H. Takata, Seok-Hwi Hong, D. Yoo, Jin-Cheul Kim, D. Cheong, B. Khim
Abstract. We investigated early to middle Holocene benthic foraminifera from four borehole cores in the Nakdong River Delta (southeast Korea) to document faunal associations and the transition of benthic foraminifera in coastal areas along the Tsushima Warm Current. We recognized four varimax factor assemblages. The varimax factor 1 assemblage (characterized by Pseudoparrella naraensis with Eilohedra nipponica) is common throughout core ND-02, which is seaward in the delta, whereas the varimax factor 2 assemblage (characterized by Haynesina sp. A) is dominated by low evenness in core 16ND-C02, which is landward in the delta. The varimax factor 4 assemblage (characterized by Buccella frigida) is generally common at the bottom and/or top part of the studied cores, whereas the varimax factor 3 assemblage (characterized by Elphidium somaense) tends to be common in the upper part of the three cores in the delta's seaward area. Both the contrasting high diversity and low diversity with low evenness of benthic foraminifera (varimax factor 1 and 2 assemblages, respectively) were present between the seaward and landward portions of the delta during the same period (∼7–6 ka), respectively. The combination of these contrasting faunas tended to appear in the delta with the intensification of the Tsushima Warm Current during ∼8–6 ka in addition to the sea-level rise. Common taxa in the Nakdong River Delta are largely neritic species of the temperate region in the East Asian margin, whereas some upper bathyal species, such as Angulogerina ikebei, Bolivina decussata, and E. nipponica, were subordinated in the delta's seaward portion. Such faunal features in the Nakdong River Delta are distinguishable from other coastal areas in the Japanese Islands.
{"title":"Fossil Benthic Foraminifera in the Nakdong River Delta (Southeast Korea) during the Early to Middle Holocene","authors":"H. Takata, Seok-Hwi Hong, D. Yoo, Jin-Cheul Kim, D. Cheong, B. Khim","doi":"10.2517/PR200037","DOIUrl":"https://doi.org/10.2517/PR200037","url":null,"abstract":"Abstract. We investigated early to middle Holocene benthic foraminifera from four borehole cores in the Nakdong River Delta (southeast Korea) to document faunal associations and the transition of benthic foraminifera in coastal areas along the Tsushima Warm Current. We recognized four varimax factor assemblages. The varimax factor 1 assemblage (characterized by Pseudoparrella naraensis with Eilohedra nipponica) is common throughout core ND-02, which is seaward in the delta, whereas the varimax factor 2 assemblage (characterized by Haynesina sp. A) is dominated by low evenness in core 16ND-C02, which is landward in the delta. The varimax factor 4 assemblage (characterized by Buccella frigida) is generally common at the bottom and/or top part of the studied cores, whereas the varimax factor 3 assemblage (characterized by Elphidium somaense) tends to be common in the upper part of the three cores in the delta's seaward area. Both the contrasting high diversity and low diversity with low evenness of benthic foraminifera (varimax factor 1 and 2 assemblages, respectively) were present between the seaward and landward portions of the delta during the same period (∼7–6 ka), respectively. The combination of these contrasting faunas tended to appear in the delta with the intensification of the Tsushima Warm Current during ∼8–6 ka in addition to the sea-level rise. Common taxa in the Nakdong River Delta are largely neritic species of the temperate region in the East Asian margin, whereas some upper bathyal species, such as Angulogerina ikebei, Bolivina decussata, and E. nipponica, were subordinated in the delta's seaward portion. Such faunal features in the Nakdong River Delta are distinguishable from other coastal areas in the Japanese Islands.","PeriodicalId":54645,"journal":{"name":"Paleontological Research","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2022-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45338226","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}
Abstract. Yezoites is a Late Cretaceous (Cenomanian–Campanian) small to very small dimorphic ammonoid genus belonging to the Scaphitidae, whose microconchs have a pair of long lateral lappets at the aperture. Based on examination of previously described material including type and figured specimens and newly recovered ones, five species of Yezoites are described herein from the circum-North Pacific regions (Japan, Sakhalin, Kamchatka, Alaska, Oregon, and California); i.e., Y. perrini (Anderson), Y. seabeensis (Cobban and Gryc), and Y. puerculus (Jimbo) from the Turonian, and Y. pseudoaequalis (Yabe) and Y. matsumotoi (Tanabe) from the Coniacian. Of these species, both microconchs and macroconchs are recognized in Y. puerculus and Y. pseudoaequalis, whereas only microconchs are known in the other three species. These Yezoites species characteristically occur in very fine-grained sandstone to silty mudstone facies suggesting an intermediate between nearshore and offshore environments, and can be used supplementarily for biozonation and correlation of the Turonian and Coniacian deposits in the North Pacific regions.
{"title":"Late Cretaceous Dimorphic Scaphitid Ammonoid Genus Yezoites from the Circum-North Pacific Regions","authors":"K. Tanabe","doi":"10.2517/PR200049","DOIUrl":"https://doi.org/10.2517/PR200049","url":null,"abstract":"Abstract. Yezoites is a Late Cretaceous (Cenomanian–Campanian) small to very small dimorphic ammonoid genus belonging to the Scaphitidae, whose microconchs have a pair of long lateral lappets at the aperture. Based on examination of previously described material including type and figured specimens and newly recovered ones, five species of Yezoites are described herein from the circum-North Pacific regions (Japan, Sakhalin, Kamchatka, Alaska, Oregon, and California); i.e., Y. perrini (Anderson), Y. seabeensis (Cobban and Gryc), and Y. puerculus (Jimbo) from the Turonian, and Y. pseudoaequalis (Yabe) and Y. matsumotoi (Tanabe) from the Coniacian. Of these species, both microconchs and macroconchs are recognized in Y. puerculus and Y. pseudoaequalis, whereas only microconchs are known in the other three species. These Yezoites species characteristically occur in very fine-grained sandstone to silty mudstone facies suggesting an intermediate between nearshore and offshore environments, and can be used supplementarily for biozonation and correlation of the Turonian and Coniacian deposits in the North Pacific regions.","PeriodicalId":54645,"journal":{"name":"Paleontological Research","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2022-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46957964","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}
Jun Zhao, Yu-jing Li, P. Selden, Pei-yun Cong, Zhixin Yang
Abstract. Sidneyia inexpectans was first excavated in Laurentia, and since then Sidneyia and Sidneyia-like euarthropods have been reported from different continents. Here we describe a new Sidneyia-like euarthropod from the Guanshan biota and, its preserved dorsal exoskeleton and appendages resemble those of S. inexpectans. The discovery in the Guanshan biota provides a new data point of Sidneyia-like euarthropod in Cambrian Stage 4 and a second occurrence on the South China plate.
{"title":"A Sidneyia-Like Euarthropod from the Guanshan Biota (Cambrian Series 2, Stage 4), Eastern Yunnan, Southwest China","authors":"Jun Zhao, Yu-jing Li, P. Selden, Pei-yun Cong, Zhixin Yang","doi":"10.2517/PR200047","DOIUrl":"https://doi.org/10.2517/PR200047","url":null,"abstract":"Abstract. Sidneyia inexpectans was first excavated in Laurentia, and since then Sidneyia and Sidneyia-like euarthropods have been reported from different continents. Here we describe a new Sidneyia-like euarthropod from the Guanshan biota and, its preserved dorsal exoskeleton and appendages resemble those of S. inexpectans. The discovery in the Guanshan biota provides a new data point of Sidneyia-like euarthropod in Cambrian Stage 4 and a second occurrence on the South China plate.","PeriodicalId":54645,"journal":{"name":"Paleontological Research","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2022-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44318278","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":"Tropical Radiolarian Biostratigraphy from the Early to Late Miocene at ODP Site 714 in the Tropical Indian Ocean","authors":"S. Kamikuri","doi":"10.2517/pr200017","DOIUrl":"https://doi.org/10.2517/pr200017","url":null,"abstract":"","PeriodicalId":54645,"journal":{"name":"Paleontological Research","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2022-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44878158","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":"Pterophyllum pachyrachis (Bennettitales) from the Upper Jurassic to Lower Cretaceous Tetori Group, Fukui Prefecture, Central Japan","authors":"T. Yamada, M. Nishino","doi":"10.2517/pr200023","DOIUrl":"https://doi.org/10.2517/pr200023","url":null,"abstract":"","PeriodicalId":54645,"journal":{"name":"Paleontological Research","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2022-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48280029","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":"Kimuriella gen. nov. (Bennettitales), a Whole-Plant Bennettite from the Oxfordian (Upper Jurassic) Tochikubo Formation of Shidazawa, Minamisōma, Fukushima Prefecture, Northeast Japan","authors":"C. Pott, H. Takimoto","doi":"10.2517/pr200020","DOIUrl":"https://doi.org/10.2517/pr200020","url":null,"abstract":"","PeriodicalId":54645,"journal":{"name":"Paleontological Research","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2022-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41264200","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":"Latest Olenekian (Early Triassic) Ammonoids from the Uppermost Part of the Osawa Formation (Inai Group) in the South Kitakami Belt, Northeast Japan","authors":"M. Ehiro","doi":"10.2517/pr200027","DOIUrl":"https://doi.org/10.2517/pr200027","url":null,"abstract":"","PeriodicalId":54645,"journal":{"name":"Paleontological Research","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2022-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44093494","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":"Tohokubelus gen. nov., the Oldest Belemnite from the Olenekian (Lower Triassic) of Northeast Japan","authors":"S. Niko, M. Ehiro","doi":"10.2517/pr200036","DOIUrl":"https://doi.org/10.2517/pr200036","url":null,"abstract":"","PeriodicalId":54645,"journal":{"name":"Paleontological Research","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2022-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49063270","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}
Shinya Miyata, Y. Yabumoto, Yasuhisa Nakajima, Yasuhiro Ito, Takenori Sasaki
{"title":"A Second Specimen of the Crossognathiform Fish Apsopelix miyazakii from the Cretaceous Yezo Group of Mikasa Area, Central Hokkaido, Japan","authors":"Shinya Miyata, Y. Yabumoto, Yasuhisa Nakajima, Yasuhiro Ito, Takenori Sasaki","doi":"10.2517/pr200024","DOIUrl":"https://doi.org/10.2517/pr200024","url":null,"abstract":"","PeriodicalId":54645,"journal":{"name":"Paleontological Research","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2022-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46521032","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":"Fossil Lateral Arm Plates of Stegophiura sladeni (Echinodermata: Ophiuroidea: Ophiurida) from the Middle Pleistocene of Japan","authors":"M. Okanishi, Shota Mitsui, B. Thuy","doi":"10.2517/pr200039","DOIUrl":"https://doi.org/10.2517/pr200039","url":null,"abstract":"","PeriodicalId":54645,"journal":{"name":"Paleontological Research","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2022-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48058522","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}
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