Early Triassic Ammonoids of the Genus Churkites Okuneva, 1990: Phylogenetic Reconstructions and New Finds in South Primorye

The stratigraphic distribution of early Olenekian ammonoids of the genus Churkites (family Arctoceratidae Arthaber, 1911) from a new locality in South Primorye (Artyomovka River basin, Shtykovskie Prudy) is studied. The new species of Churkites (Ch. ungunensis sp. nov. and Ch. subungunensis sp. nov.) are described based on the material from the lower Olenekian zones of the Khabarovsk Region (T.M. Okuneva’s collection) and South Primorye. The composition of the type species of the genus Churkites (Ch. egregius Zharnikova et Okuneva, 1990) is re-defined. It is proposed to distinguish three phylogenetic lineages within the genera Arctoceras (A. tuberculatum) and Churkites (six species): (I) Arctoceras tuberculatum–Churkites noblei–Ch. egregius, (II) Ch. egregius–Ch. syaskoi and (III) Ch. syaskoi–Ch. subungunensis–Ch. ungunensis.