Coccolithophores in Polar Waters: Papposphaera sarion HET and HOL revisited

摘要

Papposphaera sarion was first described from West Greenland waters and has not since then been reported from other sites. We present here additional material of P. sarion from the type locality, transmission electron images of P. sarion from the NEW polynya (NE Greenland) and scanning electron images from Svalbard. Study of a vastly extended source of images provides new morphological data, particularly on the variability of coccolith central area calcification in this species. Combination coccospheres involving a Turrisphaera sp. were frequently observed in samples from the NEW polynya as was also the holococcolithophore Turrisphaera phase of this species. Papposphaera sarion has in its life-cycle previously been associated with Turrisphaera arctica. However, a careful re-examination of the micrographs accompanying the description of T. arctica and unpublished material available to us clearly reveals that T. arctica combines with a different, but as yet undescribed species of Papposphaera. A striking similarity is pointed out between P. sarion HET and species of Stradnerlithus, e.g. Stradnerlithus fragilis from the middle Jurassic.