Table 1. Muscle architecture parameters for the Argentine black and white tegu (Salvator merianae) and the Virginia opossum (Didelphis virginiana).

	Salvator merianae								Didelphis virginiana
	Mm (g)	Mmtu (g)	Lm (mm)	Lmtu mm	Lf (mm)	θ (°)	PCSA (mm2)		Mm (g)	Mmtu (g)	Lm (mm)	Lmtu mm	Lf (mm)	θ (°)	PCSA (mm2)
LAD	2.73 ± 0.07	2.73 ± 0.07	93.51 ± 10.94	96.23 ± 11.63	60.12 ± 6.70	0 ± 0	43.45 ± 6.14	LAD	5.58 ± 0.59	5.68 ± 0.52	145.37 ± 7.25	152.73 ± 9.18	101.17 ± 4.78	0 ± 0	52.38 ± 6.46
PEC	5.02 ± 0.36	5.02 ± 0.36	90.14 ± 7.23	90.14 ± 7.23	50.86 ± 3.42	0 ± 0	79.19 ± 4.66	PEC	5.40 ± 0.99	5.41 ± 0.98	114.76 ± 2.98	114.76 ± 2.98	66.89 ± 7.98	0 ± 0	77.06 ± 15.05
DAC	0.45 ± 0.16	0.45 ± 0.16	26.19 ± 3.48	26.19 ± 3.48	21.57 ± 2.49	16.9 ± 1.6	18.66 ± 4.28	DAC	0.44 ± 0.09	0.46 ± 0.11	27.43 ± 3.80	29.32 ± 4.94	21.84 ± 3.53	30.0 ± 4.5	16.27 ± 1.43
DCL	1.17 ± 0.07	1.17 ± 0.07	46.33 ± 3.31	46.33 ± 3.31	35.67 ± 1.69	0 ± 0	31.28 ± 3.08	DCL	0.46 ± 0.05	0.46 ± 0.05	33.40 ± 4.06	33.40 ± 4.06	30.20 ± 1.65	0 ± 0	14.27 ± 0.77
DSC	0.87 ± 0.04	0.87 ± 0.04	37.85 ± 3.00	37.85 ± 3.00	24.10 ± 3.81	28.0 ± 4.5	30.49 ± 3.30	DSC	0.48 ± 0.06	0.50 ± 0.05	33.38 ± 3.70	35.96 ± 3.41	24.43 ± 4.41	27.6 ± 4.3	16.87 ± 4.14
SPC	0.85 ± 0.11	0.85 ± 0.11	37.51 ± 1.66	37.51 ± 1.66	21.05 ± 1.43	22.4 ± 1.3	35.50 ± 5.13	SSP	1.41 ± 0.24	1.50 ± 0.25	39.18 ± 1.50	41.08 ± 1.02	14.01 ± 1.28	37.9 ± 3.8	75.15 ± 10.74
								ISP	0.91 ± 0.13	1.04 ± 0.19	38.25 ± 2.99	40.41 ± 3.37	12.64 ± 0.78	37.0 ± 1.4	54.25 ± 6.23
SHA = TMN	0.10 ± 0.02	0.10 ± 0.01	19.75 ± 1.84	20.80 ± 2.67	18.44 ± 2.02	0 ± 0	4.94 ± 1.04	TMN = SHA	0.06 ± NA	0.06 ± NA	13.24 ± NA	13.24 ± NA	7.76 ± NA	0 ± NA	7.32±NA
SBS	0.93 ± 0.19	0.93 ± 0.19	29.06 ± 3.68	29.06 ± 3.68	19.36 ± 2.18	35.6 ± 3.0	36.80 ± 4.84	SBS	1.45 ± 0.18	1.56 ± 0.17	38.46 ± 5.53	38.46 ± 5.53	25.12 ± 3.42	35.2 ± 3.9	44.7 ± 1.01
SBC	0.70 ± 0.12	0.7 ± 0.12	29.79 ± 2.19	29.79 ± 2.19	23.04 ± 2.29	24.7 ± 2.9	26.13 ± 3.67
								TMJ	0.85 ± 0.18	0.88 ± 0.18	46.33 ± 3.39	46.33 ± 3.39	29.12 ± 3.88	29.8 ± 1.1	23.99 ± 4.58
CBB	0.31 ± 0.04	0.31 ± 0.04	19.86 ± 2.69	19.86 ± 2.69	16.49 ± 1.24	0 ± 0	17.98 ± 1.86	CBB	0.06 ± 0.02	0.07 ± 0.01	11.09 ± 0.40	16.58 ± 1.41	7.26 ± 0.97	0 ± 0	8.69 ± 2.84
CBL	0.40 ± 0.01	0.4 ± 0.01	40.17 ± 2.70	44.11 ± 3.22	26.70 ± 1.90	17.8 ± 2.8	13.71 ± 1.10
BIC	0.77 ± 0.03	0.81 ± 0.04	31.21 ± 2.51	46.11 ± 3.30	16.81 ± 2.17	21.6 ± 4.5	40.64 ± 6.93	BIC	0.99 ± 0.14	1.14 ± 0.13	39.48 ± 2.76	50.89 ± 2.78	18.76 ± 1.82	24.9 ± 1.7	45 ± 3
TRS	1.36 ± 0.11	1.4 ± 0.09	35.41 ± 3.69	39.82 ± 4.74	22.67 ± 2.07	31.8 ± 3.0	48.70 ± 8.09	TRS	2.48 ± 0.11	2.73 ± 0.11	40.54 ± 2.56	45.22 ± 2.94	26.27 ± 3.30	34.2 ± 4.1	74.31 ± 7.63
TRH = TRM + TRL	1.68 ± 0.11	1.7 ± 0.11	30.94 ± 4.54	35.48 ± 5.29	21.46 ± 3.37	28.0 ± 1.9	67.41 ± 16.10	TRH = TRM + TRL	2.45 ± 0.25	2.54 ± 0.26	37.68 ± 3.19	42.36 ± 4.06	28.10 ± 1.86	26.6 ± 2.6	74.05 ± 10.38
BRA	0.28 ± 0.05	0.28 ± 0.05	30.11 ± 4.22	30.11 ± 4.22	12.30 ± 2.68	30.1 ± 2.0	19.13 ± 3.47	BRA	0.50 ± 0.03	0.54 ± 0.03	38.05 ± 3.50	38.05 ± 3.50	12.58 ± 1.64	32.6 ± 0.4	32.23 ± 5.85

Note:

Normalized species means are scaled to a 1 kg animal. Abbreviations and symbols: M_m, muscle mass; M_mtu, muscle-tendon unit mass; L_m, muscle length; L_mtu, muscle-tendon unit length; L_f, fascicle length; θ, pennation angle; PCSA, physiological cross-sectional area; NA, insufficient samples to calculate error. Muscle abbreviations follow Fig. 2.