Tag Archives: Macrophthalmus

Macrophthalmus convexus Stimpson

Convex Sentinel Crab (Macrophthalmus convexus)

The Convex Sentinel Crabs are very small crabs having an average carapace diameter of about 1 x 1,5 cm to 1,5 x 3 cm and exceedingly long eyestalks.

They live in the intertidal zone, where they can be found abundantly on muddy places near the outlets of small streams, and are therefore absent from islands without such freshwater streams, e.g. the Tuamotus. The crabs feed on smallest food particles, which they sift out from the sand.

These crabs dig their burrows in muddy sand, in which they flee at the slightest disturbance.

On Aitutaki the crabs are called papaka.


Photo: J. Poupin; by courtesy of J. Poupin