Sprecher
Beschreibung
Cathaya, the sister taxon to Pinus, is one of the most endangered plants endemic to China. The single extant species, C. argyrophylla, survives only on open slopes and ridges in the subtropical mountainous regions of southwestern China. Although Cathaya macrofossils have been reported from several sites across the Northern Hemisphere, they have not been recorded previously from China. Here, we document several well-preserved ovuliferous Cathaya cones from the Upper Miocene Shengxian Formation of Zhejiang Province, eastern China. The ovoid to ellipsoid seed cones possess helically arranged, suborbicular or ovate ovuliferous scales, and concealed subtending triangular-caudate bracts with a tapering apex. Detailed comparisons with extant and fossil species of Cathaya favour assignment of the new fossils to Cathaya sp. cf. C. argyrophylla Chun et Kuang. This discovery shows that Cathaya had a much wider distribution during the Late Miocene than at present, including its establishment in eastern Asia by that time. Moreover, the occurrence of this taxon indicates a warm and humid subtropical climate in eastern Zhejiang during the Late Miocene, which is consistent with previous interpretations based on other plant fossils. The striking decrease in diversity and geographic contraction of Cathaya through the late Cenozoic probably resulted from: (1) regional climatic deterioration; (2) low seed production, germination rates and seeding survival rates; and (3) elevated competition from angiosperms and other gymnosperms.