Spinatrypa is somewhat common in the lower to middle Devonian of Europe while it is more prevalent in the US during the late middle to upper Devonian. To me this is an indication of the genera originating in Europe and migrating to the US as the continents moved closer during the Devonian. The specimen of
Spinatrypa aspera below comes from the Junkerberg formation (Devonian, Eifelian stage), near Gondelsheim, Eifel, Germany. It is a robust, rounded shell with the typical rippled surface that one expects.
Specimen #1
Brachial valve
Profile
Pedicle valve
Posterior
Profile
Specimen #2
Brachial valve
Anterior
Pedicle valve
Posterior
Profile
I have plenty of other examples of this genera including
S. aspera from
Poland (of which I am having doubts my specimens are labelled correctly),
S. spinoa from the Windom shale of New York (
with and
without spines preserved) as well as and
S. rockfordensis from
Iowa.
No comments:
Post a Comment