A new glyptorthid species (Brachiopoda: Orthida) from the Upper Ordovician of Estonia

作者：Hints Linda^*

来源：Estonian Journal of Earth Sciences, 2010, 59(3): 189-194.

DOI：10.3176/earth.2010.3.01

• Brachiopoda
• taxonomy
• Upper Ordovician
• northern Estonia

A new glyptorthid brachiopod species Bassettella alata with surface pits and lamellose frills is described from the Upper Ordovician Haljala and Keila stages of northern Estonia. The new species appears in the Johvi Substage of the Haljala Stage (mid-Sandbian) and is somewhat younger than the type species B. gracilis appearing in the lower Idavere Substage of the same stage in NW Russia. In the uppermost Keila Stage (lowermost Katian), B. alata belongs to a mixed faunal association of the marginal facies of the Vasalemma Formation comprising the oldest Ordovician reefs in Estonia. The distribution pattern of brachiopods of the genus Bassettella shows a westward shift in time and changes in shell morphology from subrectangular to subtriangular with alate cardinal extremities.

• 出版日期2010