Table 1.
The incubation success of eggs (hatchability) and survival rates of hatchlings.
The parental species (E. macularius—PM, E. angramainyu—PA), their hybrids of the first (F1) and second (F2) filial generations, backcrosses of F1 females to male of E. angramainyu (B1A; denoted as MAxA), the reciprocal backcrosses of F1 males or females to E. macularius (B1M; the individuals with father F1 hybrid are denoted as MxMA, while those with mother F1 hybrid as MAxM), and two categories of higher order hybrids (crosses of MxMA females with males of either E. macularius or E. angramainyu). The above mentioned generations and/or crossings refer to the embryos and hatchlings.
Fig 1.
The external appearance and coloration.
E. macularius (PM), E. angramainyu (PA), their hybrid of the first (F1) and second filial generations (F2), backcrosses of the F1 with male or female E. macularius (B1M: MAxM and B1M: MxMA, respectively), and a cross between a female of the latter backcross and a male of the E. angramainyu (B1MxPA). The scale bar used was 10mm.
Fig 2.
Measurements of the body and the head.
SVL: snout-vent length; DEX1: from the margin of the front leg to the cloacal lips; DEX2: from the margin of collar to the cloacal lips; TW: tail width; UFL: upper fore-limb length; CFW: chest and upper fore-limb width; LFL: lower fore-limb length; FL: finger length; HHW: hip upper hind-limb width; KHL: knee to heel length; HL: head length; HW: head width; EEL: length between eyes; REL: rostrum to eye length; the largest spot: length and area was measured; the number of spots was computed.
Table 2.
The effects of hybridization on the incubation success (hatchability) of the E. macularius, E. angramainyu, and their hybrids.
Hybridization crossing - factor group; hatchability - binomial response variable comparing hatched and failed eggs of each clutch. Coefficients (Estimate), its Standard errors (SE), Wald statistics (Wald) and significance of treatment contrasts against reference group E. macularius (P) are provided. The marginal model (geeglm function, logit link) accounts for a mother’s identity to avoid the problem of pseudoreplications. See Table 1 for explanations of the Generation and Crossing abbreviations.
Fig 3.
Variation in the number of dark spots on head.
E. angramainyu, E. macularius, and their F1 and B1M hybrids. The number of spots was square-root transformed.
Table 3.
Means and Standard errors (SE) for Number of spots on the head, Spot size and Spot length in the E. angramainyu (PA), E. macularius (PM), and their F1 and B1M hybrids.
Number of spots on the head—square root transformed, Spot size—area of the largest spot scaled to the head size and natural log-transformed, and Spot length—length of the largest spot scaled to the head length and natural log-transformed. In the case of the Number of spots, post hoc Tukey tests at P < 0.05 were significant for all comparisons. The same procedure revealed two homogenous groups (E. angramainyu and F1; E. macularius and B1M) for the Spot area and Spot length. N–number of animals in the testing group.
Fig 4.
Box plots of hatchling snout-vent lengths.
E. macularius (n = 32), E. angramainyu (n = 4), their hybrids of the first (F1; n = 25) and second (F2; n = 3) filial generations and the reciprocal backcrosses of F1 males or females to the E. macularius (B1M; the individuals with father F1 hybrid are denoted as MxMA, while those with the mother F1 hybrid as MAxM; n = 11 and 16, respectively). Median, quartiles and ranges are provided.
Fig 5.
Box plots of adult snout-vent lengths.
E. macularius (n = 68), E. angramainyu (n = 15), their hybrids of the first filial generation (F1; n = 27), and its reciprocal backcrosses of F1 males or females to the E.macularius (B1M; the individuals with the father F1 hybrid are denoted as MxMA, while those with the mother F1 hybrid as MAxM; n = 10 and 17, respectively). Median, quartiles and ranges are provided.
Fig 6.
Results of canonical variate analysis extracting multivariate axes (roots 1 and 2).
The results discriminated the E. macularius, E. angramainyu, and their F1 hybrids from 15 size-adjusted morphometric traits. Backcrosses of the F1 hybrids with the E. macularius were also projected into this morphospace.
Table 4.
Results of the discriminant function analysis (DFA) on 15 size-adjusted morphometric traits.
The E. macularius, E. angramainyu, and their F1 hybrids were included in the analysis. Resulting discriminant functions were then applied to the reclassification of these animals as well as additional ones belonging to other categories of their hybrids into these three groups. The numbers indicate assignation of the individual as predicted by DFA. Generation and Crossing abbreviation = see Table 1. No. of examined individuals = the observed number of animals belonging to each category; Reclassification success = percent of individuals assigned to a correct group.