The Yellow Porcelain Anemone Crab, Neopetrolisthes alobatus is not common in Tanzanian waters. In several years of searching we have only found five specimens.
They are decapod crustaceans in the Porcellanidae family. Although they resemble true crabs they are actually more closely related to squat lobsters. There seem to be two theories as to why they are called porcelain crabs. The first is that they are called porcelain crabs because they are extremely delicate and body parts such as legs and claws break off easily. These usually regenerate when they change shells.
The second is that the white edges of the crab resemble porcelain. They are much prettier just after a shell change as algae grows on their shells. Their proportionally large claws are used for protection and territorial fights with other crabs rather than for catching prey.The mouth parts have evolved into finely laced fans which are used to filter food out the substrate.
Yellow Porcelain Anemone Crabs have a light yellow coloured body with dark blue dots spread across the body and claws. Their claws are proportionally large and they have three walking legs as against a normal crab which will have four. They have a prominent set of feelers which extend outwards and the eyes are on short stalks. Compared to normal crabs the body is slightly elongated. They grow to a maximum width of 5 cm.
YELLOW PORCELAIN ANEMONE CRAB IN THE WILD
To date we have only found them on either the Beaded Anemone ( Heteractis Aurora) or the Leather Anemone (Heteractis Crispa). They have a commensal relationship with these anemones, the crabs receive protection from the anemones and the anemones are unharmed.
Yellow Porcelain Anemone Crabs are not common and after finding the first specimens and looking in several hundred anemones we have only found five specimens in Tanzanian waters. Compared to the more common Porcelain Anemone Crab, Neopetrolisthes maculatus which often sits on the top of anemones, they are far more reclusive and have always been under the edge of the anemone.
The Yellow Porcelain Anemone Crabs are found on coral and rock reefs across the Indo Pacific area.
Yellow Porcelain Anemone Crab are filter feeders and filter plankton out the water. They are also said to eat mucus given off by the anemone and clean up any debris from within the tentacles. Small pieces of debris and planktonic organisms are filtered out of the water table by repeated fast movements with the fan. The fans are retracted back towards the mouth and the particles are eaten.
As with most crustaceans, the eggs are fertilised by the male and are carried under the body of the female. Once they hatch the larvae go through a planktonic stage before settling down and growing into their adult form.
Yellow Porcelain Anemone Crab could be kept in an aquarium. Because they are filter feeders they are quite peaceful. Although they do not necessarily require an anemone as a host, they are happier if they have one. Because they also eat mucus from an anemone this helps provides a more natural diet.
While they are unlikely to obtain sufficient planktonic food in an aquarium it is possible to supplement their diet. They can be hand fed with flakes or pellets. Alternatively food can be left in close proximity to them. Brine shrimp can also be drop fed down a tube placed in proximity to them.
YELLOW PORCELAIN ANEMONE CRAB CLASSIFICATION
Species: N. alobatus
Assistance in identifying the species kindly provided by Gregory Jensen
There seems to be little literature on this species.