The morphology and evolutionary history of the glenohumeral joint of hominoids: A review

Abstract

The glenohumeral joint, the most mobile joint in the body of hominoids, is involved in the locomotion of all extant primates apart from humans. Over the last few decades, our knowledge of how variation in its morphological characteristics relates to different locomotor behaviors within extant primates has greatly improved, including features of the proximal humerus and the glenoid cavity of the scapula, as well as the muscles that function to move the joint (the rotator cuff muscles). The glenohumeral joint is a region with a strong morphofunctional signal, and hence, its study can shed light on the locomotor behaviors of crucial ancestral nodes in the evolutionary history of hominoids (e.g., the last common ancestor between humans and chimpanzees). Hominoids, in particular, are distinct in showing round and relatively big proximal humeri with lowered tubercles and flattened and oval glenoid cavities, morphology suited to engage in a wide range of motions, which enables the use of locomotor behaviors such as suspension. The comparison with extant taxa has enabled more informed functional interpretations of morphology in extinct primates, including hominoids, from the Early Miocene through to the emergence of hominins. Here, I review our current understanding of glenohumeral joint functional morphology and its evolution throughout the Miocene and Pleistocene, as well as highlighting the areas where a deeper study of this joint is still needed.

Exploring the functional morphology of the Gorilla shoulder through musculoskeletal modelling

“…The infraspinatus insertion site on the greater tubercle is increased and shifted more cranially in Pan and Gorilla compared to all other hominoids (Arias‐Martorell, 2018). The infraspinatus muscle path further differs in Gorilla compared to Homo , due to differences in scapular spine and glenoid orientation.…”

Proximal Humerus Morphology Indicates Divergent Patterns of Locomotion in Extinct Giant Kangaroos

“…These differences in humeral proximal morphology between terrestrial and arboreal forms have primarily been observed in primates (e.g., Szalay and Dagosto 1980;Rose 1989;Gebo and Sargis 1994;Ride et al 1997;Schmitt 2003;Arias-Martorell 2018), but also in other mammals such as tree shrews (Sargis 2002), tenrecs (Salton andSargis 2008), didelphid marsupials (Argot 2001;Szalay and Sargis 2001), viverrids (Taylor 1974), felids (Walmesly et al 2012), procyonids (Tarquini et al 2019), caviomorph rodents (Morgan and Álverez 2013), and xenarthrans (Toledo et al 2013). Although most authors reported a phylogenetic signal within these lineages, the overall pattern of similarities both within and between lineages, and in marsupials as well as placentals, evidences a strong functional association between morphology and locomotion that overrides any phylogenetic effects.…”

Postcranial elements of small mammals as indicators of locomotion and habitat

“…The elongation of the humeral head is especially pronounced in diggers, which also have an extremely enlarged greater tuberosity (Salton & Sargis, 2008). Some arboreal forms may have a lesser tuberosity that is robust, and medially protruding (Sargis, 2002a;Janis et al, 2020); such morphology reflects a large subscapularis muscle, which is important for medial (internal) rotation of the humerus, and so may be important for climbing (Arias-Martorell, 2018).…”

“…The most common taxa of interest have been primates (e.g., Szalay & Dagosto, 1980;Rose, 1988Rose, , 1989Rose, , 1994Gebo & Sargis, 1994;Godfrey et al, 1997;Schmitt, 2003;Youlatos, 2003;Dunn et al, 2016;Elton, 2002;Elton et al, 2016;Arias-Martorell, 2018-this is but a small sample of the voluminous primate literature); carnivorous mammals (Taylor, 1974(Taylor, , 1976Van Valkenburgh, 1987;Gebo & Rose, 1993;Iwaniuk, Pellis & Whishaw, 1999;Schutz & Guralnick, 2007;Polly & MacLeod, 2008;Meachen-Samuels & Van Valkenburgh, 2009;Walmsley et al, 2012;Fabre et al, 2013;Meloro et al, 2013;Janis & Figueirido, 2014;Martín-Serra, Figueirido & Palmqvist, 2014a, 2014bFabre et al, 2015aFabre et al, , 2015bErcoli & Youlatos, 2016;Panciroli et al, 2017;Dunn et al, 2019;Meloro & De Olivera, 2019;Tarquini, 2019); and rodents (Elissamburu & Vizcaíno, 2004;Weisbecker & Schmid, 2006;Dunn & Rasmussen, 2007;Samuels & Van Valkenburgh, 2008;Morgan, 2009;Mor...…”

“…The most common taxa of interest have been primates (e.g., Szalay & Dagosto, 1980 ; Rose, 1988 , 1989 , 1994 ; Gebo & Sargis, 1994 ; Godfrey et al, 1997 ; Schmitt, 2003 ; Youlatos, 2003 ; Dunn et al, 2016 ; Elton, 2002 ; Elton et al, 2016 ; Arias-Martorell, 2018 —this is but a small sample of the voluminous primate literature); carnivorous mammals ( Taylor, 1974 , 1976 ; Van Valkenburgh, 1987 ; Gebo & Rose, 1993 ; Iwaniuk, Pellis & Whishaw, 1999 ; Schutz & Guralnick, 2007 ; Polly & MacLeod, 2008 ; Meachen-Samuels & Van Valkenburgh, 2009 ; Walmsley et al, 2012 ; Fabre et al, 2013 ; Meloro et al, 2013 ; Janis & Figueirido, 2014 ; Martín-Serra, Figueirido & Palmqvist, 2014a , 2014b , 2016 ; Fabre et al, 2015a , 2015b ; Ercoli & Youlatos, 2016 ; Panciroli et al, 2017 ; Dunn et al, 2019 ; Meloro & De Olivera, 2019 ; Tarquini, 2019 ); and rodents ( Elissamburu & Vizcaíno, 2004 ; Weisbecker & Schmid, 2006 ; Dunn & Rasmussen, 2007 ; Samuels & Van Valkenburgh, 2008 ; Morgan, 2009 ; Morgan & Álvarez, 2013 ; Boivin et al, 2018 ; Calede, Samuels & Chen, 2019 ; Hedrick et al, 2020 ). Studies of other mammalian orders (excluding here larger mammals such as ungulates and large diprotodontid marsupials) include smaller marsupials ( Lemelin, 1999 ; Argot, 2001 , 2002 ; Szalay & Sargis, 2001 ; Weisbecker & Warton, 2006 ; Bassavora, Janis & Archer, 2009 ; Flores & Díaz, 2009 ; Warburton et al, 2011 ; ...…”