山东莒南地质公园发现小型兽脚类恐龙足迹化石MinisauripUS

Discovery of the diminutive theropod track Minisauripus from the Junan Geopark, Shandong Province, China.

在山东省莒南地质公园内发现6个小型恐龙足迹化石,被归入足迹属Minisauripus。化石产于下白垩统大盛群田家楼组,时代为早白垩世巴列姆(Barremian)—阿普特期(Aptian)。5个较大,长约6cm,产于下部"主"层面上,其中4个组成2节行迹;1个较小,长约3cm,位于"主"层面30cm之上的上部层面上。山东Minisauripus的特征是:足迹个体小(长3.1～5.6cm,宽2.0～3.7cm),三趾型,略不对称;足迹纵长,各趾近平行,趾垫较清晰;趾末端较钝,但爪迹较尖。Ⅲ趾比Ⅳ趾略长,而Ⅳ趾比Ⅱ趾略长且窄。此外,步幅较长,足长与步长之比约为10∶1。与四川、韩国的Minisauripus不同之处是:足迹个体较大,长约是它们的2倍。继中国四川和韩国之后,山东是Minisauripus在全球的第三个发现点。

Six diminutive dinosaur tracks, ascribed to the ichnogenus Miniscazripus, were discovered in the Lower Cretaceous （Baremmian-Alpin） Tianjialou Formation of the Dasheng Group in the Junan Geopark, Shandong Province, China. Of these, five are larger （-6 cm long, including claw traces） and one is smaller （-3 cm long）. The five ＂large＂ tracks, four of which form two trackway segments, occur on the lower two surfaces with Minisauripus, which we call the ＇main＇ Minisauripus level; and the ＂small＂ track occurs at a different strafigraphic level -30 cm above the lower surfaces. One of the segment consists of a right （A） and a left footprint （B）, while the other segment a left （C） and a right footprint （D）, with a pace length of -60 cm. The Shandong specimens show the following features： small, elongate and slightly asymmetrical tridactyl tracks; individual digit impressions parallel sided, and well padded with blunt distal terminations; traces of narrow claws sometimes preserved; digit Ⅲ slightly longer than digit Ⅳ, which is slightly longer and narrower than digit Ⅱ. Track length to pace length ratio is about 1,：10 for the larger tracks. The Shandong specimen is anomalous in that its five larger tracks are about twice the size of the Sichuan or Korean tracks. The discovery of Shandong Miniscazripus marks the third locality for Shandong following Sichuan and Korea worldwide.