Data description for:
Ross et al. “Evolution of locomotor rhythmicity in vertebrates”.  Evolution
Data file = finallocomotiondata.xls

Callum Ross
ross@uchicago.edu

Blob data
Data for treadmill locomotion by 4 Alligator, 3 Pseudemys, and 2 Tupinambis were collected were collected using methods described in (Butcher and Blob 2008; Butcher et al. 2008; Sheffield et al. 2011).

Carrier data
Data on Varanus and Iguana were collected were collected using methods described in (Wang et al. 1997).

Daley data 
The data from quail (Coturnix), pheasants (Phasianus), guinea fowl (Numida), and turkeys (Meleagris) running on a level treadmill and on an obstacle treadmill were collected using methods described in (Daley and Biewener 2006; Daley et al. 2006; Daley et al. 2007; Daley et al. 2009).  
For the quail and pheasant data, continuous sequences of strides were collected and analyzed by Daley, and the obstacle contacts noted.
For the guinea fowl and turkey data, only three strides in a sequence were analyzed for each obstacle contact, rather than a continuous sequence: i.e., the data consist of one stride before an obstacle, one during the obstacle, and one following the obstacle. Hence, at least one third, and probably two thirds of the strides were affected by obstacles. Estimates of variance in stride duration based on these data make a very conservative test of the hypothesis.

Deban and Schilling data
The walking data from 5 individuals of Ambystoma maculatum were collected under two conditions, walking in water and walking on a wet substrate using methods described in (Deban and Schilling 2009). Stride durations were extracted from Deban and Schilling videos by CFR. 

Delvolve data for Pleurodeles
Data for Pleurodeles waltl walking on a wet stainless steel floor were taken from (Delvolve et al. 1997).

Demes data
Data on locomotion of the primates Cebus and Pan over solid substrates were collected using methods described in (Wallace and Demes 2008; Carlson and Demes 2010).

Kilbourne and Carrier data
Data on dogs locomoting on treadmills with and without weights attached were collected using methods described in (Kilbourne 2011).

Landberg data
Data on treadmill locomotion in Terrapene and Trachemys were collected using methods described in (Landberg et al. 2003; Landberg et al. 2009). 

Polk data
Data on locomotion by human and non-human primates, dogs, and pigs over various substrates and on treadmills were collected using methods described in (Polk 2002; Lieberman et al. 2003; Polk 2004; Polk et al. 2005; Hanna et al. 2006; Polk et al. 2008).

Vanhooydonck data
The data are from 8 individuals from each of three species, Anolis carolinensis;  Anolis sagrei; A. valencienni collected using methods described in (Vanhooydonck et al. 2006). The animals were induced to locomote on dowels of two sizes. The majority of animals showed the highest rhythmicity (lowest variance) on large dowels, so only large dowel data were used. This is the most conservative test of the hypothesis.
The data mostly consisted of multiple sequences of 5 strides per individual. Data were averaged across all strides, across sequences.  The first stride from each sequence was excluded because they were highly variable in duration. This is the most conservative test of the hypothesis.

References

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Butcher, M. T., N. R. Espinoza, S. R. Cirilo, and R. W. Blob. 2008. In vivo strains in the femur of river cooter turtles (Pseudemys concinna) during terrestrial locomotion: tests of force-platform models of loading mechanics. J Exp Biol 211:2397-2407.
Carlson, K. J. and B. Demes. 2010. Gait dynamics of Cebus apella during quadrupedalism on different substrates. Am J Phys Anthropol 142:273-286.
Daley, M. A. and A. A. Biewener. 2006. Running over rough terrain reveals limb control for intrinsic stability. Proceedings Of The National Academy Of Sciences Of The United States Of America 103:15681-15686.
Daley, M. A., G. Felix, and A. A. Biewener. 2007. Running stability is enhanced by a proximo-distal gradient in joint neuromechanical control. Journal Of Experimental Biology 210:383-394.
Daley, M. A., J. R. Usherwood, G. Felix, and A. A. Biewener. 2006. Running over rough terrain: guinea fowl maintain dynamic stability despite a large unexpected change in substrate height. Journal Of Experimental Biology 209:171-187.
Daley, M. A., A. Voloshina, and A. Biewener. 2009. The role of intrinsic muscle mechanics in the neuromuscular control of stable running in the guinea fowl. The Journal of Physiology 587:2693-2707.
Deban, S. M. and N. Schilling. 2009. Activity of trunk muscles during aquatic and terrestrial locomotion in Ambystoma maculatum. Journal of Experimental Biology 212:2949-2959.
Delvolve, I., T. Bem, and J. M. Cabelguen. 1997. Epaxial and limb muscle activity during swimming and terrestrial stepping in the adult newt, Pleurodeles waltl. J Neurophysiol 78:638-650.
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Sheffield, K. M., M. T. Butcher, S. K. Shugart, J. C. Gander, and R. W. Blob. 2011. Locomotor loading mechanics in the hindlimbs of tegu lizards (Tupinambis merianae): comparative and evolutionary implications. J Exp Biol 214:2616-2630.
Vanhooydonck, B., A. Herrel, and D. J. Irschick. 2006. Out on a limb: The differential effect of substrate diameter on acceleration capacity in Anolis lizards. J Exp Biol 209:4515-4523.
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Wang, T., D. R. Carrier, and J. W. Hicks. 1997. Ventilation and gas exchange in lizards during treadmill exercise. Journal of Experimental Biology 200:2629-2639.