中亚与亚洲中部晚白垩世的陆生脊椎动物组合对比

CORRELATION OF LATE CRETACEOUS CONTINENTAL VERTEBRATE ASSEMBLAGES IN MIDDLE AND CENTRAL ASIA

通过对前人建议的26个生物地层标志化石存在与否的简约分析,中亚与亚洲中部晚白垩世的陆生脊椎动物组合的相对层位得到了更清楚的揭示。此区最古老的组合是乌兹别克斯坦克孜勒库姆沙漠的Khodzhakul组合(早塞诺曼期),其次为蒙古戈壁沙漠东部BaynShire组的下部和上部的组合(塞诺曼期至桑顿期)。中国内蒙古二连达布苏动物群与中亚的土伦期—桑顿期动物群属于同一类群,因为它们均具龟鳖类Khunnuchelys,前者时代可能为桑顿期。三个中亚的组合(Bissekty、Yalovach和Bostobe组合)中有两个地方性的鳄形类(Kansajsuchus和Tadzhikosuchus)和一个出现于戈壁沙漠的鳄形类(Shamosuchus)化石。戈壁沙漠的坎潘期至马斯特里赫特期组合与北美同期动物群为同一类群。Djadokhta组与BarunGoyot组的坎潘期脊椎动物组合具有高度的地方性,并反应了半干旱的古环境。产自Nemegt组的组合生存于比较潮湿的环境。在组成上,这一组合与其他河流相沉积环境(Bissekty、二连达布苏以及北美Judithian期和Lancian期的组合)相似。具顶饰的鸭嘴龙Saurolophus的存在,支持了Nemegt组合为马斯特里赫特期时代。戈壁沙漠的这三个组合(Djadokhta、Barun Goyot和Nemegt组合)被归为一类,因为它们共同拥有地方性的龟类Mongolemys和兽脚亚目的小驰龙类。亚洲中部和北美的坎潘期至马斯特里赫特期组合与亚洲更加古老的组合不同在于存有暴龙科、肿头龙亚目和鸭嘴龙科。在中亚,由于地区性的海侵,这一时间段内的陆生脊椎动物组合多不清楚。

The relative stratigraphic positions of the better-known assemblages of Late Cretaceous continental vertebrates from Middle and Central Asia are assessed by parsimony analysis of the presence/absence of 26 proposed bio- stratigraphic marker taxa. The oldest assemblage in the region is Khodzhakul from the Kyzylkum Desert of Uzbekistan （early Cenomanian）. The next stage includes assemblages from the lower and upper parts of the Bayn Shire Formation of the eastern Gobi Desert, Mongolia （Cenomanian to Santonian）. The Iren Dabasu fauna from Inner Mongolia, China, clusters with the Turonian-Santonian faunas from Middle Asia based on the shared presence of the trionychid turtle Khunnuchelys and is likely Santonian in age. Three Middle Asian assemblages （Bissekty, Yalovach, and Bostobe） are endemic in the presence of two crocodyliform taxa （Kansajsuchus and Tadzhikosuchus） but share another crocodyliform （Shamosuchus） with the Gobi assemblages. The Campanian-Maastrichtian assemblages from the Gobi Desert cluster with coeval North American faunas. The Campanian vertebrate assemblages from the Djadokhta and Barun Goyot for- mations are highly endemic, reflecting semi-arid paleoenvironments. The assemblage from the Nemegt Formation, which existed under more mesic conditions, is similar in composition to those from other fluvial depositional environ- ments （Bissekty, Iren Dabasu, and North American Judithian and Lancian assemblages）. The presence of the crested hadrosaurine Saurolophus supports a Maastrichtian age for the Nemegt assemblage. Three Gobi assemblages （Djadokhta, Barun Goyot, and Nemegt） are grouped together based on the shared presence of the endemic turtle Mongolemys and parvicursorine theropods. The Campanian to Maastrichtian assemblages of Central Asia and North America differ from the older assemblages in Asia in the presence of derived Tyrannosauridae, Pachycephalosauria, and Hadrosauridae. In Middle Asia, continental vertebrate assemblages from this time interval remain largely unknown due to regional marine transgressions.