Quick Search:    advanced search

GSW Home   GeoRef Home   My GSW Alerts   Contact GSW   About GSW   Journals List   Help

Journal of Paleontology

This Article Figures Only Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Web of Science (1) Citing Articles via Google Scholar Google Scholar Articles by Crampton, J. S. Articles by Gale, A. S. Search for Related Content GeoRef GeoRef Citation

Taxonomy and Biostratigraphy of the Late Albian Actinoceramus sulcatus Lineage (Early Cretaceous Bivalvia, Inoceramidae)

¹ GNS Science, PO Box 30368, Lower Hutt, New Zealand, <j.crampton{at}gns.cri.nz>
² School of Earth and Environmental Sciences, University of Portsmouth, Burnaby Building, Burnaby Road, Portsmouth PO1 3QL, United Kingdom

The Actinoceramus sulcatus lineage (Parkinson, 1819) (Bivalvia: Inoceramidae) is a very distinctive and abundant component of late Albian (Early Cretaceous) molluscan assemblages that is found throughout Europe, Central Asia, Japan and the Far East of Russia, southern and western North America, South Africa, and possibly India, in a range of shallow- to deep-marine facies. The lineage encompasses a wide and continuous range of morphologies that provide evidence of phyletic evolution at varying rates combined with large ecophenotypic plasticity within populations. The evolution of A. sulcatus marks the oldest appearance of well-developed radial folds and sulci within the Inoceramidae. The range of morphological variation makes formal taxonomic subdivision of the group problematic. Here we use a combination of formal successional subspecies and informal morphotypes to subdivide the lineage into the following taxa: A. sulcatus forma sulcatus, A. sulcatus forma subsulcatus (Wiltshire, 1869), A. sulcatus forma munsoni (Cragin, 1894), and A. sulcatus biometricus Crampton, 1996. Within these taxa and morphotypes, we synonymise a large number of earlier names that have been applied to variants within the lineage. Each of the forms recognized has biostratigraphic utility and we describe four new lineage biozones, in ascending order: A. concentricus parabolicus, A. sulcatus, A. sulcatus forma munsoni, and A. sulcatus biometricus biozones. The lowest occurrence of A. sulcatus is approximately coincident with the base of the upper Albian as currently defined, at least throughout most of Europe, and this datum provides a valuable tool in correlation. The nature of radial folds within the A. sulcatus lineage poses interesting but still unanswered questions regarding shell morphogenesis in bivalves and the functional significance (if any) of radial folds in the Inoceramidae.

This article has been cited by other articles:

				B. KROGER and E. LANDING CEPHALOPODS AND PALEOENVIRONMENTS OF THE FORT CASSIN FORMATION (UPPER LOWER ORDOVICIAN), EASTERN NEW YORK AND ADJACENT VERMONT Journal of Paleontology, September 1, 2009; 83(5): 664 - 693. [Abstract] [Full Text] [PDF]