Platypodiella picta
Speckled red-and-black crab tucked in El Hierro's rocky reefs, Canary Islands, water 18-24C, seen year-round by patient divers.
Small crab with a mottled shell pattern of deep red or orange blotches broken up by black patches, giving it a painted, patchwork look against plain rock. It sits low and tight against the substrate rather than out in the open, and its compact, rounded carapace (shell) is easy to miss until the colour pattern catches your torch beam. Legs are short and tucked close to the body, so it reads as a stationary lump of colour rather than a moving animal at first glance.
Divers most often find it wedged into a crack or ledge on rocky reef, sitting still enough that it can be overlooked as part of the rock itself. It does not flee readily when approached, relying instead on staying tucked into its hiding spot, so a slow scan with a torch across crevices is the best way to pick one out. Most sightings are logged as common at the site level, suggesting that once you know to look in the right rocky nooks, it turns up reliably rather than being a rare find.
Its blotchy red-and-black shell pattern works as camouflage against the encrusting algae and coralline growth typical of Canary Islands rocky reef, which is likely why it goes unnoticed by so many divers swimming right past it.
No clear seasonal pattern shows up in the sightings, and with water sitting in a fairly mild 18 to 24C range year-round around El Hierro, this crab appears to be a consistent, any-month find rather than a seasonal specialty.
Almost all logged sightings come from the Canary Islands, with El Hierro standing out as the strongest and most reliable region for finding this crab. It is worth checking crevices and undercuts on rocky reef sections in this area rather than open sand or coral, since that is where divers consistently report it.
Mapping where Harlequin Crab is logged…
The strongest and most consistent sightings come from El Hierro in the Canary Islands, where it is logged as common at the majority of sites checked. Look for it tucked into crevices on rocky reef rather than open ground.
There is no detected seasonal pattern, and it is found in water ranging from 18 to 24C year-round around El Hierro. That makes it a reliable find on any month's dive rather than a seasonal target.
Look for a small crab with a mottled red or orange shell broken up by black patches, sitting low and still in a rocky crevice. It rarely moves out into the open, so its patchwork colouring is usually the first giveaway.
No, this small crab poses no danger to divers. It stays tucked into crevices and is best left undisturbed to observe rather than handled.
Exact size figures are not well documented for this species, but it is a small crab typical of the xanthidae family, easily overlooked against rocky reef without a close look.
Site and sighting data is aggregated from diver logs, iNaturalist and GBIF. For taxonomy and conservation status:
Sally Lightfoot Crab
2,422 sites
