Skeletal differentiation of Macaca fascicularis and Macaca nemestrina in relation to arboreal and terrestrial quadrupedalism

Abstract

Sympatric Macaca fascicularis and M. nemestrina of Borneo coexist, in spite of similar frugivorous diets, by occupyimq habitats that differ in density of food sources. A primary specialization for I-raging on widely dispersed food sources is terrestrial travel by M. nemestrina, in contrast t o arboreal travel by M. fascicularis in the richer habitat. Theoretical biomechanical demands of terrestrial and arboreal quadrupedalism suggest the hypothesis that M. fascicularis should be built like a powerful climber and a leaper compared with M. nemestrina, which should be relatively cursorial in structure.Specific differences in skeletal proportions and muscle insertions are predicted by this hypothesis, and comparisons of the brachial index, relative length of the olecranon process, relative position of the radial tuberosity, relative length of the posterior scapular border, relative length of the ilium, relative length of the ischium, projection of the greater trochanter, and position of the lesser trochanter (but not the intermembral index or length of the clavicle) confirm these predictions. Allometric analysis of the indices reveals that allometric growth is sufficient to explain only the difference in the crural index.A central theme of evolutionary anthropology during this century has been description and analysis of skeletal differentiation of primates. There are multiple reasons for persistence of this theme, but one of the modern aims of such study is elucidation of functional patterns in skeletal morphology. In the end, results of such study may lead t o better interpretation of fossil material and ultimately to clearer understanding of the evolutionary paths to the living primates, and to Homo sapiens in particular.Past analyses have attacked large differences between genera or families of primates, or between large clusters of species with similar locomotor behavior (e.g., Erikson, '63; Oxnard, '63, '67; Napier and Walker, '67; Napier, '67; Grand, '72; Ashton and Oxnard, '63, '64). Detailed attention has been paid to problems particularly related to the morpho-

A Reappraisal of the Locomotion and Habitat Preference of Theropithecus oswaldi

“…However, there is potential confusion over the relationship between habitat and/or locomotor preference and olecranon length. It has been argued that more terrestrial monkeys have shorter olecranons than do arboreal species [23,44,49], but in the present study, this trend is reversed, with 'forest arboreal' specimens having relatively short olecranons, in contrast to the longer olecranons of the 'open mixed' and 'open terrestrial' specimens, as well as T. oswaldi (tables 13, 16). To investigate this further, olecranon length was divided by both ulna length (OLUL) and ulna length minus styloid process length (OLUL2) (table 16).…”

“…Jolly [44] argued that a short process relative to ulna length allows for full extension of the elbow, increasing the length of the forelimb during a stride, therefore being beneficial in terrestrial animals. In contrast, a longer process may be found in arboreal primates because it allows for increased forelimb power when the forelimb is habitually flexed [49]. However, Ciochon [24] found that in large-bodied papionins which have a posteriorly inclined olecranon, a relatively long olecranon would increase the mechanical advantage of the triceps at full extension of the elbow.…”

Skeletal correlates of quadrupedalism and climbing in the anthropoid forelimb: Implications for inferring locomotion in Miocene catarrhines

“…The olecranon process is relatively longer in highly quadrupedal cercopithecoids and platyrrhines compared to suspensory anthropoids (Jolly, 1967(Jolly, , 1972Harrison, 1989;Rose, 1993a;Drapeau, 2004). Contrasting results have been reported for relative length differences between arboreal and terrestrial quadrupeds (Rodman, 1979;Ciochon, 1993;Drapeau, 2004). An elongated olecranon process in arboreal quadrupeds has been related to increasing the power of the triceps brachii muscle during the bent-elbow posture performed during arboreal quadrupedalism, whereas the relatively shorter olecranon process in highly terrestrial quadrupeds has been explained as allowing fuller elbow extension when moving on the ground (Rodman 1979).…”

Diversity and development of positional behavior in non-human primates

“…YD8-j (侧面垂直下降, sideways vertical descent), 身 体与支撑物的轴线垂直、处于身体下方的前后肢提 供主要的制动力; YD8-k (匍匐滑动, pronograde slide), 头部在前, 四肢紧握支撑物, 在光滑、倾斜 的树枝上被动下降, 身体通过前、后肢及其他部位 与支撑物之间的滑行而移动, 身体匍匐并与支持物 保持平行; YD8-l (摩擦支撑滑行, fire-pole slide), 臀 部在前, 在较粗的(直径>20 cm)垂直或近似垂直的 支撑物上被动滑行, 躯干直立, 四肢环抱支撑物, 依靠身体其他部分的微小滑动来下降, 并可通过前 肢来调整下降速率 (Hunt et al, 1996) (Tuttle, 1969;Stern & Oxnard, 1973;Jenkins & Fleagle, 1975;Fleagle, 1979;Rodman, 1979 (Gebo & Chapman, 1995a;Crompton, 1984;Dagosto, 1995;McGraw, 1998b;Garber, 1998)。灵长类位置行为在 季节性和具体地点两方面具显著差异。形成这种显 著差异的主要原因可能是进食、觅食策略以及食物 供给和分配的季节性变化 (Grand, 1972;CharlesDominique, 1977;Garber, 1980Garber, , 1984Crompton, 1984;Cant, 1987a;Boinski, 1989;McGraw, 1998a (Gebo, 1992;Gebo & Chapman, 1995b) Garber, 2007;Prates & Bicca-Marques, 2008)。 研 究表明, 体型大小、动作技能和生理状态的两性差 异以及个体发育是导致个体行为差异的重要因素 (Dunbar & Badam, 1998;Chatani, 2003;Prates & Bicca-Marques, 2008 …”