The wrist joint of two-toed sloths and its relevance to brachiating adaptations in the hominoidea
β Scribed by Frank C. Mendel
- Publisher
- John Wiley and Sons
- Year
- 1979
- Tongue
- English
- Weight
- 990 KB
- Volume
- 162
- Category
- Article
- ISSN
- 0362-2525
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β¦ Synopsis
Abstract
Twoβtoed sloths have evolved a wrist complex that includes the following traits: (1) diminution and distal migration of the pisiform, with a loss of contact with the ulna; (2) reduction of the distal end of the ulna to a styloid process; and (3) extremely reduced contact between the ulna and triquetrum. These traits were proposed by Lewis ('65, '74) to be indicative of brachiating habits and to be a unique adaptation of the Hominoidea. Cartmill and Milton ('77) recently found a similar complex in the wrists of the lorisines. Very similar adaptations of the wrist among the Hominoidea, lorisines, and twoβtoed sloths clearly refute contentions of Lewis and strengthen the hypothesis of Cartmill and Milton that the traits common to those animals are due to similar slow, cautious, but acrobatic locomotion.
π SIMILAR VOLUMES
Numerous methods for reading abnormalities of rheumatoid arthritis in hand and wrist radiographs have been proposed over the past several decades. There are many differences among these methods, one of the more striking of which is the variation in the number of joints that are scored. In this study