Friday, October 21, 2011

Mediospirifer "Angustus" ?

During a recent trip up to Arkona, Canada I found this unusual Brachiopod which resembles the mutant off spring of a Mucrospirifer and a Brachyspirifer. It comes from the Middle Devonian (Givetian) aged rocks near Arkona called the Hungry Hollow member of the Widder Formation.

Stumped as the to ID of this odd looking Spiriferid, I looked it up in the most comprehensive resource available to me: Amadeus Grabau's "Geology and Paleontology of Eighteen Mile Creek" and it seems to match Spirifer("Mediospirifer") angustus (Page 213). The problem is this is not listed as a species that is found within the Widder formation. This is based on the 1958 publication "Checklist of Fossil Invertebrates Described from the Middle Devonian Rocks of the Thedford-Arkona Region of Southwestern Ontario by the University of Michigan.

So I may have found a new species that was not known from the Widder formation before now. Has anyone else seen a Brachiopod like this before?


  1. Hey!
    Neat find.. I have one valve of that guy and always thought it was a brachispirifer
    Its stuck in the matrix right now until i get an air abrader.
    Squalicorax from thefossilforum

  2. Hey Squali, yours does look like the specimen I found. I'm hoping to get mine cleaned so I can view it in total 3-D glory.

    Gery, Thanks for the compliment!