TABLE 1. Forelimb muscle belly and tendon lengths and masses as predicted from Cuff et al. (2016a). Serrat. vent. cerv. = m. serratus ventralis cervicus, Serrat. vent. thor. = m. serratus ventralis thoracis, Abd. dig. 1 = m. abductor digiti 1. Ext. = extensor, Flex. = flexor.

Muscle Belly length
(m)
Tendon length
(m)
Belly mass
(kg)
Tendon mass (kg)
Latissimus dorsi 0.646   1.776  
Trapezius cervicis 0.379   0.229  
Trapezius thoracis 0.275   0.242  
Rhomboideus capitis 0.428   0.232  
Rhomboideus cervicis 0.230   0.444  
Rhomboideus thoracis 0.204   0.156  
Omotransversarius 0.350   0.169  
Cleidocephalicus 0.405   0.484  
Cleidobrachialis 0.336 0.140 0.509  
Serrat. vent. cerv. 0.244   0.523  
Serrat. vent. thor. 0.240   0.552  
Pectoralis superficialis 0.372   0.567  
Pectoralis profundus 0.642   1.923  
Supraspinatus 0.344 0.045 1.001 0.001
Infraspinatus 0.261 0.203 0.699 0.038
Deltoideus acromion 0.184   0.162  
Deltoideus spinous 0.195 0.113 0.190 0.000
Teres major 0.286 0.002 0.554 0.001
Subscapularis 0.254 0.022 0.670 1.000
Teres minor 0.091   0.035  
Coracobrachialis 0.644   0.133  
Triceps longus 0.348 0.130 1.562 0.006
Triceps lateralis 0.277 0.101 0.582 0.005
Triceps medius 0.253 0.136 0.197 0.010
Triceps accessory 0.281   0.123  
Biceps brachi 0.257 0.102 0.531 0.012
Brachialis 0.297 0.059 0.138 0.003
Anconeus 0.165   0.072  
Ext. carpi radialis 0.310 0.163 0.201 0.008
Ext. digitorum communis 0.236 0.014 0.186 0.074
Ext. digitorum lateralis 0.415 0.169 0.054 0.008
Ext. carpi ulnaris 0.264 0.163 0.077 0.005
Flex. carpi ulnaris ulnar 0.262 0.021 0.139 0.003
Flex. carpi ulnaris humeral 0.295 0.108 0.162 0.002
Brachioradialis 2.410   0.218  
Supinator 0.147 0.002 0.039 0.004
Pronator teres 0.216   0.128  
Pronator quadratus 0.254 0.073 0.071 0.004
Flex. carpi radialis 0.259 0.081 0.058 0.002
Flex. digitorum complex 0.284 0.177 0.499 0.087
Abd. dig. 1 0.418 0.223 0.039 0.003

 

TABLE 2. Hindlimb muscle belly and tendon lengths and masses as predicted from Cuff et al. (2016b). Gastroc. = gastrocnemius, Dig. = digitorum, Supefic. = superficialis.

Muscle Belly length
(m)
Tendon length
(m)
Belly mass
(kg)
Tendon mass
(kg)
Biceps femoris 0.420   1.537  
Caudofemoralis 0.373 0.345 0.515 0.019
Sartorius 0.654   0.775  
Tensor fascia latae 0.190 0.293 0.542 0.043
Vastus lateralis 0.389   0.962  
Rectus femoris 0.419 0.650 0.693 0.079
Vastus medius 0.350 0.029 0.487 0.004
Vastus intermedius 0.486 0.002 0.168 0.000
Semitendinosus 0.464 0.134 0.684 0.005
Semimembranosus 0.718 0.043 1.369 0.003
Gracilis 0.257 0.088 0.534 0.016
Gluteus superficialis 0.184   0.153  
Gluteus medius 0.249   1.063  
Gluteus profundus 0.231 0.005 0.090 0.001
Piriformis 0.090 0.023 0.093 0.002
Gemelli 0.154   0.146  
Quadratus femoris 0.125   0046  
Obturator externus 0.124   0.168  
Obturator internus 0.118 0.078 0.178 0.008
Pectineus 0.268   0.093  
Adductor magnus 0.392   1.181  
Adductor brevis 0.214   0.211  
Iliacus 0.564   0.538  
Psoas major 0.558 0.058 0.785 0.074
Psoas minor 0.373 0.072 0.242 0.002
Gastroc. lateralis 0.334 0.072 0.377 0.021
Gastroc. medius 0.291 0.137 0.302 0.021
Superfic. dig. flexor 0.293 0.373 0.119 0.311
Soleus 0.268 0.024 0.123 0.002
Dig. extensor longus 0.291 0.269 0.084 0.105
Tibialis cranialis 0.284 0.111 0.213 0.004
Popliteus 0.189 0.095 0.054 0.003
Dig. extensor lateralis 0.215 0.320 0.026 0.003
Peroneus longus 0.222 0.166 0.185 0.062
Peroneus brevis 0.200 0.242 0.041 0.004
Deep digital flexor medial 0.298 0.299 0.165 0.062
Deep digital flexor lateral 0.324 0.465 0.137 0.040
Tibialis caudalis 0.272 0.180 0.117 0.011

 

TABLE 3. Vertebral muscle belly and tendon lengths and masses as predicted from Cuff et al. (2016a, b). Longis. = longissimus, Iliocost. = iliocostalis, Multifid. = multifidus.

Muscle Belly length
(m)
Tendon length
(m)
Belly mass
(kg)
Tendon mass
(kg)
Rectus capitis 0.112   0.098  
Splenius cervicis 0.395   0.366  
Serratus dorsalis cranialis 0.127 0.228 0.124 0.033
Serratus dorsalis caudalis 0.085 0.001 0.080 0.020
Semispinalis capitis biventer 4.009   0.325  
Semispinalis capitis complexus 0.470   0.325  
Spinalis cervicis 0.314   0.336  
Spinalis thoracis 0.641   0.877  
Longissimus capitis 0.323   0.064  
Longissimus cervicis 0.405   0.143  
Longissimus thoracis 0.827   0.916  
Iliocostalis thoracis 0.640   0.195  
Multifidis throacis 0.713   0.355  
Longis. lumborum 2.342   0.987  
Iliocost. lumborum 1.494   0.630  
Multifid. lumborum 0.381   0.661  

 

TABLE 4. Body composition of Panthera atrox from reconstructed muscles and dissections of extant P. leo specimens (Davis, 1962). “Muscle recon” is the sum of the reconstructed forelimb, hindlimb, and vertebral muscles. Additional muscle is the remaining expected muscle using the body compositions for modern lions (Davis, 1962) i.e., 57.1% - “Muscle recon”.

  Body Forelimb
muscles
Hindlimb
muscles
Vertebral
muscle
Muscle
recon
Additional
muscle
Bone Adipose Organs Skin and fur Blood and waste
Mass (kg) 207 35.2 32.2 16.9 84.4 33.7 25.7 5.5 24.4 23.8 9.56
Percentage (%) 100 17.0 15.6 8.18 40.8 16.3 12.4 2.67 11.8 11.5 4.62

 

TABLE 5. Panthera leo limb segment masses from the different mass estimate methods. “Flesh” is the weight calculated for the segment volumes (multiplied by 1060 kg m-3) from CT segmentation. “Reconstruction” was based on the muscle and bone reconstruction, although muscle masses for the manus and pes were calculated as total tendon mass for distal muscles. Convex hull bones (“CHB”) is the convex hull range of masses and the convex hull muscles (“CHM”) is the convex hull range of masses from the muscled reconstructions. The masses for both convex hull methods were calculated from the volumes using only the mean density [893.36 kg m−3 multiplied by 1.206 (Sellers et al., 2012)]. Ratios of each of these estimates are shown in the final four columns on the right side of the table. Dig_Man = digits of the manus, Dig_Pes = digits of the pes.

    Flesh Reconstruction CHB Mean CHM Mean  Flesh/Recon  Recon/CHB  CHM/Recon  Flesh/CHM
Bone mass Muscle mass Total
Humerus 7.47 0.44 3.94 4.38 1.19 7.29 1.71 3.69 1.67 1.02
Ulna/Radius 2.39 0.16 1.40 1.56 0.86 2.25 1.53 1.81 1.44 1.07
Manus 0.55 0.18 0.29 0.47 0.42   1.18 1.12    
Dig_Man 0.44 0.07   0.07 0.29   6.16 0.24    
Femur 10.9 0.62 7.23 7.85 1.50 10.6 1.39 5.23 1.35 1.03
Tibia 2.35 0.53 1.13 1.66 1.28 2.54 1.41 1.30 1.53 0.92
Pes 0.75 0.41 0.27 0.68 0.73   1.10 0.93    
Dig_Pes 0.30 0.13   0.13 0.29   2.31 0.45    

 

TABLE 6. Centre of mass (COM) validation test for extant lion limb segments. “Original COM” was derived from CT scan data for each segment, “CHM COM” from the convex hull models fitted to the muscled limbs, and “Difference” is the “Original COM” minus “CHM COM”. Italicised numbers are long axis lengths from which the percentage (%) of segment lengths were calculated. Positive x, y, and z are anterior, dorsal, and medial, respectively, relative to the origin at the proximal end of the segment. Centre of mass (COM) was expressed as % of length (from the proximal end) relative to the total proximodistal length of the segment. 

  Original COM   CHM COM   Difference Original % of length CHM % of length
x y z   X y z   x y z
Humerus 0.0003 -0.1120 0.005226   -0.0067 -0.1223 0.011691   0.0070 0.0103 -0.0065 45.6 49.8
Ulna/Radius -0.0023 -0.1093 0.001969   0.0016 -0.0935 0.002054   -0.0038 -0.0158 -0.0001 42.7 36.6
Femur -0.0201 -0.0943 -0.0177   -0.0164 -0.1098 -0.0216   -0.0037 0.0154 0.0039 32.1 37.4
Tibia -0.0219 -0.1497 -0.0004   -0.0230 -0.1607 -0.0009   0.0011 0.0111 0.0005 50.3 54.0

 

TABLE 7. Reconstructed and convex hull masses for various segments of the body of Panthera atrox. Bone mass was calculated from estimated bone density (1150 kg m-3) based on relative bone mass (25.7 kg - Table 4) divided by total bone volume (0.0223 m3). Muscle mass was calculated from the muscle and tendon that forms the majority of the segment (e.g., M. biceps brachii has tendons that extend to the scapula and the ulna, but these are all counted to the mass of the humeral segment as that is the majority of the muscle and tendon) (Table 1, Table 2, Table 3), with tendons for the distal muscles being placed in the manus and pes segments. Convex hull bones’ (CHB) and convex hull muscles’ (CHB) masses were calculated from the volumes multiplied by relative density (893.36 kg m−3 multiplied by 1.091, 1.206, and 1.322 (Sellers et al., 2012) respectively). Dig_Man and Dig_Pes are the digits for the manus and pes, respectively. The Recon/CHB is the ratio of reconstructed mass to CHB mass, and CHM/Recon is the ratio of the CHM mass to the reconstructed mass. Rad = radius, Dig_Man = digits of the manus, Fib = fibula, Dig_Pes = digits of the pes.

   Reconstruction   Convex Hull Bones   Convex Hull Muscles Recon/CHB CHM/Recon
Bone Mass Muscle Mass Total   Mean Lower Upper   Mean Lower Upper
Humerus 1.03 7.65 8.88   2.88 2.60 3.15   10.16 9.19 11.14 3.02 1.17
Ulna/Rad 0.73 1.94 2.67   2.03 1.83 2.22   4.44 4.02 4.87 1.32 1.66
Manus 0.34 0.20 0.54   0.92 0.84 1.01   1.28 1.16 1.40 0.59 2.35
Dig_Man 0.17   0.17   0.60 0.55 0.66   0.70 0.63 0.76 0.28 4.12
Femur 1.12 13.5 14.63   2.90 2.62 3.18   17.60 15.92 19.29 5.05 1.20
Tibia/Fib 0.87 1.99 2.86   1.89 1.71 2.07   4.33 3.92 4.75 1.51 1.52
Pes 0.90 0.61 1.50   1.60 1.45 1.76   2.16 1.96 2.37 0.94 1.44
Dig_Pes 0.28   0.28   0.68 0.62 0.75   0.92 0.83 1.01 0.41 3.27

 

TABLE 8. Centre of mass for Panthera atrox limb segments. Positive x, y, and z are anterior, dorsal, and medial, respectively, relative to the origin at the proximal end of the segment. Centre of mass (COM) was expressed as % of length (from the proximal end) relative to the total proximodistal length of the segment.

Segment x y z COM %
of length
Humerus 0.002 -0.119 0.009 0.372
Ulna -0.002 -0.117 0.001 0.360
Manus -0.010 -0.118 -0.001 0.622
Digits -0.015 -0.045 -0.009 0.414
Femur -0.012 -0.144 -0.018 0.380
Tibia -0.017 -0.200 -0.014 0.537
Pes -0.020 -0.114 -0.010 0.464
Digits 0.001 -0.045 -0.017 0.370

 

TABLE 9. Moments of inertia (relative to the centre of mass; Table 8) for the limb segments of Panthera atrox. Units are kg m2.

Humerus   Ulna   Manus   Digits
x y z   x Y z   x y z   x y z
0.1068 0.0616 0.1476   0.0551 0.0081 0.0576   0.0040 0.0015 0.0034   0.0012 0.0007 0.0010
Femur   Tibia   Pes   Digits
x y z   x Y z   x y z   x y z
0.3373 0.1221 0.4066   0.0460 0.0085 0.0482   0.0151 0.0025 0.0150   0.0020 0.0011 0.0015