Hostname: page-component-78c5997874-8bhkd Total loading time: 0 Render date: 2024-11-06T09:44:27.718Z Has data issue: false hasContentIssue false
  • English
  • Français

Additional information on Alainaspis and Boothiaspis, cyathaspidids (Agnatha: Heterostraci) from the Upper Silurian of Northwest Territories, Canada

Published online by Cambridge University Press:  20 May 2016

David K. Elliott  and
David L. Dineley
David K. Elliott
Affiliation:
Department of Geology, Box 6030, Northern Arizona University, Flagstaff 86011
David L. Dineley
Affiliation:
Department of Geology, University of Bristol, Avon BS8 1TR, England
Get access Rights & Permissions [Opens in a new window]

Abstract

New material of the poraspid Alainaspis platyrhina Elliott and Dineley has made it possible to provide a more extensive reconstruction of this animal. It is now clear that an elongated branchial opening was present below the lateral lamina and that a well-developed post-branchial lobe was present. No branchial plate has been identified and this may have been fused to the dorsal shield, forming the ventral lamina. The lateral lamina is now seen to terminate in a rounded angle before the posterior margin of the shield. Several ventral shields with similar ornament are identified as belonging to A. platyrhina. These are broad and deep and are consistent with the original interpretation of this animal as a filter feeder. One similar shield with a coarser ornament is tentatively assigned to the closely related species Boothiaspis ovata Broad.

Type
Research Article
Information
Journal of Paleontology , Volume 65 , Issue 2 , March 1991 , pp. 308 - 313
Copyright
Copyright © The Paleontological Society 

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Broad, D. S. 1973. Amphiaspidiformes (Heterostraci) from the Silurian of the Canadian Arctic archipelago. Geological Survey of Canada Bulletin, 222:35–50.Google Scholar
Broad, D. S., and Dineley, D. L. 1973. Torpedaspis, a new Upper Silurian and Lower Devonian genus of Cyathaspididae (Ostracodermi) from Arctic Canada. Geological Survey of Canada Bulletin, 222:53–90.Google Scholar
Denison, R. H. 1964. The Cyathaspididae: a family of Silurian and Devonian jawless vertebrates. Fieldiana, Geology, 13:309–473.Google Scholar
Dineley, D. L. 1976. New species of Ctenaspis (Ostracodermi) from the Devonian of Arctic Canada, p. 26–43. In Churcher, C. S. (ed.), Athlon: Essays on Palaeontology in Honour of Louis Shano Russell. Royal Ontario Museum, Life Sciences, Miscellaneous Publications.Google Scholar
Elliott, D. K. 1984. A new subfamily of Pteraspididae (Agnatha, Heterostraci) from the Upper Silurian and Lower Devonian of Arctic Canada. Palaeontology, 27:169–197.Google Scholar
Elliott, D. K., and Dineley, D. L. 1985. A new heterostracan from the Upper Silurian of Northwest Territories, Canada. Journal of Vertebrate Paleontology, 5:103–110.Google Scholar
Kiaer, J. 1932. The Downtonian and Dittonian vertebrates of Spitsbergen. IV. Suborder Cyathaspida. Skrifter Svalbard Ishavet, 52:7–26.Google Scholar
Mayr, U. 1978. Stratigraphy and correlation of lower Paleozoic formations subsurface of Cornwallis, Devon, Somerset and Russell Islands, Canadian Arctic Archipelago. Geological Survey of Canada Bulletin, 276:1–39.Google Scholar
Miall, A. D. 1970. Continental marine transition in the Devonian of Prince of Wales Island, Northwest Territories. Canadian Journal of Earth Sciences, 7:125–144.Google Scholar
Miall, A. D., and Kerr, J. W. 1977. Phanerozoic stratigraphy of Somerset Island and northwest Boothia Peninsula, p. 99–106. In Report of Activities, Pt. A. Geological Survey of Canada, Paper 77-1A.Google Scholar
Miall, A. D., and Gibling, M. R. 1978. The Somerset Island Formation: an Upper Silurian to ?Lower Devonian intertidal/supratidal succession, Boothia Uplift region, Arctic Canada. Canadian Journal of Earth Sciences, 15:181–189.Google Scholar
Novitskaya, L. I. 1967. O proiskhozdenii i nekotorykh napravelniyakh evolutsii amfiaspid (Heterostraci) [The origin and some trends in the evolution of the amphiaspids (Heterostraci)]. Doklady ANSSR, 172:1222–1225[in Russian].Google Scholar
Novitskaya, L. I. 1968. Novye Amfiaspidy (Heterostraci) iz nizhnego devona Sibiri i klassifikatsiya Amphiaspidiformes [New amphiaspids (Heterostraci) from the Lower Devonian of Siberia, and the classification of the Amphiaspidiformes], p. 43–62. In Ocherki po filogenii i sistematike iskopemykh ryb i beschelyustnykh [Outline of Phylogeny and Systematics of Fossil Fish and Agnatha]. Moscow [in Russian].Google Scholar
Novitskaya, L. I. 1971. Les Amphiaspides (Heterostraci) du Devonien de la Siberie. Cahiers de Paleontologie, ed. Lehman, Editions du Centre National de la Recherćhe Scientifique, 130 p.Google Scholar
Thorsteinsson, R. 1980. Stratigraphy and conodonts of Upper Silurian and Lower Devonian rocks in the environs of the Boothia Uplift, Canadian Arctic Archipelago. Part I. Contributions to stratigraphy. Geological Survey of Canada Bulletin, 292:1–38.Google Scholar
Thorsteinsson, R., and Tozer, W. 1963. Geology of northern Prince of Wales Island and northwestern Somerset Island, p. 117–129. In Fortier, Y. et al. (eds.), Geology of the North Central Part of the Arctic Archipelago, Northwest Territories (Operation Franklin). Geological Survey of Canada, Memoir 320.Google Scholar