Well-preserved Cretaceous trunk fragments of Cycadeoidea(Cycadeoidaceae)were recently found in Keshan County,Heilongjiang Province,Northeast China.These fossils represent important evidence of the distribution of this...Well-preserved Cretaceous trunk fragments of Cycadeoidea(Cycadeoidaceae)were recently found in Keshan County,Heilongjiang Province,Northeast China.These fossils represent important evidence of the distribution of this group of plants in East Asia.In these trunk fragments,the stem cortices and leaf bases with cones are preserved.The leaf bases are rhombic with cones infrequently distributed among leaf bases.The cortex is broad and consists of fundamental parenchyma cells,numerous secretory ducts and C-shaped leaf traces with adaxial secondary xylem and abaxial secondary phloem.The genus Cycadeoidea,which is widely distributed in the Cretaceous deposits of East Asia,North America and Western Europe,was an important component of Cretaceous floras.Bennettitalean trunk fossils with well-preserved anatomical structures are rarely known from China.These fossils are important for studies of the evolution of genus Cycadeoidea and for stratigraphic correlation.展开更多
基金supported by the National Natural Science Foundation of China(Grant No.31970234)the Ministry of Natural Resources,China(Grant No.12111300000018001)the Key Laboratory for the Evolution of Past Life and Environment in Northeast Asia,Ministry of Education,China(Grant No.2018JDEPw001)。
文摘Well-preserved Cretaceous trunk fragments of Cycadeoidea(Cycadeoidaceae)were recently found in Keshan County,Heilongjiang Province,Northeast China.These fossils represent important evidence of the distribution of this group of plants in East Asia.In these trunk fragments,the stem cortices and leaf bases with cones are preserved.The leaf bases are rhombic with cones infrequently distributed among leaf bases.The cortex is broad and consists of fundamental parenchyma cells,numerous secretory ducts and C-shaped leaf traces with adaxial secondary xylem and abaxial secondary phloem.The genus Cycadeoidea,which is widely distributed in the Cretaceous deposits of East Asia,North America and Western Europe,was an important component of Cretaceous floras.Bennettitalean trunk fossils with well-preserved anatomical structures are rarely known from China.These fossils are important for studies of the evolution of genus Cycadeoidea and for stratigraphic correlation.
