Lower Tithonian mono- and dicyrtid Nassellaria (Radiolaria) from the Solnhofen area (southern Germany)

A highly diverse association of monocyrtid and dicyrtid nassellarians is described from the lower Tithonian Mühlheim Member of the Solnhofen area. Nine genera and 52 species are described as new, and a new family is defined. Spicular nassellarians are first reported from the Jurassic, bridging the pre-existing long stratigraphic gap between the Middle Triassic and the Paleogene. The first occurrence of Sethoperidae Haeckel, 1881 is dated back from the Eocene to the Pliensbachian and the range of the Cuniculiformidae De Wever, 1982 is extended up to the Cenomanian by the inclusion in it of the genus Cassideus Pessagno, 1969, the definition of which is emended. The range of the family Foremanellinidae Dumitrica, 1982 is also extended up to the lower Tithonian where it is represented by the genus Sanniopileus n. gen. Among the new genera described herein it is interesting to mention Poculinapora n. gen., very close to Napora Pessagno, 1977 but bearing an apical tube. Beside the lower Tithonian species, one species is described from the Bajocian of Japan.