C. Amenábar, G. R. Guerstein, Marta I. Alperin, E. Palma, S. Casadío, Alexandra Belgaburo, Martín E. RODRÍGUEZ RAISING
A proper understanding of the palaeoceanographic evolution of the Drake Passage during the Palaeogene is hampered by the lack of precise tools to date and correlate the sedimentary units of areas adjacent to the region. In this work, considering recently published radiometric U–Pb dates, we revised the age of a previous dinoflagellate zones for the middle to upper Eocene units of the Austral–Magallanes Basin. The quantitative analysis of middle to late Eocene dinoflagellate cyst assemblages from different localities close to the Drake Passage allowed us to reconstruct the palaeoenvironmental conditions and the possible surface ocean currents during this time in the area. Assemblages dated between 41.3 and 38.1 Ma represent relatively warm waters in inner shelf settings, while those ranged between 36 and 35 Ma reflect coastal areas with cool, nutrient‐rich surface waters. The proposed surface ocean circulation pattern, based on dinoflagellate cysts distribution between 41.3 and 38.1 Ma, agrees with the results of a palaeoclimatic numerical model simulation performed with a Drake Passage shallow opening of 100 m depth. At c. 36 Ma, several Antarctic gonyaulacacean taxa tolerant to relatively warmer waters were replaced by some Antarctic peridinacean species better adapted to colder conditions. This change could be linked to a progressive deepening of the Drake Passage that is estimated to have reached 1000 m depth promoting a cooling in the South Atlantic. Such passage depth would have enabled stronger flows from the Pacific to the Atlantic Ocean, which is reflected by the increase of cosmopolitan species.
{"title":"Eocene palaeoenvironments and palaeoceanography of areas adjacent to the Drake Passage: insights from dinoflagellate cyst analysis","authors":"C. Amenábar, G. R. Guerstein, Marta I. Alperin, E. Palma, S. Casadío, Alexandra Belgaburo, Martín E. RODRÍGUEZ RAISING","doi":"10.1111/pala.12601","DOIUrl":"https://doi.org/10.1111/pala.12601","url":null,"abstract":"A proper understanding of the palaeoceanographic evolution of the Drake Passage during the Palaeogene is hampered by the lack of precise tools to date and correlate the sedimentary units of areas adjacent to the region. In this work, considering recently published radiometric U–Pb dates, we revised the age of a previous dinoflagellate zones for the middle to upper Eocene units of the Austral–Magallanes Basin. The quantitative analysis of middle to late Eocene dinoflagellate cyst assemblages from different localities close to the Drake Passage allowed us to reconstruct the palaeoenvironmental conditions and the possible surface ocean currents during this time in the area. Assemblages dated between 41.3 and 38.1 Ma represent relatively warm waters in inner shelf settings, while those ranged between 36 and 35 Ma reflect coastal areas with cool, nutrient‐rich surface waters. The proposed surface ocean circulation pattern, based on dinoflagellate cysts distribution between 41.3 and 38.1 Ma, agrees with the results of a palaeoclimatic numerical model simulation performed with a Drake Passage shallow opening of 100 m depth. At c. 36 Ma, several Antarctic gonyaulacacean taxa tolerant to relatively warmer waters were replaced by some Antarctic peridinacean species better adapted to colder conditions. This change could be linked to a progressive deepening of the Drake Passage that is estimated to have reached 1000 m depth promoting a cooling in the South Atlantic. Such passage depth would have enabled stronger flows from the Pacific to the Atlantic Ocean, which is reflected by the increase of cosmopolitan species.","PeriodicalId":56272,"journal":{"name":"Palaeontology","volume":null,"pages":null},"PeriodicalIF":2.6,"publicationDate":"2022-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41346340","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-05-01Epub Date: 2022-05-24DOI: 10.1111/pala.12600
Valentina Rossi, Richard Unitt, Maria McNamara, Roberto Zorzin, Giorgio Carnevale
Colour patterning in extant animals can be used as a reliable indicator of their biology and, in extant fish, can inform on feeding strategy. Fossil fish with preserved colour patterns may thus illuminate the evolution of fish behaviour and community structure, but are understudied. Here we report preserved melanin-based integumentary colour patterning and internal anatomy of the fossil moonfish Mene rhombea (Menidae) from the Bolca Lagerstätte (Eocene (Ypresian), north-east Italy). The melanosome-based longitudinal stripes of M. rhombea differ from the dorsal rows of black spots in its extant relative M. maculata, suggesting that the ecology of moonfish has changed during the Cenozoic. Extant moonfish are coastal schooling fish that feed on benthic invertebrates, but the longitudinal stripes and stomach contents with fish remains in M. rhombea suggest unstructured open marine ecologies and a piscivorous diet. The localized distribution of extant moonfish species in the Indo-Pacific Ocean may reflect, at least in part, tectonically-driven reorganization of global oceanographic patterns during the Cenozoic. It is likely that shifts in habitat and colour patterning genes promoted colour pattern evolution in the menid lineage.
{"title":"Skin patterning and internal anatomy in a fossil moonfish from the Eocene Bolca Lagerstätte illuminate the ecology of ancient reef fish communities.","authors":"Valentina Rossi, Richard Unitt, Maria McNamara, Roberto Zorzin, Giorgio Carnevale","doi":"10.1111/pala.12600","DOIUrl":"https://doi.org/10.1111/pala.12600","url":null,"abstract":"<p><p>Colour patterning in extant animals can be used as a reliable indicator of their biology and, in extant fish, can inform on feeding strategy. Fossil fish with preserved colour patterns may thus illuminate the evolution of fish behaviour and community structure, but are understudied. Here we report preserved melanin-based integumentary colour patterning and internal anatomy of the fossil moonfish <i>Mene rhombea</i> (Menidae) from the Bolca Lagerstätte (Eocene (Ypresian), north-east Italy). The melanosome-based longitudinal stripes of <i>M</i>. <i>rhombea</i> differ from the dorsal rows of black spots in its extant relative <i>M</i>. <i>maculata</i>, suggesting that the ecology of moonfish has changed during the Cenozoic. Extant moonfish are coastal schooling fish that feed on benthic invertebrates, but the longitudinal stripes and stomach contents with fish remains in <i>M</i>. <i>rhombea</i> suggest unstructured open marine ecologies and a piscivorous diet. The localized distribution of extant moonfish species in the Indo-Pacific Ocean may reflect, at least in part, tectonically-driven reorganization of global oceanographic patterns during the Cenozoic. It is likely that shifts in habitat and colour patterning genes promoted colour pattern evolution in the menid lineage.</p>","PeriodicalId":56272,"journal":{"name":"Palaeontology","volume":null,"pages":null},"PeriodicalIF":2.6,"publicationDate":"2022-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ftp.ncbi.nlm.nih.gov/pub/pmc/oa_pdf/f5/61/PALA-65-0.PMC9324815.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"40685446","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
J. Bestwick, Pedro L. Godoy, S. Maidment, M. Ezcurra, Mia Wroe, Thomas J. Raven, Joseph A. Bonsor, R. Butler
Little is known about the large‐scale evolutionary patterns of skull size relative to body size, and the possible drivers behind these patterns, in Archosauromorpha. For example, the large skulls of erythrosuchids, a group of non‐archosaurian archosauromorphs from the Early and Middle Triassic, and of theropod dinosaurs are regarded as convergent adaptations for hypercarnivory. However, few investigations have explicitly tested whether erythrosuchid and theropod skulls are indeed disproportionately large for their body size, and whether this trend is driven by hypercarnivory. Here, we investigate archosauromorph relative skull size evolution, examining the scaling relationships between skull and body size of Palaeozoic and Mesozoic archosauromorphs using a robust phylogenetic framework and assessing the influence of potential drivers, such as taxonomy, diet, locomotory mode and inhabited biotope. Our results show that archosauromorph relative skull sizes are largely determined by phylogeny and that the other drivers have much weaker levels of influence. We find negative allometric scaling of skull size with respect to body size when all studied archosauromorphs are analysed. Within specific groups, skull size scales with positive allometry in non‐archosaurian archosauromorphs and, interestingly, scales isometrically in theropods. Ancestral reconstructions of skull–femur size ratio reveal a disproportionately large skull at the base of Erythrosuchidae and proportionately sized skulls at the bases of Theropoda, Carnosauria and Tyrannosauroidea. Relative skull sizes of erythrosuchids and theropods are therefore distinct from each other, indicating that disproportionately large skulls are not a prerequisite for hypercarnivory in archosauromorphs, and that erythrosuchids exhibit a bauplan unique among terrestrial Mesozoic carnivores.
{"title":"Relative skull size evolution in Mesozoic archosauromorphs: potential drivers and morphological uniqueness of erythrosuchid archosauriforms","authors":"J. Bestwick, Pedro L. Godoy, S. Maidment, M. Ezcurra, Mia Wroe, Thomas J. Raven, Joseph A. Bonsor, R. Butler","doi":"10.1111/pala.12599","DOIUrl":"https://doi.org/10.1111/pala.12599","url":null,"abstract":"Little is known about the large‐scale evolutionary patterns of skull size relative to body size, and the possible drivers behind these patterns, in Archosauromorpha. For example, the large skulls of erythrosuchids, a group of non‐archosaurian archosauromorphs from the Early and Middle Triassic, and of theropod dinosaurs are regarded as convergent adaptations for hypercarnivory. However, few investigations have explicitly tested whether erythrosuchid and theropod skulls are indeed disproportionately large for their body size, and whether this trend is driven by hypercarnivory. Here, we investigate archosauromorph relative skull size evolution, examining the scaling relationships between skull and body size of Palaeozoic and Mesozoic archosauromorphs using a robust phylogenetic framework and assessing the influence of potential drivers, such as taxonomy, diet, locomotory mode and inhabited biotope. Our results show that archosauromorph relative skull sizes are largely determined by phylogeny and that the other drivers have much weaker levels of influence. We find negative allometric scaling of skull size with respect to body size when all studied archosauromorphs are analysed. Within specific groups, skull size scales with positive allometry in non‐archosaurian archosauromorphs and, interestingly, scales isometrically in theropods. Ancestral reconstructions of skull–femur size ratio reveal a disproportionately large skull at the base of Erythrosuchidae and proportionately sized skulls at the bases of Theropoda, Carnosauria and Tyrannosauroidea. Relative skull sizes of erythrosuchids and theropods are therefore distinct from each other, indicating that disproportionately large skulls are not a prerequisite for hypercarnivory in archosauromorphs, and that erythrosuchids exhibit a bauplan unique among terrestrial Mesozoic carnivores.","PeriodicalId":56272,"journal":{"name":"Palaeontology","volume":null,"pages":null},"PeriodicalIF":2.6,"publicationDate":"2022-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42584293","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Sebastian S. Groh, P. Upchurch, P. Barrett, J. J. Day
Clade ages within the crocodylomorph clade Neosuchia have long been debated. Molecular and morphological studies have yielded remarkably divergent results. Despite recent advances, there has been no comprehensive relative comparison of the major time calibration methods available to estimate clade ages based on morphological data. We used four methods (cal3, extended Hedman, smoothed ghost lineage analysis (sGLA) and the fossilized birth–death model (FBD)) to date clade ages derived from a published crocodylomorph supertree and a new neosuchian phylogeny. All time‐scaling methods applied here agree on the origination of Neosuchia during the Late Triassic or Early Jurassic, and the presence of the major extant eusuchian groups (Crocodyloidea, Gavialoidea, Alligatoroidea and Caimaininae) by the end of the Late Cretaceous. The number of distinct lineages present before the K/Pg boundary is less certain, with support for two competing scenarios in which Crocodylinae, Tomistominae and Diplocynodontinae either: (1) diverged from other eusuchian lineages before the K/Pg boundary; or (2) evolved during a ‘burst’ of diversification after the K/Pg event. Cal3 and FBD proved to be the most suitable methods for time‐scaling phylogenetic trees dominated by fossil taxa. Extended Hedman estimates are substantially older than the others, with larger standard deviations and a strong sensitivity to taxon sampling and topological changes; sGLA has similar problems. We conclude that a detailed understanding of phylogenetic relationships, tree reconstruction methods, and good taxonomic coverage (in particular the inclusion of the oldest taxon in each clade) is essential when evaluating the results of such dating analyses.
{"title":"How to date a crocodile: estimation of neosuchian clade ages and a comparison of four time‐scaling methods","authors":"Sebastian S. Groh, P. Upchurch, P. Barrett, J. J. Day","doi":"10.1111/pala.12589","DOIUrl":"https://doi.org/10.1111/pala.12589","url":null,"abstract":"Clade ages within the crocodylomorph clade Neosuchia have long been debated. Molecular and morphological studies have yielded remarkably divergent results. Despite recent advances, there has been no comprehensive relative comparison of the major time calibration methods available to estimate clade ages based on morphological data. We used four methods (cal3, extended Hedman, smoothed ghost lineage analysis (sGLA) and the fossilized birth–death model (FBD)) to date clade ages derived from a published crocodylomorph supertree and a new neosuchian phylogeny. All time‐scaling methods applied here agree on the origination of Neosuchia during the Late Triassic or Early Jurassic, and the presence of the major extant eusuchian groups (Crocodyloidea, Gavialoidea, Alligatoroidea and Caimaininae) by the end of the Late Cretaceous. The number of distinct lineages present before the K/Pg boundary is less certain, with support for two competing scenarios in which Crocodylinae, Tomistominae and Diplocynodontinae either: (1) diverged from other eusuchian lineages before the K/Pg boundary; or (2) evolved during a ‘burst’ of diversification after the K/Pg event. Cal3 and FBD proved to be the most suitable methods for time‐scaling phylogenetic trees dominated by fossil taxa. Extended Hedman estimates are substantially older than the others, with larger standard deviations and a strong sensitivity to taxon sampling and topological changes; sGLA has similar problems. We conclude that a detailed understanding of phylogenetic relationships, tree reconstruction methods, and good taxonomic coverage (in particular the inclusion of the oldest taxon in each clade) is essential when evaluating the results of such dating analyses.","PeriodicalId":56272,"journal":{"name":"Palaeontology","volume":null,"pages":null},"PeriodicalIF":2.6,"publicationDate":"2022-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47697155","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A. Brum, T. Simões, Geovane A. Souza, A. E. Pinheiro, Rodrigo G. Figueiredo, M. Caldwell, J. Sayão, A. Kellner
The Antarctic plesiosaurian record is critical for understanding the evolution of elasmosaurids in the southern hemisphere. Elasmosaurids exhibit some of the most remarkable modifications of the vertebrate axial skeleton given their extreme elongation of the cervical region. Despite a considerable amount of information available on vertebral counts within Plesiosauria throughout the decades, we have a considerably more limited understanding of the diversity of cervical vertebral shapes in elasmosaurids and how these have changed throughout ontogeny and phylogeny. Here, we compile the largest known morphometric dataset on elasmosaurid cervical vertebrae, including data on juveniles and adults, to answer some of those long‐standing questions. This dataset also includes newly recovered materials from Antarctica, which we describe herein. Using multivariate statistical approaches, we find that the two major elasmosaurid cervical morphotypes, the elasmosaurine anteroposteriorly elongate (can‐shaped) and the aristonectine anteroposteriorly short and dorsoventrally tall (disc‐like), evolved towards opposite regions of the morphospace from the plesiomorphic ‘Cimoliasaurus’‐grade condition. We also find a marked ontogenetic shift from the disc‐like to can‐shaped morphology, which is especially pronounced in elasmosaurines but more limited in aristonectines. Furthermore, we find that juvenile aristonectines occupy a specific region of the vertebral morphospace, distinct from any other group or ontogenetic stage, thus suggesting that reversal to the ‘short‐necked’ condition in elasmosaurids is mostly characterized by ontogenetic predisplacement in aristonectines. Finally, we find that it is possible to discriminate between vertebral shapes of distinct taxonomic groups regardless of ontogenetic stage, and that the diversity of Antarctic elasmosaurids was greater than previously recognized.
{"title":"Ontogeny and evolution of the elasmosaurid neck highlight greater diversity of Antarctic plesiosaurians","authors":"A. Brum, T. Simões, Geovane A. Souza, A. E. Pinheiro, Rodrigo G. Figueiredo, M. Caldwell, J. Sayão, A. Kellner","doi":"10.1111/pala.12593","DOIUrl":"https://doi.org/10.1111/pala.12593","url":null,"abstract":"The Antarctic plesiosaurian record is critical for understanding the evolution of elasmosaurids in the southern hemisphere. Elasmosaurids exhibit some of the most remarkable modifications of the vertebrate axial skeleton given their extreme elongation of the cervical region. Despite a considerable amount of information available on vertebral counts within Plesiosauria throughout the decades, we have a considerably more limited understanding of the diversity of cervical vertebral shapes in elasmosaurids and how these have changed throughout ontogeny and phylogeny. Here, we compile the largest known morphometric dataset on elasmosaurid cervical vertebrae, including data on juveniles and adults, to answer some of those long‐standing questions. This dataset also includes newly recovered materials from Antarctica, which we describe herein. Using multivariate statistical approaches, we find that the two major elasmosaurid cervical morphotypes, the elasmosaurine anteroposteriorly elongate (can‐shaped) and the aristonectine anteroposteriorly short and dorsoventrally tall (disc‐like), evolved towards opposite regions of the morphospace from the plesiomorphic ‘Cimoliasaurus’‐grade condition. We also find a marked ontogenetic shift from the disc‐like to can‐shaped morphology, which is especially pronounced in elasmosaurines but more limited in aristonectines. Furthermore, we find that juvenile aristonectines occupy a specific region of the vertebral morphospace, distinct from any other group or ontogenetic stage, thus suggesting that reversal to the ‘short‐necked’ condition in elasmosaurids is mostly characterized by ontogenetic predisplacement in aristonectines. Finally, we find that it is possible to discriminate between vertebral shapes of distinct taxonomic groups regardless of ontogenetic stage, and that the diversity of Antarctic elasmosaurids was greater than previously recognized.","PeriodicalId":56272,"journal":{"name":"Palaeontology","volume":null,"pages":null},"PeriodicalIF":2.6,"publicationDate":"2022-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46403826","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Corentin Gibert, Axelle Zacaï, F. Fluteau, G. Ramstein, O. Chavasseau, G. Thiery, Antoine Souron, William E. Banks, F. Guy, D. Barboni, P. Sepulchre, C. Blondel, G. Merceron, O. Otero
In order to understand mammalian evolution and compute a wide range of biodiversity indices, we commonly use the ‘bioregion’, a spatial division adapted to ecological and evolutionary constraints. While commonly conducted by neontologists, the establishment of bioregions in palaeontology is generally a secondary analysis, shaped on subjective time scales and areas specific to the investigated questions and groups. This heterogeneity, coupled with the scale‐dependency of biodiversity indices, prevents the clear identification of macroecological and macroevolutionary trends for large taxonomic groups like extinct mammals. Here we tackle this issue by providing a coherent framework for Neogene and Pleistocene mammals of the Old World following two steps: (1) a temporal scale adapted to mammalian evolutionary history (i.e. evolutionary fauna) is defined by poly‐cohort analysis; (2) bioregions are then computed for each evolutionary fauna by clustering, ordination and intermediate approaches at multiples spatial scales (i.e. continental to regional) for Eurasia and Africa. Additionally, providing a coherent framework for a wide range of mammalian datasets, our results show: (1) the synchronous emergence and fall of five mammalian evolutionary faunas identified at chronological scales varying from the epoch to the geological stage; (2) a transition from a longitudinal to a latitudinal biogeographical structuring between the Miocene and Pliocene, especially in Europe; (3) the long‐term affinity of southern Asian with African faunas, in sharp contrast with the modern Palaearctic bioregion extension; and (4) the establishment of a vast Mediterranean bioregion from fragmented areas in the Late Miocene to its full extent in the Pleistocene.
{"title":"A coherent biogeographical framework for Old World Neogene and Pleistocene mammals","authors":"Corentin Gibert, Axelle Zacaï, F. Fluteau, G. Ramstein, O. Chavasseau, G. Thiery, Antoine Souron, William E. Banks, F. Guy, D. Barboni, P. Sepulchre, C. Blondel, G. Merceron, O. Otero","doi":"10.1111/pala.12594","DOIUrl":"https://doi.org/10.1111/pala.12594","url":null,"abstract":"In order to understand mammalian evolution and compute a wide range of biodiversity indices, we commonly use the ‘bioregion’, a spatial division adapted to ecological and evolutionary constraints. While commonly conducted by neontologists, the establishment of bioregions in palaeontology is generally a secondary analysis, shaped on subjective time scales and areas specific to the investigated questions and groups. This heterogeneity, coupled with the scale‐dependency of biodiversity indices, prevents the clear identification of macroecological and macroevolutionary trends for large taxonomic groups like extinct mammals. Here we tackle this issue by providing a coherent framework for Neogene and Pleistocene mammals of the Old World following two steps: (1) a temporal scale adapted to mammalian evolutionary history (i.e. evolutionary fauna) is defined by poly‐cohort analysis; (2) bioregions are then computed for each evolutionary fauna by clustering, ordination and intermediate approaches at multiples spatial scales (i.e. continental to regional) for Eurasia and Africa. Additionally, providing a coherent framework for a wide range of mammalian datasets, our results show: (1) the synchronous emergence and fall of five mammalian evolutionary faunas identified at chronological scales varying from the epoch to the geological stage; (2) a transition from a longitudinal to a latitudinal biogeographical structuring between the Miocene and Pliocene, especially in Europe; (3) the long‐term affinity of southern Asian with African faunas, in sharp contrast with the modern Palaearctic bioregion extension; and (4) the establishment of a vast Mediterranean bioregion from fragmented areas in the Late Miocene to its full extent in the Pleistocene.","PeriodicalId":56272,"journal":{"name":"Palaeontology","volume":null,"pages":null},"PeriodicalIF":2.6,"publicationDate":"2022-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49137676","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
T. Cullen, Shuangquan Zhang, Joseph Spencer, B. Cousens
Stable and radiogenic isotopes represent powerful tools for reconstructing ecological and environmental patterns in ancient ecosystems. The Cretaceous of North America preserves a diverse record of fossil vertebrates well‐suited to analysis using these proxies, contained within many well‐sampled and stratigraphically well‐characterized intervals. Multiple hypotheses have been offered to explain the diverse assemblages of megaherbivores that co‐occurred in the relatively restricted available landmass here, including various forms of niche‐partitioning related to habitat preference, dietary specialization and feeding height stratification. Here we analyse the 87Sr/86Sr, δ13C and δ18O of bioapatite samples obtained from a range of herbivores, faunivores and endemic taxa, from a spatiotemporally‐constrained and intensively‐sampled site in the upper Oldman Formation, to test if megaherbivores partitioned their niches based on spatial patterns of occupation and resource‐use. We also compare measured strontium values to regional 87Sr/86Sr data to assess biogeographical range sizes, habitat breadth and migration potential. We find that hadrosaurs had broad ranges, whereas ankylosaurs and ceratopsids were more spatially restricted. The 87Sr/86Sr ranges of hadrosaurs are much wider and do not overlap with those of other ornithischians, potentially related to dietary differences driven by a combination of feeding height‐stratification and habitat breadth differences. Ankylosaurs and ceratopsids overlapped extensively in 87Sr/86Sr, δ13C and δ18O, indicating overlap in the same habitats and intake of similar resources, and suggesting more complex spatiotemporal variation in resource‐use patterns, fine‐scale dietary differences, and/or sufficient resource‐availability to reduce the degree of competition given this theoretical niche overlap. Additional analyses integrating ecomorphological proxies may elucidate these patterns further.
{"title":"Sr‐O‐C isotope signatures reveal herbivore niche‐partitioning in a Cretaceous ecosystem","authors":"T. Cullen, Shuangquan Zhang, Joseph Spencer, B. Cousens","doi":"10.1111/pala.12591","DOIUrl":"https://doi.org/10.1111/pala.12591","url":null,"abstract":"Stable and radiogenic isotopes represent powerful tools for reconstructing ecological and environmental patterns in ancient ecosystems. The Cretaceous of North America preserves a diverse record of fossil vertebrates well‐suited to analysis using these proxies, contained within many well‐sampled and stratigraphically well‐characterized intervals. Multiple hypotheses have been offered to explain the diverse assemblages of megaherbivores that co‐occurred in the relatively restricted available landmass here, including various forms of niche‐partitioning related to habitat preference, dietary specialization and feeding height stratification. Here we analyse the 87Sr/86Sr, δ13C and δ18O of bioapatite samples obtained from a range of herbivores, faunivores and endemic taxa, from a spatiotemporally‐constrained and intensively‐sampled site in the upper Oldman Formation, to test if megaherbivores partitioned their niches based on spatial patterns of occupation and resource‐use. We also compare measured strontium values to regional 87Sr/86Sr data to assess biogeographical range sizes, habitat breadth and migration potential. We find that hadrosaurs had broad ranges, whereas ankylosaurs and ceratopsids were more spatially restricted. The 87Sr/86Sr ranges of hadrosaurs are much wider and do not overlap with those of other ornithischians, potentially related to dietary differences driven by a combination of feeding height‐stratification and habitat breadth differences. Ankylosaurs and ceratopsids overlapped extensively in 87Sr/86Sr, δ13C and δ18O, indicating overlap in the same habitats and intake of similar resources, and suggesting more complex spatiotemporal variation in resource‐use patterns, fine‐scale dietary differences, and/or sufficient resource‐availability to reduce the degree of competition given this theoretical niche overlap. Additional analyses integrating ecomorphological proxies may elucidate these patterns further.","PeriodicalId":56272,"journal":{"name":"Palaeontology","volume":null,"pages":null},"PeriodicalIF":2.6,"publicationDate":"2022-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47550144","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
J. Botting, D. Janussen, L. Muir, M. Dohrmann, Junye Ma, Yuandong Zhang
The deep‐sea hexactinellid sponge Euplectella is an iconic living genus with no known fossil record. The family Euplectellidae (which includes a subset of genera that share the common name ‘Venus' flower basket’) has a very sparse record from the Middle Cretaceous onwards, and an estimated crown‐group origin at around 300 Ma based on molecular clocks. New material of Venus' flower baskets from the latest Ordovician Anji Biota of China (444 Ma) dramatically extends the known and predicted range of the group, with implications for the diversification of the class Hexactinellida and the timing of development of deep‐sea ecosystems. The new material is described as Anjiplectella davidipharus gen. et sp. nov., with an additional taxon remaining in open nomenclature but demonstrating diversification within the group by this time.
深海海鞘海绵尤普莱克是一种没有已知化石记录的标志性生物。Euplectellidae科(包括一个属的子集，它们共享一个共同的名字“维纳斯花篮”)从白垩纪中期开始就有非常稀疏的记录，根据分子钟估计，冠群的起源大约在300 Ma左右。来自中国最新的奥陶纪安吉生物群(444 Ma)的维纳斯花篮的新材料极大地扩展了该群的已知和预测范围，对Hexactinellida类的多样化和深海生态系统的发展时间具有重要意义。新材料被描述为Anjiplectella davidipharus gen. et sp. nov.，另有一个分类单元保留在开放的命名法中，但此时在该群体中显示出多样化。
{"title":"Extraordinarily early Venus' flower basket sponges (Hexactinellida, Euplectellidae) from the uppermost Ordovician Anji Biota, China","authors":"J. Botting, D. Janussen, L. Muir, M. Dohrmann, Junye Ma, Yuandong Zhang","doi":"10.1111/pala.12592","DOIUrl":"https://doi.org/10.1111/pala.12592","url":null,"abstract":"The deep‐sea hexactinellid sponge Euplectella is an iconic living genus with no known fossil record. The family Euplectellidae (which includes a subset of genera that share the common name ‘Venus' flower basket’) has a very sparse record from the Middle Cretaceous onwards, and an estimated crown‐group origin at around 300 Ma based on molecular clocks. New material of Venus' flower baskets from the latest Ordovician Anji Biota of China (444 Ma) dramatically extends the known and predicted range of the group, with implications for the diversification of the class Hexactinellida and the timing of development of deep‐sea ecosystems. The new material is described as Anjiplectella davidipharus gen. et sp. nov., with an additional taxon remaining in open nomenclature but demonstrating diversification within the group by this time.","PeriodicalId":56272,"journal":{"name":"Palaeontology","volume":null,"pages":null},"PeriodicalIF":2.6,"publicationDate":"2022-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46623434","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
S. Castiglione, C. Serio, A. Mondanaro, M. Melchionna, P. Raia
Assembling informal supertrees inclusive of extinct species is a useful but particularly long and complex procedure. We introduce a new, interactive, piece of software that allows the fast production of large, time‐calibrated informal supertrees, single‐handedly mixing multiple phylogenetic information from different sources. The software, embodied in the tree.merger function available as part of the RRphylo R package, allows the merging of different trees into one or adding individual species to a target phylogeny. Time calibration is implemented automatically within the function according to user‐specified, optional age values that can be provided for nodes and/or tips. We applied tree.merger to two different case‐studies. The first, hypothetical, case study pertains to the tree of odontocete cetaceans. The second case study regards the expansion of the new, higher‐level phylogeny of dinosaurs proposing the sister clade relationship between Ornithoscelida and Sauropodomorpha from c. 50 to a 357 species tree. The two case studies took less than five seconds each to complete, on a regular personal computer.
{"title":"Fast production of large, time‐calibrated, informal supertrees with tree.merger","authors":"S. Castiglione, C. Serio, A. Mondanaro, M. Melchionna, P. Raia","doi":"10.1111/pala.12588","DOIUrl":"https://doi.org/10.1111/pala.12588","url":null,"abstract":"Assembling informal supertrees inclusive of extinct species is a useful but particularly long and complex procedure. We introduce a new, interactive, piece of software that allows the fast production of large, time‐calibrated informal supertrees, single‐handedly mixing multiple phylogenetic information from different sources. The software, embodied in the tree.merger function available as part of the RRphylo R package, allows the merging of different trees into one or adding individual species to a target phylogeny. Time calibration is implemented automatically within the function according to user‐specified, optional age values that can be provided for nodes and/or tips. We applied tree.merger to two different case‐studies. The first, hypothetical, case study pertains to the tree of odontocete cetaceans. The second case study regards the expansion of the new, higher‐level phylogeny of dinosaurs proposing the sister clade relationship between Ornithoscelida and Sauropodomorpha from c. 50 to a 357 species tree. The two case studies took less than five seconds each to complete, on a regular personal computer.","PeriodicalId":56272,"journal":{"name":"Palaeontology","volume":null,"pages":null},"PeriodicalIF":2.6,"publicationDate":"2022-02-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41699373","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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