In her PhD volume Renz (1976) described a new Liosphaeridae as Plegmosphaera lepticali Renz 1976, holotype is illustarted on her p. 181, plate 1, fig. 14.
I guess the species in question is rather closely related, but I doubt this is the same species.
Kjell R. Bjørklund (2012/02/20)
These creatures could be cysts of Acantharia, especially picture A (not sure about B and C). Acantharia are very abundant in the Mediterranean sea and in the Marmara sea. Quaiser et al (ISME 2010 1-10) have found many environmental sequences related to Acantharia very deep (up to 1000m)in the Marmara sea. This is my personal guess and a way to check whether they are truly acantharia is to make some elemental analyses to detect strontium.
Johan Decelle (2012/02/22)