贵阳花溪早三叠世遗迹化石及其对二叠纪末生物大绝灭事件后生物复苏的启示?

报道了贵阳花溪下三叠统大冶组中14种遗迹属，它们包括Beaconichnus、Cosmorhaphe、Dendrorhaphe、Gyrochorte、Gordia、Micatuba、Mammillichnis、Megagrapton、Planolites、Palaeophycus、Phycodes、Phycosiphon、Rhizocorallium和Undichna。遗迹化石产出特征为以水平潜穴为主、浅的阶层分布（<4mm）、以觅食迹为主的遗迹组合和小型化的Planolites，这些特征表明经历了P-T事件之后，华南早三叠世浅海生态环境仍处于缺氧异常环境，这种环境直到早三叠世晚期才趋于正常。大冶组遗迹化石发展模式体现出海洋环境群落生态演替特征，造迹生物由早期单一多毛类蠕虫向物种丰富的多毛类发展，再到以甲壳纲动物在沉积物中开辟更大的生态空间和定居。这种绝灭后软躯体动物在崩溃生态系中的发展模式与贵州晚泥盆世弗拉期-法门期之交绝灭界线之上遗迹化石所表现的软躯体动物的演化特征相似。向三度空间开拓发展的复杂遗迹Rhizocorallium，Thalassinoides在绝灭前后世界范围内的分布表明，高纬度区软躯体动物的复苏比低纬度区要快。

Early Triassic trace fossils in Huaxi Region of Guiyang and their implications for biotic recovery after the end-Permian mass extinction

Fourteen ichnogenera are reported in the Daye Formation of Early Triassic from Huaxi of Guiyang,Guizhou Province of South China.They include Beaconichnus,Cosmorhaphe,Dendrorhaphe, Gyrochorte,Gordia,Micatuba,Mammillichnis,Megagrapton,Planolites,Palaeophycus,Phycodes, Phycosiphon,Rhizocorallium and Undichna,and are characterized by the fodinichnia-dominant trace fossil assemblage,distribution of paralleling bed surface,shallow tiring and minimized Planolites.The features indicate that the shallow marine environment of South China in the Early Triassic was still anoxic.Such conditions did not change until the late Early Triassic.The presence of trace fossils from Member 1 to Member 3 in the Daye Formation embodies the ecological succession of a marine ecosystem.Trace makers develop their diversity from the previously single polychaeta in Member 1 to the diversified polychaeta until the appearance of crustacean represented by Rhizocorallium-maker on the top of Member 3 of the Daye For- mation.The developing model of soft-bodied organisms herein during the recovery interval after the end- Permian mass extinction is similar to that represented by the trace fossils during the recovery interval after the Devonian Frasnian-Famennian extinction in Dushan of Guizhou.A comparison of the appearance prob- abilities of complex trace fossils such as Rhizocorallium and Thalassinoides before and after the end-Permi- an mass extinction globally reveals that the soft-bodied organisms experienced a longer protracted biotic re- covery in the lower latitude regions than that in the higher ones.