Osteomorphological features of the hind limb bones of Saiga antelope (Saiga tatarica)

Abstract

The intralimb indices and calcaneal linear metrics are known as the reliable predictors of locomotor adaptation in artiodactyls. The osteological features of hindlimb in adult Saiga (Saiga tatarica) were described, and its correlation with cursoriality and habitat adaptation was discussed. Gross anatomy data showed Saiga owned the deep acetabulum as a broad lunate surface, the large acetabular anteversion, the well‐developed ischiatic tuberosity and the prominent gluteal lines. It also presented the robust rough line and the strong gluteal tuberosity. A proximodistally elongated eminence located on the cranially distal tibia, which had not been found in goat. The tibial extensor groove was deep. The calcaneal tuberosity was robust. Digital anatomy data showed Saiga owned the higher metatarsal‐femur ratio than forest musk deer and sheep. Comparing with wild bovids and sheep, Saiga presented a transitional variation in calcaneal form. The mean greatest length of the calcaneus (GLC) and the height of the sustentacular facet (HSF) in Saiga were shorter than that in sheep and longer than that in wild bovids respectively (F = 587.492; F = 10.264, p < .05). The wild bovids had longer cubonavicular facets than the other two groups (F = 18.587, p < .05). The great metatarsal–femur ratio of Saiga implied a superior cursorial ability and high conservation confronting the different habitats. The calcaneal linear metrics might shed light on lifestyle‐related functional adaptation over decades of short‐term evolution in the semi‐free range environment.

Morphological Differences between Sheep and Goat Calcanea Using Two-Dimensional Geometric Morphometrics

“…Differences among sheep and goats in this anatomical region have not been explored, however researchers have found that the length of the cubonavicular facet is significantly longer in open-adapted bovids than in bovids from forested environments. The cubonavicular facet is also significantly longer in wild cursorial bovids than in semi-free and domestic cursorial bovids, like sheep [ 25 , 26 ]. All these results point to a functional signal in these differences.…”

“…All these results point to a functional signal in these differences. In fact, the morphology of the calcaneum is considered to clearly reflect lifestyle-related functional adaptation in artiodactyls [ 26 ]. Similarly, using GM analysis, sheep astragali have been found to have flatter and elongated plantar surfaces and to be more compressed than those of sheep [ 14 ].…”

Morphologic and mechanical adaptive variations in Saiga tatarica calcaneus: A model for interpreting the bone functional adaptation of wild artiodactyl in captivity

“…Bones were manually oriented and positioned according to the percentage length as described by Skedros et al . [ 13 ] ( Figure-2 ) [ 1 , 7 , 9 , 13 , 14 ]. The diaphyseal length of each bone was measured using a digital Vernier caliper (Mitutoyo, Japan), and the error was controlled to within 1000ths of a millimeter.…”

“…Habitual locomotor patterns determined by habitat affect the loads placed on limb bones during locomotion and influence variations in bone morphology [ 1 , 2 ]. Thus, such bone morphology variations are considered to be adaptive responses to loading conditions that directly reflect lifestyle-related functional bone adaptation [ 1 , 3 ]. The calcaneus is the main weight-bearing bone in the hock joint of artiodactyls and presents a habitually loaded cantilevered beam-like structure during bending.…”

“…It has been proposed that the skeletal physiological response to mechanical stimuli is related to loading patterns determined by different habitats; therefore, habitat has an important effect on bone developmental patterns. In Artiodactyla, differences between captive and natural habitats induce variations in the morphological response of the calcaneus to locomotor behavior [ 1 , 8 ]. Within the same habitats, calcaneal adaptive architectures of captive wild and domesticated artiodactyls may be correlated.…”