Ecology of the facultative phytotelmic crab platychirarma buettikoferi (De Man, 1883) (Decapoda, Brachyura, Sesarmidae)

The mangrove forests surrounding Douala, Cameroon, have a long history of human impact due to rapid urbanization, resulting in patches of true mangrove forest interspersed with areas dominated by the mangrove-associated Pandanus species. A survey carried out to assess the possible shift in crab fauna composition and dominance between mangrove and Pandanus dominated areas revealed an undescribed phytotelmic habitat for Platychirarma buettikoferi. This species was found colonizing the natural reservoirs of fresh water represented by Pandanus spp. Our results show P. buettikoferi to be ecologically dependent upon Pandanus spp., and absent on the mangrove floor and trees, strongly indicating a phytotelmic adaptation. Our data suggest that this species is a facultative phytotelmic species well adapted to Pandanus spp. dominated areas. Further studies on the reproductive biology and feeding behaviour of P. buettikoferi may shed light on this unique phytotelmic lifestyle and its role in mangrove ecosystem functioning.