The evolution of molar occlusion in the Cercopithecidae and early Catarrhines.
Published
Journal Article
Those Eocene prosimians which are possible catarrhine ancestors have four blade-like crests on each lower molar. Each crest shears in sequence across two upper molar crests. Occluding crests are concavely curved to hold the foods being sheared. Each of two medial lower molar crests bordering the principal crushing surface shear past single upper molar crests at about the same time the lateral lower molar crests contact the second rank of upper molar crests. Grinding and crushing areas are restricted to hypoconid, trigonid, and protocone surfaces. Oligocene catarrhine molars have increased crushing-grinding capacities and maintained but modify their shearing. As the crushing surface of the protocone expands and a crushing hypocone is added, the "second rank" upper molar shearing crests are functionally reduced. At the same time medial crests are increasingly emphasized so that the total shearing capacity remains virtually unchanged. Marginal shearing blades are straight edged; leading edges of occluding blades are set at different angles to the occlusal plane so that blades contact at only one point at any given time. Early Primates have separate crushing basins surrounded by shearing blades. Catarrhines tend to link explanding crushing surfaces anteroposteriorly into a continuous surface between all molars. A cladistic analysis based on both new and previously recognized characters indicates that: 1. Apidium may be more closely related to Aegyptopithecus than to Parapithecus; 2. cercopithecids are derived from a Parapithecus-related stock; 3. Oreopithecus could equally well have come from an Apidium or Aegyptopithecus stock.
Full Text
Duke Authors
Cited Authors
- Kay, RF
Published Date
- March 1, 1977
Published In
Volume / Issue
- 46 / 2
Start / End Page
- 327 - 352
PubMed ID
- 848569
Pubmed Central ID
- 848569
Electronic International Standard Serial Number (EISSN)
- 1096-8644
International Standard Serial Number (ISSN)
- 0002-9483
Digital Object Identifier (DOI)
- 10.1002/ajpa.1330460213
Language
- eng