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Fenestella sp.
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Fenestella is a genus of bryozoan that lived throughout much of the Palaeozoic - from the mid-Ordovician to the late Triassic. It has a distinctive, fan-like structure, composed of branches that are linked by narrower cross-growths, called dissepiments. Identification at genus level is relatively straightforward, because there are few other fossils with which it might be confused: Fenestella is finer and has wider dissepiments than other members of the fenestellid family. Some confusion is possible, however, due to the changes in names that have occurred over the years. Because it is also the name of a bivalve, the genus name Fenestella was excised for some time, and replaced by the Fenestrellina; but but after thirty years, in 1965, this decision was reversed, and Fenestella was reinstated as the accepted name. (At the same time, the common misspelling, Fenestrella, was officially condemned!)
Identification at species level poses far greater problems, because over 750 species have been identified worldwide, and distinguishing between them requires detailed study of the internal structure of the branches. For now, therefore, this specimen must be content with only its genus name.
Bryozoans are relatively common in the Permian rocks of New Zealand, and the best known fauna is that found in the Productus Creek group, in the Brook Street terrane, near Nelson. In this, a diverse fauna has been described that is similar in composition to that of Permian localities in Tasmania and New South Wales. More fragmentary faunas are also found in the rocks of the Maitai terrane around Nelson and at Parapara Peak, in the Kahurangi National Park. To date, however, none of these deposits has produced convincing examples of true Fenestella. The specimen shown here is from Parapara Peak. Thus, if this specimen is a true Fenestella, it would be the first confirmation of its existence in the Permian rocks in New Zealand.
Identification at species level poses far greater problems, because over 750 species have been identified worldwide, and distinguishing between them requires detailed study of the internal structure of the branches. For now, therefore, this specimen must be content with only its genus name.
Bryozoans are relatively common in the Permian rocks of New Zealand, and the best known fauna is that found in the Productus Creek group, in the Brook Street terrane, near Nelson. In this, a diverse fauna has been described that is similar in composition to that of Permian localities in Tasmania and New South Wales. More fragmentary faunas are also found in the rocks of the Maitai terrane around Nelson and at Parapara Peak, in the Kahurangi National Park. To date, however, none of these deposits has produced convincing examples of true Fenestella. The specimen shown here is from Parapara Peak. Thus, if this specimen is a true Fenestella, it would be the first confirmation of its existence in the Permian rocks in New Zealand.
Further Reading:
Campbell, H.J. et al.1998. Parapara Group: Permian–Triassic rocks in the Western Province, New Zealand. New Zealand Journal of Geology and Geophysics 41, 281–296.
Reid, C.M. & James, N.P. 2010 Permian higher latitude bryozoan biogeography. Palaeogeography, Palaeoclimatology, Palaeoecology 298, 31-41.
Campbell, H.J. et al.1998. Parapara Group: Permian–Triassic rocks in the Western Province, New Zealand. New Zealand Journal of Geology and Geophysics 41, 281–296.
Reid, C.M. & James, N.P. 2010 Permian higher latitude bryozoan biogeography. Palaeogeography, Palaeoclimatology, Palaeoecology 298, 31-41.