Organism · Primates
Cantius mckennai
Source time context (not species duration) · ≈ 56–48 Ma
Inferred life reconstruction
Cantius mckennai
Overview
The secrets of life in trees are hidden in feet as well. Cantius mckennai is an early Eocene North American primate whose ankle and foot bones preserve clues to a branch-grasping life.[1]
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Key facts
Researchers highlighted a combination of flexible ankles, feet that could turn inward, and a big toe opposing the other toes. This suggests it may have adjusted its grip to branches of different thicknesses and directions. Feet, as much as hands, are central to primate evolution.[1]
Time and place
It is known from early Eocene North America. This animal invites us to explore how primates used trees in the forests of an ancient continent different from the one today.[1]
The time range describes source context, not the complete duration of this species.
Size, form and skeleton
The heel bone and ankle joint surfaces reveal the directions in which the foot could move. The articulation of bones connected to the big toe and flattened terminal phalanges have also been studied. Small fragments may look modest, but several structures considered together reveal how a foot worked.[1]
A 2013 study calculated a body mass of approximately 650 g using the logarithmic mean from three heel-bone specimens. The estimate compares small foot-joint surfaces with those of living primates.[8]
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Habitat and reproduction
Analysis of foot function strongly suggested an arboreal way of life. When picturing Cantius, imagine feet wrapping around branches and supporting the body as well as feet walking on the ground. It is an example of paleontology inferring life habits from bone form.[1]
Fossil discovery
A study focused on ankle and foot form was published in 1988. Existing material also includes heel bone USGS 5897R and a separate humerus, USGS 6759. Different specimens contribute information about different body regions.[1][3][2]
References
- Covert (1988), “Ankle and foot morphology of Cantius mckennai: adaptations and phylogenetic implications,” Journal of Human Evolution 17(1–2):57–70.
- Rose et al. (2009) — Early Eocene primates from Gujarat, India
- “Evolution and Allometry of Calcaneal Elongation in Living and Extinct Primates” (2013), PLOS ONE 8(7):e67792.
- Covert (1988), “Ankle and foot morphology of Cantius mckennai: adaptations and phylogenetic implications,” Journal of Human Evolution 17(1–2):57–70.
- Secord — The Tiffanian North American mammal age
- Matthew & Granger1921 — New Palaeocene mammals
- Bloch et al.2007 — Paleocene skeletons and early relatives of primates
- Boyer et al. (2013) — The relationship between primate heel bones and body size
Research questions
Ankle features help researchers study relationships with other primates as well as ways of life. Because one structure may reflect both branch-grasping function and evolutionary history, researchers compare features across several bones.[1]
Observation
Focus on how the feet support the body.[1]
Related organisms
Ignacius frugivorusPrimatesSource time context (not species duration) · ≈ 66–56 MaPrimate-related stories from the Paleocene and Eocene
Connect the ankle and foot bones of Cantius with the teeth of Ignacius. Different evidence from early Eocene and late Paleocene North America tells an ancient story of primates and their relatives.