Paleontological Research最新文献

{"title":"Two-Tiered Transition of the North Atlantic Surface Hydrology during the Past 1.6 Ma: Multiproxy Evidence from Planktic Foraminifera","authors":"M. Yamasaki, C. Shimada, M. Ikehara, R. Schiebel","doi":"10.2517/2020PR026","DOIUrl":"https://doi.org/10.2517/2020PR026","url":null,"abstract":"Abstract. Analyses of planktic foraminiferal assemblage data, test morphology, and stable oxygen isotopes from the Integrated Ocean Drilling Program (IODP) Site U1304 in the North Atlantic reveal a stepwise regional migration of the oceanic fronts around 0.6 Ma and 0.4 Ma, i.e., during Marine Isotope Stages (MISs) 15 and 11, respectively. Both changes of planktic foraminiferal assemblages and shell carbonate isotopes indicate that the cold Arctic waters in general persisted at IODP Site U1304 from 1.6 to 0.6 Ma (MIS 15), even though the warmer waters originating from the Atlantic waters episodically bathed Site U1304 during the interglacial periods. During the time-interval from ca. 0.6 to 0.4 Ma (MISs 15–11), an alternating dominance of Artic and Atlantic waters at the Site U1304 has been suggested from isotopic evidence. In MIS 11, the dominant planktic foraminiferal species Neogloboquadrina pachyderma experienced a short-term but significant decrease in test size. The test-size change may have been caused by accelerated reproduction in more favorite feeding conditions over the long-lasting interglacial period around the Subarctic Front. This finding is supported by the presence of massive diatoms oozes in the same time-interval. The modern-type glacial/interglacial change of the surface water system established since ca. 0.4 Ma (MIS 11) followed the Mid-Brunhes Event.","PeriodicalId":54645,"journal":{"name":"Paleontological Research","volume":"25 1","pages":"345 - 365"},"PeriodicalIF":0.9,"publicationDate":"2021-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48051883","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":"The Structure of the Miocene Northwestern Pacific Ichthyofauna as Revealed By Two Fossil Fish Assemblages From Sakhalin Island, Russia","authors":"M. Nazarkin","doi":"10.2517/2021PR005","DOIUrl":"https://doi.org/10.2517/2021PR005","url":null,"abstract":"Abstract. Two coeval assemblages of fossil fishes came from the middle–late Miocene deposits of Sakhalin Island, Russia. The fish community from the Agnevo Formation consists of 28 species belonging to 15 families of shallow-water fishes, with the predominance of cottoids, stichaeoids, and pleuronectoids. The assemblage from the Kurasi Formation contains fossils of 35 species from 27 fish families and comprises mainly mesopelagic dwellers, such as myctophids, argentiniforms, stomiiforms, and aulopiforms. These assemblages differ mainly in the number of species belonging to extinct genera. Among the 28 fish genera known from the Agnevo Formation, 14 (50%) genera are extinct. In contrast, out of 35 genera described from the Kurasi Formation only three (about 8.6%) genera are extinct. The morphological distances between the fossil and recent congeneric species are more pronounced and defined in the shallow-water community than in the deep-water assemblage. The differences in taxonomic composition between the fossil assemblages likely reflect the different influence of the climatic and geographic events in the Neogene and Quarternary on the evolutionary rates of shallow- and deep-water fish communities.","PeriodicalId":54645,"journal":{"name":"Paleontological Research","volume":"25 1","pages":"366 - 374"},"PeriodicalIF":0.9,"publicationDate":"2021-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48013544","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":"An Additional New Species of Turbo (Marmarostoma) (Gastropoda: Turbinidae) from the Middle Miocene of the Izu Peninsula, Central Japan","authors":"S. Tomida, Hayato Sano, T. Kase","doi":"10.2517/2021PR006","DOIUrl":"https://doi.org/10.2517/2021PR006","url":null,"abstract":"Abstract. The turbinid gastropod Turbo (Marmarostoma) is common in the limestone bodies within the middle Miocene Sakurada and Kadono formations (Yugashima Group) on the Izu Peninsula, central Japan. The limestone bodies were originally deposited under a low-latitude, tropical climate in the northeastern Philippine Sea and then drifted northwards on the Philippine Sea Plate. This paper describes an additional species, Turbo (Marmarostoma) ishidai sp. nov., from the Ena Limestone on the south-western Izu Peninsula. This new species is characterized by its large shell size and shell form similar to the modern Australian endemic species Turbo (Marmarostoma) cepoides Smith, 1880, but differs in having thick tuberculate spiral cords on the shell surface of earlier teleoconch whorls instead of the smooth and broad spiral cords on and around the angled shoulder. The addition of this new species further highlights the presence of a biodiversity hotspot of this gastropod group in the northeastern Philippines Sea during the middle Miocene.","PeriodicalId":54645,"journal":{"name":"Paleontological Research","volume":"25 1","pages":"375 - 378"},"PeriodicalIF":0.9,"publicationDate":"2021-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47269644","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":"Nonmarine Mass Extinctions","authors":"S. Lucas","doi":"10.2517/2021PR004","DOIUrl":"https://doi.org/10.2517/2021PR004","url":null,"abstract":"Abstract. A critical review of putative nonmarine mass extinctions associated with the so-called “Big 5 mass extinctions” of marine invertebrates (Late Ordovician, Late Devonian, end Permian, end Triassic and end Cretaceous) as well as a likely sixth mass extinction in the marine realm, the end-Guadalupian extinction, reveals little evidence of coeval marine and nonmarine mass extinctions. Little lived on land during the Ordovician other than a bryophyte-like flora that appears to have been diversifying, not going extinct, during the Late Ordovician. No case can be made for mass extinctions on land coeval with the marine extinctions of the Late Devonian-land plant diversity increased into the Carboniferous, and the tetrapod fossil record is inadequate to identify any mass extinctions. A case can be made for coeval plant/tetrapod extinctions and the end-Guadalupian marine extinctions, so this may be the first coeval marine-nonmarine mass extinction. However, problems of timing and questions about the extent of the nonmarine late/end-Guadalupian extinctions indicate that further research is needed. There were no mass extinctions of land plants, insects or tetrapods across the Permo–Triassic boundary. The Late Triassic was a time of low origination and high extinction rates on land and in the seas; there was no single end-Triassic mass extinction in either realm. The end-Cretaceous provides the strongest case for coeval land–sea mass extinctions, but there is no mass extinction of land plants, evidence of insect extinction is based on assumption-laden analyses of proxies for insect diversity and the tetrapod extinction was very selective. So, whether the nonmarine extinction at the end of the Cretaceous was a mass extinction is worth questioning. Part of the inability to identify nonmarine mass extinctions stems from taphonomic megabiases due to the relatively poor quality and uneven sampling of the nonmarine fossil record. Extinction resistance and resilience of terrestrial organisms is also a likely factor in the dearth of nonmarine mass extinctions, and this merits further investigation.","PeriodicalId":54645,"journal":{"name":"Paleontological Research","volume":"25 1","pages":"329 - 344"},"PeriodicalIF":0.9,"publicationDate":"2021-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43312922","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":"Systematic Revision and Palaeobiology of Emplastron edwardsi (Van Straelen, 1928) gen. et comb. nov. (Crustacea, Decapoda, Astacidae) Entombed within Travertine, from Sézanne, France","authors":"R. O'Flynn, Denis Audo, T. Kawai","doi":"10.2517/2021PR007","DOIUrl":"https://doi.org/10.2517/2021PR007","url":null,"abstract":"Abstract. Crayfish are rare in the fossil record and therefore it is important to investigate each occurrence in detail. The only known fossil crayfish from France, Astacus edwardsi Van Straelen, 1928, is known from a replica made by pouring plaster of Paris inside the holotype (subsequently destroyed), an external mould extracted from a travertine cavity from the Thanetian of Sézanne. An evaluation of the taxonomic name, A. edwardsi, is provided; A. edwardsi is considered valid in accordance with ICZN rulings. It possesses atypical features for all other astacid genera, thus Emplastron gen. nov. is erected. Emplastron edwardsi gen. et comb. nov. inhabited a warm climate with calm waters, abundant food sources, and an ample supply of calcium carbonate: so much so that it is surprising that it is the only recovered specimen. Despite apparent North American faunal and floral affinities in the vicinity, E. edwardsi is more closely related to European crayfishes than it is to American ones.","PeriodicalId":54645,"journal":{"name":"Paleontological Research","volume":"25 1","pages":"379 - 388"},"PeriodicalIF":0.9,"publicationDate":"2021-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44054529","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":"The Great Ordovician Biodiversification Event (GOBE) is Not a Single Event","authors":"T. Servais, B. Cascales‐Miñana, D. Harper","doi":"10.2517/2021PR001","DOIUrl":"https://doi.org/10.2517/2021PR001","url":null,"abstract":"Abstract. The Ordovician biodiversification is considered one of the most significant radiations in the marine ecosystems of the entire Phanerozoic. Originally recognized as the ‘Ordovician Radiation’, a label retained during most of the 1980s and 1990s, the term ‘Great Ordovician Biodiversification Event’ (GOBE) was coined in the late 1990s and was subsequently adopted by most of the scientific community. The Ordovician biodiversification, has always been considered as a long-term adaptive radiation, resulting in the sum of the different individual diversifications of all groups of marine organisms that occurred diachronously during the entire Ordovician. More recently, based on different palaeontological datasets, comprising data from different palaeogeographical areas, the Ordovician radiation has been interpreted to occur at different times in different places. This is most probably related to the palaeogeography of the Ordovician, when the major palaeocontinents were variously located in low latitudes to develop biodiversity ‘hotspots’ during different time intervals. In particular, some authors, using the potentially biased dataset of the Paleobiology Database (PBDB), have considered the GOBE to be an early Middle Ordovician global bio-event. Accordingly, the GOBE thus apparently corresponds to a relatively short time interval, with dramatic diversity fluctuations resulting in a profound change in marine environments at a global scale, visible by a major pulse in biodiversification of all fossil groups around the world. A critical analysis of the published biodiversity curves and of our own data confirm the traditional view; the Ordovician radiation is a complex, long-term process of multiple biodiversifications of marine organisms. Rapid increases in diversity can be identified for some fossil groups, at regional or palaeocontinental levels, in particular within limited datasets. However, a short, dramatic event that triggered major biodiversity pulses of all fossil groups at a global level at a particular time interval is an oversimplification.","PeriodicalId":54645,"journal":{"name":"Paleontological Research","volume":"25 1","pages":"315 - 328"},"PeriodicalIF":0.9,"publicationDate":"2021-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42956076","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":"Special Issue “Renaissance for Paleozoic Evolution Studies: Radiation and Extinction”: Preface","authors":"Y. Isozaki","doi":"10.2517/2021PR002","DOIUrl":"https://doi.org/10.2517/2021PR002","url":null,"abstract":"Familiar landscapes with diverse biota first appeared on our planet through rapid biodiversification immediately after the termination of the Precambrian world, about 540 Myr ago. Since then the first 300 Myr of the Phanerozoic, i.e., the Paleozoic Era, witnessed irreversible changes in global environment in association with the expansion and diversification of eco-spaces, both on land and in the oceans. The causes and processes of this unidirectional evolutionary history during the Paleozoic have often been attributed to multiple punctuated episodes, each of which triggered global-scale environmental changes to constrain the direction of evolution. For example, the Cambrian explosion, the Great Ordovician Biodiversification Event (GOBE), and three major mass extinctions, at the end of the Ordovician, Devonian, and Permian, respectively, are attractive clichés/concepts for these unusual changes that have become extremely popular, not only among professional scientists, but also with journalists. Such elevated interest in Earth history was ignited by some iconic contributions; i.e., the Cambrian Explosion (Gould, 1989), the bolide impact story for the end-Cretaceous timing (Alvarez et al., 1980), the visualization of long-term biodiversity patterns in a clear diagram (Raup and Sepkoski, 1982), and the snowball Earth hypothesis (Kirschvink, 1992; Hoffman and Schrag, 1998). The search for possible causes/drivers of these “big events” of the Paleozoic has continued, yielding numerous scientific articles. In addition to extraterrestrial impact, several stimulating ideas such as ocean redox change and intermittent supervolcanism were proposed as possible key mechanisms during the 1990s; nonetheless, interest started to decline in this century. What remains at present is a huge pile of similar data produced by the same analytical techniques, particularly with various geochemical/isotopic proxies, and many similar discussions from almost the same viewpoints. This may reflect the current overemphasis on quantitative measures for evaluating research, such as the number of citations and journal impact factors, in the scientific community (Garfield, Special Issue “Renaissance for Paleozoic evolution studies: radiation and extinction”: Preface","PeriodicalId":54645,"journal":{"name":"Paleontological Research","volume":"25 1","pages":"303 - 304"},"PeriodicalIF":0.9,"publicationDate":"2021-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46984034","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":"Palynofloras from the Itsuki and Kuwajima Formations of the Tetori Group and their Correlation with Paleofloristic Provinces of Eastern Asia","authors":"J. Legrand, Toshihiro Yamada, K. Terada, H. Nishida","doi":"10.2517/2020PR017","DOIUrl":"https://doi.org/10.2517/2020PR017","url":null,"abstract":"Abstract. We collected samples from the middle part of the Tetori Group and obtained diverse spores (28 species) and gymnosperm pollen (8 species) from the Barremian Itsuki and Kuwajima formations. This is the first report of Barremian palynofloras from the Tetori-type floristic province in Japan and we compared them to coeval ones from the Ryoseki-type floristic province. These palynofloras include various cyathealean spores and cheirolepidiaceous pollen, indicating that floristic differences between the Tetori- (Inner Zone) and Ryoseki-type (Outer Zone) provinces are not so distinct during the Barremian in Japan. They also show similarities with floras of the Sindong Group of the Gyeongsang Basin, southeast Korea and Shitouhezi Formation in northeast China, thus indicating that some Ryoseki-type elements may have extended their distribution northward in the Barremian.","PeriodicalId":54645,"journal":{"name":"Paleontological Research","volume":"25 1","pages":"177 - 190"},"PeriodicalIF":0.9,"publicationDate":"2021-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43936939","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":"Morphological Study of Qaidamestheria (Spinicaudata) from the Middle Jurassic in Qinghai, Northwestern China","authors":"Xiao Teng, Gang Li","doi":"10.2517/2020PR019","DOIUrl":"https://doi.org/10.2517/2020PR019","url":null,"abstract":"Abstract. The Triglypta–Qaidamestheria clam shrimp assemblage, widely known from the non-marine Jurassic deposits in northern China, is important for biostratigraphic correlation of the fossil bearing strata. Qaidamestheria Wang, 1983, an essential component of the assemblage, was originally described from the upmost oil shale member of the Dameigou Formation at the northern margin of the Qaidam Basin, northwest China. Though the original description of the genus Qaidamestheria was based on SEM microscopy, the published pictures of the type specimens are unclear, and the type specimens were lost. We collected new specimens of the type species Qaidamestheria dameigouensis Wang, 1983 from the 7th unit of the Dameigou Formation in the Dameigou section, where the holotype of the species was originally collected. The examination of the specimens under SEM has revealed three critical taxonomic features for the genus: the fine reticulation (mesh diameter 7–18 µm) on the larval valve and several adjacent growth bands; the transitional (reticulated-punctate) ornamentation on the middle–ventral part of the carapace; and linearly arranged puncta appearing only on growth bands near the antero-ventral margin of the carapace, puncta never clustered.","PeriodicalId":54645,"journal":{"name":"Paleontological Research","volume":"25 1","pages":"165 - 176"},"PeriodicalIF":0.9,"publicationDate":"2021-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49372942","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":"Smithian (Olenekian, Early Triassic) Conodonts from Ammonoid-Bearing Limestone Blocks at Crittenden Springs, Elko County, Nevada, USA","authors":"T. Maekawa, J. Jenks","doi":"10.2517/2020PR022","DOIUrl":"https://doi.org/10.2517/2020PR022","url":null,"abstract":"Abstract. The ammonoid-bearing limestone blocks at the classic Crittenden Springs ammonoid site belong to the lower part of the Lower Triassic Thaynes Group. These 0.5–1.2 m thick blocks, consisting mainly of bioclastic floatstone and rudstone, contain abundant macro- and micro-fossils such as ammonoids, gastropods, bivalves and scaphopod shells, as well as conodont elements, fish and echinoid remains. Ammonoid and conodont assemblages obtained from three blocks are utilized for biostratigraphical analysis. Twelve informal Smithian ammonoid biostratigraphic intervals from a previous study are condensed into four ammonoid beds, based on the range of age-diagnostic taxa, in ascending order: Meekoceras millardense-M. aff. olivieri beds, Owenites koeneni beds, Anasibirites multiformis bed, and Condensoceras youngi bed. Conodonts recovered from the three blocks consist of 30 species distributed among 15 genera, including one newly described taxon, i.e., Guangxidella minuta Maekawa and Jenks sp. nov. The blocks are divided into two conodont interval zones, i.e., the Novispathodus ex gr. waageni Interval Zone and Nv. pingdingshanensis Interval Zone, based on the first occurrences of their eponymous taxa. Additionally, four conodont range zones, i.e., the Paullella meeki Range Zone, Guangxidella bransoni Range Zone, Scythogondolella milleri Range Zone, and Borinella buurensis Range Zone are recognized, based on the ranges of these four index species. Conodonts within these interval and range zones vary in age from middle Smithian to latest Smithian. The presence of key ammonoid and conodont taxa regarding the Smithian-Spathian boundary (SSB) such as the AW (Anasibirites and Wasatchites) and GXP (Glyptophiceras, Xenoceltites and Pseudosageceras) ammonoid assemblages and the conodonts B. buurensis, Nv. pingdingshanensis and S. milleri demonstrate that the study area is an important reference site for the SSB in the eastern Panthalassa area.","PeriodicalId":54645,"journal":{"name":"Paleontological Research","volume":"25 1","pages":"201 - 245"},"PeriodicalIF":0.9,"publicationDate":"2021-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48362413","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}