Late Cretaceous octobrachiate coleoid lower jaws from the north Pacific regions

2008 ◽  
Vol 82 (2) ◽  
pp. 398-408 ◽  
Author(s):  
Kazushige Tanabe ◽  
Pat Trask ◽  
Rick Ross ◽  
Yoshinori Hikida
Keyword(s):  
Late Cretaceous ◽  
North Pacific ◽  
Upper Cretaceous ◽  
Large Body ◽  
Three Dimensional ◽  
New Genera ◽  
Large Body Size ◽  
Diagnostic Features ◽  
The North ◽  
The North Pacific

Eight well-preserved cephalopod jaw fossils were discovered from the Upper Cretaceous (Santonian and Campanian) deposits of Vancouver Island, Canada, and Hokkaido, Japan. They occur individually in calcareous concretions and retain their three-dimensional architecture. Seven of them consist of a widely open outer lamella and a posteriorly projected inner lamella with a pointed rostrum. Both lamellae are made of fluorapatite, which may represent diagenetically altered chitin, and lack a calcareous element. Based on these diagnostic features, the seven jaw fossils are identified as lower jaws of the Coleoidea. Comparison with the lower jaws of modern coleoids allows us to distinguish the following new genera and species among them;Nanaimoteuthis jeletzkyiof the Order Vampyromorphida, andPaleocirroteuthis haggartiandP. pacificaof the Order Cirroctopodida. The lower jaws of these new taxa are clearly distinguished by having a much less projected inner lamella from those of modern and extinct species of the Superorder Decabrachia and the Order Octopodida. The maximum lengths of their outer lamellae (35.0-67.1 mm) are much larger than those of most modern vampyromorph and cirroctopodid species, indicating the large body size and weight of their owners. One of the other three lower jaws examined, characterized by a posteriorly extended outer lamella, may be assigned to the Octopodida. This study clearly demonstrates that large octobrachiate coleoids existed in the Late Cretaceous North Pacific.

scholarly journals Mass Footprints of the North Pacific Atmospheric Blocking Highs

2015 ◽  
Vol 28 (12) ◽  
pp. 4941-4949 ◽  
Author(s):  
Tae-Won Park ◽  
Yi Deng ◽  
Wenhong Li ◽  
Song Yang ◽  
Ming Cai
Keyword(s):  
Mass Loss ◽  
North Pacific ◽  
Three Dimensional ◽  
Low Frequency ◽  
Lower Troposphere ◽  
Decay Stage ◽  
The North ◽  
Detection And Attribution ◽  
Blocking High ◽  
The North Pacific

Abstract The mass footprints associated with atmospheric blocks over the North Pacific are evaluated by constructing daily tendencies of total mass over the blocking domain from three-dimensional mass fluxes throughout the life cycle of a composite blocking event. The results highlight the major role of mass convergence driven by low-frequency (with periods >1 week) atmospheric disturbances during both the development and decay stage of a block. Specifically, low-frequency eddies are responsible for the accelerated mass buildup 4 days prior to the peak intensity of a block, and they also account for the rapid mass loss afterward. High-frequency, subweekly scale disturbances have statistically significant positive contributions to the mass loss during the decay stage, and also show weak negative contributions to the development of the blocking high prior to the peak of the high. The majority of the mass convergence (divergence) responsible for the intensification (decay) of the blocking high occurs in the middle-to-lower troposphere and is largely attributed to mass flux driven by low-frequency meridional (zonal) winds. Also discussed are the implications of this new mass perspective of atmospheric blocks for understanding dynamics of blocking highs and for model bias detection and attribution.

3D Structure of Striations in the North Pacific

2021 ◽  
Author(s):  
YU ZHANG ◽  
YU PING GUAN ◽  
RUI XIN HUANG
Keyword(s):  
North Pacific ◽  
3D Structure ◽  
Three Dimensional ◽  
Vertical Plane ◽  
Dimensional Structure ◽  
The North ◽  
Layer Analysis ◽  
Fluid Potential ◽  
The North Pacific

AbstractOcean striations are composed of alternating quasi-zonal band-like flows; this kind of organized structure of currents be found in all world’s oceans and seas. Previous studies have mainly been focused on the mechanisms of their generation and propagation. This study uses the spatial high-pass filtering to obtain the three-dimensional structure of ocean striations in the North Pacific in both the z-coordinate and σ-coordinate based on 10-yr averaged SODA3 data. First, we identify an ideal-fluid potential density domain where the striations are undisturbed by the surface forcing and boundary effects. Second, using the isopycnal layer analysis, we show that on isopycnal surfaces the orientations of striations nearly follow the potential vorticity (PV) contours, while in the meridional-vertical plane the central positions of striations are generally aligned with the latitude of zero gradient of the relative PV. Our analysis provides a simple dynamical interpretation and better understanding for the role of ocean striations.

A revised inoceramid biozonation for the Upper Cretaceous based on high-resolution carbon isotope stratigraphy in northwestern Hokkaido, Japan

2013 ◽  
Vol 63 (2) ◽  
pp. 239-263 ◽  
Author(s):  
Tatsuya Hayakawa ◽  
Hiromichi Hirano
Keyword(s):  
High Resolution ◽  
Carbon Isotope ◽  
North Pacific ◽  
Upper Cretaceous ◽  
Northwest Pacific ◽  
Terrestrial Organic Matter ◽  
Carbon Isotope Stratigraphy ◽  
The North ◽  
Isotope Stratigraphy ◽  
The North Pacific

Abstract Hayakawa, T., Hirano, H. 2013. A revised inoceramid biozonation for the Upper Cretaceous based on high-resolution carbon isotope stratigraphy in northwestern Hokkaido, Japan. Acta Geologica Polonica, 63 (2), 239-263. Warszawa. Biostratigraphic correlations of inoceramid bivalves between the North Pacific and Euramerican provinces have been difficult because the inoceramid biostratigraphy of the Japanese strata has been based on endemic species of the northwest Pacific. In this study, carbon stable isotope fluctuations of terrestrial organic matter are assembled for the Upper Cretaceous Yezo Group in the Haboro and Obira areas, Hokkaido, Japan, in order to revise the chronology of the inoceramid biozonation in Japan. The carbon isotope curves are correlated with those of marine carbonates in English and German sections with the aid of age-diagnostic taxa. According to the correlations of the carbon isotope curves, 11 isotope events are recognised in the sections studied. As a result of these correlations, the chronology of the inoceramid biozones of the Northwest Pacific has been considerably revised. The revised inoceramid biozones suggest that the timing of the origination and extinction of the inoceramids in the North Pacific biotic province is different from the stage/substage boundaries defined by inoceramids, as used in Europe and North America.

scholarly journals Taxonomy of the fossil marine diatom resting spore morpho-genera <i>Xanthioisthmus</i> Suto gen. nov. and <i>Quadrocistella</i> Suto gen. nov. in the North Pacific and Norwegian Sea

2006 ◽  
Vol 25 (1) ◽  
pp. 3-22 ◽  
Author(s):  
Itsuki Suto
Keyword(s):  
North Pacific ◽  
Marine Diatom ◽  
Northwest Pacific ◽  
New Genera ◽  
Norwegian Sea ◽  
The North ◽  
Resting Spore ◽  
Resting Spores ◽  
Diatom Genus ◽  
The North Pacific

Abstract. The morphology and taxonomy of the fossil diatom resting spore morpho-genera Xanthioisthmus Suto gen. nov. and Quadrocistella Suto gen. nov. are described. The two new genera are probably fossil resting spores of the marine diatom genus Chaetoceros. They were studied by examining samples from DSDP Sites 436, 438 (northwest Pacific) and 338 (Norwegian Sea), and the Newport Beach Section (California). The genus Xanthioisthmus is characterized by an elongate valve composed of two flat circles joined together by a hyaline broad isthmus and includes five species: X. biscoctiformis (Forti) Suto comb. nov., X. specticularis (Hanna) Suto comb. nov., X. panduraeformis (Pantocsek) Suto comb. nov., X. praemaculata sp. nov. and X. maculata (Hanna) Suto comb. nov. The genus Quadrocistella differs from Xanthioisthmus by its elongate and rectangular valve and bears five new species: Q. rectagonuma sp. nov., Q. tubera sp. nov., Q. paliesa sp. nov., Q. montana sp. nov. and Q. palmesa sp. nov.

scholarly journals Revision of Metaconchoecia (Ostracoda: Halocyprididae) and the designation of two new tribes Conchoeciini and Metaconchoeciini

Zootaxa ◽  
2011 ◽  
Vol 2857 (1) ◽  
pp. 1 ◽  
Author(s):  
VLADIMIR G. CHAVTUR ◽  
MARTIN V. ANGEL
Keyword(s):  
New Species ◽  
North Pacific ◽  
Type Species ◽  
New Genera ◽  
The North ◽  
New Tribe ◽  
The North Pacific ◽  
A New Species ◽  
Size Data ◽  
Pelagic Ostracoda

A new tribe of pelagic Ostracoda (Halocyprididae), the Metaconchoeciini, is established to encompass all the species formerly classified in the genus Metaconchoecia. All the remaining genera in the subfamily Conchoecinae are, therefore, assigned to another new tribe, the Conchoeciini. The original genus Metaconchoecia is subdivided into ten genera. Metaconchoecia is retained and nine new genera established namely: Austrinoecia, Clausoecia, Deeveyoecia, Juryoecia, Kyrtoecia, Muelleroecia, Nasoecia, Rotundoecia and Vityazoecia. Keys to these new genera and their component species are provided. Tables summarize the characters that most readily distinguish between the most closely related taxa. Appendices summarize the taxonomic characters and detailed size data for the majority of species that occur in the Atlantic and the North Pacific. A new species, Vityazoecia distoglandula, is described, which is designated as the type species of its genus.

scholarly journals Three-Dimensional Structure and Temporal Evolution of Submesoscale Thermohaline Intrusions in the North Pacific Subtropical Frontal Zone

2010 ◽  
Vol 40 (8) ◽  
pp. 1669-1689 ◽  
Author(s):  
A. Y. Shcherbina ◽  
M. C. Gregg ◽  
M. H. Alford ◽  
R. R. Harcourt
Keyword(s):  
North Pacific ◽  
Frontal Zone ◽  
Opposite Sign ◽  
Three Dimensional ◽  
Three Dimensions ◽  
Dimensional Structure ◽  
Subtropical Front ◽  
The North ◽  
Lateral Advection ◽  
The North Pacific

Abstract Four instances of persistent intrusive deformation of the North Pacific Subtropical Front were tagged individually by a Lagrangian float and tracked for several days. Each feature was mapped in three dimensions using repeat towed observations referenced to the float. Isohaline surface deformations in the frontal zone included sheetlike folds elongated in the alongfront direction and narrow tongues extending across the front. All deformations appeared as protrusions of relatively cold, and fresh, water across the front. No corresponding features of the opposite sign or isolated lenslike structures were observed. The sheets were O(10 m) thick, protruded about 10 km into the warm saline side of the front, and were coherent for 10–30 km along the front. Having about the same thickness and cross-frontal extent as the sheets, tongues extended less than 5 km along the front. All of the intrusions persisted as long as they were followed, several days to one week. Their structures evolved on both inertial (23 h) and subinertial (∼10 days) time scales in response to differential lateral advection. The water mass surrounding the intrusions participated in gradual anticyclonic rotation as a part of a mesoscale meander of the subtropical front. The intrusions may be interpreted as a manifestation of three-dimensional submesoscale turbulence of the frontal zone, driven by the mesoscale. Absence of large features of the opposite sign may be indicative of the asymmetry of the underlying dynamics.

Late Cretaceous gastropods from the Izumi Group of southwest Japan

1990 ◽  
Vol 64 (4) ◽  
pp. 563-578 ◽  
Author(s):  
Tomoki Kase
Keyword(s):  
Late Cretaceous ◽  
North American ◽  
Upper Cretaceous ◽  
Coastal Areas ◽  
Basal Part ◽  
Northwestern Pacific ◽  
New Genera ◽  
Southwest Japan ◽  
The North ◽  
The Family

The basal part of the Upper Cretaceous, mid-Campanian to Maastrichtian Izumi Group of the Izumi Mountains and Awaji Island, Southwest Japan, contains the most diverse gastropod fauna of this age in Japan. This paper discriminates 19 species and describes two new genera: Atira tricarinata n. sp., Ataphrus (s.s.) sp. A, Ataphrus (s.s.) sp. B, Globularia (s.s.) izumiensis n. sp., Lysis izumiensis n. sp., Trichotropis? sp., Deussenia takinoikensis n. sp., Volutilithes antiqua n. sp., Pseudoperissitys bicarinata Nagao and Otatume, Nekewis sp., Nipponitys inouei n. gen. and sp., Nipponitys acutangularis n. gen. and sp., Nipponitys sp. cf. N. magna (Kalishevitsch), Calorebama cretacea n. sp., Taniella japonica n. gen. and sp., Amuletum (s.s.) sp., Biplica osakensis n. sp., Biplica sphaerica n. sp., and Cylichna sp. The family Ampullospiridae is assigned to the suborder Architaenioglossa from the superfamily Naticacea. The enigmatic genus Lysis is tentatively assigned to the Calyptraeidae. Taniella japonica n. sp. is the oldest member of the family Olividae, and Calorebama cretacea n. sp. is the oldest member of the subfamily Pseudolivinae. Occurrence of Atira, Ataphrus, Biplica, and five perissityids further supports close communication of the northwestern Pacific Late Cretaceous gastropod faunas with those of the North American Pacific coastal areas.

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