TAXONOMIC REEXAMINATION AND TYPE-LOCALITY ASSEMBLAGE CHARACTERIZATION OF THE LATE ALBIAN PLANKTONIC FORAMINIFERA HEDBERGELLA YEZOANA TAKAYANAGI AND IWAMOTO, 1962, FROM JAPAN

Abstract

Research Article| October 01, 2012 TAXONOMIC REEXAMINATION AND TYPE-LOCALITY ASSEMBLAGE CHARACTERIZATION OF THE LATE ALBIAN PLANKTONIC FORAMINIFERA HEDBERGELLA YEZOANA TAKAYANAGI AND IWAMOTO, 1962, FROM JAPAN Atsushi Ando Atsushi Ando * Department of Paleobiology, National Museum of Natural History, Smithsonian Institution, P.O. Box 37012, MRC 121, Washington, D.C. 20013-7012 *Correspondence author: E-mail: AndoA@si.edu Search for other works by this author on: GSW Google Scholar Author and Article Information Atsushi Ando * Department of Paleobiology, National Museum of Natural History, Smithsonian Institution, P.O. Box 37012, MRC 121, Washington, D.C. 20013-7012 *Correspondence author: E-mail: AndoA@si.edu Publisher: Cushman Foundation for Foraminiferal Research Received: 21 Jul 2011 Accepted: 30 Jun 2012 First Online: 03 Mar 2017 Online ISSN: 1943-264X Print ISSN: 0096-1191 © 2012 Cushman Foundation for Foraminiferal Research Journal of Foraminiferal Research (2012) 42 (4): 271–285. https://doi.org/10.2113/gsjfr.42.4.271 Article history Received: 21 Jul 2011 Accepted: 30 Jun 2012 First Online: 03 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation Atsushi Ando; TAXONOMIC REEXAMINATION AND TYPE-LOCALITY ASSEMBLAGE CHARACTERIZATION OF THE LATE ALBIAN PLANKTONIC FORAMINIFERA HEDBERGELLA YEZOANA TAKAYANAGI AND IWAMOTO, 1962, FROM JAPAN. Journal of Foraminiferal Research 2012;; 42 (4): 271–285. doi: https://doi.org/10.2113/gsjfr.42.4.271 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyJournal of Foraminiferal Research Search Advanced Search Abstract The late Albian planktonic foraminifera Hedbergella trocoidea yezoanaTakayanagi and Iwamoto, 1962, from Japan, whose primary distinguishing feature is 7–8 chambers in the final whorl, has been internationally cited with a species rank as Hedbergella yezoana. Still, its taxonomic position is not well understood, as manifested by the fact that published hypotypes have six or fewer chambered forms, and such ambiguity is due partly to a lack of updated knowledge about the primary types (a holotype and single paratype), topotypes, and hypotypes from the northwestern Pacific region. This study reexamines the species concept of Hd. yezoana through uncoated SEM observations of the primary types and newly obtained type-locality material. The holotype is synonymous with Ticinella primula Luterbacher, 1963, as judged by its uneven wall surface, pseudoplanispiral (slightly streptospiral) mode of coiling, somewhat tangentially elongate last chambers, and a possible porticus-like structure. The topotypes exhibit important characters such as supplementary apertures and well-developed portici, thus confirming the synonymy of Hd. yezoana and T. primula. This outcome, however, is troublesome because T. primula is the widely used name for this morphology, and accepting the priority of “Ticinella yezoana” affects the nomenclatural stability in Cretaceous planktonic foraminifera. Conservation of the junior name T. primula is supported not only by the insufficient preservation of the Hokkaido material but also by the concept of Article 23.9 (reversal of precedence) in the International Code of Zoological Nomenclature (4th edition, 1999), although a ruling from the Zoological Commission would be eventually necessary. The paratype, in contrast, exhibits a smooth, microperforate wall, and is identified in open nomenclature as Microhedbergella sp. A (multi-chambered form). In addition to this wall-surface feature, this potential new Microhedbergella taxon differs from the “Hd. yezoana” holotype (and hence from T. primula) by lacking a streptospiral mode of coiling, exhibiting isomorphic globular chambers between the umbilical and spiral sides, and possessing a very poorly developed or nearly absent lip.The type-locality assemblage of “Hd. yezoana” is marked by the common occurrence of several other “ticinellid” taxa (Biticinella breggiensis and at least three species of Ticinella) and Microhedbergella with very rare Favusella. The Microhedbergella specimens have a remarkably wide range of morphologies, some comparable to those recorded in a local Texas assemblage, but the rest undescribed. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.