TY - JOUR
T1 - The skeleton of early Eocene Cantius, oldest lemuriform primate
AU - Rose, Kenneth D.
AU - Walker, Alan
PY - 1985/1
Y1 - 1985/1
N2 - A recently discovered partial skeleton of the adapid Cantius trigonodus from the early Eocene Willwood Formation of the Bighorn Basin, Wyoming, documents substantial new information about the anatomy of the oldest lemuriform primates. It is very similar in all features to its descendant, middle Eocene Notharctus, and both exhibit numerous resemblances to certain extant Malagasy lemurs, particularly Lepilemur, Propithecus, Lemur, and Hapalemur griseus. Like these forms, Cantius had relatively long hind limbs and short forelimbs. Forelimb traits (prominent brachialis flange of the humerus, well‐developed olecranon process of the ulna, and strong shafts of the ulna and radius) suggest active use of the forelimbs in progression. Specializations in the hind limb (e.g., expanded articular surface of the femoral head, narrow and elevated patellar trochlea and prominent lateral trochlear ridge, posteriorly oriented femoral and tibial condyles, narrow and elongate talus, and hallucal metatarsal with prominent peroneal tubercle) indicate capabilities for leaping and for powerful grasping with an opposable hallux. Cantius was presumably primitive in having a relatively long ischium and much more distal inferior tibial tuberosity than most extant lemurs—traits suggesting that powerful extension of the thigh and flexion at the knee were important in its locomotion and posture. We interpret Cantius as an active arboreal quadruped with a propensity for leaping. The existence of this skeletal structure in one of the oldest primates of modern aspect suggests that it represents the primitive lemuriform morphology.
AB - A recently discovered partial skeleton of the adapid Cantius trigonodus from the early Eocene Willwood Formation of the Bighorn Basin, Wyoming, documents substantial new information about the anatomy of the oldest lemuriform primates. It is very similar in all features to its descendant, middle Eocene Notharctus, and both exhibit numerous resemblances to certain extant Malagasy lemurs, particularly Lepilemur, Propithecus, Lemur, and Hapalemur griseus. Like these forms, Cantius had relatively long hind limbs and short forelimbs. Forelimb traits (prominent brachialis flange of the humerus, well‐developed olecranon process of the ulna, and strong shafts of the ulna and radius) suggest active use of the forelimbs in progression. Specializations in the hind limb (e.g., expanded articular surface of the femoral head, narrow and elevated patellar trochlea and prominent lateral trochlear ridge, posteriorly oriented femoral and tibial condyles, narrow and elongate talus, and hallucal metatarsal with prominent peroneal tubercle) indicate capabilities for leaping and for powerful grasping with an opposable hallux. Cantius was presumably primitive in having a relatively long ischium and much more distal inferior tibial tuberosity than most extant lemurs—traits suggesting that powerful extension of the thigh and flexion at the knee were important in its locomotion and posture. We interpret Cantius as an active arboreal quadruped with a propensity for leaping. The existence of this skeletal structure in one of the oldest primates of modern aspect suggests that it represents the primitive lemuriform morphology.
KW - Adapidae
KW - Cantius
KW - Eocene
KW - Lemuriformes
KW - Locomotion
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U2 - 10.1002/ajpa.1330660107
DO - 10.1002/ajpa.1330660107
M3 - Article
C2 - 3976872
AN - SCOPUS:0021946849
SN - 0002-9483
VL - 66
SP - 73
EP - 89
JO - American journal of physical anthropology
JF - American journal of physical anthropology
IS - 1
ER -