2026/04/01 by Y. D. Zakharov, А. М. Попов, A. M. Popov +4
Earth and Planetary Sciences · Agricultural and Biological Sciences · #Paleontology and Stratigraphy of Fossils #Paleontology and Evolutionary Biology #Fossil Insects in Amber
paper · doi:10.1134/s0031030126600770
Abstract The first discovery of Parapopanoceras in the Anisian of South Primorye prompted the authors to consider the stratigraphic significance of ammonoids of the suborder Ptychitina, which includes this genus. New taxa are described (Neopopanoceratidae fam. nov., Stenopopanoceratidae fam. nov., Subjaponites gen. nov., and Parapopanoceras izosovi sp. nov.), and new data on the systematic composition of ammonoid assemblage of the Lower Anisian Leiophyllites pradyumna Zone are presented. Early representatives of the suborder Ptychitina (Melagathiceratidae and Paranannitidae) are assigned to the superfamily Melagathiceratoidea, while the genera Neopopanoceras and Zhitkovites are assigned the new family Neopopanoceratidae. It appears that in the Melagathiceratoidea–Prosphingitidaе and Prosphingitoides–Zhitkovites–Neopopanoceras lineages, evolution proceeded through anaboly, resulting in the development of additional umbilical lobes of the suture or significant segmentation of its saddles during the adult stage of ontogeny. In the other phylogenetic lineages under consideration (Prosphingitoides–Owenites and Stenopopanoceras–Parapopanoceras), on the contrary, development likely proceeded through deviation—with the siphuncle moving to a central position early in ontogeny. The close relationship between the late Olenekian genera Neopopanoceras and Zhitkovites of the family Neopopanoceratidae suggests a potential correlation between the Subfengshanites multiformis Zone of South Primorye, in which Zhitkovites is recorded, and the Neopopanoceras haugi Zone of the western United States. Stenopanoceras and Parapopanoceras, which are most widespread in the Boreal Superrealm, can serve as reliable marker taxa for the Anisian.