Tree-climbing decapods of Kenyan mangroves

Abstract

The investigation of arboreal habits in 16 species of Kenyan mangroves decapods indicates that a total of seven are true arboreal species, three of which can be defined as exclusively arboreal (Sesarma leptosoma, S. brocki, S. elongatum) while the remaining four are mainly arboreal (Metopograpsus oceanicus, M. thukuhar, Petrolisthes lamarckii and Merguia oligodon). The other species climbed trees only occasionally. Among the true arboreal species, only S. leptosoma show the ability to climb the entire length of the tree and feed on its canopy. All the true arboreal species are iso-phasic, while occasional tree climbers are considered iso-zonal. Within the Grapsidae, the tree-dwelling habit is well correlated with morphological adaptations such as the flat and square shape of the carapace, the relative shortening of the dactylus on the walking legs and the lengthening of the propodus.