Palaeontologia Electronica最新文献

{"title":"A novel distance that reduces information loss in continuous characters with few observations","authors":"Gerardo A. Lo Valvo, Oscar E. R. Lehmann, Diego Balseiro","doi":"10.26879/1250","DOIUrl":"https://doi.org/10.26879/1250","url":null,"abstract":"The calculation of pairwise distances is a fundamental step in many statistical analyses in biology and paleontology. The most commonly used distances work with a single observation per object and character, but there are scenarios where multiple observations are available per object. In these situations, the information for the character spans an interval, and pairs of objects can have overlapping intervals, which further complicates the distance calculation. Some coefficients can deal with this wealth of information but are either too coarse to provide detailed results or too computationally demanding for even moderately large data sets. Here, we present the Distance Between Intervals (DBI) as a novel semi-metric distance that can accommodate both singular and multiple observations per object by analyzing them as intervals. The DBI ranges from 0 to 1 when there is an overlap between the objects and from 1 to infinity when there is no overlap between them. It is easy to calculate and can be applied to a wide variety of data types. Both simulated and empirical test cases show that the DBI correctly ranks pairs of objects by their level of overlap and non-overlap, while other distances struggle to do it. Therefore, the DBI can provide a finer level of definition than other available distances for empirical data sets, while generally agreeing with the broad results they provide. An implementation of DBI is provided for the R program-ming language.","PeriodicalId":56100,"journal":{"name":"Palaeontologia Electronica","volume":null,"pages":null},"PeriodicalIF":2.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69148778","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"New look at Concavicaris woodfordi (Euarthropoda: Pancrustacea?) using micro-computed tomography","authors":"Thomas Laville, T. Hegna, M. Forel, S. Darroch, S. Charbonnier","doi":"10.26879/1218","DOIUrl":"https://doi.org/10.26879/1218","url":null,"abstract":"Known from at least the Silurian to the Cretaceous, Thylacocephala is an enigmatic fossil euarthropod ingroup, often allied with Pancrustacea. Previous studies show that thylacocephalans are characterized by a folded protective shield, hypertrophied compound eyes, three pairs of raptorial appendages, a posterior trunk comprised of eight to 22 segments bearing appendages, and eight pairs of gills. Despite this knowledge of their anatomy, many questions remain, especially surrounding the anatomy of Paleozoic representatives. The Upper Devonian Woodford Shale (upper Famennian, Oklahoma, USA) has yielded several fossil euarthropods, including two species of Thylacocephala: Concavicaris elytroides and Concavicaris woodfordi. Here, we use micro-computed Xray tomography to re-explore the anatomy of the holotype of C. woodfordi, illustrating fine details of the shield structure, of the circulatory, digestive and reproductive systems, and of the appendages. A marginal fold of the shield as well as an inner layer are described for the first time in a thylacocephalan. Concavicaris woodfordi shares similarities with Concavicaris submarinus, another Famennian species, including the morphology of the shield and the internal anatomy. It also displays a similar organisation as Mesozoic taxa, such as Dollocaris ingens. All of this provides important information that will be crucial to reconstruct the evolution and the affinities of Thylacocephala. Thomas Laville. Muséum national d’Histoire naturelle, Centre de Recherche en Paléontologie-Paris (UMR7207), MNHN-Sorbonne Université-CNRS, Paris, France and Biogéosciences, UMR 6282CNRS, Université Bourgogne Franche-Comté, EPHE, Dijon, France. Corresponding author. thomas.laville@ecomail.fr Thomas A. Hegna. Department of Geology and Environmental Science, State University of New York at Fredonia, New York, USA thomas.hegna@fredonia.edu Marie-Béatrice Forel. Muséum national d’Histoire naturelle, Centre de Recherche en Paléontologie-Paris (UMR7207), MNHN-Sorbonne Université-CNRS, Paris, France. marie-beatrice.forel@mnhn.fr Simon Darroch. Department of Earth and Environmental Sciences, Vanderbilt University, Nashville, LAVILLE ET AL.: NEW LOOK AT CONCAVICARIS WOODFORDI 2 Tennessee, USA. simon.a.darroch@vanderbilt.edu Sylvain Charbonnier. Muséum national d’Histoire naturelle, Centre de Recherche en Paléontologie-Paris (UMR7207), MNHN-Sorbonne Université-CNRS, Paris, France. sylvain.charbonnier@mnhn.fr","PeriodicalId":56100,"journal":{"name":"Palaeontologia Electronica","volume":null,"pages":null},"PeriodicalIF":2.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69147969","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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 new approach to the systematics of Laeviprosopon (Brachyura: Homolidae), with remarks on molting process of the early brachyurans","authors":"Natalia Starzyk, B. V. van Bakel, A. Klompmaker, G. Schweigert, René H. B. Fraaije","doi":"10.26879/1204","DOIUrl":"https://doi.org/10.26879/1204","url":null,"abstract":"Our understanding of the molting process in the Jurassic brachyurans is very scarce because useful material is rare. New specimens from Poland and Germany, in addition to previously known specimens, let us further investigate the molting process. Specimens of Laeviprosopon laeve reveal characters not known before. On the dorsal carapace, molting lines are confirmed in three species of Laeviprosopon : the type species L. laeve , L. laculatum and L. fraasi . This brought questions about the systematic position of Laeviprosopon , which we here reassign to Homolidae within Homoloidea. Furthermore, two specimens ascribed previously to L. sublaeve are transferred to L. fraasi","PeriodicalId":56100,"journal":{"name":"Palaeontologia Electronica","volume":null,"pages":null},"PeriodicalIF":2.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69148263","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Middle Eocene cartilaginous fishes (Vertebrata: Chondrichthyes) of the Dnieper–Donets Basin, northern Ukraine","authors":"O. Kovalchuk, J. Kriwet, K. Shimada, T. Ryabokon, Z. Barkaszi, Anastasiia Dubikovska, G. Anfimova, S. Davydenko","doi":"10.26879/1283","DOIUrl":"https://doi.org/10.26879/1283","url":null,"abstract":"Marine basins that existed in present-day Ukraine during the Eocene harboured various groups of cartilaginous and bony fishes, reptiles, aquatic birds, and marine mammals. Fish remains from Paleogene deposits of Kyiv and its vicinities were first collected and described by O.S. Rogovich in the mid-19th century. Here we have carried out a re-examination of chondrichthyan fossils from Rogovich’s collection and evaluated several later records, all of which were recovered from middle Eocene","PeriodicalId":56100,"journal":{"name":"Palaeontologia Electronica","volume":null,"pages":null},"PeriodicalIF":2.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69148743","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Biostratigraphy and biochronology of late Cenozoic North American rodent assemblages","authors":"Robert Martin, Thomas S. Kelly","doi":"10.26879/1303","DOIUrl":"https://doi.org/10.26879/1303","url":null,"abstract":"Late Cenozoic rodent assemblages from western North America were added to a previous database limited to the central and eastern United States to develop a continental correlational system for the past 5 million years. Three hundred and twelve species representing 124 rodent assemblages were included, from which 12 Cenozoic Mammal Zones (CMZs) were constructed. Replacement chronologies for rodent assemblages based upon superposition, radiometric dates, paleomagnetic profiles, and evolutionary stages of dentitions from various depositional basins formed the skeleton for the chronological ordering of assemblages, and those lacking one or more information sources were sequenced based upon greatest concordance with available data. Arvicoline cricetids provided the most useful information for sequencing assemblages, followed by neotomine and sigmodontine cricetids and geomyids. The appearance of modern-sized cotton rats in CMZ 4, followed by the immigration of Allophaiomys across Beringia in CMZ 3, heralds the shift to the dominance of cotton rats and arhizodont voles in North American grassland ecosystems. No rapid bouts of significant turnover are associated with the beginning of the Pleistocene at 2.58 Ma (million years ago), but a pronounced turnover event was observed in the Meade Basin of southwestern Kansas immediately following the Huckleberry Ridge ash-fall at 2.07 Ma. Preliminary observations suggest two categories of rodent turnover; low-level background rotation determined by stochastic short-term regional and long-term global environmental change, and short-term turnover spikes mediated by catastrophic events such as volcanic eruptions.","PeriodicalId":56100,"journal":{"name":"Palaeontologia Electronica","volume":null,"pages":null},"PeriodicalIF":2.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69149115","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Redescription of soft tissue preservation in the holotype of Scaphognathus crassirostris (Goldfuß, 1831) using reflectance transformation imaging","authors":"Nils Henkemeier, K. Jäger, M. Sander","doi":"10.26879/1070","DOIUrl":"https://doi.org/10.26879/1070","url":null,"abstract":"The description of the holotype of the non-pterodactyloid pterosaur Scaphog-nathus crassirostris from the Upper Jurassic Solnhofen Formation by the German palaeontologist Georg August Goldfuß in 1831 was the basis for the first published scientific life reconstruction of a pterosaur. In the time since Goldfuß, the technologies used in imaging soft parts in fossils have advanced greatly, but despite its historical importance, the holotype of S. crassirostris has received relatively little attention, limiting comparisons to more recent pterosaurian soft part finds. In this study, reflectance transformation imaging (RTI) was used to investigate fine surface details of the S. cras-sirostris type specimen. The observations of Goldfuß concerning the existence of different preservational patterns of the hair-like integumentary structures (pycnofibres) in this specimen were confirmed. Individual pycnofibre types differ both in their position and frequency and may indicate variation in pycnofibre morphology across different body regions in the living animal. Pycnofibre types forming a ‘tuft’ or a ‘feather-like’ structure are similar to those of other pterosaur fossils from the southern German Sol-nhofen Formation and the northeastern Chinese Tiaojishan Formation. However, some types, such as ‘forked’ pycnofibre impressions, could be artefacts of taphonomic processes. This study provides further evidence for the similarity in the preservation of integumentary appendages and associated preservational patterns in pterosaurs across different localities, palaeoenvironments, stratigraphic ages","PeriodicalId":56100,"journal":{"name":"Palaeontologia Electronica","volume":null,"pages":null},"PeriodicalIF":2.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69147122","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Description of contents of unopened bamboo corsets and crates from Quarry Ig/WJ of the Tendaguru locality (Late Jurassic, Tanzania, East Africa) as revealed by medical CT data and the potential of this data under paleontological and historical aspects","authors":"D. Schwarz, G. Fritsch, A. Issever, Thomas Hildebrandt","doi":"10.26879/1231","DOIUrl":"https://doi.org/10.26879/1231","url":null,"abstract":"The German Tendaguru Expedition from 1909 to 1913 to Southern Tanzania (then the German colony Deutsch-Ostafrika) was one of the most successful field campaigns for fossil vertebrates. Forty still originally packed and unopened bamboo corsets and six wooden crates containing vertebrate fossils excavated at Quarry Ig/WJ in the Tend-aguru area are preserved at the Museum für Naturkunde Berlin. Studies of the containers with a medical CT scanner made it possible to visualize the packed fossil specimens, which had either a clay protection cover, were still in sediment, or were found as clusters of small vertebrae and tin cans filled with small bones. The majority of bones belong to the small ornithopod Dysalotosaurus, supplemented by a few remains of the thyreophoran dinosaur Kentrosaurus and sauropod dinosaurs. Criteria for the prioritization of preparation of the material are defined based on their paleonto-logical importance plus their historical value as evidence for an excavation campaign carried out under colonial conditions. Therefore, it is suggested that a few of the original containers be preserved in their original condition. This study provides a nonde-structive way to assess information about historical, unprepared fossil material, as well as virtual access to these containers. In its original preservation, the described whole suite of containers is historical evidence of the hard and substantial excavation work of many local people from the Tendaguru area, and it documents historical collection practices including colonial preparation and field practices at the Tendaguru fossil site.","PeriodicalId":56100,"journal":{"name":"Palaeontologia Electronica","volume":null,"pages":null},"PeriodicalIF":2.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69148105","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Late Pleistocene and Holocene pikas (Mammalia, Lagomorpha) from Europe and the validity of Ochotona spelaea: New insights based on mtDNA analysis","authors":"Emilia Rabiniak, L. Rekovets, J. Stewart, L. Dalén, N. Barton, T. Strzała, Z. Barkaszi, O. Kovalchuk","doi":"10.26879/1241","DOIUrl":"https://doi.org/10.26879/1241","url":null,"abstract":"Pikas were among small mammals that inhabited mammoth steppes during the last glacial. The evolutionary history of ochotonids in Europe is relatively well studied, although the taxonomic status of many described forms remains ambiguous","PeriodicalId":56100,"journal":{"name":"Palaeontologia Electronica","volume":null,"pages":null},"PeriodicalIF":2.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69148288","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Simulating our ability to accurately detect abrupt changes in assemblage-based paleoenvironmental proxies","authors":"C. Belanger, David W. Bapst","doi":"10.26879/1282","DOIUrl":"https://doi.org/10.26879/1282","url":null,"abstract":"Resolving abrupt environmental changes in sedimentary records is critical to understanding environmental perturbations relevant on human timescales. The paleontological assemblage mixer (paleoAM) framework developed here simulates sedimentary records to measure the preservation potential of abrupt changes in assemblage-based faunal proxies while varying environmental background conditions, excursion magnitudes and durations, bioturbation, sedimentation rates, and sampling completeness. Using a record of fossil benthic foraminifera, we apply paleoAM to quantitatively determine how distinct from background conditions and how enduring an assemblage change must be to be accurately detected. At the high sedimentation rates of the case study, century-long low-oxygen events frequently have a high probability of being sampled and accurately detected, quantitatively estimated with simulations across varying sedimentation rates","PeriodicalId":56100,"journal":{"name":"Palaeontologia Electronica","volume":null,"pages":null},"PeriodicalIF":2.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69148731","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Anchitheriomys buceei (Rodentia, Castoridae) from the Miocene of Texas and a review of the Miocene beavers from the Texas Coastal Plain, USA","authors":"S. May, Matthew Brown","doi":"10.26879/1236","DOIUrl":"https://doi.org/10.26879/1236","url":null,"abstract":"The record of fossil beavers from Miocene age strata in the Texas Coastal Plain is sparse. The first occurrence of fossil beavers is in Arikareean age faunas. One fossil beaver specimen was reported from a Hemingfordian fauna near Navasota, TX. Both Monosaulax and Anchitheriomys are described here from multiple early Barstovian faunas including a new taxon, Anchitheriomys buceei. The taxon, A. buceei, was a relatively large beaver, similar to A. fluminis in size, and shares characters with both A. fluminis and A. nanus. The holotype of Anchitheriomys buceei is a partial skull and endocast that preserves key features of the orbital foramina and palatine. Referred specimens include a partial dentary, isolated cheek teeth, and two post-cranial elements. The co-occurrence of this taxon and a small beaver identified as Monosaulax sp. in early Barstovian faunas is coeval with the first occurrence of proboscideans along the Texas Coastal Plain. Beavers are unknown in late Barstovian and Clarendonian faunas, although rodent fossils are uncommon from these faunas in general. Most of the fossil beaver specimens were obtained in the early twentieth century by collectors affiliated with Dr. Mark Francis at Texas A&M University, or with the State-Wide Paleontologic-Mineralogic Survey in Texas and are curated at the Texas Vertebrate Paleontology Collections. Archival materials housed at that facility have been instrumental in unraveling the history of collection, the distribution of localities and the evolving understanding of Miocene vertebrate biostratigraphy on the Texas Coastal Plain. Steven R. May, Jackson School Museum of Earth History, The University of Texas at Austin, Austin, Texas 78758, USA. srmay@utexas.edu Matthew A. Brown, Jackson School Museum of Earth History, The University of Texas at Austin, Austin, Texas 78758, USA. matthewbrown@utexas.edu","PeriodicalId":56100,"journal":{"name":"Palaeontologia Electronica","volume":null,"pages":null},"PeriodicalIF":2.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69148221","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}