Porsildia, Thomsen & Østergaard, 2015

Thomsen, Helge A. & Østergaard, Jette B., 2015, Coccolithophorids in Polar Waters: Quaternariella and Porsildia gen. nov. Mercedesia gen. nov., Ericiolus,, Acta Protozoologica 54 (3), pp. 155-169 : 164

Porsildia gen. nov.

Diagnosis: Coccosphere dimorphic. Circumflagellar coccoliths have a central process formed proximally by numerous densely aggregated elements and distally terminating in two closely aligned elongate elements. Body coccoliths oval. In both coccolith types the vertical wall consists of slightly overlapping elements that vary in size and shape. The central area of the body coccoliths has a low central structure of irregularly piled elements that vary in size and shape; this structure is not connected to the rim.

Type species: Porsildia acerviphora sp. nov.

Etymology: Genus named in honour of Dr. Morten Porsild – a Danish botanist – who founded the University of Copenhagen Arctic Station (Qeqertarsuaq, West Greenland) in 1906.

Porsildia gen. nov. bears resemblance to genera of the Papposphaeraceae Jordan and Young 1990, and in particular to Papposphaera Tangen 1972 and Pappomonas Manton and Oates 1975 . Both genera have coccoliths with a characteristic murolith rim, a narrow wall, and a distally protuding structure in a wide variety of shapes on the central area. Central area and process structure are the key features with respect to species identification. The coccosphere may be monomorphic, dimorphic, varimorphic or polymorphic. Porsildia body coccoliths on the other hand have a unique and very different structure of the central area.