Phylum: Mollusca
Class: Cephalopoda
Order: Actinocerida
Family: Armenoceratidae Troedsson, 1926
Cincinnatian Genera: Armenoceras

Geologic Range
Middle Ordovician – Silurian

Common Paleoecology
Armenoceratidae is an extinct family of nektobenthic carnivores

Description of the Family

  • Large, straight or slightly curved shell
  • Siphuncle broadly expanded
  • Segments strongly expanded between septa
  • Radial canals often complex and arc-like
  • Long, recurved brims
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Serventi (2010):

  • In many families (e.g. Armenoceratidae) the septal neck is strongly recumbent and the brim is near to or in contact with the inferior part of the septa.

Treatise on Invertebrate Paleontology, Part K, Vol. 3 (1964):

  • Large, straight or slightly curved shells. Siphuncle large, segments strongly expanded between septa; septal necks very short, with abruptly recurved long brims; endosiphuncular canals well developed, remainder of siphuncle calcified; endosiphuncular structure commonly complex. Cameral deposits rare.

Flower and Kummel (1950):

  • Siphuncle broadly expanded, brims greater than necks, often recumbent, connecting ring broadly adnate to septum at both ends. Radial canals often complex, of several series, arc-like, becoming transverse later. Ordovician to Lower Devonian.

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