Fiddler Crab

Description:

Dark grey tiny crab, not more than 2cm across the body. Males (pic No 2 and 3) wave one disproportionately large arm/claw - it seems that enormous claw can be on any side of the body, saw lefties and righties equally... Females (pics 1 and 3) have two small claws.

Habitat:

Found on sandy beaches and brackish lagoons around Freetown, in mangrove ecosystem - coastal ecosystem composed mainly of Red Mangrove tree (Rhizophora mangle, pic No 4).

Notes:

Earlier, it seems that all fiddler crabs were classified into the same genus, genus Uca of Ocypodidae family. This has changed in 2016, and fiddler crabs constitute 11 genera today. I kept the old classification as I don't really know how to ID these crabs...