论文部分内容阅读
描述了戈壁锥齿兽科 (Gobiconodontidae)一个新的属种———陆家屯弥曼齿兽 (Meeman nodonlujiatunensisgen .etsp .nov.)。标本产于辽宁西部朝阳市上园镇陆家屯下白垩统义县组一段的凝灰质砂岩层中 ,为一具完整齿列的左下颌骨。新属与戈壁锥齿兽 (Gobiconodon)共有以下区别于其他三尖齿兽类的特征 :2颗下门齿 ,i1增大 ,后部门齿、犬齿和前部前臼齿尖锥形 ,前臼齿具有高的中央尖和小的附尖 ,i～p1向前平伏。因此 ,新属被归入戈壁锥齿兽科。弥曼齿兽与戈壁锥齿兽及其相近属的区别在于 :下门齿和下犬齿更加平伏 ,i1在比例上更大 ,而i2则更小 ;最后一枚下前臼齿与第一枚下臼齿之间没有齿隙 ;前臼齿退化 ;下臼齿长度大于高度 ,主尖向后倾斜 ,与b尖和c尖相比 ,a尖较低 ,m1显著小于m2～ 4。新属下臼齿没有齿带 ,与爬兽 (Repenomamus)相似 ,而与戈壁锥齿兽不同。基于与爬兽齿列的对比 ,讨论了戈壁锥齿兽类的齿式 ,认为其应具有两颗门齿 ,而不是以前认为的 1颗门齿 ,从而将戈壁锥齿兽类下齿列齿式修订为 :2·1·2～ 3·5。
Describes a new genus of the genus Gobiconodontidae, Meeman nodonlujiatunensisgen. Etap. Nov. Specimens were found in the tuffaceous sandstone of the first member of the Lower Cretaceous Yixian Formation in Lujiatun, Shangyuan Town, Chaoyang City, western Liaoning Province, and are a complete mandibular left mandible. The new genus shares the following characteristics with the Gobiconodon in distinguishing the other three-toothed beasts from the two other lower incisors: i1 increases, the posterior incisors, canines, and anterior premolar teeth taper, and the premolar teeth high The central tip and the small tip, i ~ p1 forward flat volts. Therefore, the new genus is classified as a Gobi conic tooth beast. Miman tooth beast and Gobi cone beast and its adjacent genus difference is that: lower incisors and lower canines more equidistant, i1 in a larger proportion, and i2 is smaller; the last lower premolar and the first lower molars There was no backlash between the teeth and the premolar teeth. The length of the lower molar was larger than the height, and the main tip was tilted backward. Compared with the b and c, the a tip was lower and the m1 was significantly smaller than m2 ~ 4. The new lower molar does not have a toothed belt, similar to Repenomamus, but unlike Gobi Conger. Based on a comparison with the dentition of the creeping beasts, the discussion of the geogrids of the Gobi tapering beasts, which are supposed to have two incisors rather than the previously considered one incisor, Is: 2.1-2-3.5.