Original paper
Exaptations in Argonautoidea (Cephalopoda: Coleoidea: Octopoda)
Bello, Giambattista
Neues Jahrbuch für Geologie und Paläontologie - Abhandlungen Band 266 Heft 1 (2012), p. 85 - 92
38 references
published: Oct 1, 2012
DOI: 10.1127/0077-7749/2012/0290
ArtNo. ESP155026601010, Price: 29.00 €
Abstract
The holopelagic mode of life in the superfamily Argonautoidea was achieved thanks to the evolution of peculiar characters, mainly relating to neutral buoyancy and egg brooding away from the sea floor. Some of these adaptations – egg-carrying structures in females of Tremoctopus and Argonauta, ovoviviparity in Ocythoe, swimbladder in females of Tremoctopus, Haliphron and Ocythoe, buoyancy regulating egg-case in female Argonauta – are indeed exaptations, i. e. either characters previously shaped by natural selection for particular functions (adaptations) or characters whose origin cannot be ascribed to the direct action of natural selection (nonaptations) that are coopted for new uses. Other exaptations are the pouch holding the coiled long hectocotylus in the males of all argonautoid genera and the autotomizing dorsal arms and adjoining pieces of web for defensive purposes in female Tremoctopus.
Keywords
Cephalopoda • Octopoda • Argonautoidea • exaptation • evolution • buoyancy • reproduction