Data from: The dentary of Wareolestes rex (Megazostrodontidae): a new specimen from Scotland and implications for morganucodontan tooth replacement

The Middle Jurassic morganucodontan, Wareolestes rex, was previously known from only four isolated molars from Kirtlington, England. There has been debate over the position of the holotype tooth as an upper or lower molar. We describe a new Wareolestes specimen from the Kilmaluag Formation of Scotland: a partial left dentary with two erupted molars, one unerupted molar and three unerupted premolars. Empty alveoli for a canine, p1 and p3 are also present. Through detailed comparison of the morphology of the holotype and our new material, we support the original diagnosis of the holotype Wareolestes as a lower molar, most likely m1. The position of erupted and unerupted replacement teeth in the newly discovered specimen supports a diphyodont pattern of tooth replacement of premolariform dentition in Wareolestes, as suggested for other morganucodontans such as Morganucodon, Megazostrodon and Dinnetherium. However, damage to the dentary means that questions remain regarding the sequence of replacement in Wareolestes along the tooth row.雷克斯沃勒兽（Wareolestes rex）是一类中侏罗世的摩根齿兽类（morganucodontan），此前仅依据英国柯廷顿（Kirtlington）出土的4枚孤立臼齿被认知。学界此前对其正模标本牙齿属于上臼齿还是下臼齿一直存在争议。本次研究报道了一件产自苏格兰基尔马卢格组（Kilmaluag Formation）的沃勒兽新标本：一件局部保存的左侧齿骨（dentary），带有2枚已萌出臼齿、1枚未萌出臼齿与3枚未萌出前臼齿，同时还保留有犬齿、p1及p3的空齿槽。通过对正模标本与本次新发现标本的形态学详细对比，我们支持将正模标本判定为下臼齿（极大概率为m1）的原始诊断结论。新标本中已萌出与未萌出替换齿的位置分布，佐证了沃勒兽前臼齿型齿列具备双替换齿型（diphyodont）的牙齿替换模式，这一结论与摩根齿兽类其他类群（如摩根齿兽Morganucodon、巨扎斯特罗兽Megazostrodon及迪内特兽Dinnetherium）的相关研究推测相符。但由于该齿骨存在破损，学界关于沃勒兽沿齿列的牙齿替换序列仍存有诸多疑问。