Four species of Louisea endemic to southwestern Cameroon, right cheliped merus. a Second largest adult male (CW 16.1 mm) of L. edeaensis from Lake Ossa wetland complex (ZMB Crust. 30335) b largest adult male (CW 16.2 mm) of L. balssi from Man’s Crater Lake Manengouba (ZMB Crust. 30319) (missing left p5) (‘Mvogo Ndongo et al. 2018: fig. 3d’, www.mapress.com/j/zt) c adult male, holotype (CW 18.1 mm) of L. yabassi sp. nov. from Yabassi (ZMB Crust. 21575) d largest adult male, holotype (CW 20.0 mm) of L. nkongsamba sp. nov. from Mt. Nlonako (ZMB Crust. 31618). Scale bars: 5 mm (a, c), 2 mm (b), 10 mm (d).