Under Construction

Cretaceous spirulidsgroup is extinct

Dirk Fuchs
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Containing group: Spirulida

Introduction

While Cenozoic representatives of the Spirulida are well-known since the 19th century, Cretaceous ancestors of Spirula are first evident since Jeletzky (1966). Owing to a Spirula-like caecum that enters the lumen of the protoconch of a Late Cretaceous orthoconic phragmocone with conspicuously long chambers and without a belemnite-like rostrum, Jeletzky (1966) established the family Groenlandibelidae. Today, four species in three genera can reliably be placed within this spirulid family (Fuchs et al. 2012). Groenlandibelidae differ from belemnoids by the presence of a caecum, a narrow rod-like proostracum, wide soft tissue attachment scars, and the absence of a solid rostrum and tabular nacre in the shell wall (Fuchs et al. 2012). In contrast to Cenozoic spirulids (e.g. Beloptera, Spirulirostra), groenlandibelid phragmocones are not yet coiled.

The origin of groenlandibelids is still enigmatic. Morphologically, Cenomanian-Maastrichtian Longibelus matsumotoi and Aptian Longibelus kabanovi appear to be intermediate between belemnoid diplobelids and groenlandibelids (Fuchs & Tanabe 2010, Fuchs et al., 2013).

Soft tissues are unknown from the fossil record (except soft tissue attachment scars on the inside of each chamber ).

Classification

References

Fuchs, D., Iba, Y., Ifrim, Ch.; Nishimura, T., Kennedy, J., Keupp, H., Stinnesbeck, W. and Tanabe, K. 2013. Longibelus n. gen. a new Cretaceous coleoid genus linking Belemnoidea and early Decabrachia. Palaeontology, 56 (5): 1081-1106. DOI:10.1111/pala.12036

Fuchs, D., Keupp, H., Trask, P. and Tanabe, K. 2012. Taxonomy, morphology and phylogeny of Late Cretaceous spirulid coleoids (Cephalopoda) from Greenland and Canada. Palaeontology, 55 (2): 285-303. DOI: 10.1111/j.1475-4983.2011.01125.x

Fuchs, D. and Tanabe, K. 2010. Re-investigation of the shell morphology and ultrastructure of the late Cretaceous spirulid coleoid Naefia matsumotoi. In: Proceedings of the 7th International Symposium - Cephalopods - Present & Past, Sapporo. 195-207.

Jeletzky, J. A. 1966. Comparative morphology, phylogeny and classification of fossil Coleoidea. Paleontological Contributions, University of Kansas, Mollusca, 7, 1166.

Title Illustrations
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Scientific Name Cyrtobelus hornbyense
Location Hornby Island (Vancouver Island, Canada
Specimen Condition Fossil -- Period: Late Cretaceous (Campanian)
Identified By Dirk Fuchs
Body Part phragmocone
View lateral
Size 17mm
Type Holotype
Image Use creative commons This media file is licensed under the Creative Commons Attribution-NonCommercial License - Version 3.0.
Copyright © Dirk Fuchs
About This Page

Dirk Fuchs
Hokkaido University

Correspondence regarding this page should be directed to Dirk Fuchs at

Page: Tree of Life Cretaceous spirulids. Authored by Dirk Fuchs. The TEXT of this page is licensed under the Creative Commons Attribution-NonCommercial License - Version 3.0. Note that images and other media featured on this page are each governed by their own license, and they may or may not be available for reuse. Click on an image or a media link to access the media data window, which provides the relevant licensing information. For the general terms and conditions of ToL material reuse and redistribution, please see the Tree of Life Copyright Policies.

Citing this page:

Fuchs, Dirk. 2015. Cretaceous spirulids. Version 26 February 2015 (under construction). http://tolweb.org/Cretaceous_spirulids/148172/2015.02.26 in The Tree of Life Web Project, http://tolweb.org/

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