Caridina spongicola, new species, a freshwater shrimp (Crustacea: Decapoda: Atyidae) from the ancient Malili lake system of Sulawesi, Indonesia

The ancient Malili lake system of Sulawesi, Indonesia, harbours an endemic species flock of atyid shrimps. Caridina spongicola, new species, is described from the outlet of Lake Towuti, the largest of the five connected lakes. The new species differs from all other Caridina species by a combination of morphological features and a unique colour pattern, and is unusual among atyid shrimps in being associated with an undescribed species of freshwater sponge. The shrimps are most likely commensals: they appear to feed on diatoms accumulating on or within the sponge, and do no harm. the host. Caridina spongicola, new species, is the second reported atyid shrimp that lives in symbiosis with another organism.