Gondwanaspis (Taemasaspis) mrirtensis
Trilobites Order Lichida (Some list as Odontopleurida), Family Odontopleuridae
Geological Time: Middle Devonian
Size (25.4 mm = 1 inch): Trilobite is 28 mm long by 27 mm wide (counting spines) on a 65 mm by 80 mm matrix
Fossil Site: Jebel Issoumour, Alnif , Morocco
Fossil Code: 12093
Price: $895.00
 Description:
Elegant example of an unusual trilobite which has recently become
available, which currently goes under the name Gondwanaspis, but
has also been renamed Taeasaspis. Whatever name you choose to call
it, it is a most unusual odontopleurid. Here again nomenclature
is in flux with members of the family Odonotopleuridae being assigned
to a new order Odontopleurida. I will stay with the more conservative
assignment to Lichida until the scientific community makes up its
mind. Whatever the name and order, this taxon has the distinguishing
feature of being the last odontopleurids to go extinct during the
Frasnian/Famenian Great Extinction Event, leaving the Proetida
and Phacopida as the sole surviving orders going forward. The genus
was somewhat cosmopolitan in its distribution, having been found
in France, Germany, Morocco, Siberia, and Australia. This one has
been prepared with the cephalic and pleural spines protected by
matrix. The genal and cephalic spines are thought to have rested
on the surface of the substrate allowing them to form a “basket” for
feeding. No collection of trilobites can be considered complete
without an example of this unusual taxon. See my other offerings
for an example in which the cephalicand genals have been prepared
freestanding, a most labor-intensive effort.
Reference: Geol. Mag. 144 (3), pp777-796, 2007 |
