Early-Middle Jurassic stepwise deepening in the transitional facies belt between the Adriatic Carbonte Platform Basement and Neo-Tethys open shelf in northeastern Montenegro evidenced by new ammonoid data from the early Late Pliensbachian (Lavinianum Zone)

New ammonoid data prove an early Late Pliensbachian deepening event above the ?Late Hettangian-Sinemurian shallow-subtidal gray-reddish micro-oncoidal-foraminifera grainstone facies and ?early deeper-marine micro-oncoidal-crinoidal-ammonoid wacke- to packstone facies. Based on presence of Fuciniceras lavinianum (Fucini), Lytoceras ovimontanum Geyer Arieticeratinae gen. indet. from a hardground deeper-water micro-oncoidal limestones in Mihajlovici section (north - eastern Montenegro) Toarcian condensation horizon is proven. The Middle ammonoid-bearing also yielded species not known previous studies: Calliphylloceras capitanii (cATuLLo), Harpoceras subplanatum (oPPeL) Furloceras aff. chelussii (PAriScH & ViALe), described present paper. These new stepwise depositional area during Jurassic reflected detail four sedimentary members: 1) Hettangian Sine murian/?earliest open-marine shallow subtital limestones; 2) condensed with few micro-oncoids more influence; 3) red hardgrounds; 4) nodular Bositra Limestone. members are separated by hard rounds representing stratigraphic gaps deposition. early-Middle follows general trend deposition as whole Western Tethys realm Triassic Dachstein carbonate Platform.