Fig. 9

Size differences between the gill arch skeletons of CA, DC and F1 hybrids. a–c Dissected, alizarin red-/alcian blue-stained gill arch skeletons of CA (a), DC (b) and F1 (c) specimens. Scale bar 5 mm. d–f Mean and distribution of CA, DC and F1 CB1 length (d), gill raker number (e) and gill raker spacing (f) (n = 5, each). h–j Dissected, alizarin red-/alcian blue-stained lower tooth plates of CA (h, h′), DC (i, i′) and F1 (j, j′) specimens. Scale bar 2.5 mm (h–j) and 1.0 mm (h′, i′, j′). g, k, l Mean and distribution of CA, DC and F1 lower tooth plate surface area (g), angle (k) and tooth spacing (l) (n = 5, each). m–o Dissected, alizarin red-/alcian blue-stained upper tooth plates of CA (m, m′), DC (n, n′) and F1 (o, o′) specimens. Scale bar 2.5 mm. p, q Mean and distribution of CA, DC and F1 upper tooth plate surface area (p) and tooth spacing (q) (n = 5, each). ***p < 0.001, Tukey’s HSD test. Bone nomenclature after [64]. CB ceratobranchial, HB hypobranchial, LTP lower tooth plate, UTP upper tooth plate