Papers in Palaeontology最新文献

{"title":"Astogenetic morphological variation in the bryozoan Prophyllodictya gracilis from the Middle Ordovician of Russia and inferred colony‐wide feeding currents","authors":"M. Key, P. N. Wyse Jackson, Madelaine S. McDowell, M. Nestell","doi":"10.1002/spp2.1492","DOIUrl":"https://doi.org/10.1002/spp2.1492","url":null,"abstract":"The discovery of a relatively large and complete ptilodictyid bryozoan colony enabled morphometric analysis of astogenetic change from the colony base to the periphery. This enabled us to test the hypothesis that the relative area of feeding and non‐feeding zooids must be relatively constant across astogenetic growth in this colony. The colony is a stenolaemate cryptostome belonging to the cribrate species Prophyllodictya gracilis (Eichwald). It was recovered from the Volkhov Formation (Dapingian Stage of the Middle Ordovician) from the Putilovo Quarry east of St Petersburg, Russia. The colony was digitally imaged so lacuna and branch dimensions could be measured relative to the colony base and colony edge. Branch thickness and width decreased from the colony base to the top of the colony. Lacuna area and the number of autozooecial rows per branch also decreased distally while the number of lacunae per area increased. As a result, there was an astogenetically stable ratio of autozooid‐bearing skeletal branch area to the total lacuna area across the colony. This characteristic is interpreted as a requirement of colony‐wide feeding currents in this cribrate cryptostome colony.","PeriodicalId":48705,"journal":{"name":"Papers in Palaeontology","volume":"20 1","pages":""},"PeriodicalIF":2.3,"publicationDate":"2023-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83342416","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}

{"title":"Influence of abiotic and biotic factors on benthic marine community composition, structure and stability: a multidisciplinary approach to molluscan assemblages from the Miocene of northern Germany","authors":"Daria Carobene, R. Bussert, U. Struck, Carl J. Reddin, M. Aberhan","doi":"10.1002/spp2.1496","DOIUrl":"https://doi.org/10.1002/spp2.1496","url":null,"abstract":"The Miocene mica‐clay deposits of Groß Pampau (northern Germany) are well known for their diverse assemblages of marine mammals. Despite numerous systematic and biostratigraphic studies, an in‐depth palaeoecological analysis of its molluscan assemblages and a comprehensive palaeoenvironmental reconstruction are lacking. Here, we integrate new faunal, sedimentological and geochemical data to reconstruct the marine palaeoecosystem of the Upper Miocene sedimentary succession of Groß Pampau, and to identify the drivers controlling the composition, ecological structure and temporal dynamics of its macrobenthic molluscan assemblages. Fossil evidence, coupled with analyses of clay mineral composition, grain size distribution and geochemical data (total organic carbon, total nitrogen, δ13C, δ18O, δ15N of sediment and shells), suggests a warm–temperate, mesotrophic, low‐energy, offshore marine setting mostly below storm wave base and a pronounced surface‐to‐bottom water temperature gradient. Low variability in sedimentological and geochemical signals indicates generally stable physicochemical conditions, whereas the occurrence of the opportunistic species Varicorbula gibba suggests occasionally unfavourable bottom conditions, possibly related to transient hypoxia. Canonical correspondence analysis indicates that the distribution of molluscan assemblages correlates with total organic carbon and nitrogen content, suggesting organic matter availability at the sea floor as a controlling factor. A pattern of repetitive punctuated stasis of molluscan assemblages is defined by the temporal persistence in taxonomic and ecological composition, occasionally interrupted by shifts to a different faunal configuration. We suggest that both stable environmental conditions and biotic interactions (i.e. the top‐down control exerted by carnivorous gastropods and environmental modification by ubiquitous burrowing deposit feeders) probably contributed to the observed temporal stability.","PeriodicalId":48705,"journal":{"name":"Papers in Palaeontology","volume":"43 1","pages":""},"PeriodicalIF":2.3,"publicationDate":"2023-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85108442","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}

{"title":"Two almost‐forgotten Trypanites ichnospecies names for the most common Palaeozoic macroboring","authors":"D. Knaust, A. Dronov, U. Toom","doi":"10.1002/spp2.1491","DOIUrl":"https://doi.org/10.1002/spp2.1491","url":null,"abstract":"Trypanites is the most common macroboring with a global occurrence throughout the Phanerozoic and is the eponym of the Trypanites ichnofacies. It has great value for the recognition of discontinuity and hiatal surfaces on top of carbonate hardgrounds. Four ichnospecies of this ichnogenus are currently regarded as valid, while a characteristic fifth form from the early Palaeozoic is frequently reported in open nomenclature. The latter commonly occurs in lithic hardgrounds and skeletal hard substrates (such as stromatoporoids, bryozoans and corals) in Ordovician and Silurian carbonates of the Baltic region. A review of the old literature found that this ichnospecies has previously been introduced twice, as Trypanites sozialis Eisenack from a Silurian erratic boulder found on the Sambia Peninsula near Kaliningrad (now Russia), and as T. keilaensis Orviku from the Ordovician of Estonia. Both ichnospecies became forgotten names for unknown reasons. A morphometric analysis of the type material and topotype specimens indicates gradational transitions between both ichnospecies, rendering T. sozialis as the senior synonym of T. keilaensis. A lectotype from the type series of both ichnospecies is defined and additional material from Ordovician and Silurian carbonates of Estonia and Russia is described and illustrated to show the morphological and morphometric variation of this important bioerosion trace fossil. To enable interspecies comparison, a lectotype of the type ichnospecies of Trypanites, T. weisei Mägdefrau, is selected. Trypanites sozialis is a common boring in Cambrian to Devonian hardgrounds and occurs on the palaeocontinents of Baltica, Laurentia and Gondwana.","PeriodicalId":48705,"journal":{"name":"Papers in Palaeontology","volume":"35 1","pages":""},"PeriodicalIF":2.3,"publicationDate":"2023-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77213841","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}

{"title":"An abundant sea anemone from the Carboniferous Mazon Creek Lagerstӓtte, USA","authors":"R. Plotnick, G. Young, J. Hagadorn","doi":"10.1002/spp2.1479","DOIUrl":"https://doi.org/10.1002/spp2.1479","url":null,"abstract":"Sea anemones (Actiniaria) are among the rarest of recognized fossil organisms, even rarer than jellyfish. Here we demonstrate that the most abundant fossil in the Pennsylvanian Mazon Creek Lagerstätte of Illinois, Essexella asherae, is an infaunal or semi‐infaunal anemone. Essexella is redescribed based on a taphonomic analysis of thousands of specimens, as well as associated medusae and trace fossils. Specimens of Essexella (also known as the ‘blobs’) were long believed to be medusae, but we reassign Essexella to the order Actiniaria and reinterpret the putative jellyfish Reticulomedusa as the pedal or oral disc of Essexella. We also implicate Essexella as a producer of Conostichus, a widespread plug‐shaped trace fossil that occurs in coeval strata in the same region. Radiate structures comparable to the bases of Conostichus and the ichnofossil Bergaueria, as well as the pedal discs of modern anemones, characterize Reticulomedusa. Bona fide medusae are present in the Mazon Creek biota, and include Anthracomedusa turnbulli and Octomedusa pieckorum, whereas the soft‐bodied fossil Lascoa mesostaurata is referred to Problematica.","PeriodicalId":48705,"journal":{"name":"Papers in Palaeontology","volume":"19 1","pages":""},"PeriodicalIF":2.3,"publicationDate":"2023-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75913724","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}

{"title":"Putative hydroid symbionts recorded by bioclaustrations in fossil molluscan shells: a revision and reinterpretation of the cecidogenus Rodocanalis","authors":"M. Wisshak, S. Schneider, R. Mikuláš, S. Richiano, F. Ramil, Mark A. Wilson","doi":"10.1002/spp2.1484","DOIUrl":"https://doi.org/10.1002/spp2.1484","url":null,"abstract":"The fossil record yields a peculiar phenomenon in different kinds of molluscan shells: bioclaustrations formed around (epi)symbionts during growth of the hosts' shell margin. Four morphologies, two of them formerly considered bioerosion traces, are here united in the parataxonomy of bioclaustration structures under the revised cecidogenus Rodocanalis. These are: (1) simple linear grooves (Rodocanalis linearis csp. nov.) formed below the periostracum in Pleistocene to Recent endobenthic bivalves; (2) series of distally ramifying grooves (Rodocanalis runicus) in Silurian orthoconic nautiloids; (3) irregular networks of grooves (Rodocanalis reticulatus) in Jurassic to Cretaceous bivalves and gastropods; and (4) regular reticulate networks (Rodocanalis geometricus csp. nov.) in Jurassic to Cretaceous gastropods. The linear grooves might be associated with commensal worms, while multiple lines of reasoning point towards hydrozoan symbionts in the case of the branched and anastomosing grooves. After the hydrozoan larva settles and the first polyp becomes fixed on the calcareous ostracum at the shell margin, the process of bioclaustration commences when the periostracum surrounds the base of the polyp, which moves towards the external shell surface, while the hydrorhizae develop in the only possible direction: towards the shell growth margin. This enables new polyps to originate at the shell edge by budding, while the bioclaustration of the stolonial hydrorhizae advances. We consider the nature of this symbiotic relationship as mutualism, with the hydrozoan symbiont taking advantage of the host's feeding current or food debris, and the molluscan host profiting from the defensive capability of the hydrozoan's cnidocysts.","PeriodicalId":48705,"journal":{"name":"Papers in Palaeontology","volume":"72 1","pages":""},"PeriodicalIF":2.3,"publicationDate":"2023-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89523682","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}

{"title":"A peirosaurid mandible from the Albian–Cenomanian (Lower Cretaceous) of Algeria and the taxonomic content of Hamadasuchus (Crocodylomorpha, Peirosauridae)","authors":"Yohan Pochat‐Cottilloux, V. Perrier, R. Amiot, J. Martin","doi":"10.1002/spp2.1485","DOIUrl":"https://doi.org/10.1002/spp2.1485","url":null,"abstract":"Peirosaurids form an extinct clade of terrestrial crocodylomorphs from the Cretaceous of Africa and South America. Here, we describe a new mandibular ramus attributable to Hamadasuchus cf. rebouli from the Albian–Cenomanian of La Gara Samani (Algeria). We propose an emended diagnosis for this taxon, originally described from a left dentary fragment from the Kem Kem Group of Morocco and discuss the assignment of the specimens currently referred to it. Using ontogenetic series of extant crocodylians, we show that several mandibular characters commonly used to differentiate between close taxa instead record intraspecific or ontogenetic variability. In contrast, reliable mandibular characters enable us to propose that the current taxonomic content of Hamadasuchus rebouli should be reduced to three specimens, pending future description of relatable cranial remains. Finally, we demonstrate the importance of mandibular characters in phylogenies, by recovering the new specimen from La Gara Samani as closely related to North African peirosaurids on the basis of a data matrix designed solely on mandibular characters.","PeriodicalId":48705,"journal":{"name":"Papers in Palaeontology","volume":"19 1","pages":""},"PeriodicalIF":2.3,"publicationDate":"2023-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91074021","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}

{"title":"Bivalves from the Changhsingian (upper Permian) Bellerophon Formation of the Dolomites (Italy): ancestors of Lower Triassic post‐extinction benthic communities","authors":"H. Prinoth, R. Posenato","doi":"10.1002/spp2.1486","DOIUrl":"https://doi.org/10.1002/spp2.1486","url":null,"abstract":"Diverse shallow marine fossil assemblages from the Changhsingian Bellerophon Formation (Dolomites) record late Palaeozoic marine life immediately before the end‐Permian mass extinction. We classified c. 6500 bivalves from western Dolomites localities, identifying 26 species including one new family (Ladinomyidae), three new genera (Ladinomya, Lovaralucina, Gardenapecten) and 10 new species: Acharax frenademezi, Bakevellia (Bakevellia) preromangica, Edmondia hautmanni, Etheripecten stuflesseri, Ladinomya fosteri, Lovaralucina covidi, Palaeolima badiotica, Promytilus merlai, Tambanella? stetteneckensis and Volsellina carinata. The occurrence of three Eumorphotis species with different stratigraphic distributions, leads us to propose an upper Permian ‘Lower Eumorphotis Zone’, divided into E. praecurrens, E. striatocostata and E. lorigae subzones, and distinct from the existing Lower Triassic Eumorphotis Zone (here renamed ‘Upper Eumorphotis Zone’). Palaeoecological analysis produced six biofacies and four ecofacies, based on richness, dominance and ecological lifestyle. The bivalves inhabited lagoonal to nearshore environments affected by stressed conditions: high temperatures, high salinity, shallow water depths, low oxygen and high terrigenous input. The upper Bellerophon Fm is characterized by increasingly fully marine conditions, although eurytopic taxa still suggest stressed conditions. Bivalve richness of the upper Permian Bellerophon and Lower Triassic Werfen formations was compared to estimate the genus‐level extinction rate. The disappearance of almost half (47%) of Bellerophon Fm genera is remarkably low compared with other, coeval bivalve faunas. Pre‐extinction bivalve faunas were dominated by stress‐adapted taxa (Unionites, Eumorphotis, Bakevellia, Towapteria) able to thrive in extreme environmental conditions, survive the end‐Permian mass extinction, and become the dominant biotic component of Lower Triassic benthic communities globally.","PeriodicalId":48705,"journal":{"name":"Papers in Palaeontology","volume":"4 1","pages":""},"PeriodicalIF":2.3,"publicationDate":"2023-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75561770","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}

{"title":"On the occurrence of rare nannoliths (calcareous nannofossils) in the Early Jurassic and their implications for the end‐Triassic mass extinction","authors":"M. Paulsen, N. Thibault","doi":"10.1002/spp2.1489","DOIUrl":"https://doi.org/10.1002/spp2.1489","url":null,"abstract":"A peculiar record of previously undescribed and/or rarely described nannoliths from the Hettangian to lower Pliensbachian of the Llanbdr (Mochras Farm) core, Wales (UK) is documented here. Some of the observed morphotypes are assigned to didemnid ascidians, commonly observed in the upper Rhaetian, as evidence of the resilience of ascidian tunicates during the end‐Triassic mass extinction. One newly described nannolith present throughout the Hettangian and Sinemurian, Quadrifolium hesselboi, is similar to forms previously observed in the upper Rhaetian, and is therefore considered to be a new nannofossil survivor from the end‐Triassic mass extinction. High‐amplitude changes observed in the absolute and relative abundances of nannoliths, schizosphaerellids and coccoliths across the Hettangian suggest a recovery interval from the end‐Triassic crisis spanning the planorbis–liasicus ammonite zones in four distinct steps with high volatility in environmental conditions, followed by the establishment of more stable environmental conditions in the angulata ammonite zone.","PeriodicalId":48705,"journal":{"name":"Papers in Palaeontology","volume":"319 1","pages":""},"PeriodicalIF":2.3,"publicationDate":"2023-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75443783","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}

{"title":"Burrows provided shelter for tetrapods in a Permo‐Triassic desert","authors":"H. Francischini, P. Dentzien‐Dias, Francesco Battista, Gabriel S. Sipp, T. P. Melo, C. Scherer, C. Schultz","doi":"10.1002/spp2.1490","DOIUrl":"https://doi.org/10.1002/spp2.1490","url":null,"abstract":"We describe for the first time the presence of straight, curved and quasi‐helical burrows preserved in plan, oblique and transversal views in the aeolian strata of the Permo‐Triassic Buena Vista Formation (Paraná Basin), Rio Grande do Sul, southern Brazil. The morphology of the burrows is similar to that of others found in Guadalupian to Early Triassic‐aged deposits in several parts of the world. Of these, middle Permian dicynodont‐bearing helical burrows (Daimonelix) and Early–Middle Triassic kidney‐shaped burrows (Reniformichnus), both from the Karoo Basin of South Africa, show a remarkable similarity to the Brazilian burrows, prompting a discussion of the probable producers. Dicynodonts, cynodonts, therocephalian and/or procolophonians are among the probable producers of such burrows, based on size compatibility between the burrows and estimates of body size for the fossil taxa, along with the presence of skeletal adaptations in Permo‐Triassic tetrapods for digging (bone micro‐ and macrostructure). Last, we discuss some behavioural aspects of the producer of the burrows, mainly due to the presence of passive filling and bilobate bottoms in the tunnels, which indicates that they remained open as long as they were occupied. The burrows were excavated in a dry aeolian system that occurred in the Guadalupian–Induan interval of Brazil, representing the oldest unambiguous record of tetrapod dwelling structures in such an environment, and providing new and unprecedented information regarding the colonization of deserts by tetrapods during the end‐Permian biotic crisis.","PeriodicalId":48705,"journal":{"name":"Papers in Palaeontology","volume":"120 1","pages":""},"PeriodicalIF":2.3,"publicationDate":"2023-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77012457","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}

{"title":"Machine learning confirms new records of maniraptoran theropods in Middle Jurassic UK microvertebrate faunas","authors":"S. Wills, C. Underwood, P. Barrett","doi":"10.1002/spp2.1487","DOIUrl":"https://doi.org/10.1002/spp2.1487","url":null,"abstract":"Current research suggests that the initial radiation of maniraptoran theropods occurred in the Middle Jurassic, although their fossil record is known almost exclusively from the Cretaceous. However, fossils of Jurassic maniraptorans are scarce, usually consisting solely of isolated teeth, and their identifications are often disputed. Here, we apply different machine learning models, in conjunction with morphological comparisons, to a suite of isolated theropod teeth from Bathonian microvertebrate sites in the UK to determine whether any of these can be confidently assigned to Maniraptora. We generated three independent models developed on a training dataset with a wide range of theropod taxa and broad geographical and temporal coverage. Classification of the Middle Jurassic teeth in our sample against these models and comparison of the morphology indicates the presence of at least three distinct dromaeosaur morphotypes, plus a therizinosaur and troodontid in these assemblages. These new referrals significantly extend the ranges of Therizinosauroidea and Troodontidae by some 27 myr. These results indicate that not only were maniraptorans present in the Middle Jurassic, as predicted by previous phylogenetic analyses, but they had already radiated into a diverse fauna that pre‐dated the break‐up of Pangaea. This study also demonstrates the power of machine learning to provide quantitative assessments of isolated teeth in providing a robust, testable framework for taxonomic identifications, and highlights the importance of assessing and including evidence from microvertebrate sites in faunal and evolutionary analyses.","PeriodicalId":48705,"journal":{"name":"Papers in Palaeontology","volume":"40 1","pages":""},"PeriodicalIF":2.3,"publicationDate":"2023-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80337868","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}