2008b), which is a holobenthic
species, in which it is relatively straightforward to obtain known-age individuals because there is no pelagic stage.
Either the ancestor was holopelagic (and therefore planktotrophic) and a new sexually mature benthic stage was added to the life cycle with the pelagic, planktotrophic stage retained as a larva (the "terminal addition" theory), or new larval stages became "intercalated" into the ancestral holobenthic
life cycle in several lineages.
Assessing the stock status of holobenthic
octopus fisheries: is catch per unit effort sufficient?
The second proposal for the origin of the pelago-benthic life cycle, the intercalation hypothesis, reconstructs the first bilaterians as holobenthic
The basic patterns in reproductive strategies of marine benthic invertebrates include holobenthic
cycles, with (a) direct larval development and no pelagic larval phase; (b) completely pelagic cycles and (c) pelagic-benthic cycles where larval development is mixed.