Sympagurus dimorphus (Studer, 1883)

da Silva, Adriane Candiotto Caio S. Nogueira Laura Schejter Alexandre R., 2023, Sexual and size dimorphism in two deep-water hermit crabs (Decapoda: Parapaguridae) from the Western Atlantic Ocean, Nauplius (e 2023026) 31, pp. 1-14 : 6-7

Sympagurus dimorphus

The shape of CPS (Hotelling T ² = 174.1, F =6.59, p <0.001), MaP (Hotelling T ² = 101.27, F = 8.25, p <0.001), and MiP (Hotelling T ² = 70.76, F = 3.85, p <0.001) were different between males and females. The discriminant analysis accurately distinguished all individuals in the comparison between CPS and MaP, and about 86 % for MiP.

The frontal region of the CPS exhibited a similar shape between males and females. However, the posterior region of the CPS was wider in females than in males ( Fig. 4A). In contrast, MaP was more robust in females than in males. Additionally, males displayed a slight projection of the fixed finger of the MaP, while females did not exhibit this characteristic ( Fig. 4B). The differences in the shape of MiP between males and females were smaller compared to the other structures. This structure was slightly more robust in females, whereas the fixed finger of males was more robust than that of females ( Fig. 4C).

Sexual size dimorphism was evident between males and females in all structures analyzed, CPS (t -test; t = -9.69, p <0.001), MaP (t -test; t = -9.07, p <0.001), and MiP (t -test; t = -11.04, p <0.001) ( Fig. 3B).