The Phylogeny of the Reverse Life-Cycle: Difference Between Species

Turritopsis nutricula

Turritopsis rubra

Little is known about how such an unusual behavior as the reverse life-cycle could have become established although, given the obvious reproductive advantage is appears to confer, it is easy to see why the behavior has persisted. Nonetheless, the Atlantic T. nutricula (shown at left) can be deduced with some certainty to share common heritage with Oceanian T. rubra (at right) or Mediterranean T. dohmii, to the extent where no taxonomic distinction was made between these groups until recent genetic analyses.

It remains uncertain if all of the other genera within Turritopsis are capable of life-cycle reversal, but numerous studies on the reversal have sampled populations taken from the Italian coast, suggesting that T. dohmii at least shares this characteristic with T. nutricula.

(images from Google)