Early Cretaceous angiosperm leaves from the Dakota Formation, Hoisington III locality, Kansas, USA

[摘要] This study reports the results of an examination of about 1,500 fossil leaf impressions from the Early Cretaceous (Albian) strata at the Hoisington III locality, Kansas, USA. We recognize 24 fossil angiosperm leaf species, of which seven are assignable to the modern orders Illiciales (1), Laurales (4) and Magnoliales (2). Two species show close relationship with modern family Nymphaeaceae. Three species are possibly related to the Chloranthaceae. One species shows affinity with the Nelumbonaceae. Three species are closely related to the Platanaceae. One new genus,Wingia gen. nov., is established. A total of seven new species and new combinations are proposed. They include: Longstrethia aspera (Lesquereux) comb. nov., Sapindopsis powelliana (Lesquereux) comb. nov., Anisodromum schimperi (Lesquereux) comb. nov., Wingia expansolobum (Upchurch and Dilcher) comb. nov., Sapindopsis retallackii sp. nov., cf. Anisodromum upchurchii sp. nov., andDicotylophyllum skogii sp. nov. Comparisons with the angiosperm leaf assemblages from other localities indicate that the Hoisington locality represents the most species-rich leaf assemblage from the Dakota Formation along the east side of the Cretaceous Western Interior Seaway (KWIS) and equivalent units. The result provides new information for understanding the early diversity and evolution of the angiosperms during the mid-Cretaceous (late Albian - early Cenomanian), a critical time during which angiosperms began a rapid adaptive radiation.

[学科分类] 地质学

[关键词] Hongshan Wang;David L. Dilcher;new species;new genus;angiosperm;Dakota Formation;Early Cretaceous;Western Interior Seaway (WIS)