Abstract Well-preserved Mesozoic terrestrial fossils were discovered in the Haifanggou Formation and the overlying Lanqi Formation (or their correlative strata) in NE China. The recent discoveries of Schmeissneria sinensis and Xingxueanthus sinensis from the middle and upper Jurassic Haifanggou Formation provide evidence that the origin of angiosperms could be predate the Early Cretaceous. In addition to the finding of pre-Cretaceous angiosperms from the Haifanggou Formation, the overlying Lanqi Formation yields a rich and varied terrestrial flora. The high diversity and abundance of the palaeoflora from these formations provide a unique window to understand floral evolution and its diversification in the Mesozoic. Two tuff samples and one andesite sample collected from the Haifanggou and Lanqi formations near Beipiao City, Liaoning, NE China yield robust 40 Ar/ 39 Ar age results. Our 40 Ar/ 39 Ar age of 166.7 ± 1.0 Ma for plagioclases from one tuff interbedded in the fossiliferous horizons of the middle Haifanggou Formation provides accurate age calibration for the pre-Cretaceous angiosperms for the first time. Moreover, our age results for these fossil-bearing formations will improve our knowledge of the Jurassic environment in general, including the link between plants and atmospheric CO 2 . Supplementary material: Details of analysis procedures, Ar isotopic data corrected for blanks, mass discrimination, radioactive decay and J values are available at: http://www.geolsoc.org.uk/SUP18575 .

Abstract Fossil clam shrimp are widely distributed in the Jurassic terrestrial sediments of China. The Yanliao Biota, consisting of abundant and diverse well-preserved fossil vertebrates and invertebrates, is one of the most famous Mesozoic terrestrial biotas from around the world. The border area between western Liaoning, northern Hebei and southeastern Inner Mongolia is the core area for the biota. Clam shrimp are abundant and widely distributed in different localities in the area. Research on these clam shrimp has been conducted for decades. However, with advances in research instruments and technologies, great changes have taken place in the taxonomy of these clam shrimp and, consequently, our understanding of the biota in recent years. The fossil content of the Yanliao Biota in the core area consists of an early assemblage and a late assemblage, which are characterized by distinctly different clam shrimp. These clam shrimp all belong to one family: Triglyptidae. Members of the family are widely distributed in the Bathonian to Kimmeridgian of northeastern, northwestern and southwestern China.