Obtusoconus Yu, 1979

Kouchinsky, Artem, Bengtson, Stefan, Landing, Ed, Steiner, Michael, Vendrasco, Michael & Ziegler, Karen, 2017, Terreneuvian stratigraphy and faunas from the Anabar Uplift, Siberia, Acta Palaeontologica Polonica 62 (2), pp. 311-440 : 338

Genus Obtusoconus Yu, 1979

Type species: Obtusoconus paucicostatus Yu, 1979 ; middle Meishucunian Stage ( upper Fortunian –lower part of Cambrian Stage 2), lower Cambrian ; Yichang County, western Hubei Province, South China .

Remarks.— Obtusoconus spp. occur in the uppermost part of Assemblage Zone 2 in South China, where Yang et al. (2014) recognized a new Annelitellus yangtzensis ‒ Obtusoconus honorabilis Subzone in which the index taxa may co-occur with Obtusoconus rostriptuetus . Obtusoconus honorabilis reportedly ranges from the upper Fortunian to Cambrian Stage 4 (Anhui Province, Lengquanwang Formation; see Parkhaev and Demidenko 2010). A Latouchella ‒ Obtusoconus Assemblage Zone is known from Iran (upper part of Upper Shale Member, Soltanieh Formation, Alborz Mountains; Hamdi 1995) and correlated with upper Fortunian–Cambrian Stage 2. O. honorabilis also occurs in the upper Fortunian–Cambrian Stage 2 equivalents of western Mongolia (Voronin et al. 1982; Esakova and Zhegallo 1996; Parkhaev and Demidenko 2010). In our material, Obtusoconus cf. honorabilis is found above the first Watsonella crosbyi , in beds that would correspond to the Watsonella crosbyi Assemblage Zone of South China.