The Carboniferous fish genera Strepsodus and Archichtys (Sarcopterygii: Rhizodontida): Clarifying 150 years of confusion

  • Jeffrey J
  • 29


    Mendeley users who have this article in their library.
  • 8


    Citations of this article.


The Carboniferous genus Strepsodus contains several described species, but has been mired in taxonomic confusion for nearly 150 years. The little-known genus Archichthys (with two described species) is usually treated as a junior synonym of Strepsodus. These problems have been caused by, among other things, the poor quality of most specimens, and a heavy reliance on tooth and scale morphology when erecting new species. Both genera are known from Upper and Lower Carboniferous river and lake deposits in the UK, particularly coal shales, cementstones and freshwater limestones. However, Strepsodus has also been discovered at a number of North American localities (e.g. Greer in Iowa, USA, and Horton Bluff in Nova Scotia, Canada) and more recently in Australia (Ducabrook, Queensland). Rhizodontid remains from two Upper Devonian sites (one in Colombia, one in Turkey) have been attributed to Strepsodus, due to a misunderstanding of the defining characteristics (autapomorphies) of the genus. This paper reviews what is known of Strepsodus and Archichthys, and advocates that each be treated as a monospecific genus until reliable morphological evidence of further speciation is found. A neotype specimen for Strepsodus sauroides is proposed, and a check-list of published rhizodontid species is appended.

Author-supplied keywords

  • Neotype
  • Species definition
  • Taxonomy

Get free article suggestions today

Mendeley saves you time finding and organizing research

Sign up here
Already have an account ?Sign in

Find this document


  • Jonathan E. Jeffrey

Cite this document

Choose a citation style from the tabs below

Save time finding and organizing research with Mendeley

Sign up for free