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Sorting through boxes of fossils collected 14 years ago, a Canadian PhD student discovered the deadly, poisonous bite of a 60 million-year-old mammal the size of a mouse

The first "venom delivery apparatus" ever found in an extinct mammal is described in the Thursday issue of the research journal Nature by the student, Craig Scott, and his professor, vertebrate paleontologist Richard C. Fox at the University of Alberta, Edmonton.

Why more mammals didn't continue to use poison into the modern era remains a mystery, he said.

A lab technician, Yong-Qin Sun, who was helping to remove the rock from the fossilized bones, first noticed the upper front canine teeth on the recovered jaw of Bisonalveus browni. Puzzled by the long grooves running the length of the teeth, she showed them to Scott.

Scott said he saw the groove as a system for delivering venom. "The groove in these teeth would have acted as a gutter, conducting fluid from its source in glandular tissues in the upper jaw down the height of the crown to its tip," he said

"This is an interesting discovery," said William Turnbull, emeritus curator of fossil mammals at the Field Museum. "Fox has also found isolated grooved teeth from another, larger mammal in the same formation, so it looks like there were a number of [venomous mammal species] out there




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