Table 2.

Hierarchical analysis of molecular variance (AMOVA) of 8 populations belonging to the two parental species (A. charrua and A. reicherti) and six putative hybrid populations from a contact zone in the DMS in South America (Figure 1, Table S1).

Hypothesis	Source of Variation	df	Sum of Squares	Variance Components	Percentage of Variation	Φ Statistics
a	Among groups	3	217.221	1.41953 Va	26.25	ΦCT = −0.263 (0.001)
	Among population within groups	4	39.714	0.29998 Vb	5.55	ΦSC = 0.075 (0.000)
	Among individuals within populations	86	304.043	−0.15252 Vc	−2.82	ΦIS = −0.041 (0.885)
	Within populations	94	361.000	3.84043 Vd	71.02	ΦIT = 0.290 (0.000)
b	Among groups	2	1423.097	15.54290 Va	65.39	ΦCT = 0.653 (0.010)
	Among population within groups	5	144.291	1.24626 Vb	5.24	ΦSC = 0.151 (0.000)
	Within populations	147	1026.096	6.98024 Vc	29.37	ΦST = 0.706 (0.000)

For each molecular marker, the more plausible grouping hypothesis among all tested, was: a) based on 103 SNPs, four groups of populations as follows: one group constituted by CH43 of A. reicherti; a second group integrated by putative hybrids from ponds CH54-61, CHN3, CHN4 and CH64; a third group including putative hybrids from ponds CHN6 and CH60; a fourth group integrated by ponds CH66; b) based on Cytb separating three groups of samples as follows: one group integrated by CH43 of A. reicherti and the hybrid pond CHN6; a second group including the pond CH66 of A. charrua; a third group comprising the putative hybrid ponds CH54-61, CH60, CHN3, CHN4 and CH64. p-values are given in parentheses.