Kazutaka Amano, 2019: Two New Gastropods from the Late Pliocene Omma-Manganji Fauna in the Japan Sea Borderland of Honshu, Japan. Paleontological Research, Vol.23 No.2, 85-94. 10.2517/2018PR011. https://doi.org/10.2517/2018PR011
A new genus and species of the gastropod family Capulidae, Vermeijia japonica, is described from the upper Pliocene Kuwae Formation in Niigata Prefecture and the lowermost part of the Sasaoka Formation in Akita Prefecture, Japan. This genus is similar to the boreal genus Ariadnaria although it was collected in association with several warm-water species. In another gastropod family, Nassariidae, Cyllene satoi is a new species from the upper Pliocene Tentokuji Formation in Akita Prefecture. Nine warm-water taxa in the Omma-Manganji fauna, including Cyllene, no longer live in the Japan Sea, except for its westernmost part. They suggest that the Tsushima Current had a higher SST during the late Pliocene than at present. Vermeijia is the fourth extinct genus of the Omma-Manganji fauna, but it disappeared in the Japan Sea by Datum A (2.75 Ma), earlier than the other three genera, which became extinct by the end of the early Pleistocene.
Jun-Ichi Tazawa and Yasufumi Iryu, 2019: Early Carboniferous (Early Visean) Brachiopod Fauna from the Middle Part of the Arisu Formation in the Shimoarisu Area, South Kitakami Belt, Japan. Paleontological Research, Vol.23 No.2, 95-109. 10.2517/2018PR012. https://doi.org/10.2517/2018PR012
In this paper, we describe an early Carboniferous (early Visean) brachiopod fauna from the middle part of the Arisu Formation in the type locality, Shimoarisu, South Kitakami Belt, northeastern Japan. The Shimoarisu fauna consists of 11 species in seven genera: Ovatia elongata, Rhipidomella michelini, Schizophoria resupinata, Sch. pinguis, Sch. woodi, Unispirifer striatoconvolutus, Unispirifer sp., Kitakamithyris hikoroitiensis, Syringothyris texta, S. platypleura and Pseudosyrinx jumonjiensis. The fauna is assigned to the early Visean. In terms of palaeobiogeography, the Shimoarisu fauna has an affinity with those of the brachiopod province that developed in present-day northwestern-northeastern China in the early Carboniferous. Therefore, South Kitakami, including the Shimoarisu area, was probably located near and to the east of North China in the early Visean.
Naoshi Kitamura, 2019: Features and Paleoecological Significance of the Shark Fauna from the Upper Cretaceous Hinoshima Formation, Himenoura Group, Southwest Japan. Paleontological Research, Vol.23 No.2, 110-130. 10.2517/2018PR013. https://doi.org/10.2517/2018PR013
The shark fauna of the Upper Cretaceous Hinoshima Formation (Santonian: 86.3-83.6 Ma) of the Himenoura Group (Kamiamakusa, Kumamoto Prefecture, Kyushu, Japan) was investigated based on fossil shark teeth found at five localities: Himedo Park, Kugushima, Wadanohana, Higashiura, and Kotorigoe. A detailed geological survey and taxonomic analysis was undertaken, and the habitat, depositional environment, and associated mollusks of each locality were considered in the context of previous studies. Twenty-three species, 15 genera, 11 families, and 6 orders of fossil sharks are recognized from the localities. This assemblage is more diverse than has previously been reported for Japan, and Lamniformes and Hexanchiformes were abundant. Three categories of shark fauna are recognized: a coastal region (Himedo Park; probably a breeding site), the coast to the open sea (Kugushima and Wadanohana), and bottom-dwelling or near-seafloor fauna (Kugushima, Wadanohana, Higashiura, and Kotorigoe). The shark fauna of the Hinoshima Formation is similar to that of the Yezo and Futaba groups, and also to faunas from Angola, Australia, and Antarctica. However, based on the composition of taxa, the fauna differs from that of the Upper Cretaceous shark fauna of the Western Interior Seaway and Europe. The Upper Cretaceous shark fauna of Japan, including the Hinoshima Formation, contained active pelagic (Squalicorax and Cretoxyrhina mantelli) and bentho-pelagic (e.g. Notidanodon, Chlamydoselachus, Sphenodus) predators. These taxa probably coexisted, as they occupied different ecological niches. The characteristics of the Late Cretaceous shark fauna in Japan are similar to those of the contemporaneous Southern Hemisphere fauna (e.g. Angola, Australia, and Antarctica). This shows that the characteristic shark fauna (e.g. Notidanodon, Chlamydoselachus, Sphenodus) of the Southern Hemisphere had spread to the middle latitudes of the Northern Hemisphere by the Late Cretaceous.
Fumio Kobayashi, Hiroshi Furutani, 2019: Late Early Permian Fusulines along Gongendani, South of Mt. Ryozen, Shiga Prefecture, Central Japan. Paleontological Research, Vol.23 No.2, 131-151. 10.2517/2018PR014. https://doi.org/10.2517/2018PR014
Twenty species of fusulines and ten species of non-fusuline foraminifers have been identified from 20 limestone samples along Gongendani, a valley south of Mt. Ryozen, Shiga Prefecture, Japan. They are dominated by Pseudofusulina norikurensis, Ps. isomie, and Acervoschwagerina gongendaniensis, and considered to be late Cisuralian (late early Permian) based on their coexistence with five subordinate species reported from the Yakhtashian (Artinskian) and the Bolorian (lower Kungurian) in the southeast Pamir and other Tethyan regions. Taxonomic composition of the schwagerinids of Gongendani and other faunas in the Mino Terrane is considerably different from that of coeval faunas in the Permian Akiyoshi Terrane. It is highly probable that Acervoschwagerina is Yakhtashian and possibly ranging up to Bolorian. Thirteen species of fusulines including two new species, Acervoschwagerina gongendaniensis Kobayashi and Cuniculinella omiensis Kobayashi are described systematically.
Kazushige Tanabe, Akihiro Misaki, Tetsuya Ikeda, Masataka Izukura, Kazuyoshi Moriya, 2019: Taxonomic Relationships and Paleoecological Significance of Two Exceptionally Large Lower Jaws of Late Cretaceous Ammonoids from Japan. Paleontological Research, Vol.23 No.2, 152-165. 10.2517/2018PR015. https://doi.org/10.2517/2018PR015
Yoshihiro Tanaka and Hiroyuki Taruno, 2019: The First Cetacean Record from the Osaka Group (Middle Pleistocene, Quaternary) in Osaka, Japan. Paleontological Research, Vol.23 No.2, 166-173. 10.2517/2018PR016. https://doi.org/10.2517/2018PR016
A new partial skeleton consisting of a left mandible and five caudal vertebrae, OMNH-QV 282 from the Osaka Group (Middle Pleistocene, about 0.3 million years ago) of Osaka City is reported as the first cetacean record from the group. The skeleton is identified as Balaenopteridae gen. et sp. indet. based on the combination of mandibular characters, such as having a small mandibular foramen, reflected neck in dorsal view and lack of a satellite process of the mandible. OMNH-QV 282 expands diversity for the local fauna, and also adds evidence for the existence of large-sized balaenopterids from a poorly known epoch, the Middle Pleistocene.