Subject:
Decoy defense. It took us a while before we could name this misleading stranger. Ceratophyllidia (more than likely it is Ceratophyllidia africana) is its name, deception its specialty!
Since many Opisthobranchs evolved into shell-less creatures they had to come up with new ways to defend themselves: Some have tough skin or protective appendages, others secrete chemicals or use stinging cells gained from their food source, some show off warning behaviour, expel ink or flash light while others just swim away. Ceratophyllidia (sp? ,africana?) uses autotomy as a survival strategy.
The word autotomy comes from Greek and means self-severing. This little nudibranch shed its bubbles or papillae the moment it felt threatened by the movement of the camera. The rolling bubbles intent to distract a predator thus giving the snail a chance to hit the road. The papillae grow back from the numerous tubercles covering its body.
Relatively many Opisthobranchs use autotomy: it occurs in all suborders of the Nudibranchs as well as in de order of the sap-sucking slugs (Sacoglossa) and the order of the side-gill slugs (Notaspidae). The body parts that are sacrificed range from pieces of the mantle, some of the cerata, parts of the gills, the tail and the parapodial lobes. Sometimes a sticky secretion emitting an aromatic scent accompanies the discarded body parts. Rejected cerata may even squirm and wriggle for a while... just like a shedded lizard’s tail.
Beside lizards and the nudibranch described here there are other examples of animals using autotomy;
Sea cucumbers: Sea cucumbers are soft-bodied marine animals that are often targeted by predators. When threatened, some species of sea cucumbers can expel their internal organs through their anus as a defense mechanism. The expelled organs will eventually regenerate.
Salamanders: Many species of salamanders are capable of regenerating lost body parts, including limbs, tails, and even parts of their spinal cord. When threatened, some salamanders may shed their tails as a distraction.
Spiders: Some species of spiders can shed their legs as a defence mechanism. The lost leg will eventually regenerate, but it may not be the same size or shape as the original leg.
Sea stars: Sea stars, also known as starfish, can shed their arms as a defence mechanism. In addition to distracting predators, shedding an arm can also help sea stars escape from tight spaces. Some species of sea stars can even regenerate an entire body from just a single arm.
Octopuses: Octopuses are masters of camouflage, but they also have an escape trick up their sleeves (or tentacles). If an octopus is threatened, it can detach one or more of its arms, which will continue to move and distract the predator while the octopus makes its escape. The detached arm will eventually regrow, but it may take several months.
Technique:
While filming this strange looking nudibranch in Bali/Indonesia the animal suddenly started to loose almost all of the papillae when I repositioned myself. Unfortunately the shedding itself, which happened in less than a second or so, was not caught on camera. Probably I came too close with my camera’s dome for the little nudibranch’s comfort. We often do not keep the record button pushed in long enough to catch the image of a lifetime. Be patient, continue to film and expect the unexpected to happen.
Filming location:
This short underwater videoclip has been filmed in Bali, Indonesia 🇮🇩
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