[A]中国科学院古脊椎动物与古人类研究所研究员董枝明在2002年第四期《古脊椎动物学报》上,报道了步氏克氏龙,其化石发现于北票市下府乡双庙村孙家湾组地层中,地质时代属晚白垩世早期,距今有9000万至1亿年。这次发现的步氏克氏龙化石包括有3枚牙齿的下颌骨和—些颈椎、脊椎、荐椎和部分肢骨以及破碎的甲板等。科学家认为,该甲龙为中等大小,估计体长约3米。董枝明研究员称,步氏克氏龙的发现对探讨辽宁北票地区晚中生代地层划分和时代归宿,以及对甲龙类的系统演化和地理分布均有重要意义。
步氏克氏龙为中等大小的甲龙,体长约3米,下颌骨较低,外侧无骨甲覆盖;牙齿小,齿冠上有垂直向棱嵴和边缘小齿,齿环发育不全,有愈合的颈甲板,膜质骨甲形态多样,尾后部的椎体相连成棒状,两侧有排列对称的甲板。
步氏克氏龙的发现地点为辽宁北票市下府乡双庙村孙家湾组(Wang et al.,1989) [B]英文版:The generic name is dedicated to Mr. Michael Crichton, author of the book "Jurassic Park". Dinosaurs became one of the most popular scientific subject due to this book. The specific name is dedicated to Dr. B. Bohlin, a well-known Swedish collector of vertebrate fossil including several ankylosaurs along the Silk Road, Northwestern China.
The specimens came from the Sunjiawan Formation of Beipiao Basin, Liaoning Province, northeastern China. The newly found ankylosaur fossil supports the Late Cretaceous age of this unit (Cenomanian-Turonian). The materials contain a fragment of left mandible bearing three teeth (IVPP V 12745); two cervical vertebrae, a complete dorsal (IVPP V12746); four sacral and caudal vertbrae, complete scapula, coracoid, humerus, and femur, as well as various plates and scutes of dermal armor (LPM 101). LPM is the abbreviation of the Paleontology Museum of Liaoning. Crichtonsaurus is a medium-sized ankylosaur, 3 meters in length on the basis length of vertebrae. The mandible is thin and without outer surface ornamentation. The teeth are small, and typically ankylosaurid in shape. The crown of each tooth is symmetrical with 4 or 5 marginal denticles. The cingulum is strong on the base of crown. Small ridges are found on flatter side of the crown. The centra of cervical vertebrae are short and amphicoelous. The cnetra of dorsal vertebrae are amphiplatyan, with upward-pointing diapophyses. The centra of anterior caudal vertebrae are broad and comparatively short with long transverse precesses. the scapula and coracoid are not fused together as a scapulocoracoid. Dermal plates,scutes, and spikes vary in size and form. IVPP V12745: Partial dentary w/ teeth Hypodigm APK:5/5: IVPP V12746-2 dorsal vertebra and LPM 101-1–4
postcrania, in addition to holotype specimen .下图为左下颌骨化石
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