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Identifying competitive exclusion at the macroevolutionary scale has
typically relied on demonstrating a reciprocal, contradictory response by
two co-occurring, functionally similar clades. Finding definitive examples
of such a response in fossil time-series has proven challenging however,
as has controlling for the effects of a changing physical environment. We
take a novel approach to this issue by quantifying variation in trait
values that capture almost the entirety of function for steam locomotives
(SL), a known example of competitive exclusion from material culture, with
the goal of identifying patterns suitable for assessing clade replacement
in the fossil record. Our analyses find evidence of an immediate,
directional response to the first appearance of a direct competitor, with
subsequent competitors further reducing the realized niche of SLs, until
extinction was the inevitable outcome. These results demonstrate when
interspecific competition should lead to extinction and suggest that clade
replacement may only occur when niche overlap between an incumbent and its
competitors is near absolute and where the incumbent is incapable of
transitioning to a new adaptive zone. Our findings provide the basis for a
new approach to analyze putative examples of competitive exclusion that is
largely free of a priori assumptions.
138 views reported since publication in 2023.