West African Fiddler Crab

Afruca tangeri is one of the largest species of fiddler crab, with a carapace up to 50 mm (2.0 in) wide and up to 25 mm (1.0 in) long. Males have one claw much larger than the other, used for communication. Body coloration is generally dull; however, some individuals display a range of colors from shades of brown to bright orange, red, or purple.

In adults, the carapace typically reaches about 35 mm (1.4 in). The dorsal surface of the carapace is mainly covered with tubercles, and the species lacks posterolateral striae. The frontal region between the eyes is broad, and the cornea is round. The eyestalks are thin and elongated. The orbital floor bears a spinous tubercle near the inner corner of the eye socket, appearing as a small, pointed projection.

Afruca tangeri can be found anywhere from the southern Portugal southwards to Angola. The species is the only fiddler crab on the eastern Atlantic coast and the most abundant crab species in The Gambia.

The general habitat of A. tangeri's consists of intertidal mudflats and estuaries. Specific microhabitats include mudflat zones, creeks and marshes. Smaller A. tangeri often cohabit near creeks, whereas larger A. tangeri more commonly reside in salt marsh zones. Young crabs are found in the middle of mudflats.

Afruca tangeri is an omnivorous animal. It feeds on various food items found in its habitats, including detritus, diatoms, and algae. Although it has a varied diet, this species prefers plant material. Therefore, its feeding behavior has a significant impact on the ecological conditions of mangrove forests through the removal of dead leaves. Using its small claws, Afruca tangeri scrapes off the top layer of sediment. Then, in its mouth cavity, particles in sediments are sorted, and either ingested or dropped off on the ground as individual particle pellets. The presence of this crab is indicated by the mud balls that pile up in front of its burrow entrances. This behavior also has ecological importance; it not only controls algae populations in the sediment during spring and summer, but also bioturbates the wetland substrate to prevent the formation of anaerobic conditions.

This organism is known for its extensive signaling and territorial behavior. Using both claw waving and substrate drumming around the entrances to their burrows, they attempt to attract females while also signaling to their rival males to retreat. As females get closer in proximity to the burrows which would demonstrate that signaling plays a significant role in both the courtship process and female choice. Research has also found that males may also build structures with mud at the entrances of their burrow as another visual signal to influence both potential female mates and to deter possible competition

Courtship plays a crucial role in Afruca tangeri's reproductive process and involves factors such as female choice and signal intensity. Male courtship involves claw waving as a signal to attract females. Female mate choice is based on male behavioral signals. Burrowing is also used in reproduction and mating systems, which demonstrates sexual selection. In terms of the life cycle, juveniles can live in different environments than adults. For example, small crabs are often near creeks, larger crabs near salt marshes, and juveniles in the mid-mudflat. This demonstrates how size influences habitat and can result in habitat shifts.