I was thinking that this fore-aft bicephalization I've been experimenting with recently (i.e. [link] [link]
) might be explained by the conjoinment of extreme sexually dimorphic conspecifics, as per anglerfish. Here, the male and female merge as larvae and develop into adulthood as a fused composite organism--or perhaps the process has become so entrenched that the fusion takes place at an even earlier phase. This still wouldn't necessarily explain the apparent transphyleticism seen in animals like the Orchid Sloth and Cormorape, but it can't hurt.
There are all kinds of aero- and hydrodynamic possibilities for that stacked "biplane" fin configuration, methinks--i.e. one pair forward-swept and the other delta-winged, allowing different angles of attack and feeding styles depending on which "head" is in charge. But such lofty and/or soggy flights of fancy will have to wait for another day....
Inspired by and loosely referenced from a Brian Skerry photo of mating bobtail squid:[link]
This one is also a hybrid Salamandroid, combining aspects of Rachel's Mulsapultra or [link]
and her flying squid. I think of the top one as female and the bottom as male, but I can't quite explain why!