped sporangia. This unique combination of characters distinguishes Floratheca from the more than 25 Permo-Carboniferous marattialean genera known from compressions. Floratheca exhibits variable synangium morphology during development and variation in pinnule base morphology due to a combination of adaxial-abaxial asymmetry of ultimate rachises and taphonomic effects. Conclusions. Floratheca is one of only three late Paleozoic bona fide marattialean compression genera endemic to Gondwana and the second late Paleozoic endemic South American marattialean with preserved fertile structures. Floratheca adds to an increasing diversity of fossils that diminish the disparity between the Southern and Northern Hemispheres, in terms of the extent and intensity of exploration of the plant fossil record, currently skewed taxonomically toward Northern Hemisphere taxa. Variability of synangium and pinnule base morphology in Floratheca cautions against potential taxonomic inflation produced by establishment of new taxa based on small numbers of specimens and incomplete understanding of development and taphonomy. [ABSTRACT FROM AUTHOR]

Premise of research. Numerous leaf remains of pteridosperms occur at a new locality of the Early Jurassic Cañadón Asfalto Formation, in Patagonia, Argentina. Fossils consist of adpressions with superb cuticular preservation and are herein assigned to Lepidopteris (Peltaspermaceae). Methodology. Fossils were studied using normal light, epifluorescence, and scanning electron microscopy. The cuticles of 25 specimens were chemically prepared following standard methods. The remains were described in detail and compared with other pteridosperm genera and Lepidopteris species. Pivotal results. We erect Lepidopteris scassoi sp. nov. Elgorriaga, Escapa et Cúneo, based on its novel combination of characters. Among other features, L. scassoi has a bipinnate-tripinnatifid architecture, smooth rachis, 1–3 pairs of intercalary pinnules, and entire to deeply lobed pinnules with pinnate venation. Fronds are amphistomatic with a 0.5–0.7∶1 adaxial to abaxial ratio; stomata occur scattered on rachides and pinnules and have a ring of usually seven subsidiary cells with papillae oriented toward the stomatal pit; and the guard cells are sunken. A single solid papilla is usually present on epidermal cells of pinnules and pinnae. Structures resembling isolated Peltaspermum disks, with similar stomata as L. scassoi , were found in the same locality. Conclusions. We interpret L. scassoi and other members of its lineage as fast-growing, long-lived shrubby to herbaceous plants that thrived in waterside environments. Lepidopteris scassoi represents the youngest occurrence of the genus by more than 20 Myr. Lepidopteris and Dicroidium lineages, dominant in Southern Hemisphere Triassic ecosystems, show a similar overall pattern of origination (Late Permian), diversification (late Early-Middle Triassic), and decline (Late Triassic), with relict occurrences during the Early Jurassic. The systematic affiliation of a considerable number of Mesozoic pteridosperm records remains contentious, and future efforts should be oriented toward a better understanding of the position of each group on the gymnosperm tree of life. [ABSTRACT FROM AUTHOR]

Huncocladus laubenfelsii gen. et sp. nov. is described from the early Eocene (52 million years old) Laguna del Hunco site in Patagonia, Argentina, on the basis of a compression fossil with cuticle remains. The taxon has several similarities with Phyllocladus , together with characters that are absent in extant Phyllocladus species but are otherwise typical of the enclosing scale-leaved clade. Consequently, Huncocladus is interpreted as a relative of Phyllocladus , possibly belonging to its stem group. This view is supported by a phylogenetic analysis of Podocarpaceae, which recovers Huncocladus as sister to Phyllocladus within the here-termed phyllocladoid clade (Phyllocladus + Huncocladus). Huncocladus laubenfelsii is the first macrofossil record of the phyllocladoid lineage in South America or anywhere in the western hemisphere, vastly extending its historical range and constituting an additional lineage shared between Eocene Patagonia and extant and extinct Australasian and South-east Asian rainforests. The disappearance of phyllocladoids from South America adds to the general extinction pattern described previously for southern hemisphere Podocarpaceae, associated with the family's low drought tolerance in the face of climate change (i.e. aridification). Huncocladus is the oldest record of the phyllocladoids, and it represents a new reference point for temporal calibration and biogeographic inference for the evolution of conifers and Australasian rainforests. [ABSTRACT FROM AUTHOR]

Premise of the Study: The fossil record of Agathis historically has been restricted to Australasia. Recently described fossils from the Eocene of Patagonian Argentina showed a broader distribution than found previously, which is reinforced here with a new early Paleocene Agathis species from Patagonia. No previous phylogenetic analyses have included fossil Agathis species., Methods: We describe macrofossils from Patagonia of Agathis vegetative and reproductive organs from the early Danian, as well as leaves with Agathis affinities from the latest Maastrichtian. A total evidence phylogenetic analysis is performed, including the new Danian species together with other fossil species having agathioid affinities., Key Results: Early Danian Agathis immortalis sp. nov. is the oldest definite occurrence of Agathis and one of the most complete Agathis species in the fossil record. Leafy twigs, leaves, pollen cones, pollen, ovuliferous complexes, and seeds show features that are extremely similar to the living genus. Dilwynites pollen grains, associated today with both Wollemia and Agathis and known since the Turonian, were found in situ within the pollen cones., Conclusions: Agathis was present in Patagonia ca. 2 million years after the K-Pg boundary, and the putative latest Cretaceous fossils suggest that the genus survived the K-Pg extinction. Agathis immortalis sp nov. is recovered in a stem position for the genus, while A. zamunerae (Eocene, Patagonia) is recovered as part of the crown. A Mesozoic divergence for the Araucariaceae crown group, previously challenged by molecular divergence estimates, is supported by the combined phylogenetic analyses including the fossil taxa., (© 2018 Botanical Society of America.)

Premise of the Study: We describe a new araucarian species, Araucaria lefipanensis, from the Late Cretaceous flora of the Lefipán Formation, in Patagonia (Argentina) based on reproductive and vegetative remains, with a combination of characters that suggest mosaic evolution in the Araucaria lineage., Methods: The studied fossils were found at the Cañadón del Loro locality. Specimens were separated into two leaf morphotypes, and their morphological differences were tested with MANOVA., Key Results: The new species Araucaria lefipanensis is erected based on the association of dimorphic leaves with cuticle remains and isolated cone scale complexes. The reproductive morphology is characteristic of the extant section Eutacta, whereas the vegetative organs resemble those of the sections Intermedia, Bunya, and Araucaria (the broad-leaved clade)., Conclusions: The leaf dimorphism of A. lefipanensis is similar to that of extant A. bidwillii, where dimorphism is considered to be related to seasonal growth. The leaf dimorphism in A. lefipanensis is consistent with the paleoclimatic and paleoenvironmental reconstructions previously suggested for the Lefipán Formation, which is thought to have been a seasonal subtropical forest. The new species shows evidence of mosaic evolution, with cone scale complexes morphologically similar to section Eutacta and leaves similar to the sections of the broad-leaved clade, constituting a possible transitional form between these two well-defined lineages. More complete plant concepts, especially those including both reproductive and vegetative remains are necessary to understand the evolution of ancient plant lineages. This work contributes to this aim by documenting a new species that may add to the understanding of the early evolution of the sections of Araucaria., (© 2018 Botanical Society of America.)

Premise of the Study: Seed cone morphology and anatomy reflect some of the most important changes in the phylogeny and evolutionary biology of conifers. Reexamination of the enigmatic Jurassic seed cone Pararaucaria patagonica reveals previously unknown systematically informative characters that demonstrate affinities with the Cheirolepidiaceae. This paper documents, for the first time, internal anatomy for seed cones of this important extinct Mesozoic conifer family, which may represent the ghost lineage leading to modern Pinaceae., Methods: Morphology and anatomy of cones from the Jurassic La Matilde Formation in Patagonia are described from a combination of polished wafers and thin section preparations. New photographic techniques are employed to reveal histological details of thin sections in which organic cell wall remains are not preserved. Specific terminology for conifer seed cones is proposed to help clarify hypotheses of homology for the various structures of the cones., Key Results: Specimens are demonstrated to have trilobed ovuliferous scale tips along with a seed enclosing pocket of ovuliferous scale tissue. Originally thought to represent a seed wing in P. patagonica, this pocket-forming tissue is comparable to the flap of tissue covering seeds of compressed cheirolepidiaceous cones and is probably the most diagnostic character for seed cones of the family., Conclusions: Pararaucaria patagonica is assigned to Cheirolepidiaceae, documenting anatomical features for seed cones of the family and providing evidence for the antiquity of pinoid conifers leading to the origin of Pinaceae. A list of key morphological and anatomical characters for seed cones of Cheirolepidiaceae is developed to facilitate assignment of a much broader range of fossil remains to the family. This confirms the presence of Cheirolepidiaceae in the Jurassic of the Southern Hemisphere, which was previously suspected from palynological records.