The 6-foot-long (1.8-meter-long) Laccognathus embryi was "the kind of fish that was waiting to lunge out to grab whatever was in front of it," said study co-author Ted Daeschler, a vertebrate zoologist at the Academy of Natural Sciences in Philadelphia.

The fish's 1.5-inch-long (3.8-centimeter-long) fangs would have definitely sunk into flesh, he added.

In addition, the 375-million-year-old fish had thick, quarter-size scales; tiny eyes; a flat head; and a wide mouth—sort of like a modern-day grouper.

The fossil head "looks like a big, smiling face looking up at you," added Daeschler, who received funding for his research from the National Geographic Society's Committee for Research and