从其分布区类型和形态特征上推断本种为残遗种，起源地可能就在劳亚古陆的南部，当今它的分布区这一范围内。
Based on the distributional and morphological characters , the auther supposes that the origin of this species is located in the south area of Laurasia and become a survivor up to now .
劳亚古陆