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Beast evolved “steak-knife” teeth before dinosaurs

Feb. 7, 2014
Courtesy of the University of Toronto
and World Science staff

The first top preda­tors to walk on land weren’t afraid to bite off more than they could chew, a study sug­gests.

Researchers found that Di­me­tro­don, a meat-eater that lived be­tween 298 mil­lion and 272 mil­lion years ago, was the first land-dwelling ver­te­brate known to have ser­rat­ed teeth si­m­i­lar to those of meat-eat­ing di­no­saurs.

A portrayal of Di­me­tro­don by art­ist Dan­ielle Du­fault.


“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,” said re­search­er Rob­ert Reisz, both of the Uni­vers­ity of To­ron­to Mis­sis­sau­ga.

Grad­u­ate stu­dent Kir­stin Brink, who car­ried out the study with Reisz and is the lead au­thor of a re­port on the find­ings, said the change led to a more ef­fi­cient bite and would have let Di­me­tro­don eat prey much larg­er than it­self.

Dimetrodon had “ziphodont” teeth, which are curved back­ward, flat­tened and ser­rat­ed, ac­cord­ing to the re­search, pub­lished in the jour­nal Na­ture Com­mu­nica­t­ions. While most meat-eating di­no­saurs had zi­pho­dont teeth, the find­ings sug­gest Di­me­tro­don had these as much as 40 mil­lion years ear­li­er.

The study ex­am­ined “these teeth in de­tail to re­veal pre­vi­ously un­known pat­terns in the ev­o­lu­tion­ary his­to­ry of Di­me­tro­don,” Brink said. Di­me­tro­don, about four me­ters or yards long, was the top of the ter­res­tri­al food chain dur­ing its ge­o­log­i­cal pe­ri­od, called the Early Per­mi­an, and is con­sid­ered the fore­run­ner of mam­mals, the re­search­ers added.

Ac­cord­ing to the re­search, Di­me­tro­don had var­i­ous pre­vi­ously un­known tooth struc­tures and was al­so the first ter­res­tri­al ver­te­brate, or back­boned an­i­mal, with cusps – teeth with raised points on the crown, which are dom­i­nant in mam­mals.

The study al­so sug­gests ear­li­er spe­cies of Di­me­tro­don lacked zi­pho­dont teeth, 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.”


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The first top predators to walk on land weren’t afraid to bite off more than they could chew, a study suggests. The study found that that Dimetrodon, a meat-eater that lived between 298 million and 272 million years ago, was the first land-dwelling vertebrate known to have serrated teeth similar to those of the dinosaurs. “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,” said researcher Robert Reisz, both of the University of Toronto Mississauga. Graduate student Kirstin Brink, who carried out the study with Reisz and is the lead author of a report on the findings, said the change led to a more efficient bite and would have let Dimetrodon eat prey much larger than itself. Dimetrodon had “ziphodont” teeth, which are curved backward, flattened and serrated, according to the research, published in the journal Nature Communications. While most meat-eating dinosaurs had ziphodont teeth, the findings suggest Dimetrodon had these as much as 40 million years earlier. The study examined “these teeth in detail to reveal previously unknown patterns in the evolutionary history of Dimetrodon,” Brink said. Dimetrodon, about four meters or yards long, was the top of the terrestrial food chain during its geological period, called the Early Permian, and is considered the forerunner of mammals, the researchers added. According to the research, Dimetrodon had various previously unknown tooth structures and was also the first terrestrial vertebrate, or backboned animal, with cusps – teeth with raised points on the crown, which are dominant in mammals. The study also suggests earlier species of Dimetrodon lacked ziphodont teeth, 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.”