Tinn, O.; Meidla, T. (2003). Ontogeny and thanatocoenoses of Early Middle Ordovician palaeocope ostracode species Brezelina palmata (Krause, 1889) and Ogmoopsis bocki (Öpik, 1935). Journal of Paleontology. 77 (1): 64-72.
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Tinn, O.; Meidla, T.
2003
Ontogeny and thanatocoenoses of Early Middle Ordovician palaeocope ostracode species <em>Brezelina palmata</em> (Krause, 1889) and <em>Ogmoopsis bocki</em> (Öpik, 1935)
The ctenonotellid ostracode species Brezelina palmata (Krause,1 889) and the tetradellids pecies Ogmoopsis bocki (Opik, 1935) are represented by seven and five moltings tages, respectively. Both species display an association of velar and size dimorphism in the three last instars.The analysis of the juvenile morphology of 0. bocki provides evidence for a close relationship with the earliest known palaeocope ostracode species Nanopsis nanella (Moberg and Segerberg, 1906). The population age structure of B. palmata in synchronous beds at two localities reveals different types of thanatocoenoses, supporting the hypothesis of a deepening gradient along the Baltic-Ladoga Klint.