New Data on the Bajocian–Bathonian Parkinsoniidae (Ammonoidea, Perisphinctoidea)

Some structural features of the suture line of adult representatives of the family Parkinsoniidae are analyzed. It has been established that in the genera Caumontisphinctes, Pseudocosmoceras, Sokurella and most Rarecostites, the ventral lobe (V) is deeper than the first lateral lobe (U). On the contrary, in the microconchs of the later Rarecostites, as well as in the genera Parkinsonia and Oraniceras, lobe V is smaller than lobe U; in...