Uca (Xeruca) formosensis Rathbun, 1921

(Fig. 7F–H)

Uca formosensis Rathbun, 1921: 155 [type locality: Lugang, Changhua, Taiwan] (see Shih 2015 for list of synonyms). Uca (Tubuca) formosensis —Ng et al. 2008: 242 [list].

Uca (Xeruca) formosensis — Shih 2015: 162, figs. 2, 3, 4A, 5A, 6, 7.

Material examined. See Shih (2015) for material from Taiwan (including Penghu).

Ecology. A chimney is built by the male after attracting a female into his burrow during the neap tide (see Shih et al. 2005).

Distribution. Endemic to Taiwan (including Penghu).

Remarks. Based on morphological and molecular evidence, Shih (2015) established a new subgenus Xeruca for this endemic species to solve its uncertain position. Xeruca is also a subgenus with the smallest distribution among the subgenera of Uca . Detailed information on the history, morphology, coloration, and distribution can be found in Shih et al. (1999) and Shih (2015). Shih et al. (2005) also investigated the possible function of chimney building and its ecology. The conservation of this endemic species has become important and critical due to the diminishing populations (e.g. in Penghu, Fig. 7H) because the sediment has been changed by the introduced mangroves, and by being less competitive than U. arcuate, which is dominant in mangrove habitats (Shih et al. 1999; Hsieh et al. 2004; Shih 2015).