Abstract: A new species of Leptarctus is described on the basis of a well— preserved skull from the North American Miocene. Leptarctus is only known from the Miocene of Nei Mongol (Inner Mongolia) and North America. The new specimen differs from other species in having an unusually enlarged upper dentition and a hooked process on the tympanic bullae. The third upper incisors are caniniform and are curved toward the canine. The dental characters of this new species indicate it had omnivorous diet.

摘要： 记述了采自美国内布拉斯加州中新统的一保存较完整的美獾(Leptarctus)头骨化石。与美灌属的其他已知种相比，该标本的颊齿粗壮，P4臼齿化，近方形，宽略大于长，齿尖磨蚀均匀，I3犬齿化，且向犬齿方向弯曲;M1宽略大于长，且比已知种的M1大;听泡具钩状突，突起上有一明显的舌骨关节面。依据上述与已知种的差别，我们将其定为一新种Leptarctus martini sp. nov.。新种的牙齿形态及齿尖磨蚀状况显示其为杂食动物。