Odd Crustaceans

Crustacean evolution has gone in odd directions (odd for my fish-centric mind). The stiff carapace of crabs and shrimps has allowed evolution to mold it in a particularly extreme number of shapes and forms, to fulfill adaptive functions from camouflage on the surface of larger invertebrates, camouflage in the sand, to maximum mechanical stability.

In recent weeks I had the chance to film some very unusual crabs. The best crab encounters in the Philippines I always have during night dives, when many crabs, now more safe from predation by fishes, come out.

In this video I filmed a crab which had such an extremely modified body, covered in sand, so that I am wasn’t even remotely certain what the genus or species of the animal is. According to Dr.  Jo Wolfe, via Twitter, the animal belongs to the Parthenopidae.

What kind of #crab person are we looking at here? Negros Island, Philippines, at night, ~10 cm diameter, 10 m deep. Thanks in advance! #IDmissing #invert #crustacean pic.twitter.com/7JGsPrO7mz

— Klaus Stiefel (@Pacificklaus) September 3, 2022

 

In this video, just after the urchin-snappers (video starts at 3:15), a decorator crab put such a massive log on its head  that it barely could walk around with it. while the log likely protected the crab, it must also draw attention to the animal’s presence.

I hope you enjoyed the videos,

Best Fishes (and crabs!),

Klaus