The marine crab Plagusia depressa, despite its broad geographic range, is not well known. Here, we attempt to fill this gap by studying several aspects of its biology. We sampled P. depressa in the reefs of Coruripe, Brazil and investigated the sex ratio, body size, maturity, the allometric growth of the gonopod in males and of the abdomen in females, the reproductive effort, the breeding season and the influence of environmental variables. We found that 1) the sex ratio, overall, does not deviate from 1:1; 2) females (33.71±10.62 mm) are larger than males (30.45±9.94 mm; t_1,764: -4.40, p<0.001); 3) males (23.42±0.24 mm) mature at smaller sizes than females (26.78±0.19 mm); 4) the growth of the gonopod is positive allometric in juveniles (slope = 1.66±0.04), but negative allometric in adolescents (0.93±0.02) and adults (slope = 0.86±0.03). In females, the abdomen undergoes a positive allometry in juveniles (slope = 1.74±0.04) and adolescents (slope = 1.97±0.09), but an isometric growth in adults (slope = 0.99±0.04); 5) the breeding period is continuous and not influenced by rainfall, water temperature and salinity; 6) egg mass strongly increases with body mass (slope = 1.56, R²=0.84, p<0.001).

所述蛑Plagusia扁，尽管它的宽的地理范围内时，不熟知的。在这里，我们试图通过研究其生物学的几个方面来填补这一空白。我们采样P.扁在科鲁里皮，巴西的珊瑚礁和研究性别比例，机身大小，成熟度，在gonopod的男性和女性腹部的异速生长，繁殖的努力，在繁殖季节和环境的影响变量。我们发现1）总体上性别比例不偏离1：1；2）女性（33.71±10.62 mm）比男性（30.45±9.94 mm; t _1,764：-4.40，p <0.001）；3）雄性（23.42±0.24 mm）的成熟个体小于雌性（26.78±0.19 mm）；4）角足类的生长在幼年（斜度= 1.66±0.04）为正异体，但在青少年（0.93±0.02）和成人（斜度= 0.86±0.03）中为负异体。在女性中，青少年（青少年斜率= 1.74±0.04）和青少年（青少年斜率= 1.97±0.09）的腹部呈正向异形性，而成年人（中斜率= 0.99±0.04）则等距增长。5）繁殖期是连续的，不受降雨，水温和盐度的影响；6）鸡蛋质量随体重而强烈增加（斜率= 1.56，R ² = 0.84，p <0.001）。