Xeruca formosensis (Rathbun, 1921)
The fiddler crab is an endemic species of Taiwan, belonging to the large genus Uca. It has a carapace width of about 3 cm, which is ladder-shaped in deep brown. For the male, the right pincer gradually turns from deep brown to white from the base to the tip, and the palm is yellowish brown with white spots. During breeding, they would build a chimney-like nest.
The fiddler crab likes to dwell in the sticky sandy places. Recently due to the mass increase of mangrove lands, their proper habitats have reduced and the advantageous Uca arcuata have become fierce competition for them. Moreover, one of the habitats in the wetland of Xiangshan, Hsinchu has been severely damaged owing to the construction of a sewage treatment plant.