Agoniatitida, also known as the Anarcestida, is the ancestral order within the cephalopod Subclass Ammonoidea, that lived in what would become Africa, Asia, Australia, Europe, and North America during the Devonian from about 410—385 mya, existing for approximately 25 million years.

  Agoniatitida are primitive ammonoids with a ventral retrochoanitic siphuncle (septal necks point to the rear) reflective of their nautiloid ancestors.and goniatitic sutures with a variable number of lobes. Shells vary from discoidal to globular. Coiling may be loose with whorls barely touching or tight with a dorsal impression.

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