Brooding and embryonic development in the crustacean Paragnathia formica (Hesse, 1864) (Peracarida: Isopoda: Gnathiidae)

► Novel observations on in utero embryological development in Paragnathia formica. ► Blastodisc and germ cell migration within developing eggs. ► Release of Stage 2 embryos by rupture of embryonic membranes. ► In utero moult of Stage 2 to Stage 3 embryos. ► Asynchronous development of the brood within paired uterine sacs.