Skip to main content Accessibility help

On Cephalaspis magnifica Traquair, 1893, from the Middle Devonian of Scotland, and the relationships of the last osteostracans

  • Philippe Janvier (a1) and Michael J. Newman (a2)

The large Middle Devonian osteostracan Cephalaspis magnifica Traquair, 1893a, from the Late Eifelian Upper Caithness Flagstone Group of Caithness, Scotland, is redescribed on the basis of the holotype and a second, hitherto undescribed specimen. This species is assigned to a new genus, Trewinia gen. nov. and, on account of its probable lack of lateral cephalic fields, is regarded as a possible member of the Escuminaspididae, which are hitherto only known from the Late Devonian of Quebec, Canada. Other characters of the head shield of T. magnifica also accord with the structure of the largest known escuminaspidid Escuminaspis. The morphology, relationships and biogeography of the few other Middle and Late Devonian osteostracans are discussed. North American osteostracans are generally quite distinctive from European ones throughout the Devonian, and only few taxa seem common to the two areas. The Escuminaspididae could be one of these, and this would agree with similar distributions met with in other Middle and Late Devonian vertebrates from similar environments. The question of the possible causes of the decline and extinction of the various ‘ostracoderm’ groups after the end of the Early Devonian is briefly discussed, and environmental factors are favoured to account for their decline in abundance and diversity.

Recommend this journal

Email your librarian or administrator to recommend adding this journal to your organisation's collection.

Earth and Environmental Science Transactions of The Royal Society of Edinburgh
  • ISSN: 1755-6910
  • EISSN: 1755-6929
  • URL: /core/journals/earth-and-environmental-science-transactions-of-royal-society-of-edinburgh
Please enter your name
Please enter a valid email address
Who would you like to send this to? *



Full text views

Total number of HTML views: 0
Total number of PDF views: 0 *
Loading metrics...

Abstract views

Total abstract views: 0 *
Loading metrics...

* Views captured on Cambridge Core between <date>. This data will be updated every 24 hours.

Usage data cannot currently be displayed