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Mesozoic mammals affected by evolution of angiosperms

From: Ben Creisler

A new paper:

David M. Grossnickle and P. David Polly (2013)
Mammal disparity decreases during the Cretaceous angiosperm radiation.
Proceeding of the Royal Society B  280 (1) 1771 20132110
doi: 10.1098/rspb.2013.2110

Fossil discoveries over the past 30 years have radically transformed
traditional views of Mesozoic mammal evolution. In addition, recent
research provides a more detailed account of the Cretaceous
diversification of flowering plants. Here, we examine patterns of
morphological disparity and functional morphology associated with diet
in early mammals. Two analyses were performed: (i) an examination of
diversity based on functional dental type rather than higher-level
taxonomy, and (ii) a morphometric analysis of jaws, which made use of
modern analogues, to assess changes in mammalian morphological and
dietary disparity. Results demonstrate a decline in diversity of molar
types during the mid-Cretaceous as abundances of triconodonts,
symmetrodonts, docodonts and eupantotherians diminished.
Multituberculates experience a turnover in functional molar types
during the mid-Cretaceous and a shift towards plant-dominated diets
during the late Late Cretaceous. Although therians undergo a taxonomic
expansion coinciding with the angiosperm radiation, they display small
body sizes and a low level of morphological disparity, suggesting an
evolutionary shift favouring small insectivores. It is concluded that
during the mid-Cretaceous, the period of rapid angiosperm radiation,
mammals experienced both a decrease in morphological disparity and a
functional shift in dietary morphology that were probably related to
changing ecosystems.


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