Fig. 8. A–G in Variability of conch morphology in a cephalopod species from the Cambrian to Ordovician transition strata of Siberia

Fig. 8. A–G. Phosphatised siphuncle connecting rings of ellesmeroceratid nautiloids (interpreted below as Ruthenoceras elongatum Korde, 1949) from sample Ang-6, block No. 2, probably latest Furongian Ust-kut Formation found at Pashino on the Angara River, Siberia, Russia. ZPAL N. IV/152, 148, 147, 153, 151, 149, 150, respectively. Specimens in dorsal views, also details in higher magnification (B2 and B3; see also Dzik 2010: fig. 7f), except ventral (E1) and lateral (E2) views. ZPAL N. IV/148 and 150 (see also Dzik 2010: fig. 7b and c). H. For comparison the earliest Cambrian (Tommotian) " hyolith" Turcutheca crassaecochlia Syssoiev, 1962, ZPAL MoXX/7 from the Tommotian (Dokidocyathus lenaicus Zone) at Bydyangaia on the Lena River, central Yakutia of possible distant cephalopod affinity, probably mature specimen with displaced embryonic part preserved as a glauconitic internal mold, lateral (H1) and posterior ("ventral") (H2) views (see also Dzik 2010: fig. 7b and c).