Diagonal gaits in the feathertail glider Acrobates pygmaeus (Acrobatidae, Diprotodontia): Insights for the evolution of primate quadrupedalism

Effects of support diameter and compliance on common marmoset (Callithrix jacchus) gait kinematics

“…Similar kinematic adjustments have been documented in studies of squirrels (Schmidt, 2011) and mouse lemurs (Shapiro et al, 2016) using asymmetrical gaits on flat versus narrow substrates, and several studies have found a general tendency to increase substrate contact duration on cylindrical supports (Schmitt, 1999;Lemelin and Cartmill, 2010;Schmidt and Fischer, 2010;Shapiro and Young, 2012;Shapiro et al, 2014;Karantanis et al, 2015;Hsieh, 2016). In contrast, differences in gait kinematics among variably sized cylindrical substrates are generally subtler (Schmitt, 2003a;Shapiro and Young, 2010;Hyams et al, 2012;Hsieh, 2016) -as was observed in the current study.…”

“…Though faster speeds may facilitate dynamic stability, particularly in the rolling plane (Bruijn et al, 2009), fast travel also reduces agility (Hyams et al, 2012;Wheatley et al, 2015;Wynn et al, 2015) and increases peak force production (Weyand et al, 2000) -both of which may compromise stability when moving on a precariously narrow support. Indeed, substrate narrowness has previously been shown to be associated with slower travel speeds in many arboreal tetrapods, including tree frogs (Herrel et al, 2013), anoles (Losos and Sinervo, 1989; Losos and Irschick, 1996; Mattingly and Jayne, 2004;Hsieh, 2016), fence lizards (Sinervo and Losos, 1991), marsupial gliders (Karantanis et al, 2015), opossums (Lammers and Biknevicius, 2004;Shapiro et al, 2014), mice (Hyams et al, 2012), squirrels (Schmidt, 2011) and strepsirrhine primates (Stevens, 2007). Other gait adjustments were subtler, often displaying a complex interaction with speed.…”

“…Because arboreal substrates are heterogeneous in geometry, spatial orientation and material properties, they challenge locomotor stability to a degree not typically encountered in terrestrial environments. Though the precariousness of the arboreal environment fundamentally depends on a complex interplay between the size of the animal and the size of the locomotor substrate (Jenkins, 1974), even very small mammals have been shown to adjust locomotor kinematics in response to simulated variation in branch diameter and orientation Young, 2010, 2012;Shapiro et al, 2014;Karantanis et al, 2015). Challenges to stability should be particularly acute during locomotion in the 'fine-branch niche' -the zone of terminal branches found at the edges of tree canopies where supports are both narrow in diameter and compliant.…”

Effects of Substrate Size and Orientation on Quadrupedal Gait Kinematics in Mouse Lemurs (Microcebus murinus)

“…Although there remains disagreement in the literature as to primate ancestral body size (Soligo and Martin, , ; Silcox et al., ), a presumed small body size for the primate ancestral condition (i.e., less than 100 g) (e.g., Cartmill, ; Gebo, ) is well supported by the small size of the earliest fossil euprimates (Silcox et al., ; Fleagle, ), and by the fact that agreement between paleontological and molecular estimates of primate divergence times improves when molecular models account for the fast life history patterns associated with a small bodied last common ancestor (Steiper and Seiffert, ). Accordingly, insights on primate locomotor evolution have been gained from studies examining the unique biomechanical benefits and challenges encountered by small primates or other small mammals moving quadrupedally on arboreal substrates (Pridmore, ; Preuschoft et al., ; Arms et al., ; Lemelin et al., ; Lammers and Biknevicius, ; Lammers et al., ; Lemelin and Schmitt, ; Lammers, , ; Lammers and Gauntner, ; Schmidt, ; Youlatos, ; Young, ; Samaras and Youlatos, ; Schmidt and Fischer, , ; Shapiro and Young, , ; Byron et al., ; Lammers and Zurcher, ; Stevens et al., ; Urbani and Youlatos, ; Shapiro et al., ; Chadwell and Young, ; Hesse et al., ; Karantanis et al., ). Most previous studies of primate quadrupedalism have been restricted to the analysis of symmetrical gaits.…”

Patterns of quadrupedal locomotion in a vertical clinging and leaping primate (Propithecus coquereli) with implications for understanding the functional demands of primate quadrupedal locomotion

“…The use of DS footfall patterns is thought to be adopted by primates to ensure that a grasping hindfoot is placed on a tested support when the contralateral forefoot touches down on an untested support (Cartmill et al, 2002(Cartmill et al, , 2007Lemelin et al, 2003;Schmitt, 2010). Although there has been some debate on this issue, particularly whether DS gaits are necessary for arboreal locomotion Raichlen, 2005, 2007;Shapiro and Young, 2010), the presence of DS footfall patterns in other highly arboreal nonprimate mammals Karantanis et al, 2015), the increased frequency of DS footfall patterns on arboreal supports in capuchin monkeys (Wallace and Demes, 2008), and the increase in DS gaits on arboreal supports in sugar gliders [who also use LS and DS gaits on arboreal supports, but rarely use DS on the ground (Shapiro and Young, 2010)] further strengthens the association of the DS footfall pattern with locomotion and foraging on thin branches.…”