DILCHER, D. L.1*, GE SUN2, K. C. NIXON3, and QIANG JI4. 1Florida Museum of Natural History, University of Florida, Gainesville, FL 32611, USA; 2Research Center of Palaeontology, Jilin University, Changchun 130026, China; 3L. H. Bailey Hortorium, Cornell University, Ithaca, NY 14853, USA; 4Geological Institute of Chinese Academy of Geosciences, Beijing 100037, China. - A new basal angiosperm family.
Archaefructaceae has been proposed as a monotypic family including two
species, Archaefructus liaoningensis , and A. sinensis
sp. nov. These fossils are known to occur in the latest
Jurassic-Lower Cretaceous sediments in Liaoning Province, China.
Nearly whole plants have been found of A. sinensis and more
complete remains are now known for A. liaoningensis . All
organs of the plants of A. sinensis are similar to the
leaves, stems, stamens, and fruits in A. liaoningensis . The
paired stamens on short stalks appear to be unique to angiosperms. The
lax nature of the stems, the dissected leaves and closely associated
fish suggest that both species of Archaefructus were aquatic
plants. The plants bear stamens and carpels on the same axis and the
stamens appear to mature before the carpels. Numerous morphological
characters of these fossils have been integrated within a
morphological matrix of living angiosperms for which molecular
characters are also known. When the combined molecular-morphological
characters are plotted on a cladogram, the Archaefructaceae appears to
be among the basal angiosperms.
Key words: Archaefructus liaoningensis , Archaefructus sinensis China, Angiosperm, Archaefructaceae, Yixian Formation