Dromaeosaurs were small to medium-sized dinosaurs, ranging from about 0.7 meters in length (2.3 ft, in the case of "Mahakala") to over 6m (20 ft, in "Utahraptor" and "Achillobator"). Some were larger; undescribed specimens of "Utahraptor" in BYU collections may have been up to long. Large size appears to have evolved at least twice among dromaeosaurs. A possible third lineage of giant dromaeosaurs is represented by isolated teeth found on the Isle of Wight, England. The teeth belong to a "Utahraptor"-sized animal but are more similar in shape to the teeth of velociraptorines.