Abstract. A new gobiiform fish Odontobutis hayashitokuei sp. nov. is decribed from middle Miocene freshwater deposits of the Chojabaru Formation in Iki Island, Nagasaki, Japan based on a single specimen. This new species differs from other species of the genus Odontobutis in having 21 caudal vertebrae and a smaller head. Odontobutis hayashitokuei sp. nov. is most similar to O. obscura in having almost the same position of dorsal and anal fins. This is the first fossil species of the genus Odontobutis and suggests that the origin of the genus extends to the middle Miocene, about 15 Ma.
{"title":"A New Miocene Gobiiform Fish, Odontobutis hayashitokuei from Iki, Nagasaki, Japan","authors":"Y. Yabumoto, Chun-guang Zhang","doi":"10.2517/PR210039","DOIUrl":"https://doi.org/10.2517/PR210039","url":null,"abstract":"Abstract. A new gobiiform fish Odontobutis hayashitokuei sp. nov. is decribed from middle Miocene freshwater deposits of the Chojabaru Formation in Iki Island, Nagasaki, Japan based on a single specimen. This new species differs from other species of the genus Odontobutis in having 21 caudal vertebrae and a smaller head. Odontobutis hayashitokuei sp. nov. is most similar to O. obscura in having almost the same position of dorsal and anal fins. This is the first fossil species of the genus Odontobutis and suggests that the origin of the genus extends to the middle Miocene, about 15 Ma.","PeriodicalId":54645,"journal":{"name":"Paleontological Research","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2023-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47258516","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. Ontogenetic development of ornamentation and whorl geometry of the Cretaceous ammonoids Parajaubertella kawakitana and P. zizoh are studied based on well-preserved specimens collected from the lower Cenomanian in the Horokanai area, Hokkaido, Japan. Our results indicate that their comparably sized immature stages share identical ornamentation and shell morphology, while the size of their adult shells is distinctly bimodal. They also share the same stratigraphic ranges in the lower Cenomanian and have overlapping geographic distributions in Northwest Pacific region, and lastly, they co-occur in the same concretions. This evidence strongly suggests that the two taxa should be considered as dimorphs, microconch and macroconch of a single species, which is herein described as P. kawakitana.
{"title":"Dimorphism in the Early Cenomanian (Late Cretaceous) Ammonoid Parajaubertella","authors":"Y. Shigeta, Haruyoshi Maeda, Toshihiro Sakai","doi":"10.2517/PR220023","DOIUrl":"https://doi.org/10.2517/PR220023","url":null,"abstract":"Abstract. Ontogenetic development of ornamentation and whorl geometry of the Cretaceous ammonoids Parajaubertella kawakitana and P. zizoh are studied based on well-preserved specimens collected from the lower Cenomanian in the Horokanai area, Hokkaido, Japan. Our results indicate that their comparably sized immature stages share identical ornamentation and shell morphology, while the size of their adult shells is distinctly bimodal. They also share the same stratigraphic ranges in the lower Cenomanian and have overlapping geographic distributions in Northwest Pacific region, and lastly, they co-occur in the same concretions. This evidence strongly suggests that the two taxa should be considered as dimorphs, microconch and macroconch of a single species, which is herein described as P. kawakitana.","PeriodicalId":54645,"journal":{"name":"Paleontological Research","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2023-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49214626","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. In this study, we describe and illustrate a new fossil species of Nymphalidae (Lepidoptera, Papilionoidea), Neptis kabutoiwaensis sp. nov., based on an impression fossil from the Upper Pliocene Motojuku Group, Gunma Prefecture, central Japan, which is the first fossil representative belonging to the subfamily Limenitidinae of Nymphalidae. In addition, our study is the first to report the discovery of a named Papilionoidea fossil from the Pliocene Series. The fossil shares characteristics, such as the reduced forelegs, open discal cell in the forewing, and short Sc + R1 vein in the hindwing, with the tribe Neptini of Limenitidinae. However, the presence of the CuP vein in the forewing suggests that the studied fossil is clearly different from known species of tribe Neptini. This is an important discovery that can assist us in exploring the evolution of the tribe Neptini during the Pliocene, because this new species has the possible ancestral characteristic of a CuP vein in its forewing.
{"title":"A New Species of Fossil Nymphalidae (Lepidoptera, Papilionoidea) from the Upper Pliocene Motojuku Group, Gunma Prefecture, Japan","authors":"Hiroaki Aiba, Yui Takahashi, Y. Sakamaki","doi":"10.2517/PR220018","DOIUrl":"https://doi.org/10.2517/PR220018","url":null,"abstract":"Abstract. In this study, we describe and illustrate a new fossil species of Nymphalidae (Lepidoptera, Papilionoidea), Neptis kabutoiwaensis sp. nov., based on an impression fossil from the Upper Pliocene Motojuku Group, Gunma Prefecture, central Japan, which is the first fossil representative belonging to the subfamily Limenitidinae of Nymphalidae. In addition, our study is the first to report the discovery of a named Papilionoidea fossil from the Pliocene Series. The fossil shares characteristics, such as the reduced forelegs, open discal cell in the forewing, and short Sc + R1 vein in the hindwing, with the tribe Neptini of Limenitidinae. However, the presence of the CuP vein in the forewing suggests that the studied fossil is clearly different from known species of tribe Neptini. This is an important discovery that can assist us in exploring the evolution of the tribe Neptini during the Pliocene, because this new species has the possible ancestral characteristic of a CuP vein in its forewing.","PeriodicalId":54645,"journal":{"name":"Paleontological Research","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2023-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44860255","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. Within the genera of fossil Echinodermata three junior homonyms are found and the following replacement names are proposed: Edrioblastocystis nom. nov. pro Blastocystis Jaekel, 1918 nec Aléxéieff, 1911 and consequently Edrioblastocystidae nom. nov. to replace Blastocystidae Jaekel, 1918; Euzonohymenosoma nom. nov. = Hymenosoma Lehmann, 1957 nec Desmarest, 1823; Pennsylvanicycloscapus nom. nov. = Cycloscapus Moore and Jeffords, 1968 nec Erdös and Novicky in Erdös, 1951. Accordingly, also three new combinations (comb. nov.) are established.
摘要在棘皮动物化石属中，发现了三个初级同音异名，并提出了以下替代名称：Edrioblastophis nom。nov.pro-Blastocystis Jaekel，1918 nec Aléxéieff，1911，因此Edrioblastopsidae命名。nov.取代Jaekel芽囊虫科，1918年；Euzonohymenosma nom。nov.=Hymenosoma Lehmann，1957 nec Desmarest，1823；宾夕法尼亚旋风花。nov.=Cycloscapus Moore和Jeffords，1968 nec Erdös和Novicky in Erdös，1951。因此，还建立了三个新的组合（comb.nov.）。
{"title":"New Replacement Names in Fossil Echinoderms (Echinodermata)","authors":"F. Ceccolini, F. Cianferoni","doi":"10.2517/PR210029","DOIUrl":"https://doi.org/10.2517/PR210029","url":null,"abstract":"Abstract. Within the genera of fossil Echinodermata three junior homonyms are found and the following replacement names are proposed: Edrioblastocystis nom. nov. pro Blastocystis Jaekel, 1918 nec Aléxéieff, 1911 and consequently Edrioblastocystidae nom. nov. to replace Blastocystidae Jaekel, 1918; Euzonohymenosoma nom. nov. = Hymenosoma Lehmann, 1957 nec Desmarest, 1823; Pennsylvanicycloscapus nom. nov. = Cycloscapus Moore and Jeffords, 1968 nec Erdös and Novicky in Erdös, 1951. Accordingly, also three new combinations (comb. nov.) are established.","PeriodicalId":54645,"journal":{"name":"Paleontological Research","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2023-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48347518","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. Six early late Maastrichtian (Late Cretaceous) ammonoid taxa are reported from the Krasnoyarka Formation of the Yezo Group in the Naiba area, southern Sakhalin, Russian Far East. These taxa are grouped into “immigrant species”, i.e., those that migrated from other regions (Pachydiscus subcompressus, Anagaudryceras mikobokense, Gaudryceras seymouriense and Zelandites varuna) and “indigenous species” with a North Pacific distribution (Anagaudryceras matsumotoi). It is unclear to which group Tetragonites sp. belongs. Zelandites varuna and G. seymouriense occur in both the lower upper Maastrichtian as well as the upper lower Maastrichtian in southern Sakhalin, but they have never been found in the middle Maastrichtian. The appearance of these two species in the cold-water regions, i.e., North Pacific and Antarctic, as well as intermediate southern mid-latitudes regions suggests that cooling events occurred during the late early and early late Maastrichtian in the Northwest Pacific region. Their disappearance during the middle Maastrichtian may indicate that the Northwest Pacific region was affected by the greenhouse Middle Maastrichtian Event (MME). This hypothesis suggests that the influx (e.g. P. subcompressus and A. mikobokense) and reappearance (e.g. Z. varuna and G. seymouriense) of many immigrant species into the Northwest Pacific region during late Maastrichtian time may have been associated with the post-MME cooling.
{"title":"Late Maastrichtian (latest Cretaceous) Ammonoids from the Naiba Area, Southern Sakhalin, Russian Far East","authors":"Y. Shigeta, Haruyoshi Maeda","doi":"10.2517/PR210021","DOIUrl":"https://doi.org/10.2517/PR210021","url":null,"abstract":"Abstract. Six early late Maastrichtian (Late Cretaceous) ammonoid taxa are reported from the Krasnoyarka Formation of the Yezo Group in the Naiba area, southern Sakhalin, Russian Far East. These taxa are grouped into “immigrant species”, i.e., those that migrated from other regions (Pachydiscus subcompressus, Anagaudryceras mikobokense, Gaudryceras seymouriense and Zelandites varuna) and “indigenous species” with a North Pacific distribution (Anagaudryceras matsumotoi). It is unclear to which group Tetragonites sp. belongs. Zelandites varuna and G. seymouriense occur in both the lower upper Maastrichtian as well as the upper lower Maastrichtian in southern Sakhalin, but they have never been found in the middle Maastrichtian. The appearance of these two species in the cold-water regions, i.e., North Pacific and Antarctic, as well as intermediate southern mid-latitudes regions suggests that cooling events occurred during the late early and early late Maastrichtian in the Northwest Pacific region. Their disappearance during the middle Maastrichtian may indicate that the Northwest Pacific region was affected by the greenhouse Middle Maastrichtian Event (MME). This hypothesis suggests that the influx (e.g. P. subcompressus and A. mikobokense) and reappearance (e.g. Z. varuna and G. seymouriense) of many immigrant species into the Northwest Pacific region during late Maastrichtian time may have been associated with the post-MME cooling.","PeriodicalId":54645,"journal":{"name":"Paleontological Research","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2023-01-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47761114","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. More than 23 extinct species and 10 extant species of the Balaenopteridae are known. Our knowledge of the family Balaenopteridae is increasing quickly, however, few fossil records support a circum-North Pacific distribution of balaenopterid genera and species. Because of limited preservations, most rorqual fossils reported from the western North Pacific can only be identified to the family level. A skull from the Shinazawa Formation (late Pliocene to Early Pleistocene) in Yamagata, Japan, is identified as aff. Balaenoptera bertae by possessing two diagnostic features of the species: large occipital condyles, and a posteriorly elongate postglenoid process. Combination of four more features also support that the specimen is a closely related to B. bertae. The specimen is probably a slightly older individual than the holotype of B. bertae, based on the estimated bizygomatic width and slightly longer posterior process of the tympanoperiotic. The first and only report of B. bertae was from the Pliocene Purisima Formation in California, USA. The specimen from Japan is incompletely preserved, but shows the occurrence of B. bertae in the western North Pacific for the first time, as many living balaenopterids are distributed across the North Pacific, such as Balaenoptera musculus, B. physalus, B. borealis, B. acutorostrata, and Megaptera novaeangliae.
{"title":"A New Fossil Rorqual Aff. Balaenoptera Bertae Specimen from the Shinazawa Formation (Late Pliocene to Early Pleistocene), Yamagata, Japan","authors":"Yoshihiro Tanaka, K. Nagasawa, Suburu Oba","doi":"10.2517/PR210038","DOIUrl":"https://doi.org/10.2517/PR210038","url":null,"abstract":"Abstract. More than 23 extinct species and 10 extant species of the Balaenopteridae are known. Our knowledge of the family Balaenopteridae is increasing quickly, however, few fossil records support a circum-North Pacific distribution of balaenopterid genera and species. Because of limited preservations, most rorqual fossils reported from the western North Pacific can only be identified to the family level. A skull from the Shinazawa Formation (late Pliocene to Early Pleistocene) in Yamagata, Japan, is identified as aff. Balaenoptera bertae by possessing two diagnostic features of the species: large occipital condyles, and a posteriorly elongate postglenoid process. Combination of four more features also support that the specimen is a closely related to B. bertae. The specimen is probably a slightly older individual than the holotype of B. bertae, based on the estimated bizygomatic width and slightly longer posterior process of the tympanoperiotic. The first and only report of B. bertae was from the Pliocene Purisima Formation in California, USA. The specimen from Japan is incompletely preserved, but shows the occurrence of B. bertae in the western North Pacific for the first time, as many living balaenopterids are distributed across the North Pacific, such as Balaenoptera musculus, B. physalus, B. borealis, B. acutorostrata, and Megaptera novaeangliae.","PeriodicalId":54645,"journal":{"name":"Paleontological Research","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2023-01-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49154213","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. A fragmentary and the largest single bone element from the Lower Cretaceous Kanmon Group in Kyushu Island, southwestern Japan reported yet to date is described. This specimen has a fossa and lenticular foramen on its lateral surface and internal chambers of both large and small sizes. It was identified as the cervical vertebra of a titanosauriform sauropod dinosaur mainly based on such pneumatic structure. This specimen represents the first titanosauriform to be described from the Kanmon Group.
{"title":"Description of a Titanosauriform (Sauropoda, Dinosauria) Cervical Vertebra from the Lower Cretaceous Kanmon Group, Southwestern Japan","authors":"Jun-Ichiro Tatehata, T. Mukunoki, Kyo Tanoue","doi":"10.2517/PR220009","DOIUrl":"https://doi.org/10.2517/PR220009","url":null,"abstract":"Abstract. A fragmentary and the largest single bone element from the Lower Cretaceous Kanmon Group in Kyushu Island, southwestern Japan reported yet to date is described. This specimen has a fossa and lenticular foramen on its lateral surface and internal chambers of both large and small sizes. It was identified as the cervical vertebra of a titanosauriform sauropod dinosaur mainly based on such pneumatic structure. This specimen represents the first titanosauriform to be described from the Kanmon Group.","PeriodicalId":54645,"journal":{"name":"Paleontological Research","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2023-01-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48468377","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. Fossils of Microporina species were collected and examined from the Soebetsu Sandstone Member of the Pleistocene Setana Formation in southwestern Hokkaido. A description is provided for M. japonica Canu and Bassler, and four species (M. sakakurai, M. minuta, M. quadristoma and M. soebetsuensis) are newly described. Some of them were previously reported as M. articulata (Fabricius). Among the five species, three (M. japonica, M. sakakurai, M. minuta) have a semielliptical or elliptical orifice, relatively large and deep frontal pseudopores, opesiules occluded with a thin plate showing vein-like surface sculpturing, and avicularia that are longer than wide. The other two (M. quadristoma, M. soebetsuensis) have a rounded-quadrate orifice (sometimes with a convex proximal margin), smaller frontal pseudopores, opesiules occluded but lacking vein-like surface sculpturing, and avicularia that are circular or wider than long. Marked orificial dimorphism is observed in two species, M. sakakurai and M. soebetsuensis.
摘要对北海道西南部更新世Setana组Soebetsu砂岩段的小孔虫化石进行了研究。对粳稻Canu和Bassler进行了描述，并对sakakurai、minuta、quadristoma和soebetsuensis等4种进行了新描述。其中一些以前被报道为M. articulata (Fabricius)。在这五种中，有三种(日本、樱井、minuta)有半椭圆形或椭圆形的孔口，相对较大和较深的正面假孔，小孔被薄板封闭，表面呈静脉状雕刻，avicularia长而宽。另外两种(M. quadristoma, M. soebetsuensis)有一个圆形的方形孔(有时近缘凸)，较小的正面假孔，小孔闭塞但缺乏静脉状表面雕刻，和avicularia圆形或宽于长。在sakakurai和soebetsuensis两个物种中观察到明显的口型二态性。
{"title":"Five Species of Microporina (Bryozoa, Cheilostomata) from the Pleistocene Setana Formation at Kuromatsunai, Hokkaido, Japan","authors":"S. Arakawa","doi":"10.2517/PR210017","DOIUrl":"https://doi.org/10.2517/PR210017","url":null,"abstract":"Abstract. Fossils of Microporina species were collected and examined from the Soebetsu Sandstone Member of the Pleistocene Setana Formation in southwestern Hokkaido. A description is provided for M. japonica Canu and Bassler, and four species (M. sakakurai, M. minuta, M. quadristoma and M. soebetsuensis) are newly described. Some of them were previously reported as M. articulata (Fabricius). Among the five species, three (M. japonica, M. sakakurai, M. minuta) have a semielliptical or elliptical orifice, relatively large and deep frontal pseudopores, opesiules occluded with a thin plate showing vein-like surface sculpturing, and avicularia that are longer than wide. The other two (M. quadristoma, M. soebetsuensis) have a rounded-quadrate orifice (sometimes with a convex proximal margin), smaller frontal pseudopores, opesiules occluded but lacking vein-like surface sculpturing, and avicularia that are circular or wider than long. Marked orificial dimorphism is observed in two species, M. sakakurai and M. soebetsuensis.","PeriodicalId":54645,"journal":{"name":"Paleontological Research","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2023-01-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43092339","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}
Mark Williams, T. Komatsu, P. Nguyen, D. Siveter, A. McGairy, Harrison Bush, Robert H. Goodall, T. Harvey, C. Stocker, J. Legrand, Toshihiro Yamada, C. Miller
Abstract. The first detailed, systematic record of Silurian ostracod crustaceans from Vietnam is presented. Ostracods from the upper Silurian (upper Ludlow–lower Pridoli) Si Ka Formation of Ha Giang Province, northern Vietnam comprise ca. 10 species, including two new species of hollinoideans, two beyrichioideans, three species of eridostracine, at least one putative paraparchitoidean, and two indeterminate palaeocopid species. The fauna co-occurs with macroplant and fish fragments, and pterineid bivalves, in lithofacies that are interpreted as estuarine. The presence of beyrichioideans is consistent with their reported occurrence in marine, marginal-marine and estuarine ostracod assemblages elsewhere in the late Silurian and Devonian. One of the beyrichioidean species possibly represents Qujingsia nonaculeata, a species known from the Ludlow–Pridoli of South China, thus endorsing the supposed late Silurian age of the Vietnam fauna and its paleogeographical position on the South China paleo-plate. The other beyrichioidean is Beyrichia (Beyrichia), a globally distributed taxon in the Silurian and Early Devonian. Three species of eridostracine are referred to Cryptophyllus, a genus with a global distribution and temporal range from the Ordovician to Carboniferous. Hollinoidean taxa, whilst endemic at the genus-level, show affinities with glossomorphitine and sigmoopsinae taxa from Europe.
{"title":"Ostracods from the Upper Silurian Si Ka Formation, Northern Vietnam, and Their Paleobiogeographical Significance","authors":"Mark Williams, T. Komatsu, P. Nguyen, D. Siveter, A. McGairy, Harrison Bush, Robert H. Goodall, T. Harvey, C. Stocker, J. Legrand, Toshihiro Yamada, C. Miller","doi":"10.2517/PR210032","DOIUrl":"https://doi.org/10.2517/PR210032","url":null,"abstract":"Abstract. The first detailed, systematic record of Silurian ostracod crustaceans from Vietnam is presented. Ostracods from the upper Silurian (upper Ludlow–lower Pridoli) Si Ka Formation of Ha Giang Province, northern Vietnam comprise ca. 10 species, including two new species of hollinoideans, two beyrichioideans, three species of eridostracine, at least one putative paraparchitoidean, and two indeterminate palaeocopid species. The fauna co-occurs with macroplant and fish fragments, and pterineid bivalves, in lithofacies that are interpreted as estuarine. The presence of beyrichioideans is consistent with their reported occurrence in marine, marginal-marine and estuarine ostracod assemblages elsewhere in the late Silurian and Devonian. One of the beyrichioidean species possibly represents Qujingsia nonaculeata, a species known from the Ludlow–Pridoli of South China, thus endorsing the supposed late Silurian age of the Vietnam fauna and its paleogeographical position on the South China paleo-plate. The other beyrichioidean is Beyrichia (Beyrichia), a globally distributed taxon in the Silurian and Early Devonian. Three species of eridostracine are referred to Cryptophyllus, a genus with a global distribution and temporal range from the Ordovician to Carboniferous. Hollinoidean taxa, whilst endemic at the genus-level, show affinities with glossomorphitine and sigmoopsinae taxa from Europe.","PeriodicalId":54645,"journal":{"name":"Paleontological Research","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2023-01-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46907257","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}
Y. Ishida, Minoru Kaneko, Asaka Yokobori, Rin Mita, Hiroyuki Ishikawa, B. Thuy, Lea D. Numberger-Thuy, T. Fujita
Abstract. Over 100 well-preserved dissociated ophiuroid arm ossicles, i.e., lateral arm plates, dorsal arm plates, ventral arm plates, vertebrae and arm spines, were recovered from the upper Pleistocene Kioroshi Formation in the core of borehole GS-NY-1 at Nagareyama, Chiba Prefecture, central Japan. Following comparison with the lateral arm plates of ten extant amphiurid species occurring in the seas around Japan and with previously published fossil taxa in this family, the ossicles from Nagareyama were identified as belonging to the extant species, Amphiura multispina. This is the first fossil record of this form and the stratigraphically youngest of the Amphiuridae. The taphonomy and paleoenvironment of the brittle star fossils described are also discussed.
{"title":"Amphiura multispina (Ophiuroidea, Amphiuridae) from the Upper Pleistocene Kioroshi Formation in a Drill Core at Nagareyama, Chiba, Central Japan","authors":"Y. Ishida, Minoru Kaneko, Asaka Yokobori, Rin Mita, Hiroyuki Ishikawa, B. Thuy, Lea D. Numberger-Thuy, T. Fujita","doi":"10.2517/PR220001","DOIUrl":"https://doi.org/10.2517/PR220001","url":null,"abstract":"Abstract. Over 100 well-preserved dissociated ophiuroid arm ossicles, i.e., lateral arm plates, dorsal arm plates, ventral arm plates, vertebrae and arm spines, were recovered from the upper Pleistocene Kioroshi Formation in the core of borehole GS-NY-1 at Nagareyama, Chiba Prefecture, central Japan. Following comparison with the lateral arm plates of ten extant amphiurid species occurring in the seas around Japan and with previously published fossil taxa in this family, the ossicles from Nagareyama were identified as belonging to the extant species, Amphiura multispina. This is the first fossil record of this form and the stratigraphically youngest of the Amphiuridae. The taphonomy and paleoenvironment of the brittle star fossils described are also discussed.","PeriodicalId":54645,"journal":{"name":"Paleontological Research","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2023-01-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41824982","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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