Abstract
The Pliocene hominins Australopithecus anamensis and Australopithecus afarensis likely represent ancestor-descendent taxa-possibly an anagenetic lineage-and capture significant change in the morphology of the canine and mandibular third premolar (P3) crowns, dental elements that form the canine honing complex in nonhuman catarrhines. This study focuses on the P3 crown, highlighting plesiomorphic features in A. anamensis. The A. afarensis P3 crown, in contrast, is variable in its expression of apomorphic features that are characteristic of geologically younger hominins. Temporal variation characterizes each taxon as well. The A. anamensis P3 from Allia Bay, Kenya expresses apomorphic character states, shared with A. afarensis, which are not seen in the older sample of A. anamensis P3s from Kanapoi, Kenya, while spatiotemporal differences in shape exist within the A. afarensis hypodigm. The accumulation of derived features in A. afarensis results in an increased level of P3 molarisation. P3 molarisation did not evolve concurrent with postcanine megadontia and neither did the appearance of derived aspects of P3 occlusal form coincide with the loss of canine honing in hominins, which is apparent prior to the origin of the genus Australopithecus. A. afarensis P3 variation reveals the independence of shape, size, and occlusal form. The evolution of the P3 crown in early Australopithecus bridges the wide morphological gap that exists between geologically younger hominins on the one hand and extant apes and Ardipithecus on the other.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 711-730 |
| Number of pages | 20 |
| Journal | Journal of Human Evolution |
| Volume | 60 |
| Issue number | 6 |
| DOIs | |
| State | Published - Jun 2011 |
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Keywords
- Australopithecus afarensis
- Australopithecus anamensis
- Canine honing complex
- Hadar
- Kanapoi
- Laetoli
- Premolar molarisation
ASJC Scopus subject areas
- Ecology, Evolution, Behavior and Systematics
Cite this
Evolution of the mandibular third premolar crown in early Australopithecus. / Delezene, Lucas K.; Kimbel, William.
In: Journal of Human Evolution, Vol. 60, No. 6, 06.2011, p. 711-730.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Evolution of the mandibular third premolar crown in early Australopithecus
AU - Delezene, Lucas K.
AU - Kimbel, William
PY - 2011/6
Y1 - 2011/6
N2 - The Pliocene hominins Australopithecus anamensis and Australopithecus afarensis likely represent ancestor-descendent taxa-possibly an anagenetic lineage-and capture significant change in the morphology of the canine and mandibular third premolar (P3) crowns, dental elements that form the canine honing complex in nonhuman catarrhines. This study focuses on the P3 crown, highlighting plesiomorphic features in A. anamensis. The A. afarensis P3 crown, in contrast, is variable in its expression of apomorphic features that are characteristic of geologically younger hominins. Temporal variation characterizes each taxon as well. The A. anamensis P3 from Allia Bay, Kenya expresses apomorphic character states, shared with A. afarensis, which are not seen in the older sample of A. anamensis P3s from Kanapoi, Kenya, while spatiotemporal differences in shape exist within the A. afarensis hypodigm. The accumulation of derived features in A. afarensis results in an increased level of P3 molarisation. P3 molarisation did not evolve concurrent with postcanine megadontia and neither did the appearance of derived aspects of P3 occlusal form coincide with the loss of canine honing in hominins, which is apparent prior to the origin of the genus Australopithecus. A. afarensis P3 variation reveals the independence of shape, size, and occlusal form. The evolution of the P3 crown in early Australopithecus bridges the wide morphological gap that exists between geologically younger hominins on the one hand and extant apes and Ardipithecus on the other.
AB - The Pliocene hominins Australopithecus anamensis and Australopithecus afarensis likely represent ancestor-descendent taxa-possibly an anagenetic lineage-and capture significant change in the morphology of the canine and mandibular third premolar (P3) crowns, dental elements that form the canine honing complex in nonhuman catarrhines. This study focuses on the P3 crown, highlighting plesiomorphic features in A. anamensis. The A. afarensis P3 crown, in contrast, is variable in its expression of apomorphic features that are characteristic of geologically younger hominins. Temporal variation characterizes each taxon as well. The A. anamensis P3 from Allia Bay, Kenya expresses apomorphic character states, shared with A. afarensis, which are not seen in the older sample of A. anamensis P3s from Kanapoi, Kenya, while spatiotemporal differences in shape exist within the A. afarensis hypodigm. The accumulation of derived features in A. afarensis results in an increased level of P3 molarisation. P3 molarisation did not evolve concurrent with postcanine megadontia and neither did the appearance of derived aspects of P3 occlusal form coincide with the loss of canine honing in hominins, which is apparent prior to the origin of the genus Australopithecus. A. afarensis P3 variation reveals the independence of shape, size, and occlusal form. The evolution of the P3 crown in early Australopithecus bridges the wide morphological gap that exists between geologically younger hominins on the one hand and extant apes and Ardipithecus on the other.
KW - Australopithecus afarensis
KW - Australopithecus anamensis
KW - Canine honing complex
KW - Hadar
KW - Kanapoi
KW - Laetoli
KW - Premolar molarisation
UR - http://www.scopus.com/inward/record.url?scp=79955475780&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=79955475780&partnerID=8YFLogxK
U2 - 10.1016/j.jhevol.2011.01.006
DO - 10.1016/j.jhevol.2011.01.006
M3 - Article
C2 - 21481921
AN - SCOPUS:79955475780
VL - 60
SP - 711
EP - 730
JO - Journal of Human Evolution
JF - Journal of Human Evolution
SN - 0047-2484
IS - 6
ER -