1973/07/01 by Ellis L. Yochelson, Rousseau H. Flower, Gerald F. Webers · 6 citations
Agricultural and Biological Sciences · Earth and Planetary Sciences · Environmental Science · #Cephalopods and Marine Biology #Marine Biology and Ecology Research #Isotope Analysis in Ecology
paper · doi:10.1111/j.1502-3931.1973.tb01199.x
openalex publication_date 1973/07/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/30
Yochelson, E. L., Flower, R. H. & Webers, G. F.: The hearing of the new Late Cambrian monoplacophoran genus Knightoconus upon the origin of the Cephalopoda. Knightoconus, a new genus of the Hypseloconidae (Mollusca: Monoplacophora) from rocks of early Franconian age in Antarctica, is multiseptate. The multiple septa are a critical feature to be expected in a form ancestral to cephalopods. Fossil cephalopods, however, invariably have a siphuncle as well as septa; some gastropods, some hyolithids, and some monoplacophorans also have septa but lack a siphuncle. Therefore, only the siphuncle can be considered a unique and particularly significant feature of the cephalopod shell. Hypothetical reconstructions of molluscan anatomy support the notion that cephalopods may have been derived directly from a hypseloconid having a high, slightly curved, multiseptate, bilaterally symmetrical shell, by the subsequent development of a siphuncle.