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Ventral valve
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Schizophoria vulvaria
Phylum: Brachiopoda
Genus: Schizophoria Species: Schizophoria vulvaria Location found: Reefton |
Two Schizophoria species have previously been described from the Devonian rocks of New Zealand. Schizophoria vulvaria is described as occurring only in the Reefton deposits, while S. provulvaria is defined in the Baton River deposits. Morphologically the two species are very similar, and it is difficult to tell them apart; whether they really are separate species is a matter of some uncertainty. Here, I have defined them purely in terms of their locality - though it may be noted that there are suggestions of a third species in the Reefton deposits! Key features of S. vulvaria are their more-or-less circular shape, the very strong and prominent umbo on the dorsal valve, the large and the deep crenellations that the ribs make on the outer margin of both shells, and the deep sockets and central groove in the ventral valve.
Globally S. vulvaria is important, because it seems to have disappeared rapidly at the end of the Emsian stage, and this provides a marker for the beginning of the succeeding Eifelian stage. |
Dorsal valve
Further Reading: Strusz, D.L. et al. 1972 Correlation of the Lower Devonian rocks of Australasia. Journal of the Geological Society of Australia 18(4), 427-455. |