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Dental formulae and dental eruption patterns in Parapithecidae (Primates, Anthropoidea)
American Journal of Physical Anthropology
|December 1, 1983
Summary
The study details the eruption sequences and dental formulas of early primates Apidium phiomense and Parapithecus grangeri. Findings suggest unique evolutionary paths for Parapithecus, particularly regarding incisor reduction.
Area of Science:
- Paleontology
- Primate Evolution
- Dental Morphology
Background:
- Primate dental development and formula evolution are key to understanding evolutionary relationships.
- Previous studies on parapithecids like Apidium and Parapithecus have provided insights but require further data on dental eruption and formulae.
- Comparative dental analysis is crucial for tracing primate ancestry and distinguishing between convergent and divergent traits.
Purpose of the Study:
- To establish the precise lower dental eruption sequences for Apidium phiomense and Parapithecus grangeri.
- To confirm and revise the dental formulae for these early primate species based on new fossil evidence.
- To evaluate the phylogenetic implications of dental traits, such as canine and M3 eruption timing and incisor number, in relation to other primate groups.
Main Methods:
- Analysis of eruption sequences from 18 juvenile Apidium phiomense specimens.
- Examination of developing lower teeth in five Parapithecus grangeri specimens.
- Determination of adult and deciduous lower dental formulae for Apidium phiomense and Parapithecus grangeri using tooth socket counts and direct observation.
Main Results:
- The lower dental eruption sequence for Apidium phiomense was determined as dP3, dP4, M1, M2, P2, P4, (P3, M3), C.
- In Parapithecus grangeri, P2, M1, and M2 erupted before P3 and P4, with C and M3 erupting last.
- Apidium phiomense has a confirmed lower dental formula of 2.1.3.3, while Parapithecus grangeri has a revised adult formula of 0.1.3.3 and a juvenile formula of 1.1.3.
Conclusions:
- Late eruption of lower canines in parapithecids may link them to Anthropoidea and Adapidae, distinguishing them from Omomyidae and Tarsiidae.
- Late M3 eruption in parapithecids is a shared derived trait specifically with Anthropoidea.
- The anterior tooth reduction in Parapithecus grangeri, evidenced by fewer incisors than Apidium, evolved independently of Tarsiidae.