We use cookies to ensure that we give you the best experience on our website. By continuing to browse this repository, you give consent for essential cookies to be used. You can read more about our Privacy and Cookie Policy.

Durham Research Online
You are in:

An Ordovician nectocaridid hints at an endocochleate origin of Cephalopoda.

Smith, Martin R. (2020) 'An Ordovician nectocaridid hints at an endocochleate origin of Cephalopoda.', Journal of paleontology., 94 (1). pp. 64-69.


Nectocaridids are soft-bodied Cambrian organisms that have been controversially interpreted as primitive cephalopods, contradicting the long-held belief that these molluscs evolved from a shell-bearing ancestor. Here I document a new nectocaridid from the Whetstone Gulf formation, extending the group’s range into the Late Ordovician. <i>Nectocotis rusmithi</i> n. gen, n. sp. possesses a robust internal element that resembles a non-mineralized phragmocone or gladius. <i>Nectocotis</i> can be accommodated in the cephalopod total group if (1) cephalopods inherited a non-mineralized shell field from the ancestral mollusc; (2) the earliest cephalopods bore internal shells. This evolutionary scenario would overturn the traditional ectocochleate, <i>Nautilus</i>-like reconstruction, and indicate a trend towards increased metabolic efficiency through the course of Cambrian–Ordovician evolution.

Item Type:Article
Full text:(AM) Accepted Manuscript
Available under License - Creative Commons Attribution Non-commercial No Derivatives.
Download PDF
Publisher Web site:
Publisher statement:This article has been published in a revised form in Journal of Paleontology 10.1017/jpa.2019.57. This version is published under a Creative Commons CC-BY-NC-ND. No commercial re-distribution or re-use allowed. Derivative works cannot be distributed. © 2019 The Paleontological Society.
Date accepted:14 June 2019
Date deposited:18 June 2019
Date of first online publication:15 August 2019
Date first made open access:15 February 2020

Save or Share this output

Look up in GoogleScholar