Stephan N. F. Spiekman, Vincent Fernandez, Richard J. Butler, Kathleen N. Dollman, Susannah C. R. Maidment
Non-crocodyliform crocodylomorphs, formerly referred to the informal group ‘Sphenosuchia’, are the earliest known crocodylomorph precursors of extant crocodylians. They are therefore crucial for our understanding of early crocodylian evolution and the origin of typical crocodylian characteristics, such as the formation of a secondary palate, complex cranial pneumaticity, and a reinforced braincase. Terrestrisuchus gracilis, known from the Upper Triassic fissure fill deposits of Pant-y-Ffynnon in southern Wales, is represented by almost 200 specimens, comprising articulated, partially associated, and isolated remains. In this contribution we provide a taxonomic revision of Terrestrisuchus gracilis and redescribe its cranial anatomy in detail, based in part on novel micro-computed tomography data. The posterior skull region is extensively pneumatized as indicated, among other features, by large pre- and postcarotid recesses on the parabasisphenoid, and a large pneumatic cavity in the articular of the mandible. In contrast, the quadrate forms only a small, unfused contact with the prootic, suggesting that complex pneumatization of the postorbital region pre-dated the co-ossification of the quadrate and braincase in Crocodylomorpha. Terrestrisuchus gracilis preserves an ossified basihyal, which represents the first occurrence of this bone in non-avemetatarsalian archosaurs. Finally, we show that Terrestrisuchus gracilis was probably cathemeral (i.e. active in a range of light levels), based on a phylogenetic flexible discriminant analysis of the relative dimensions of the sclerotic ring and orbit.
{"title":"A taxonomic revision and cranial description of Terrestrisuchus gracilis (Archosauria, Crocodylomorpha) from the Upper Triassic of Pant-y-Ffynnon Quarry (southern Wales)","authors":"Stephan N. F. Spiekman, Vincent Fernandez, Richard J. Butler, Kathleen N. Dollman, Susannah C. R. Maidment","doi":"10.1002/spp2.1534","DOIUrl":"https://doi.org/10.1002/spp2.1534","url":null,"abstract":"Non-crocodyliform crocodylomorphs, formerly referred to the informal group ‘Sphenosuchia’, are the earliest known crocodylomorph precursors of extant crocodylians. They are therefore crucial for our understanding of early crocodylian evolution and the origin of typical crocodylian characteristics, such as the formation of a secondary palate, complex cranial pneumaticity, and a reinforced braincase. <i>Terrestrisuchus gracilis</i>, known from the Upper Triassic fissure fill deposits of Pant-y-Ffynnon in southern Wales, is represented by almost 200 specimens, comprising articulated, partially associated, and isolated remains. In this contribution we provide a taxonomic revision of <i>Terrestrisuchus gracilis</i> and redescribe its cranial anatomy in detail, based in part on novel micro-computed tomography data. The posterior skull region is extensively pneumatized as indicated, among other features, by large pre- and postcarotid recesses on the parabasisphenoid, and a large pneumatic cavity in the articular of the mandible. In contrast, the quadrate forms only a small, unfused contact with the prootic, suggesting that complex pneumatization of the postorbital region pre-dated the co-ossification of the quadrate and braincase in Crocodylomorpha. <i>Terrestrisuchus gracilis</i> preserves an ossified basihyal, which represents the first occurrence of this bone in non-avemetatarsalian archosaurs. Finally, we show that <i>Terrestrisuchus gracilis</i> was probably cathemeral (i.e. active in a range of light levels), based on a phylogenetic flexible discriminant analysis of the relative dimensions of the sclerotic ring and orbit.","PeriodicalId":48705,"journal":{"name":"Papers in Palaeontology","volume":"19 1","pages":""},"PeriodicalIF":2.3,"publicationDate":"2023-11-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138523760","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}
Here we report two new small-bodied pachycephalosaurines: one from the Dinosaur Park Formation of Alberta and the other from the Hell Creek Formation of Montana, each represented by an isolated squamosal. These two new specimens are approximately the same size as squamosals of Sphaerotholus buchholtzae, and possess several overlapping morphologies with the genus (such as a strongly posteroventrally projecting and laterally tapering parietosquamosal bar). Therefore, these two new specimens are identified as belonging to the genus Sphaerotholus. However, a suite of characters and combinations differentiate these two new specimens from the other three Sphaerotholus species. Most notably, they possess multiple posterior and lateral node rows on the squamosal, and lack a parietosquamosal node (a single row and a parietosquamosal node define these other species in the genus). Specifically, the Alberta specimen possesses two posterior and two lateral node rows, whereas the Montana specimen has three of each. This analysis provides phylogenetic support for the evolutionary hypothesis that a single-rowed and parietosquamosal node-less taxon underwent a cladogenetic event that gave rise to a single-rowed and parietosquamosal node-bearing lineage and a multi-rowed, parietosquamosal node-less lineage (the two taxa described herein). In turn, these two Sphaerotholus lineages possibly underwent anagenetic change throughout the latest Maastrichtian. Additionally, these new taxa suggest that while large-bodied taxa from well sampled formations are to be found with decreasing frequency, the inverse holds true for small-bodied taxa and that pachycephalosaurines were more diverse than previously recognized, and continued to diversify up until the very end of the Cretaceous.
{"title":"Two new species of small-bodied pachycephalosaurine (Dinosauria, Marginocephalia) from the uppermost Cretaceous of North America suggest hidden diversity in well-sampled formations","authors":"D. Cary Woodruff, Ryan K. Schott, David C. Evans","doi":"10.1002/spp2.1535","DOIUrl":"https://doi.org/10.1002/spp2.1535","url":null,"abstract":"Here we report two new small-bodied pachycephalosaurines: one from the Dinosaur Park Formation of Alberta and the other from the Hell Creek Formation of Montana, each represented by an isolated squamosal. These two new specimens are approximately the same size as squamosals of <i>Sphaerotholus buchholtzae</i>, and possess several overlapping morphologies with the genus (such as a strongly posteroventrally projecting and laterally tapering parietosquamosal bar). Therefore, these two new specimens are identified as belonging to the genus <i>Sphaerotholus</i>. However, a suite of characters and combinations differentiate these two new specimens from the other three <i>Sphaerotholus</i> species. Most notably, they possess multiple posterior and lateral node rows on the squamosal, and lack a parietosquamosal node (a single row and a parietosquamosal node define these other species in the genus). Specifically, the Alberta specimen possesses two posterior and two lateral node rows, whereas the Montana specimen has three of each. This analysis provides phylogenetic support for the evolutionary hypothesis that a single-rowed and parietosquamosal node-less taxon underwent a cladogenetic event that gave rise to a single-rowed and parietosquamosal node-bearing lineage and a multi-rowed, parietosquamosal node-less lineage (the two taxa described herein). In turn, these two <i>Sphaerotholus</i> lineages possibly underwent anagenetic change throughout the latest Maastrichtian. Additionally, these new taxa suggest that while large-bodied taxa from well sampled formations are to be found with decreasing frequency, the inverse holds true for small-bodied taxa and that pachycephalosaurines were more diverse than previously recognized, and continued to diversify up until the very end of the Cretaceous.","PeriodicalId":48705,"journal":{"name":"Papers in Palaeontology","volume":"17 1","pages":""},"PeriodicalIF":2.3,"publicationDate":"2023-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138523740","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}
Lina B. Golovneva, Аnastasia А. Zolina, Robert A. Spicer
The early Paleocene (Danian) Barentsburg flora from the Firkanten Formation, Svalbard, provides a valuable insight into the environment and climate of the Arctic early in the warm Palaeogene prior to the Paleocene–Eocene Thermal Maximum (PETM) event. The flora includes c. 50 species of ferns, ginkgos, conifers and angiosperms. Angiosperms predominate and are represented by the families Platanaceae, Cercidiphyllaceae, Trochodendraceae, Hamamelidaceae, Fagaceae, Betulaceae, Nyssaceae and several taxa of uncertain taxonomic position. Palaeoclimate parameters, calculated using a new calibration of the Climate Leaf Analysis Multivariate Program (CLAMP), indicate that Svalbard in the early Paleocene was characterized by a temperate, maritime, humid, seasonal climate with cool mild winters and warm summers. Humidity was highest during winter months. Short-term winter snow cover and light frosts were likely to have been frequent. The CLAMP analysis yields a mean annual temperature of 10.1 ± 1.98°С, a warmest month mean temperature of 19.2 ± 2.49°C and a coldest month mean temperature of 1.7 ± 3.24°С. The growing season lasted c. 6 months. Precipitation during this growth period was 572.4 ± 296.50 mm, while vapour pressure deficit and potential evapotranspiration indicate very high humidity year-round, with summer being only slightly drier than winter. Taken together with data from other early Paleocene circum-Arctic sites, these results point to highly uniform, temperate and extremely humid conditions around the margins of the early Cenozoic Arctic Ocean. This condition represents the warm background condition that dominated in the Arctic prior to the anomalous extreme warmth of the early Eocene.
{"title":"The early Paleocene (Danian) climate of Svalbard based on palaeobotanical data","authors":"Lina B. Golovneva, Аnastasia А. Zolina, Robert A. Spicer","doi":"10.1002/spp2.1533","DOIUrl":"https://doi.org/10.1002/spp2.1533","url":null,"abstract":"The early Paleocene (Danian) Barentsburg flora from the Firkanten Formation, Svalbard, provides a valuable insight into the environment and climate of the Arctic early in the warm Palaeogene prior to the Paleocene–Eocene Thermal Maximum (PETM) event. The flora includes <i>c.</i> 50 species of ferns, ginkgos, conifers and angiosperms. Angiosperms predominate and are represented by the families Platanaceae, Cercidiphyllaceae, Trochodendraceae, Hamamelidaceae, Fagaceae, Betulaceae, Nyssaceae and several taxa of uncertain taxonomic position. Palaeoclimate parameters, calculated using a new calibration of the Climate Leaf Analysis Multivariate Program (CLAMP), indicate that Svalbard in the early Paleocene was characterized by a temperate, maritime, humid, seasonal climate with cool mild winters and warm summers. Humidity was highest during winter months. Short-term winter snow cover and light frosts were likely to have been frequent. The CLAMP analysis yields a mean annual temperature of 10.1 ± 1.98°С, a warmest month mean temperature of 19.2 ± 2.49°C and a coldest month mean temperature of 1.7 ± 3.24°С. The growing season lasted <i>c.</i> 6 months. Precipitation during this growth period was 572.4 ± 296.50 mm, while vapour pressure deficit and potential evapotranspiration indicate very high humidity year-round, with summer being only slightly drier than winter. Taken together with data from other early Paleocene circum-Arctic sites, these results point to highly uniform, temperate and extremely humid conditions around the margins of the early Cenozoic Arctic Ocean. This condition represents the warm background condition that dominated in the Arctic prior to the anomalous extreme warmth of the early Eocene.","PeriodicalId":48705,"journal":{"name":"Papers in Palaeontology","volume":"35 1","pages":""},"PeriodicalIF":2.3,"publicationDate":"2023-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138523737","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}
Tory L. Botha, Emma Sherratt, Mary L. Droser, Jim G. Gehling, Diego C. García‐Bellido
Abstract Eoandromeda octobrachiata is a poorly understood Ediacaran organism, with spiral octoradial arms, found in South Australia and South China. The informal Nilpena member of the Rawnsley Quartzite, Flinders Ranges in South Australia preserves more than 200 specimens of Eoandromeda . Here we use the novel application of rotational geometric morphometrics together with palaeoenvironmental information to provide a better insight into their palaeobiology and ecology, and to address conflicting hypotheses regarding mode of life and taxonomic affinity. We find that Eoandromeda probably had a radially symmetrical shape in life, was cone shaped and had a high relief off the microbial mat. Analysis of the symmetric and asymmetric shape components showed that they deform strongly in the direction of palaeocurrent, therefore they are thought to be made of a flexible material. Almost all specimens are compressed flat. Specimens that appear to have not fully collapsed support the idea that Eoandromeda was probably cone shaped and suggest that they possibly collapsed spirally. Our shape analysis, along with observed morphological features, support a benthic rather than pelagic mode of life. Morphological and ecological inconsistencies do not fully support the hypothesis of a Ctenophora taxonomic affinity.
{"title":"Elucidating the morphology and ecology of <i>Eoandromeda octobrachiata</i> from the Ediacaran of South Australia","authors":"Tory L. Botha, Emma Sherratt, Mary L. Droser, Jim G. Gehling, Diego C. García‐Bellido","doi":"10.1002/spp2.1530","DOIUrl":"https://doi.org/10.1002/spp2.1530","url":null,"abstract":"Abstract Eoandromeda octobrachiata is a poorly understood Ediacaran organism, with spiral octoradial arms, found in South Australia and South China. The informal Nilpena member of the Rawnsley Quartzite, Flinders Ranges in South Australia preserves more than 200 specimens of Eoandromeda . Here we use the novel application of rotational geometric morphometrics together with palaeoenvironmental information to provide a better insight into their palaeobiology and ecology, and to address conflicting hypotheses regarding mode of life and taxonomic affinity. We find that Eoandromeda probably had a radially symmetrical shape in life, was cone shaped and had a high relief off the microbial mat. Analysis of the symmetric and asymmetric shape components showed that they deform strongly in the direction of palaeocurrent, therefore they are thought to be made of a flexible material. Almost all specimens are compressed flat. Specimens that appear to have not fully collapsed support the idea that Eoandromeda was probably cone shaped and suggest that they possibly collapsed spirally. Our shape analysis, along with observed morphological features, support a benthic rather than pelagic mode of life. Morphological and ecological inconsistencies do not fully support the hypothesis of a Ctenophora taxonomic affinity.","PeriodicalId":48705,"journal":{"name":"Papers in Palaeontology","volume":"16 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135410197","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}
Christos Psarras, Philip C.J. Donoghue, Russell J. Garwood, Dmitriy V. Grazhdankin, Luke A. Parry, Vladimir I. Rogov, Alexander G. Liu
Abstract Fossil material assigned to Nenoxites from the late Ediacaran Khatyspyt Formation of Arctic Siberia (550–544 Ma) has been presented as evidence for bioturbation prior to the basal Cambrian boundary. However, that ichnological interpretation has been challenged, and descriptions of similar material from other global localities support a body fossil origin. Here we combine x‐ray computed tomography, scanning electron microscopy and petrographic methods to evaluate the body or trace fossil nature of Nenoxites from the Khatyspyt Formation. The fossilized structures consist of densely packed chains of three‐dimensionally preserved silicic, bowl‐shaped elements surrounded by distinct sedimentary halos, in a dolomitized matrix. Individual bowl‐shaped elements can exhibit diffuse mineralogical boundaries and bridging connections between elements, both considered here to result from silicification and dolomitization during diagenesis. This new morphological and petrological evidence, in conjunction with recent studies of the late Ediacaran tubular taxa Ordinilunulatus and Shaanxilithes from China, suggest that the Khatyspyt specimens most probably reflect a coquina deposit of Shaanxilithes‐ like body fossils. Our data support the possibility of Shaanxilithes ‐like organisms representing total group eumetazoans.
北极西伯利亚晚埃迪卡拉世Khatyspyt组(550-544 Ma)的Nenoxites化石材料被认为是基底寒武纪边界之前生物扰动的证据。然而，这种技术解释受到了挑战，来自全球其他地区的类似材料的描述支持人体化石的起源。在这里，我们结合x射线计算机断层扫描，扫描电子显微镜和岩石学方法来评估来自Khatyspyt组的Nenoxites的体或痕迹化石性质。在白云化的基质中，化石结构由高密度的三维保存的硅链组成，碗状元素被明显的沉积晕包围。单个碗状元素可以表现出分散的矿物学边界和元素之间的桥接连接，这两者都被认为是成岩过程中硅化和白云化的结果。这一新的形态学和岩石学证据，结合最近对中国埃迪卡拉纪晚期管状分类群Ordinilunulatus和Shaanxilithes的研究，表明Khatyspyt标本很可能反映了Shaanxilithes - like body化石的coquina矿床。我们的数据支持了Shaanxilithes‐‐类生物代表整个类群真生动物的可能性。
{"title":"Three‐dimensional reconstruction, taphonomic and petrological data suggest that the oldest record of bioturbation is a body fossil coquina","authors":"Christos Psarras, Philip C.J. Donoghue, Russell J. Garwood, Dmitriy V. Grazhdankin, Luke A. Parry, Vladimir I. Rogov, Alexander G. Liu","doi":"10.1002/spp2.1531","DOIUrl":"https://doi.org/10.1002/spp2.1531","url":null,"abstract":"Abstract Fossil material assigned to Nenoxites from the late Ediacaran Khatyspyt Formation of Arctic Siberia (550–544 Ma) has been presented as evidence for bioturbation prior to the basal Cambrian boundary. However, that ichnological interpretation has been challenged, and descriptions of similar material from other global localities support a body fossil origin. Here we combine x‐ray computed tomography, scanning electron microscopy and petrographic methods to evaluate the body or trace fossil nature of Nenoxites from the Khatyspyt Formation. The fossilized structures consist of densely packed chains of three‐dimensionally preserved silicic, bowl‐shaped elements surrounded by distinct sedimentary halos, in a dolomitized matrix. Individual bowl‐shaped elements can exhibit diffuse mineralogical boundaries and bridging connections between elements, both considered here to result from silicification and dolomitization during diagenesis. This new morphological and petrological evidence, in conjunction with recent studies of the late Ediacaran tubular taxa Ordinilunulatus and Shaanxilithes from China, suggest that the Khatyspyt specimens most probably reflect a coquina deposit of Shaanxilithes‐ like body fossils. Our data support the possibility of Shaanxilithes ‐like organisms representing total group eumetazoans.","PeriodicalId":48705,"journal":{"name":"Papers in Palaeontology","volume":"7 4","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135714385","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}
Abstract Trilobites from the middle Koumenzi Formation (Katian, Upper Ordovician) of the North Qilian Mountains, Menyuan, northeastern Qinghai Province are systematically documented for the first time. The fauna consists of five families, seven genera and seven species, one of which is new ( Remopleurides zhangi ), showing a close relationship to those of the Kazakh terranes (such as the Chu‐Ili terrane, Chingiz‐Tarbagatai area and the Karatau‐Naryn and North‐Tien Shan microcontinents), and the North China and Laurentia palaeoplates during the Katian (Late Ordovician). The cluster and non‐metric multidimensional scaling analyses of the Middle–Late Ordovician (late Darriwilian–Katian) trilobite faunas with 299 genera or subgenera from 46 horizons of 37 areas, provide valuable information for the palaeogeographical reconstruction of the Proto‐Tethys Archipelagic Ocean (PTAO) of this interval. The Qilian terrane and adjacent areas are essential components of the PTAO, some of which include the Qilian terrane, the North Qilian Mountains area, the Altun faulted terrane, the Hexi Corridor area and the East Qinling terrane. Their relative positions in the PTAO are inferred by the palaeobiogeography of trilobite faunas. Furthermore, based on discussions of the spatiotemporal distribution of those faunas, the Pliomerina and/or Sinocybele Province of the Middle–Late Ordovician (late Darriwilian–Katian) age is defined as a trilobite faunal province of the PTAO. Moreover, a distinct faunal subprovince, essentially comprising the South China Palaeoplate and its neighbours (e.g. Tarim, Annamia, Sibuma, East Qinling, Turkestan‐Alai and probably Talesh), might be surrounded by the equatorial cold‐water tongue.
{"title":"Katian (Late Ordovician) trilobites of the North Qilian Mountains and their palaeogeographical implications for the Proto‐Tethys Archipelagic Ocean","authors":"Xin Wei, Xiaocong Luan, Yuchen Zhang, Guanzhou Yan, Renbin Zhan","doi":"10.1002/spp2.1532","DOIUrl":"https://doi.org/10.1002/spp2.1532","url":null,"abstract":"Abstract Trilobites from the middle Koumenzi Formation (Katian, Upper Ordovician) of the North Qilian Mountains, Menyuan, northeastern Qinghai Province are systematically documented for the first time. The fauna consists of five families, seven genera and seven species, one of which is new ( Remopleurides zhangi ), showing a close relationship to those of the Kazakh terranes (such as the Chu‐Ili terrane, Chingiz‐Tarbagatai area and the Karatau‐Naryn and North‐Tien Shan microcontinents), and the North China and Laurentia palaeoplates during the Katian (Late Ordovician). The cluster and non‐metric multidimensional scaling analyses of the Middle–Late Ordovician (late Darriwilian–Katian) trilobite faunas with 299 genera or subgenera from 46 horizons of 37 areas, provide valuable information for the palaeogeographical reconstruction of the Proto‐Tethys Archipelagic Ocean (PTAO) of this interval. The Qilian terrane and adjacent areas are essential components of the PTAO, some of which include the Qilian terrane, the North Qilian Mountains area, the Altun faulted terrane, the Hexi Corridor area and the East Qinling terrane. Their relative positions in the PTAO are inferred by the palaeobiogeography of trilobite faunas. Furthermore, based on discussions of the spatiotemporal distribution of those faunas, the Pliomerina and/or Sinocybele Province of the Middle–Late Ordovician (late Darriwilian–Katian) age is defined as a trilobite faunal province of the PTAO. Moreover, a distinct faunal subprovince, essentially comprising the South China Palaeoplate and its neighbours (e.g. Tarim, Annamia, Sibuma, East Qinling, Turkestan‐Alai and probably Talesh), might be surrounded by the equatorial cold‐water tongue.","PeriodicalId":48705,"journal":{"name":"Papers in Palaeontology","volume":"9 2","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135714546","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}
Derek J. Siveter, Romain Sabroux, Derek E. G. Briggs, David J. Siveter, Mark D. Sutton
Abstract The three‐dimensionally preserved Haliestes dasos from the Silurian (Wenlock) Lagerstätte is the most complete fossil sea spider and the oldest unambiguous pycnogonid known from the fossil record. The discovery of two new specimens to add to the holotype reveals new features including proximal annulations of the appendages and segmentation of the trunk end, critical details for comparison with pycnogonids from the Devonian (Emsian) Hunsrück Slate and for the interpretation of the evolutionary significance of Palaeozoic genera. There is some evidence of sexual dimorphism. Haliestes dasos was nektobenthic and its morphology indicates an unusual mode of feeding compared with living pycnogonids. The new morphological features of H. dasos are closely similar to those in Palaeoisopus problematicus from the Hunsrück Slate and it clearly belongs, together with that species, in stem Pycnogonida and not the crown group.
{"title":"Newly discovered morphology of the Silurian sea spider <i>Haliestes</i> and its implications","authors":"Derek J. Siveter, Romain Sabroux, Derek E. G. Briggs, David J. Siveter, Mark D. Sutton","doi":"10.1002/spp2.1528","DOIUrl":"https://doi.org/10.1002/spp2.1528","url":null,"abstract":"Abstract The three‐dimensionally preserved Haliestes dasos from the Silurian (Wenlock) Lagerstätte is the most complete fossil sea spider and the oldest unambiguous pycnogonid known from the fossil record. The discovery of two new specimens to add to the holotype reveals new features including proximal annulations of the appendages and segmentation of the trunk end, critical details for comparison with pycnogonids from the Devonian (Emsian) Hunsrück Slate and for the interpretation of the evolutionary significance of Palaeozoic genera. There is some evidence of sexual dimorphism. Haliestes dasos was nektobenthic and its morphology indicates an unusual mode of feeding compared with living pycnogonids. The new morphological features of H. dasos are closely similar to those in Palaeoisopus problematicus from the Hunsrück Slate and it clearly belongs, together with that species, in stem Pycnogonida and not the crown group.","PeriodicalId":48705,"journal":{"name":"Papers in Palaeontology","volume":"81 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135891235","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}
Annabel K. Hunt, D. P. Ford, Vincent Fernandez, J. Choiniere, R. Benson
The late Permian reptile Youngina capensis (c. 254 Ma) is a non‐saurian neodiapsid whose anatomy has been used to represent the reptilian condition prior to the divergence of Sauria (crown‐group reptiles). However, despite being first described over 100 years ago, the anatomy of Youngina remains incompletely documented. Here we use synchrotron x‐ray micro‐computed tomography to document new features of the palate, braincase and mandible of Youngina. New observations include an anteriorly bifurcating vomer, dentition on the ventral surface of the parasphenoid body and cultriform process, and a strongly convex coronoid eminence. Our anatomical observations suggest that Youngina may represent a more stemward lineage among non‐saurian neodiapsids and this is supported by our phylogenetic analysis, which places Youngina as an early diverging neodiapsid. Our research will benefit future studies on saurian origins by providing improved constraints on neodiapsid anatomy prior to the divergence of the reptilian crown group.
{"title":"A description of the palate and mandible of Youngina capensis (Sauropsida, Diapsida) based on synchrotron tomography, and the phylogenetic implications","authors":"Annabel K. Hunt, D. P. Ford, Vincent Fernandez, J. Choiniere, R. Benson","doi":"10.1002/spp2.1521","DOIUrl":"https://doi.org/10.1002/spp2.1521","url":null,"abstract":"The late Permian reptile Youngina capensis (c. 254 Ma) is a non‐saurian neodiapsid whose anatomy has been used to represent the reptilian condition prior to the divergence of Sauria (crown‐group reptiles). However, despite being first described over 100 years ago, the anatomy of Youngina remains incompletely documented. Here we use synchrotron x‐ray micro‐computed tomography to document new features of the palate, braincase and mandible of Youngina. New observations include an anteriorly bifurcating vomer, dentition on the ventral surface of the parasphenoid body and cultriform process, and a strongly convex coronoid eminence. Our anatomical observations suggest that Youngina may represent a more stemward lineage among non‐saurian neodiapsids and this is supported by our phylogenetic analysis, which places Youngina as an early diverging neodiapsid. Our research will benefit future studies on saurian origins by providing improved constraints on neodiapsid anatomy prior to the divergence of the reptilian crown group.","PeriodicalId":48705,"journal":{"name":"Papers in Palaeontology","volume":"284 1","pages":""},"PeriodicalIF":2.3,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76843101","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}
Aixa Tosal, Anne‐Laure Decombeix, Brigitte Meyer‐Berthaud, Jean Galtier, Carles Martín‐Closas
Abstract The first anatomically preserved wood specimens of an upland Carboniferous flora from the Iberian Peninsula are reported from the Erillcastell Basin (Eastern Pyrenees, Catalonia, Spain). Two taxa are described, a calamitacean Equisetales ( Arthropitys sp.) and a Cordaitales ( Dadoxylon sp.). The Arthropitys specimen has fusiform multiseriate rays composed of square parenchyma cells with conspicuous uniseriate or multiseriate simple pits. These pits are located near the transverse walls and occasionally in the tangential walls. The tracheids vary in lumen size, with scalariform‐bordered pits on their radial walls and multiseriate pits in their cross‐field areas. The Dadoxylon specimen commonly has uniseriate fusiform rays. The tracheids are long, with a square shape in transverse section. Their radial walls bear araucarian pitting with a uniseriate to triseriate arrangement. The pits are circular with a spindle‐shaped aperture. Comparison of the Erillcastell specimens with coeval species from Europe indicates that they could belong to new species. The good preservation of the new fossil wood yields significant palaeoenvironmental information. The lack of marked growth rings in both specimens and the presence of tyloses in Dadoxylon suggest that the climate in the intramontane basins of the Pyrenees was slightly seasonal towards the end of the Carboniferous. This contrasts with the marked seasonality of coeval lowland basins. Such upland habitats may have enhanced the survival of plants adapted to humid conditions in a global context of increasing aridity.
{"title":"First report of silicified wood from a late Pennsylvanian intramontane basin in the Pyrenees: systematic affinities and palaeoecological implications","authors":"Aixa Tosal, Anne‐Laure Decombeix, Brigitte Meyer‐Berthaud, Jean Galtier, Carles Martín‐Closas","doi":"10.1002/spp2.1524","DOIUrl":"https://doi.org/10.1002/spp2.1524","url":null,"abstract":"Abstract The first anatomically preserved wood specimens of an upland Carboniferous flora from the Iberian Peninsula are reported from the Erillcastell Basin (Eastern Pyrenees, Catalonia, Spain). Two taxa are described, a calamitacean Equisetales ( Arthropitys sp.) and a Cordaitales ( Dadoxylon sp.). The Arthropitys specimen has fusiform multiseriate rays composed of square parenchyma cells with conspicuous uniseriate or multiseriate simple pits. These pits are located near the transverse walls and occasionally in the tangential walls. The tracheids vary in lumen size, with scalariform‐bordered pits on their radial walls and multiseriate pits in their cross‐field areas. The Dadoxylon specimen commonly has uniseriate fusiform rays. The tracheids are long, with a square shape in transverse section. Their radial walls bear araucarian pitting with a uniseriate to triseriate arrangement. The pits are circular with a spindle‐shaped aperture. Comparison of the Erillcastell specimens with coeval species from Europe indicates that they could belong to new species. The good preservation of the new fossil wood yields significant palaeoenvironmental information. The lack of marked growth rings in both specimens and the presence of tyloses in Dadoxylon suggest that the climate in the intramontane basins of the Pyrenees was slightly seasonal towards the end of the Carboniferous. This contrasts with the marked seasonality of coeval lowland basins. Such upland habitats may have enhanced the survival of plants adapted to humid conditions in a global context of increasing aridity.","PeriodicalId":48705,"journal":{"name":"Papers in Palaeontology","volume":"57 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135249449","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}
Adriana M. Candela, María A. Abello, Marcelo A. Reguero, César M. García Esponda, Ulyses F.J. Pardiñas, Alfredo A. Zurita, Francois Pujos, Ángel Miño‐Boilini, Sofía Quiñones, Claudia I. Galli, Carlos Luna, Damián Voglino, Martín De Los Reyes, Pedro Cuaranta
Abstract We describe new Late Miocene mammalian specimens from the Maimará Formation (Late Miocene to Early Pliocene) exposed at Humahuaca Basin (23°–24°S), northwestern Argentina (NWA), and analyse their taxonomy and relevance for our understanding of the initial stages of the Great American Biotic Interchange (GABI). The stratigraphical and geochronological control of the studied specimens indicates a time window of c . 6.6–5.8 Ma. These data are crucial for establishing the oldest records of the Holarctic immigrants of the GABI. The first record of cricetid rodents from the Maimará Formation is reported. Moreover, with an age of c . 6 Ma it is the first appearance datum (FAD) of these rodents in South America. The age of the procyonid Cyonasua recorded in this unit is estimated between c . 6.6 and c . 6.4 Ma. The record of procyonids and cricetids in the same continuous sedimentary sequence suggests that the time interval between the dispersion of both groups into the continent during GABI was c. 1 myr. Of the autochthonous mammals from the Maimará Formation, the first records of litopterns, chlamyphorid and mylodontine xenarthrans, and caviomorph rodents (including new species Pithanotomys ? solisae and Palaeocavia humahuaquense ) are described. FADs of immigrant and autochthonous mammals in NWA suggest a major faunal turnover during GABI at the Messinian, probably linked to global climatic changes and the tectonic activity that affected the Humahuaca Basin at that time. Hypsodonty, a dominant feature among Maimaran mammals, may be related to a landscape strongly influenced by the Andean uplift.
{"title":"The Late Miocene mammals from the Humahuaca Basin (northwestern Argentina) provide new evidence on the initial stages of the Great American Biotic Interchange","authors":"Adriana M. Candela, María A. Abello, Marcelo A. Reguero, César M. García Esponda, Ulyses F.J. Pardiñas, Alfredo A. Zurita, Francois Pujos, Ángel Miño‐Boilini, Sofía Quiñones, Claudia I. Galli, Carlos Luna, Damián Voglino, Martín De Los Reyes, Pedro Cuaranta","doi":"10.1002/spp2.1527","DOIUrl":"https://doi.org/10.1002/spp2.1527","url":null,"abstract":"Abstract We describe new Late Miocene mammalian specimens from the Maimará Formation (Late Miocene to Early Pliocene) exposed at Humahuaca Basin (23°–24°S), northwestern Argentina (NWA), and analyse their taxonomy and relevance for our understanding of the initial stages of the Great American Biotic Interchange (GABI). The stratigraphical and geochronological control of the studied specimens indicates a time window of c . 6.6–5.8 Ma. These data are crucial for establishing the oldest records of the Holarctic immigrants of the GABI. The first record of cricetid rodents from the Maimará Formation is reported. Moreover, with an age of c . 6 Ma it is the first appearance datum (FAD) of these rodents in South America. The age of the procyonid Cyonasua recorded in this unit is estimated between c . 6.6 and c . 6.4 Ma. The record of procyonids and cricetids in the same continuous sedimentary sequence suggests that the time interval between the dispersion of both groups into the continent during GABI was c. 1 myr. Of the autochthonous mammals from the Maimará Formation, the first records of litopterns, chlamyphorid and mylodontine xenarthrans, and caviomorph rodents (including new species Pithanotomys ? solisae and Palaeocavia humahuaquense ) are described. FADs of immigrant and autochthonous mammals in NWA suggest a major faunal turnover during GABI at the Messinian, probably linked to global climatic changes and the tectonic activity that affected the Humahuaca Basin at that time. Hypsodonty, a dominant feature among Maimaran mammals, may be related to a landscape strongly influenced by the Andean uplift.","PeriodicalId":48705,"journal":{"name":"Papers in Palaeontology","volume":"58 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135686487","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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