Abstract

Two poorly known species of Candeina from the Southern Hemisphere, C. cecionii Canon and Ernst and C. zeocenica Hornibrook and Jenkins, are believed to be part of a lineage that evolved in the temperate Southern Ocean during the Paleogene. Candeina cecionii is known from the early Eocene or early middle Eocene of the Magallanes Basin (southern Chile) while C. zeocenica has only been found in late middle Eocene to early Oligocene age sediments of New Zealand. Paleoceanographic circulation patterns and widespread hiatuses may be responsible for their present geographic and stratigraphic distribution. This suspected lineage probably gave rise to Candeina antarctica, n. sp., described here from the late Oligocene to middle Miocene of the Ross Sea, Antarctica. Candeina antarctica was part of a nearly monospecific planktonic foraminiferal assemblage during this period of deteriorating climatic conditions on and around Antarctica and was probably restricted to this region. As glacial conditions intensified during the middle and late Miocene, calcareous plankton were displaced northwards and replaced by siliceous planktonic assemblages. This transition corresponds with the last known occurrence of C. antarctica. Other workers have suggested that Candeina nitida s.l. evolved from Globigerina juvenilis (= Globigerinita glutinata) near the base of the late Miocene. An alternative explanation for the origin of C. nitida (late Miocene to Recent) is suggested in light of the Paleogene-early Neogene Candeina morphoseries proposed here.

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