Table 1. Morphological staging definitions and values from quantitative time-lapse analyses at 30°C (see also Fig. 1).

Label	Stage name	Agea	n	Definition
BL	Blastoderm	Underway at filming start (4.8 h; 6.7%)b	38	Generation of a monolayered epithelium over the complete egg surface
PP	Primitive pit	7.7±1.3 (10.7±1.8%)	37	First detectable flattening of cells at the posterior pole
SW	Serosal window	12.1±1.3 (16.8±1.8%)	33	Closure of the serosal window over the embryo: detachment of serosa from internal tissue allows the abrupt anteriorward extension of the head
GBE	Extended germband	20.2±0.8 (28.1±1.1%)c	13	Maximum germband extension first attained
GBR	Retracted germband	42.1±1.7 (58.5±2.4%)	12	Complete germband retraction first attained
SR	Serosal rupture	52.1±2.3 (72.4±3.2%)	32	First detection of rupture at the onset of serosal withdrawald
MT	Muscle twitches	59.7±2.6 (82.9±3.6%)	28	First detection of embryonic twitching due to lateral muscle activity

^aAge is given in hours after egg lay for the minimum age from a 4-hour range, as the mean ± standard deviation. Parenthetical values for percent of development are based on a total embryogenesis period of 72 hours.

^bAs the complete blastoderm stage was not quantified, we do not provide a definitive staging landmark and hence do not plot this stage in Figure 1H.

^cFor GBE, data were pooled from movie recordings 1 and 2. The separate values are shown in Fig. 1H.

^dNote that the staging landmark definition corresponds to the “SR” plot point in Figure 1H, whereas the designations SR1–SR4 in Figure 1 micrographs subdivide the subsequent morphological progression of serosal tissue contraction and withdrawal from the embryo.