中国科学院南京地质古生物研究所机构知识库

As an important component of the Mesozoic flora, the extinct fern genus Eboracia Thomas (Dicksoniaceae, Filicales) is widely
reported in China with diverse fossil records. New material of Eboracia lobifolia, represented by a nearly intactly preserved fossil frond,
is described herein from the Middle Jurassic Haifanggou Formation in Beipiao of western Liaoning, Northeast China. The frond is
lanceolate in gross outline, at least 38.0 cm long, and can be divided into the basal sterile part, the upper fertile part and a transitional
part in between. The new discovery confirms for the first time that the frond of E. lobifolia is hemidimorphic rather than holodimorphic.
Many in-situ spores were detached from the sori of the fertile pinnae, which are characterized by rounded-tetrahedral shape, smooth
surface, distinct border, and a wide, long triradiate crack almost reaching the equator. Comparing with dispersed spores in the same
horizon, these in-situ spores seem to be most similar to Cyathidites minor Couper in morphology. A spatio-temporal analysis of Eboracia
in China shows that Eboracia with totally four species occurred in a time interval ranging from the Late Triassic to the Early Cretaceous
in China, and mostly flourished in the Middle Jurassic; the genus was widely distributed in both the Northern and Southern Phytofloristic
Provinces of China, particularly in southern China during the Late Triassic to Early Jurassic, while more abundant and diverse in
northern China during the Middle Jurassic to Early Cretaceous.