https://elifesciences.org/articles/90908
Jun20, 2024
The trunk replaces the longer mandible as
the main feeding organ in elephant evolution
Abstract
The long-trunked elephantids underwent
a significant evolutionary stage
characterized by an exceptionally
elongated mandible. The initial
elongation and subsequent regression
of the long mandible, along with its
co-evolution with the trunk, present
an intriguing issue that remains
incompletely understood. Through
comparative functional and
eco-morphological investigations, as
well as feeding preference analysis,
we reconstructed the feeding behavior
of major groups of longirostrine
elephantiforms. In the Platybelodon
clade, the rapid evolutionary changes
observed in the narial region,
strongly correlated with mandible and
tusk characteristics, suggest a
crucial evolutionary transition where
feeding function shifted from the
mandible to the trunk, allowing
proboscideans to expand their niches
to more open regions. This functional
shift further resulted in elephantids
relying solely on their trunks for
feeding. Our research provides
insights into how unique environmental
pressures shape the extreme evolution
of organs, particularly in large
mammals that developed various
peculiar adaptations during the late
Cenozoic global cooling trends.
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