Table 2.

Comparisons of mean angles (±SE) of the quadrate and lower jaw bones for snakes at rest and maximal gape.

	Brown treesnake (BTS)		Burmese python (BP)		BTS vs. BP at max gape
angle	max gape (n = 6)	Rest (n = 2)	max gape (n = 6)	Rest (n = 2)	2-tail t (df = 10)	P
Dyz	64.1 ± 2.5	−36.9 ± 0.8	101.9 ± 2.3	1.1 ± 0.9	−11.11	<0.001
LJyz	91.5 ± 1.7	28.1 ± 0.2	123.5 ± 1.5	11.7 ± 0.0	−14.01	<0.001
Qyz	136.5 ± 1.3	129.7 ± 3.6	139.8 ± 1.5	128.0 ± 2.0	−1.70	0.12
Dxy	42.7 ± 5.6	79.3 ± 0.3	197.3 ± 7.5	72.5 ± 0.4	−16.50	<0.001
Ljxy	94.6 ± 4.6	75.3 ± 2.4	149.2 ± 3.4	78.1 ± 0.8	−9.54	<0.001
Qxy	200.0 ± 2.8	231.6 ± 1.3	174.5 ± 2.2	198.5 ± 4.4	7.20	<0.001
Dxz	65.6 ± 2.9	−7.9 ± 0.0	88.1 ± 1.1	1.3 ± 0.2	−7.31	<0.001
LJxz	70.5 ± 0.4	8.4 ± 1.4	68.1 ± 3.1	1.7 ± 0.1	0.77	0.46
Qxz	110.9 ± 3.5	135.9 ± 2.4	84.2 ± 2.8	105.5 ± 5.1	5.94	<0.001

See Fig. 3 for the conventions used to determine angles in the transverse (yz), frontal (xy), and sagittal (xz) planes, and see Fig. 7 for a graphical summary of these values. All values are in degrees. D, LJ, and Q are the dentary, proximal lower jaw, and quadrate, respectively. For the comparisons of angles of BTS versus BP at maximum gape, when a significant difference occurred between species, the greater mean value is indicated in bold.