Differential masculinization of the chelipeds in two simultaneously hermaphroditic Apseudes tanaidaceans (Crustacea: Malacostraca) Author Kakui, Keiichi Author Hiruta, Chizue text Zoologischer Anzeiger 2023 2023-07-31 305 23 27 http://dx.doi.org/10.1016/j.jcz.2023.05.004 journal article 10.1016/j.jcz.2023.05.004 1873-2674 10660411 3.1. Apseudes nipponicus All individuals we observed bore a genital cone (a male trait) on the ventral surface of pereonite 6 ( Fig. 1A ). Ranges in CW were 1.55–2.33 mm (ln CW, 0.44–0.84) for oostegite-lacking individuals, 2.16–3.39 mm (ln CW, 0.77–1.22) for preparatory individuals, and 2.61–3.12 mm (ln CW, 0.96–1.14) for ovigerous individuals ( Fig. 2A–D ). Paired ovaries and testes were evident in an ovigerous individual (CW, 2.94 mm ; Fig. 1B and C ). The growth of CarW and CheW relative to CW was diphasic. The breakpoint for CarW–CW was ln CW = 0.790 (standard error, 0.045) ( Fig. 2A, C ), with the regressions ln CarW = 1.522 (ln CW) – 2.103 before the breakpoint and ln CarW = 2.246 (ln CW) – 2.675 after the breakpoint (R 2 = 0.979). The breakpoint for CheW–CW was ln CW = 0.824 (standard error, 0.046) ( Fig. 2B, D ), with the regressions ln CheW =1.290 (ln CW) – 1.825 before the breakpoint and ln CheW =2.301 (ln CW) – 2.658 after the breakpoint (R 2 = 0.945). Individuals in the CW range 1.55–2.23 mm (ln CW, 0.44–0.80) lacked a dorsal process on the fixed finger, whereas those in the range 2.06–3.39 mm (ln CW, 0.72–1.22) had a process ( Fig. 2C, D, F, H ); the process varied in size and was generally smaller in smaller individuals. Individuals of CW 2.61–3.39 mm (ln CW, 0.96–1.22) had four ventral processes on the carpus ( Fig. 2C, D, E, G ); in smaller individuals, the ventral margin of the carpus was smooth or bore one small process.