Maria A. Gandolfo - Academia.edu (original) (raw)
Papers by Maria A. Gandolfo
Plant Systematics and Evolution, 2000
We report here on a series of specimens of charcoalified sorophores with characteristics of the e... more We report here on a series of specimens of charcoalified sorophores with characteristics of the extant fern genus Lygodium (Schizaeaceae) collected from sediments of the Raritan Formation (Late Cretaceous). Each elongate lobed fertile pinnule (sorophore) is flattened and bears alternately arranged sporangia on one surface. Each sporangium is covered by an indusium continuous with the margin of the lamina. Sporangia are oblong in shape, short stalked, and have an apical annulus formed by a single ring of radiating cells that dehisces longitudinally. The 'sporangial cap' or 'distal face' is formed by only one cell. All of these features are characteristic of the extant genus Lygodium. Small numbers of trilete, psilate spores are found in the sporangia. Megafossils assignable to Lygodium are known from the Upper Cretaceous of North America and Germany with worldwide distribution during the Tertiary. The new Lygodium fossils are compared with others previously referred to the genus.
Bulletin of the Torrey Botanical Club, 1988
ABSTRACT New specimens of Akania americana Romero & Hickey and a new species in the same ... more ABSTRACT New specimens of Akania americana Romero & Hickey and a new species in the same genus, Akania patagonica n. sp. are described. Comparisons are made with the only living species, A. hilli, endemic to east Australia. All the fossils are found in the La Huitrera Formation (Paleocene), Chubut Province, Argentina. The fossils support the idea that the Akaniaceae were diversified and widespread in the southern hemisphere during the Paleogene, and that close relationships existed between South America and Australia at that time.
American Journal of Botany, 2005
A new fossil genus and species, Jerseyanthus calycanthoides, is described from the Late Cretaceou... more A new fossil genus and species, Jerseyanthus calycanthoides, is described from the Late Cretaceous (Turonian, ∼90 MYBP) Raritan Formation of New Jersey. Flowers have cupulate receptacles bearing imbricately arranged tepals that subtend a series of recurved tepals near the cup margin. Recurved tepal subtends a “stamen‐staminode” pair, that includes a laminar stamen with ramified connective extensions, and an outer staminode. Outer staminodes are geniculate and incurved, and in aggregate their inner extremities define a circular area above the carpels and carpellodes. Each “stamen‐staminode” pair apparently subtends (is opposite to) an inner tepal. Pollen is rounded and disulculate, with tectate columellate wall structure. Carpels are located at the center of the receptacle and have elongate styles that extend to and beyond the opening defined by the staminodal organs. Carpels are surrounded by tomentose carpellodes. Carpels include one marginally ridged seed. While these fossils do n...
In recent years, paleobotanical explorations in southern South America have recovered an increasi... more In recent years, paleobotanical explorations in southern South America have recovered an increasing number of taxa currently restricted to Australasian rainforests, highlighting biotic connectivity between these areas in the geologic past and suggesting a complex biogeographic history. The Eocene deposits of Laguna del Hunco (51.9 Ma), Patagonia, Argentina, bear remains of the oldest known Eucalyptus (Myrtaceae), as well as many rainforest-associated gymnosperm taxa including Papuacedrus (Cupressaceae), Agathis (Araucariaceae), and Dacrycarpus (Podocarpaceae) and several angiosperm taxa such as Gymnostoma (Casuarinaceae), Proteaceae, Atherospermataceae and Cunoniaceae. Herein, we show that the pattern of widespread Gondwanan distribution observed for angiosperms and gymnosperms is also evident for the pteridophyte component of this flora. Three fern species have been recently recovered and identified based on the preservation of fertile fronds and sporangial remains. One fossil species bears acrosticoid sporangia on pinnatifid frond fragments typical of Osmundaceae. Dicksoniaceae is recognized based on remains of fronds with marginal sori covered by a bivalved indusium, while the presence of Gleicheniaceae is confirmed by fertile fronds that have naked, round sori composed of 3-5 sporangia restricted to the upper branch of bifurcating secondary veins. Total evidence approaches based on morphology and previously sequenced chloroplast (rbcL, atpB, rps4) and nuclear genes (18S rDNA) were used for testing the natural affinities of these fossils. Each fossil species was scored for 25-35 characters of frond and reproductive structure morphology, rendering hypotheses of relationships of the fossils to each of the three mentioned families. The results suggest intrafamilial affinities to Todea (Osmundaceae), Dicksonia (Dicksoniaceae), and Sticherus (Gleicheniaceae). These genera include species native to Australia and have varying number of endemic species in montane and lowland rainforests. Todea is now restricted to montane, humid subtropical and tropical Australasia and South Africa, and has been reported for the Jurassic of Argentina. Dicksonia is present in the wet subtropics and tropics of Australasia and South America, while Sticherus is pantropical and austral, and mostly humid montane. Although the fossil record for Dicksonia and Sticherus is sparse; both genera are known from Oligocene deposits of Tasmania, and the former was previously reported from the middle Eocene of Argentina. The records from the Eocene of Patagonia show a wider distribution for these three genera in the past, and the same long-term patterns of shared lineages between Australasia and South America observed before in angiosperms and conifers. Whether the extant distribution of fern lineages shared between Australia and South America is a product of independent colonization events, or evidence of a shared, widespread ancestral biota remains unknown. However, the warmer climate that predominated the Eocene, and the closer proximity of both South America and Australia to Antarctica support the hypothesis of a nearly continuous forest cover throughout these landmasses. The widespread-Gondwana biogeographical pattern shared by multiple lineages in this Eocene flora suggests that an important
Plant Systematics and Evolution, 2001
. Fossil vegetative and reproductive structures from deposits of the Raritan Formation in New J... more . Fossil vegetative and reproductive structures from deposits of the Raritan Formation in New Jersey (Turonian, Upper Cretaceous, ∼90 MYBP) include ferns, gymnosperms, and angiosperms. Gymnosperms collected from this formation have been known since the beginning of the 20th century. Fossil leaves, wood and seed cones have been are identified as belonging to the Cupressaceae, Pinaceae, and Taxodiaceae. In the present contribution, we describe a series of fossil dwarf shoots, leaves and a pollen cone belonging to the family Pinaceae. Fossils are charcoalified with preserved three-dimensional structure and excellent cellular detail. The dwarf shoots are assigned to a new species Prepinus crossmanensis sp. nov. and to the previously described Pinus quinquefolia Jeffrey. The new species Prepinus crossmanensis differs in size, shape, presence of hypodermis, sclerenchyma and stomata in the cataphylls, and number and shape of needle leaves from previously known species. Also, isolated leaves were found that were assigned to the new species, Prepinus raritanensis sp. nov. The new species is differentiated by the size and shape of stomata, the presence of number of layers of the hypodermis; and the cell-shape and number of layers of the mesophyll and transfusion tissue. A previously undescribed male cone, Amboystrobus cretacicum gen. and sp. nov., has an axis with spirally attached microsporophylls, each bearing two abaxial ovoid microsporangia. The pollen grains are monosulcate and bisaccate (eusaccate), with an elliptical corpus, granulate exine sculpture, and honeycomb-like wall structure.
Japanese Journal of Palynology
Bridges, respectively. However, newly discovered winged fruits that have characters consistent wi... more Bridges, respectively. However, newly discovered winged fruits that have characters consistent with Engelhardioideae from the early Eocene (ca. 52 Ma) Laguna del Hunco flora of southern Argentina complicate this scenario, not only because the Engelhardioideae were previously not thought to have any significant presence in South America, but because this is among the oldest known occurrences of the clade in the fossil record. We will discuss how phylogeny may help us to better understand the development of the biogeographic range exhibited by this clade. The surprising occurrence of fossil Engelhardioideae in southern South America mirrors reports of other taxa that were previously cryptic in the Cretaceous to Paleogene of Argentina, such as Potamogetonaceae (Baibiancarpus chubutensis), Nelumbo (Nelumbo puertae), and the ferns Regnellidium (Marsileaceae). These taxa were previously known as macrofossils only from the Northern Hemisphere, suggesting that continuing work on Southern Hemisphere floras may yield interesting biogeographic results.
Japanese Journal of Palynology
Upper Cretaceous sediments are widespread in northern Patagonia, with several geological units be... more Upper Cretaceous sediments are widespread in northern Patagonia, with several geological units bearing diverse aquatic paleobiotas that accumulated as the result of complex and dynamic coastal sedimentary processes. One of these units is the La Colonia Formation. The entire sequence representing this formation is dominated primarily by fine-grained clay facies that are interpreted as having been deposited in coastal fresh water lakes or lagoons sporadically affected by brackish conditions. The La Colonia fauna includes terrestrial and aquatic reptiles, mammals, and fish; the flora is largely undescribed. In this report, we discuss the aquatic paleoflora of three La Colonia Formation localities: Cañadón de los Helechos, Cerro Bosta and Cañadón del Irupé. The flora of the first two localities consists entirely of the aquatic fern Regnellidium (Marsileaceae), suggesting a low-diversity, perhaps monospecific plant community. The last locality, in contrast, is dominated angiosperm taxa belonging to the families Nelumbonaceae and Araceae, and also includes the remains of ferns belonging to the families Marsileaceae and Salviniaceae. Modern species of these groups have a worldwide distribution and comparable extant taxa are found in freshwater lakes or lagoons, suggesting a similar environment for the fossils. Each of the localities is characterized by a relatively high accumulation of biomass, which, along with the excellent preservation of delicate plant organs, indicates that deposition was autochtonous. This corroborates the inference from taxonomic affinities that these plants inhabited low-energy aquatic environments. The presence of a diverse tetrapod fauna and palm remains in the surrounding landscape is a clear indication that climate conditions in Patagonia at the close of the Cretaceous were warm enough to sustain a diverse biota.
PhytoKeys, 2020
During the early Eocene, Patagonia had highly diverse floras that are primarily known from compre... more During the early Eocene, Patagonia had highly diverse floras that are primarily known from compression and pollen fossils. Fossil wood studies from this epoch are scarce in the region and largely absent from the Laguna del Hunco flora, which has a highly diverse and excellently preserved compression assemblage. A collection of 26 conifer woods from the Laguna del Hunco fossil-lake beds (early Eocene, ca. 52 Ma) from central-western Patagonia was studied, of which 12 could be identified to genus. The dominant species is Phyllocladoxylon antarcticum, which has affinity with early-diverging Podocarpaceae such as Phyllocladus and Prumnnopitys. A single specimen of Protophyllocladoxylon francisiae probably represents an extinct group of Podocarpaceae. In addition, two taxonomic units of cf. Cupressinoxylon with putative affinity to Podocarpaceae were found. Diverse Podocarpaceae taxa consistent with the affinities of these woods were previously reported from vegetative and reproductive m...
During the early Eocene, Patagonia had highly diverse floras that are primarily known from compre... more During the early Eocene, Patagonia had highly diverse floras that are primarily known from compression and pollen fossils. Fossil wood studies from this epoch are scarce in the region and largely absent from the Laguna del Hunco flora, which has a highly diverse and excellently preserved compression assemblage. A collection of 26 conifer woods from the Laguna del Hunco fossil-lake beds (early Eocene, ca. 52 Ma) from central-western Patagonia was studied, of which 12 could be identified to genus. The dominant species is Phyllocladoxylon antarcticum, which has affinity with early-diverging Podocarpaceae such as Phyllocladus and Prumnnopitys. A single specimen of Protophyllocladoxylon francisiae probably represents an extinct group of Podocarpaceae. In addition, two taxonomic units of cf. Cupressinoxylon with putative affinity to Podocarpaceae were found. Diverse Podocarpaceae taxa consistent with the affinities of these woods were previously reported from vegetative and reproductive macrofossils as well as pollen grains from the same source unit. Some of the woods have galleries filled with frass. Distinct growth ring boundaries indicate seasonality, inferred to represent seasonal light availability. Growth ring widths suggest that the woods came from mature trees, whereas the widths and types of some rings denote near-uniform temperature and water availability conditions.
Science, 2019
Denk et al . agree that we reported the first fossil Fagaceae from the Southern Hemisphere. We ap... more Denk et al . agree that we reported the first fossil Fagaceae from the Southern Hemisphere. We appreciate their general enthusiasm for our findings, but we reject their critiques, which we find misleading and biased. The new fossils unequivocally belong to Castanopsis , and substantial evidence supports our Southern Route to Asia hypothesis.
Cretaceous Research, 2019
A new genus and species, Austrocupressinoxylon barcinense, based on remains of cupressaceous wood... more A new genus and species, Austrocupressinoxylon barcinense, based on remains of cupressaceous wood is described for the Lower Cretaceous of central Patagonia, Argentina. The studied specimens are silicified fragments of picnoxylic and homoxylic wood that exhibit a combination of characters not previously reported, therefore a new genus is erected. The characters are: 1-growth ring boundaries distinct, 2-transition from earlywood to latewood gradual, 3-axial parenchyma diffuse,4-radial tracheid pitting predominantly abietinean,5cross-field pitting cupressoid, arranged in both cupressoid and araucarioid patterns, 6-rays uniseriate heterocellular, 7-end and horizontal walls of ray parenchyma cells smooth or slightly nodular, and 8-ray tracheids with smooth walls. The cross-field pitting patterns and the
American Journal of Botany, 2018
We present the first plastome phylogeny encompassing all 77 monocot families, estimate branch sup... more We present the first plastome phylogeny encompassing all 77 monocot families, estimate branch support, and infer monocot-wide divergence times and rates of species diversification. METHODS: We conducted maximum likelihood analyses of phylogeny and BAMM studies of diversification rates based on 77 plastid genes across 545 monocots and 22 outgroups. We quantified how branch support and ascertainment vary with gene number, branch length, and branch depth. KEY RESULTS: Phylogenomic analyses shift the placement of 16 families in relation to earlier studies based on four plastid genes, add seven families, date the divergence between monocots and eudicots+Ceratophyllum at 136 Mya, successfully place all mycoheterotrophic taxa examined, and support recognizing Taccaceae and Thismiaceae as separate families and Arecales and Dasypogonales as separate orders. Only 45% of interfamilial divergences occurred after the Cretaceous. Net species diversification underwent four large-scale accelerations in PACMAD-BOP Poaceae, Asparagales sister to Doryanthaceae, Orchidoideae-Epidendroideae, and Araceae sister to Lemnoideae, each associated with specific ecological/morphological shifts. Branch ascertainment and support across monocots increase with gene number and branch length, and decrease with relative branch depth. Analysis of entire plastomes in Zingiberales quantifies the importance of non-coding regions in identifying and supporting short, deep branches. CONCLUSIONS: We provide the first resolved, well-supported monocot phylogeny and timeline spanning all families, and quantify the significant contribution of plastomescale data to resolving short, deep branches. We outline a new functional model for the evolution of monocots and their diagnostic morphological traits from submersed aquatic ancestors, supported by convergent evolution of many of these traits in aquatic Hydatellaceae (Nymphaeales).
American journal of botany, 2017
The flip-leaved podocarp Retrophyllum has a disjunct extant distribution in South American and Au... more The flip-leaved podocarp Retrophyllum has a disjunct extant distribution in South American and Australasian tropical rainforests and a Gondwanic fossil record since the Eocene. Evolutionary, biogeographic, and paleoecological insights from previously described fossils are limited because they preserve little foliar variation and no reproductive structures. We investigated new Retrophyllum material from the terminal Cretaceous Lefipán, the early Eocene Laguna del Hunco, and the early/middle Eocene Río Pichileufú floras of Patagonian Argentina. We also reviewed type material of historical Eocene fossils from southern Chile. Cretaceous Retrophyllum superstes sp. nov. is described from a leafy twig, while Eocene R. spiralifolium sp. nov. includes several foliage forms and a peduncle with 13 pollen cones. Both species preserve extensive damage from sap-feeding insects associated with foliar transfusion tissue. The Eocene species exhibits a suite of characters linking it to both Neotropic...
Annals of botany, Jan 5, 2018
Early Palaeocene (Danian) plant fossils from Patagonia provide information on the recovery from t... more Early Palaeocene (Danian) plant fossils from Patagonia provide information on the recovery from the end-Cretaceous extinction and Cenozoic floristic change in South America. Actinomorphic flowers with eight to ten perianth parts are described and evaluated in a phylogenetic framework. The goal of this study is to determine the identity of these fossil flowers and to discuss their evolutionary, palaeoecological and biogeographical significance. More than 100 fossilized flowers were collected from three localities in the Danian Salamanca and Peñas Coloradas Formations in southern Chubut. They were prepared, photographed and compared with similar extant and fossil flowers using published literature and herbarium specimens. Phylogenetic analysis was performed using morphological and molecular data. The fossil flowers share some but not all the synapomorphies that characterize the Schizomerieae, a tribe within Cunoniaceae. These features include the shallow floral cup, variable number of...
PloS one, 2017
Southern-Hemisphere terrestrial communities from the early Paleocene are poorly known, but recent... more Southern-Hemisphere terrestrial communities from the early Paleocene are poorly known, but recent work on Danian plant fossils from the Salamanca Formation in Chubut Province, Argentina are providing critical data on earliest Paleocene floras. The fossils described here come from a site in the Salamanca Formation dating to ca. 1 million years or less after the end-Cretaceous extinction event; they are the first fossil flowers reported from the Danian of South America, and possible the entire Southern Hemisphere. They are compressions and impressions in flat-laminated light gray shale, and they belong to the family Rhamnaceae (buckthorns). Flowers of Notiantha grandensis gen. et sp. nov. are pentamerous, with distinctly keeled calyx lobes projecting from the hypanthium, clawed and cucullate emarginate petals, antepetalous stamens, and a pentagonal floral disk that fills the hypanthium. Their phylogenetic position was evaluated using a molecular scaffold approach combined with morphol...
Botany, 2016
A new species of anatomically preserved Cupressaceae is described from the Upper Cretaceous Rarit... more A new species of anatomically preserved Cupressaceae is described from the Upper Cretaceous Raritan Formation (New Jersey, USA). The fossils are charcolified isolated ovuliferous complexes that were studied by means of a combination of SEM images and micro-computed tomography (micro-CT), allowing the observation of morphological and anatomical characters. Each ovuliferous complex bears 3–4 anatropous winged seeds, disposed in one row on a thin medial part of the adaxial side of the ovuliferous complex. Based on the combination of characters such as ovuliferous complex morphology, arrangement of vascular tissues and resin canals, seed number and their morphology, orientation and disposition, these fossils are placed within a new species of the fossil genus Athrotaxites. The developmental stage of the specimens is analyzed base on comparisons with living representatives of the subfamily Athrotaxoideae (i.e., Athrotaxis spp.), which supports a post-pollination stage for these fossils. ...
International Journal of Plant Sciences, 2016
Premise of research: The Cenozoic fossil record is crucial for understanding the evolution of the... more Premise of research: The Cenozoic fossil record is crucial for understanding the evolution of the remarkably high diversity of angiosperms. However, the quality and biases of the angiosperm fossil record remain unclear mainly due to the lack of a global database. Methodology: We introduce a new global occurrence-based database for Cenozoic angiosperm macrofossils, the Cenozoic Angiosperm Database. We test the temporal, spatial, and phylogenetic biases of the Cenozoic angiosperm macrofossil record and explore their causes. Pivotal results: The data presented here include 2478 assemblages from all Cenozoic epochs and 1961 sites from all continents, as well as representatives of 221 families (of 445 recognized) and 1859 genera, and show that the Cenozoic angiosperm macrofossil record is extraordinarily rich. However, this rich record is temporally, spatially, and phylogenetically biased: the Miocene is much better sampled than the rest of Cenozoic, the Northern Hemisphere is better sampled than the Southern Hemisphere, and the rosids are better sampled than the rest of the angiosperms. The sampling bias might be caused by collecting effort, geological history, or diverse features of the families, such as growth form and distribution. Conclusions: The Cenozoic macrofossil record of angiosperms is remarkably rich, especially of woody families found in the Northern Hemisphere. Even if there are numerous biases in these data, a judicious use of the database should be highly informative.
Botanical Journal of the Linnean Society, 2015
PLoS ONE, 2014
The study of biodiversity spans many disciplines and includes data pertaining to species distribu... more The study of biodiversity spans many disciplines and includes data pertaining to species distributions and abundances, genetic sequences, trait measurements, and ecological niches, complemented by information on collection and measurement protocols. A review of the current landscape of metadata standards and ontologies in biodiversity science suggests that existing standards such as the Darwin Core terminology are inadequate for describing biodiversity data in a semantically meaningful and computationally useful way. Existing ontologies, such as the Gene Ontology and others in the Open Biological and Biomedical Ontologies (OBO) Foundry library, provide a semantic structure but lack many of the necessary terms to describe biodiversity data in all its dimensions. In this paper, we describe the motivation for and ongoing development of a new Biological Collections Ontology, the Environment Ontology, and the Population and Community Ontology. These ontologies share the aim of improving data aggregation and integration across the biodiversity domain and can be used to describe physical samples and sampling processes (for example, collection, extraction, and preservation techniques), as well as biodiversity observations that involve no physical sampling. Together they encompass studies of: 1) individual organisms, including voucher specimens from ecological studies and museum specimens, 2) bulk or environmental samples (e.g., gut contents, soil, water) that include DNA, other molecules, and potentially many organisms, especially microbes, and 3) survey-based ecological observations. We discuss how these ontologies can be applied to biodiversity use cases that span genetic, organismal, and ecosystem levels of organization. We argue that if adopted as a standard and rigorously applied and enriched by the biodiversity community, these ontologies would significantly reduce barriers to data discovery, integration, and exchange among biodiversity resources and researchers.
Plant Systematics and Evolution, 2000
We report here on a series of specimens of charcoalified sorophores with characteristics of the e... more We report here on a series of specimens of charcoalified sorophores with characteristics of the extant fern genus Lygodium (Schizaeaceae) collected from sediments of the Raritan Formation (Late Cretaceous). Each elongate lobed fertile pinnule (sorophore) is flattened and bears alternately arranged sporangia on one surface. Each sporangium is covered by an indusium continuous with the margin of the lamina. Sporangia are oblong in shape, short stalked, and have an apical annulus formed by a single ring of radiating cells that dehisces longitudinally. The 'sporangial cap' or 'distal face' is formed by only one cell. All of these features are characteristic of the extant genus Lygodium. Small numbers of trilete, psilate spores are found in the sporangia. Megafossils assignable to Lygodium are known from the Upper Cretaceous of North America and Germany with worldwide distribution during the Tertiary. The new Lygodium fossils are compared with others previously referred to the genus.
Bulletin of the Torrey Botanical Club, 1988
ABSTRACT New specimens of Akania americana Romero & Hickey and a new species in the same ... more ABSTRACT New specimens of Akania americana Romero & Hickey and a new species in the same genus, Akania patagonica n. sp. are described. Comparisons are made with the only living species, A. hilli, endemic to east Australia. All the fossils are found in the La Huitrera Formation (Paleocene), Chubut Province, Argentina. The fossils support the idea that the Akaniaceae were diversified and widespread in the southern hemisphere during the Paleogene, and that close relationships existed between South America and Australia at that time.
American Journal of Botany, 2005
A new fossil genus and species, Jerseyanthus calycanthoides, is described from the Late Cretaceou... more A new fossil genus and species, Jerseyanthus calycanthoides, is described from the Late Cretaceous (Turonian, ∼90 MYBP) Raritan Formation of New Jersey. Flowers have cupulate receptacles bearing imbricately arranged tepals that subtend a series of recurved tepals near the cup margin. Recurved tepal subtends a “stamen‐staminode” pair, that includes a laminar stamen with ramified connective extensions, and an outer staminode. Outer staminodes are geniculate and incurved, and in aggregate their inner extremities define a circular area above the carpels and carpellodes. Each “stamen‐staminode” pair apparently subtends (is opposite to) an inner tepal. Pollen is rounded and disulculate, with tectate columellate wall structure. Carpels are located at the center of the receptacle and have elongate styles that extend to and beyond the opening defined by the staminodal organs. Carpels are surrounded by tomentose carpellodes. Carpels include one marginally ridged seed. While these fossils do n...
In recent years, paleobotanical explorations in southern South America have recovered an increasi... more In recent years, paleobotanical explorations in southern South America have recovered an increasing number of taxa currently restricted to Australasian rainforests, highlighting biotic connectivity between these areas in the geologic past and suggesting a complex biogeographic history. The Eocene deposits of Laguna del Hunco (51.9 Ma), Patagonia, Argentina, bear remains of the oldest known Eucalyptus (Myrtaceae), as well as many rainforest-associated gymnosperm taxa including Papuacedrus (Cupressaceae), Agathis (Araucariaceae), and Dacrycarpus (Podocarpaceae) and several angiosperm taxa such as Gymnostoma (Casuarinaceae), Proteaceae, Atherospermataceae and Cunoniaceae. Herein, we show that the pattern of widespread Gondwanan distribution observed for angiosperms and gymnosperms is also evident for the pteridophyte component of this flora. Three fern species have been recently recovered and identified based on the preservation of fertile fronds and sporangial remains. One fossil species bears acrosticoid sporangia on pinnatifid frond fragments typical of Osmundaceae. Dicksoniaceae is recognized based on remains of fronds with marginal sori covered by a bivalved indusium, while the presence of Gleicheniaceae is confirmed by fertile fronds that have naked, round sori composed of 3-5 sporangia restricted to the upper branch of bifurcating secondary veins. Total evidence approaches based on morphology and previously sequenced chloroplast (rbcL, atpB, rps4) and nuclear genes (18S rDNA) were used for testing the natural affinities of these fossils. Each fossil species was scored for 25-35 characters of frond and reproductive structure morphology, rendering hypotheses of relationships of the fossils to each of the three mentioned families. The results suggest intrafamilial affinities to Todea (Osmundaceae), Dicksonia (Dicksoniaceae), and Sticherus (Gleicheniaceae). These genera include species native to Australia and have varying number of endemic species in montane and lowland rainforests. Todea is now restricted to montane, humid subtropical and tropical Australasia and South Africa, and has been reported for the Jurassic of Argentina. Dicksonia is present in the wet subtropics and tropics of Australasia and South America, while Sticherus is pantropical and austral, and mostly humid montane. Although the fossil record for Dicksonia and Sticherus is sparse; both genera are known from Oligocene deposits of Tasmania, and the former was previously reported from the middle Eocene of Argentina. The records from the Eocene of Patagonia show a wider distribution for these three genera in the past, and the same long-term patterns of shared lineages between Australasia and South America observed before in angiosperms and conifers. Whether the extant distribution of fern lineages shared between Australia and South America is a product of independent colonization events, or evidence of a shared, widespread ancestral biota remains unknown. However, the warmer climate that predominated the Eocene, and the closer proximity of both South America and Australia to Antarctica support the hypothesis of a nearly continuous forest cover throughout these landmasses. The widespread-Gondwana biogeographical pattern shared by multiple lineages in this Eocene flora suggests that an important
Plant Systematics and Evolution, 2001
. Fossil vegetative and reproductive structures from deposits of the Raritan Formation in New J... more . Fossil vegetative and reproductive structures from deposits of the Raritan Formation in New Jersey (Turonian, Upper Cretaceous, ∼90 MYBP) include ferns, gymnosperms, and angiosperms. Gymnosperms collected from this formation have been known since the beginning of the 20th century. Fossil leaves, wood and seed cones have been are identified as belonging to the Cupressaceae, Pinaceae, and Taxodiaceae. In the present contribution, we describe a series of fossil dwarf shoots, leaves and a pollen cone belonging to the family Pinaceae. Fossils are charcoalified with preserved three-dimensional structure and excellent cellular detail. The dwarf shoots are assigned to a new species Prepinus crossmanensis sp. nov. and to the previously described Pinus quinquefolia Jeffrey. The new species Prepinus crossmanensis differs in size, shape, presence of hypodermis, sclerenchyma and stomata in the cataphylls, and number and shape of needle leaves from previously known species. Also, isolated leaves were found that were assigned to the new species, Prepinus raritanensis sp. nov. The new species is differentiated by the size and shape of stomata, the presence of number of layers of the hypodermis; and the cell-shape and number of layers of the mesophyll and transfusion tissue. A previously undescribed male cone, Amboystrobus cretacicum gen. and sp. nov., has an axis with spirally attached microsporophylls, each bearing two abaxial ovoid microsporangia. The pollen grains are monosulcate and bisaccate (eusaccate), with an elliptical corpus, granulate exine sculpture, and honeycomb-like wall structure.
Japanese Journal of Palynology
Bridges, respectively. However, newly discovered winged fruits that have characters consistent wi... more Bridges, respectively. However, newly discovered winged fruits that have characters consistent with Engelhardioideae from the early Eocene (ca. 52 Ma) Laguna del Hunco flora of southern Argentina complicate this scenario, not only because the Engelhardioideae were previously not thought to have any significant presence in South America, but because this is among the oldest known occurrences of the clade in the fossil record. We will discuss how phylogeny may help us to better understand the development of the biogeographic range exhibited by this clade. The surprising occurrence of fossil Engelhardioideae in southern South America mirrors reports of other taxa that were previously cryptic in the Cretaceous to Paleogene of Argentina, such as Potamogetonaceae (Baibiancarpus chubutensis), Nelumbo (Nelumbo puertae), and the ferns Regnellidium (Marsileaceae). These taxa were previously known as macrofossils only from the Northern Hemisphere, suggesting that continuing work on Southern Hemisphere floras may yield interesting biogeographic results.
Japanese Journal of Palynology
Upper Cretaceous sediments are widespread in northern Patagonia, with several geological units be... more Upper Cretaceous sediments are widespread in northern Patagonia, with several geological units bearing diverse aquatic paleobiotas that accumulated as the result of complex and dynamic coastal sedimentary processes. One of these units is the La Colonia Formation. The entire sequence representing this formation is dominated primarily by fine-grained clay facies that are interpreted as having been deposited in coastal fresh water lakes or lagoons sporadically affected by brackish conditions. The La Colonia fauna includes terrestrial and aquatic reptiles, mammals, and fish; the flora is largely undescribed. In this report, we discuss the aquatic paleoflora of three La Colonia Formation localities: Cañadón de los Helechos, Cerro Bosta and Cañadón del Irupé. The flora of the first two localities consists entirely of the aquatic fern Regnellidium (Marsileaceae), suggesting a low-diversity, perhaps monospecific plant community. The last locality, in contrast, is dominated angiosperm taxa belonging to the families Nelumbonaceae and Araceae, and also includes the remains of ferns belonging to the families Marsileaceae and Salviniaceae. Modern species of these groups have a worldwide distribution and comparable extant taxa are found in freshwater lakes or lagoons, suggesting a similar environment for the fossils. Each of the localities is characterized by a relatively high accumulation of biomass, which, along with the excellent preservation of delicate plant organs, indicates that deposition was autochtonous. This corroborates the inference from taxonomic affinities that these plants inhabited low-energy aquatic environments. The presence of a diverse tetrapod fauna and palm remains in the surrounding landscape is a clear indication that climate conditions in Patagonia at the close of the Cretaceous were warm enough to sustain a diverse biota.
PhytoKeys, 2020
During the early Eocene, Patagonia had highly diverse floras that are primarily known from compre... more During the early Eocene, Patagonia had highly diverse floras that are primarily known from compression and pollen fossils. Fossil wood studies from this epoch are scarce in the region and largely absent from the Laguna del Hunco flora, which has a highly diverse and excellently preserved compression assemblage. A collection of 26 conifer woods from the Laguna del Hunco fossil-lake beds (early Eocene, ca. 52 Ma) from central-western Patagonia was studied, of which 12 could be identified to genus. The dominant species is Phyllocladoxylon antarcticum, which has affinity with early-diverging Podocarpaceae such as Phyllocladus and Prumnnopitys. A single specimen of Protophyllocladoxylon francisiae probably represents an extinct group of Podocarpaceae. In addition, two taxonomic units of cf. Cupressinoxylon with putative affinity to Podocarpaceae were found. Diverse Podocarpaceae taxa consistent with the affinities of these woods were previously reported from vegetative and reproductive m...
During the early Eocene, Patagonia had highly diverse floras that are primarily known from compre... more During the early Eocene, Patagonia had highly diverse floras that are primarily known from compression and pollen fossils. Fossil wood studies from this epoch are scarce in the region and largely absent from the Laguna del Hunco flora, which has a highly diverse and excellently preserved compression assemblage. A collection of 26 conifer woods from the Laguna del Hunco fossil-lake beds (early Eocene, ca. 52 Ma) from central-western Patagonia was studied, of which 12 could be identified to genus. The dominant species is Phyllocladoxylon antarcticum, which has affinity with early-diverging Podocarpaceae such as Phyllocladus and Prumnnopitys. A single specimen of Protophyllocladoxylon francisiae probably represents an extinct group of Podocarpaceae. In addition, two taxonomic units of cf. Cupressinoxylon with putative affinity to Podocarpaceae were found. Diverse Podocarpaceae taxa consistent with the affinities of these woods were previously reported from vegetative and reproductive macrofossils as well as pollen grains from the same source unit. Some of the woods have galleries filled with frass. Distinct growth ring boundaries indicate seasonality, inferred to represent seasonal light availability. Growth ring widths suggest that the woods came from mature trees, whereas the widths and types of some rings denote near-uniform temperature and water availability conditions.
Science, 2019
Denk et al . agree that we reported the first fossil Fagaceae from the Southern Hemisphere. We ap... more Denk et al . agree that we reported the first fossil Fagaceae from the Southern Hemisphere. We appreciate their general enthusiasm for our findings, but we reject their critiques, which we find misleading and biased. The new fossils unequivocally belong to Castanopsis , and substantial evidence supports our Southern Route to Asia hypothesis.
Cretaceous Research, 2019
A new genus and species, Austrocupressinoxylon barcinense, based on remains of cupressaceous wood... more A new genus and species, Austrocupressinoxylon barcinense, based on remains of cupressaceous wood is described for the Lower Cretaceous of central Patagonia, Argentina. The studied specimens are silicified fragments of picnoxylic and homoxylic wood that exhibit a combination of characters not previously reported, therefore a new genus is erected. The characters are: 1-growth ring boundaries distinct, 2-transition from earlywood to latewood gradual, 3-axial parenchyma diffuse,4-radial tracheid pitting predominantly abietinean,5cross-field pitting cupressoid, arranged in both cupressoid and araucarioid patterns, 6-rays uniseriate heterocellular, 7-end and horizontal walls of ray parenchyma cells smooth or slightly nodular, and 8-ray tracheids with smooth walls. The cross-field pitting patterns and the
American Journal of Botany, 2018
We present the first plastome phylogeny encompassing all 77 monocot families, estimate branch sup... more We present the first plastome phylogeny encompassing all 77 monocot families, estimate branch support, and infer monocot-wide divergence times and rates of species diversification. METHODS: We conducted maximum likelihood analyses of phylogeny and BAMM studies of diversification rates based on 77 plastid genes across 545 monocots and 22 outgroups. We quantified how branch support and ascertainment vary with gene number, branch length, and branch depth. KEY RESULTS: Phylogenomic analyses shift the placement of 16 families in relation to earlier studies based on four plastid genes, add seven families, date the divergence between monocots and eudicots+Ceratophyllum at 136 Mya, successfully place all mycoheterotrophic taxa examined, and support recognizing Taccaceae and Thismiaceae as separate families and Arecales and Dasypogonales as separate orders. Only 45% of interfamilial divergences occurred after the Cretaceous. Net species diversification underwent four large-scale accelerations in PACMAD-BOP Poaceae, Asparagales sister to Doryanthaceae, Orchidoideae-Epidendroideae, and Araceae sister to Lemnoideae, each associated with specific ecological/morphological shifts. Branch ascertainment and support across monocots increase with gene number and branch length, and decrease with relative branch depth. Analysis of entire plastomes in Zingiberales quantifies the importance of non-coding regions in identifying and supporting short, deep branches. CONCLUSIONS: We provide the first resolved, well-supported monocot phylogeny and timeline spanning all families, and quantify the significant contribution of plastomescale data to resolving short, deep branches. We outline a new functional model for the evolution of monocots and their diagnostic morphological traits from submersed aquatic ancestors, supported by convergent evolution of many of these traits in aquatic Hydatellaceae (Nymphaeales).
American journal of botany, 2017
The flip-leaved podocarp Retrophyllum has a disjunct extant distribution in South American and Au... more The flip-leaved podocarp Retrophyllum has a disjunct extant distribution in South American and Australasian tropical rainforests and a Gondwanic fossil record since the Eocene. Evolutionary, biogeographic, and paleoecological insights from previously described fossils are limited because they preserve little foliar variation and no reproductive structures. We investigated new Retrophyllum material from the terminal Cretaceous Lefipán, the early Eocene Laguna del Hunco, and the early/middle Eocene Río Pichileufú floras of Patagonian Argentina. We also reviewed type material of historical Eocene fossils from southern Chile. Cretaceous Retrophyllum superstes sp. nov. is described from a leafy twig, while Eocene R. spiralifolium sp. nov. includes several foliage forms and a peduncle with 13 pollen cones. Both species preserve extensive damage from sap-feeding insects associated with foliar transfusion tissue. The Eocene species exhibits a suite of characters linking it to both Neotropic...
Annals of botany, Jan 5, 2018
Early Palaeocene (Danian) plant fossils from Patagonia provide information on the recovery from t... more Early Palaeocene (Danian) plant fossils from Patagonia provide information on the recovery from the end-Cretaceous extinction and Cenozoic floristic change in South America. Actinomorphic flowers with eight to ten perianth parts are described and evaluated in a phylogenetic framework. The goal of this study is to determine the identity of these fossil flowers and to discuss their evolutionary, palaeoecological and biogeographical significance. More than 100 fossilized flowers were collected from three localities in the Danian Salamanca and Peñas Coloradas Formations in southern Chubut. They were prepared, photographed and compared with similar extant and fossil flowers using published literature and herbarium specimens. Phylogenetic analysis was performed using morphological and molecular data. The fossil flowers share some but not all the synapomorphies that characterize the Schizomerieae, a tribe within Cunoniaceae. These features include the shallow floral cup, variable number of...
PloS one, 2017
Southern-Hemisphere terrestrial communities from the early Paleocene are poorly known, but recent... more Southern-Hemisphere terrestrial communities from the early Paleocene are poorly known, but recent work on Danian plant fossils from the Salamanca Formation in Chubut Province, Argentina are providing critical data on earliest Paleocene floras. The fossils described here come from a site in the Salamanca Formation dating to ca. 1 million years or less after the end-Cretaceous extinction event; they are the first fossil flowers reported from the Danian of South America, and possible the entire Southern Hemisphere. They are compressions and impressions in flat-laminated light gray shale, and they belong to the family Rhamnaceae (buckthorns). Flowers of Notiantha grandensis gen. et sp. nov. are pentamerous, with distinctly keeled calyx lobes projecting from the hypanthium, clawed and cucullate emarginate petals, antepetalous stamens, and a pentagonal floral disk that fills the hypanthium. Their phylogenetic position was evaluated using a molecular scaffold approach combined with morphol...
Botany, 2016
A new species of anatomically preserved Cupressaceae is described from the Upper Cretaceous Rarit... more A new species of anatomically preserved Cupressaceae is described from the Upper Cretaceous Raritan Formation (New Jersey, USA). The fossils are charcolified isolated ovuliferous complexes that were studied by means of a combination of SEM images and micro-computed tomography (micro-CT), allowing the observation of morphological and anatomical characters. Each ovuliferous complex bears 3–4 anatropous winged seeds, disposed in one row on a thin medial part of the adaxial side of the ovuliferous complex. Based on the combination of characters such as ovuliferous complex morphology, arrangement of vascular tissues and resin canals, seed number and their morphology, orientation and disposition, these fossils are placed within a new species of the fossil genus Athrotaxites. The developmental stage of the specimens is analyzed base on comparisons with living representatives of the subfamily Athrotaxoideae (i.e., Athrotaxis spp.), which supports a post-pollination stage for these fossils. ...
International Journal of Plant Sciences, 2016
Premise of research: The Cenozoic fossil record is crucial for understanding the evolution of the... more Premise of research: The Cenozoic fossil record is crucial for understanding the evolution of the remarkably high diversity of angiosperms. However, the quality and biases of the angiosperm fossil record remain unclear mainly due to the lack of a global database. Methodology: We introduce a new global occurrence-based database for Cenozoic angiosperm macrofossils, the Cenozoic Angiosperm Database. We test the temporal, spatial, and phylogenetic biases of the Cenozoic angiosperm macrofossil record and explore their causes. Pivotal results: The data presented here include 2478 assemblages from all Cenozoic epochs and 1961 sites from all continents, as well as representatives of 221 families (of 445 recognized) and 1859 genera, and show that the Cenozoic angiosperm macrofossil record is extraordinarily rich. However, this rich record is temporally, spatially, and phylogenetically biased: the Miocene is much better sampled than the rest of Cenozoic, the Northern Hemisphere is better sampled than the Southern Hemisphere, and the rosids are better sampled than the rest of the angiosperms. The sampling bias might be caused by collecting effort, geological history, or diverse features of the families, such as growth form and distribution. Conclusions: The Cenozoic macrofossil record of angiosperms is remarkably rich, especially of woody families found in the Northern Hemisphere. Even if there are numerous biases in these data, a judicious use of the database should be highly informative.
Botanical Journal of the Linnean Society, 2015
PLoS ONE, 2014
The study of biodiversity spans many disciplines and includes data pertaining to species distribu... more The study of biodiversity spans many disciplines and includes data pertaining to species distributions and abundances, genetic sequences, trait measurements, and ecological niches, complemented by information on collection and measurement protocols. A review of the current landscape of metadata standards and ontologies in biodiversity science suggests that existing standards such as the Darwin Core terminology are inadequate for describing biodiversity data in a semantically meaningful and computationally useful way. Existing ontologies, such as the Gene Ontology and others in the Open Biological and Biomedical Ontologies (OBO) Foundry library, provide a semantic structure but lack many of the necessary terms to describe biodiversity data in all its dimensions. In this paper, we describe the motivation for and ongoing development of a new Biological Collections Ontology, the Environment Ontology, and the Population and Community Ontology. These ontologies share the aim of improving data aggregation and integration across the biodiversity domain and can be used to describe physical samples and sampling processes (for example, collection, extraction, and preservation techniques), as well as biodiversity observations that involve no physical sampling. Together they encompass studies of: 1) individual organisms, including voucher specimens from ecological studies and museum specimens, 2) bulk or environmental samples (e.g., gut contents, soil, water) that include DNA, other molecules, and potentially many organisms, especially microbes, and 3) survey-based ecological observations. We discuss how these ontologies can be applied to biodiversity use cases that span genetic, organismal, and ecosystem levels of organization. We argue that if adopted as a standard and rigorously applied and enriched by the biodiversity community, these ontologies would significantly reduce barriers to data discovery, integration, and exchange among biodiversity resources and researchers.