Agoniatitida, also known as the Anarcestida, is the ancestral order within the cephalopod subclass Ammonoidea originating from bactritoid nautiloids, that lived in what would become Africa, Asia, Australia, Europe, and North America during the Devonian from about the lower boundary of Zlichovian stage (corresponding to late Pragian, after 409.1 mya) into Taghanic event during upper middle Givetian (between 385 and 384 mya), existing for approximately 25 million years.

[2] Accordingly, the name Anarcerstida is based on the family Anarcestidae (ex Anarcestinae) of Steinmann 1890.

Saunders, Work, and Nikolaeva, 1999,[3] refer to the Anarcestida, with Agoniatina a suborder, maintaining the priority as found in the Treatise.

Agoniatitids 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.

Coiling may be loose with whorls barely touching or tight with a dorsal impression.