Commensal amphipod living in solitary ascidian

I was searching for miniature pygmy seahorses on the reefs of West Papua when I happened across this tiny amphipod crustacean. Just 0.5–1cm long, this male is sitting at the mouth of the sea squirt to guard the females and young within. According to an amphipod expert, this is likely a new species.

Raja Ampat, West Papua, Indonesia

Nikon D800, Nikkor 105mm macro, 1/125, f/14, ISO 100, twin INON Z240 strobes, handheld, Subal underwater housing

by Richard Smith, United Kingdom