randi,and E.coloradorum, frogs with rapid developmrntb(Tablr1).Similarly,elongstion of the notochord overlapped with gastrulation in the rapidly developing embryos of the centrolenid frogs H.Aeischmanni and E.callistomma(Figs.8D,F;9C-D;10A-D;11B-C,E-F;12D;Table2).In contrast,gastrulation mpvements occurred before the onset of notochord elongation in the slowly developing dendrobatids E.machilla and E.tricolor,and in the M arsupial frog,G. riobambae.Egg size is larger in these slowly developing frogs in comparison with the rapidly developing species (Table1),(Elinson and del Pino 2012;del Pino et al.2007).The modular nature of gastrulation allows the separtion of dorsal convergence and extension,the mechanism that triggers elongation of the notochord and the body, from gastrulation in the slowly developing frogs,and fig