A transparent larva with outsized eyes and folded raptorial arms already in place.
A glass-clear animal with a domed carapace, a long slender abdomen and a pair of eyes far too large for it, set on stalks and often the only part that registers in the beam. The raptorial appendages are already formed and folded beneath the head. Which mantis shrimp it will become is not readable from a photograph — the larvae are separated on spine counts and carapace shape under magnification — so this entry is pitched at the order.
Stomatopod larvae spend weeks to months in the plankton and are predators throughout, taking copepods, fish larvae and each other with the same strike the adult uses. The eyes are functional early and are among the most complex in the animal kingdom; even at this size they carry the several-row midband that gives adult mantis shrimps their unusual colour and polarisation vision. At settlement the larva goes to the bottom and becomes the burrowing or reef-dwelling animal a muck diver meets by day.
They are strong swimmers by planktonic standards and will leave a light rather than drift in it, which makes them harder work than most blackwater subjects. The eyes reflect well, so an exposure set for the eyes will usually lose the body, and the reverse.
Ratings are per location: 1 means found on most dives that look for it, 5 means a handful of records. Where enough dives have been logged the figure is calculated from them; otherwise it is an editorial estimate, and says so. We publish habitat and destination, not the dive site.
