Article: New ammonites from the Barremian of north Bulgaria
In the Barremian of North Bulgaria are found some new ammonite genera and species; Phyllopa-chyceras bontshevi sp. nov. occurs in the Upper Barremian, Costidiscus recticostatus Zone. Pseudothurmannia karakaschi sp. nov. and Holcodiscus caseyi sp. nov. are found in the Lower Barremian. Eoleptoceras (Tzankovi-ceras) tzankovigen. et sp. nov., Eoleptoceras (Wrightites) wrighti gen. et sp. nov., E. (W.) parvulum kraptshen-ensis gen. and subsp. nov., and Hemibaculites zaharievae sp. nov. occur in the Lower Barremian of Northwestern Bulgaria, in the Crioceratites emericianus Zone. Eoleptoceras gen. nov., with its subgenera Tzankoviceras subgen. nov. and Wrightites subgen. nov., represents one of the latest members of the morphological series of Leptoceratinae. The latter is a new subfamily of Ancyloceratidae, created for the unification of the early representatives of the family, and showing close relations with Leptoceras. Acanthoptychoceras spinatocostatutn gen. et sp. nov., described from the Lower Barremian of North Bulgaria, is one of the earliest representatives of the Ancyloceratinae. It appears to be an intermediate link between Acantholytoceras Spath and Lithancylus Casey, and shows the origin of the Ancyloceratinae from a group of coarsely sculptured Ptychoceratidae.