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'Steak-knife'
teeth reveal ecology of oldest land predators
Date:
February 7,
2014
Source:
University of Toronto
Summary:
The first top predators to walk on
land were not afraid to bite off more than they could chew, a study has found.
Researchers suggest that Dimetrodon, a carnivore that walked on land between
298 million and 272 million years ago, was the first terrestrial vertebrate to
develop serrated ziphodont teeth.
…………………..
The first
top predators to walk on land were not afraid to bite off more than they could
chew, a University of Toronto Mississauga study has found.
Graduate
student and lead author Kirstin Brink along with Professor Robert Reisz from U
of T Mississauga's Department of Biology suggest that Dimetrodon, a
carnivore that walked on land between 298 million and 272 million years ago,
was the first terrestrial vertebrate to develop serrated ziphodont teeth.
According to
the study published in Nature Communications, ziphodont teeth, with
their serrated edges, produced a more-efficient bite and would have allowed Dimetrodon
to eat prey much larger than itself.
While most
meat-eating dinosaurs possessed ziphodont teeth, fossil evidence suggests
serrated teeth first evolved in Dimetrodon some 40 million years earlier
than theropod dinosaurs.
"Technologies
such as scanning electron microscope (SEM) and histology allowed us to examine
these teeth in detail to reveal previously unknown patterns in the evolutionary
history of Dimetrodon," Brink said.
The
four-meter-long Dimetrodon was the top of the terrestrial food chain in
the Early Permian Period and is considered to be the forerunner of mammals.
According to
Brink and Reisz's research, Dimetrodon had a diversity of previously
unknown tooth structures and were also the first terrestrial vertebrate to
develop cusps -- teeth with raised points on the crown, which are dominant in
mammals.
The study
also suggests ziphodont teeth were confined to later species of Dimetrodon,
indicating a gradual change in feeding habits.
"This
research is an important step in reconstructing the structure of ancient
complex communities," Reisz said.
"Teeth
tell us a lot more about the ecology of animals than just looking at the
skeleton."
"We
already know from fossil evidence which animals existed at that time but now with
this type of research we are starting to piece together how the members of
these communities interacted."
Brink and
Reisz studied the changes in Dimetrodon teeth across 25 million years of
evolution.
The analysis
indicated the changes in tooth structure occurred in the absence of any
significant evolution in skull morphology. This, Brink and Reisz suggest,
indicates a change in feeding style and trophic interactions.
"The
steak knife configuration of these teeth and the architecture of the skull
suggest Dimetrodon was able to grab and rip and dismember large
prey," Reisz said.
"Teeth
fossils have attracted a lot of attention in dinosaurs but much less is known
about the animals that lived during this first chapter in terrestrial
evolution."
Story Source:
The above
story is based on materials provided by University of Toronto. Note: Materials may be
edited for content and length.
Journal
Reference:
- Kirstin S. Brink, Robert R. Reisz. Hidden dental diversity in the oldest terrestrial apex predator Dimetrodon. Nature Communications, 2014; 5 DOI: 10.1038/ncomms4269