Registered users receive a variety of benefits including the ability to customize email alerts, create favorite journals list, and save searches.
Please note that a BioOne web account does not automatically grant access to full-text content. An institutional or society member subscription is required to view non-Open Access content.
Contact firstname.lastname@example.org with any questions.
Lower Jurassic Radiolaria have been recovered from limestone beds and concretions in the sandstone member of the San Hipólito Formation near Punta San Hipólito, Baja California Sur, Mexico. The San Hipólito Formation and underlying Upper Triassic ophiolite form part of the Vizcaíno Sur terrane. The faunas are well-preserved, abundant, and diverse. Assemblages are dominated by spumellarians, but small cyrtid nassellarians are strongly varied also; multicyrtid nassellarians comprise a lesser component of the fauna.
The Baja faunas are dated mainly by comparison to radiolarians from the Queen Charlotte Islands that co-occur with ammonites of Pliensbachian age. New ammonite zones for North America established by Smith and Tipper (1996) provide precise age control for equivalent radiolarian faunas that has not been possible in the past. Baja radiolarians are also compared with faunas from east-central Oregon, Turkey, and Japan. The strong similarity between Baja California radiolarians and Tethyan faunas from Turkey supports existing paleomagnetic evidence that the Vizcaíno terrane may have occupied a low-latitude position in Early Jurassic time.
Two radiolarian genera (Ducatus and Religa) and twenty-two species are described as new; many other forms are discussed informally. Thirty-six previously described taxa are also documented.
The Tacipi Formation of Sulawesi was deposited during the late middle Miocene to early Pliocene in a large area of shallow water, marine carbonate production with deeper water sediments deposited to the north. A detailed biostratigraphical study of 580 samples from 58 measured outcrop sections has led to an understanding of sequence stratigraphic and facies relationships of Cenozoic carbonates in Sulawesi, their importance as the product and record of climatic/oceanic conditions and interchange in tropical/subtropical inner shelf environments, and their role as hydrocarbon reservoirs. Fifteen larger benthic foraminifera species are described and illustrated with one newly proposed taxon: Lepidocyclina pillaria. Analysis of the larger benthic foraminifera in relationship to the planktonic foraminifera allows correlation of the larger foraminiferal assemblage zones (“letter stages”) of the Far East with the N zones of the Neogene based on planktonic foraminiferal evolution patterns. The co-occurrence and recognition of planktonic foraminifera and larger benthic foraminifera species in the same thin sections is a rare opportunity for correlating the biostratigraphic frameworks based on these two groups and is of regional stratigraphic importance. This has resulted in the refinement of the biostratigraphic ranges of the larger benthic foraminifera Katacyclocypeus and Flosculinella, and enlargement of our knowledge about the Tg and Th “letter stages”.
The Hocaköy section, measured in the Alakirçay Nappe of Antalya Nappes in SW Turkey, is one of the key sections that contains Upper Triassic to Middle Cretaceous Radiolaria bearing pelagic sediments. The lower part of the section is the Upper Triassic Gökdere Formation (cherty-limestone/limestone-chert alternation), while the upper part is the Jurassic-Cretaceous Hocaköy Radiolarite (mainly chert-mudstone alternation with some limestone interlayers). Thin bedded limestone beds at base of the Hocaköy Radiolarite contain moderately to well-preserved middle Hettangian-lower upper Sinemurian radiolarians.
Radiolaria obtained from these basal limestone beds resemble and are correlative to the fauna from Queen Charlotte Island, British Columbia by Carter et al. (1998). Pantanellium browni (middle-upper Hettangian), Crucella hettangica (uppermost Hettangian-lowermost Sinemurian), Parahsuum simplum (lower Sinemurian) and Canutus rockfishensis-Wrangellium thurstonense (lower upper Sinemurian) radiolarian zones are recognized in this part of the section. In this study, 61 species and 14 taxa belonging to open nomenclature are investigated and 4 species are described as new, namely Bistarkum equalum, Praehexasaturnalis merici, Katroma hocakoeyensis and K. sashidai.
Sphaerogypsina anatolica n.sp. (Foraminifera), is described from the shallow water sediments of Lutetian age in the vicinity of Andırın town, west of Kahramanmaraş city (southeastern Turkey). The new species may be distinguished from the other known species by its coarse perforate wall, spiral early chambers, two layered chamber walls and coarse inner structure.