The Muensterelloidea: phylogeny and character evolution of Mesozoic stem octopods

The Muensterelloidea is a superfamily of teudopseid octobrachians with a posteriorly patella-shaped gladius. A morphometric comparison based on 148 muensterelloid gladii has yielded five new species accommodated in three new genera: Engeseriteuthis arcuatus gen. nov. sp. nov., Muensterella jillae sp. nov., Muensterella spinosa sp. nov., Tyrionella fauseri gen. nov. sp. nov., and Muensterellina johnjagti gen. nov. sp. nov. Cretaceous taxa “Tusoteuthis” cobbani and “Muensterella” tonii are re-combined and placed within the genus Enchoteuthis. We introduce categories for gladius proportions applicable for both muensterelloid and non-muensterelloid octobrachian gladii. 2D-landmark analyses including 64 muensterelloid and non-muensterelloid gladii statistically confirms that the Muensterelloidea possess the smallest median field sizes of all Mesozoic gladii. The lateral field-dominated “gladius” of the family Patelloctopodidae (Patelloctopus, Pearceiteuthis) is considered to be vestigial; i...