The Lauraceae is a large family comprising 58 genera with 2500–3500 species distributed in tropical and subtropical regions worldwide. Cryptocarya is one of the largest and widespread genera in Lauraceae. Many fossil records of Cryptocarya have been previously reported, but their affinity to extant genera of Lauraceae needs more research to clarify.
During their field investigation,researchers from Xishuangbanna Tropical Botanical Garden (XTBG) collected some lauraceous fossil woods from Shengli Coal Mine, located near Meizi town in Ninger County, Yunnan Province, Southwest China. After careful anatomical and morphological studies, the researchers confirmed the fossil wood as a new species in the genus Cryptocarya. They named it as Cryptocarya latiradiata to refer to the wide rays in the woods.
The fossils of Cryptocarya latiradiata show a close affinity to Cryptocarya (Lauraceae), and are most similar to C. hainanensis from South China, northern Vietnam and Laos. They show similar anatomical traits of the large genus Laurinoxylon, but have distinctly broader (up to 12-seriate) rays. They also have scalariform perforation plates, the oil/mucilage cells in rays, axial parenchyma and among fibers.
According to the researchers, the nearly coeval fossil woods of Cryptocarya latiradiata from the southern Yunnan are the second reliable pre-Quaternary macrofossil records of this genus known to date. The presence of this genus both in Yunnan and Fujian strongly suggests that in the middle Miocene, the Cryptocarya was widely ranged across southern China.
“Cryptocarya latiradiata is the first record of Lauraceae from the Dajie Formation,” said SU Tao of XTBG.
The researchers also carried out paleoclimatic reconstructions.
The data suggest that at least some extant species of Cryptocarya could survive in the middle Miocene of southern Yunnan, but that climate was too cool and dry for most species of this genus. The winter temperature (MCMT) was probably a limiting factor for them.
"Our data provide new evidence for the occurrence of termophyllous genus Cryptocarya in the middle Miocene vegetation in the region of southern Yunnan,” said a researcher.
The study entitled “Fossil woods of Cryptocarya (Lauraceae) from the middle Miocene of Southwest China” was published in Review of Palaeobotany and Palynology.
Contact
SU Tao Ph.D Principal Investigator
Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, Yunnan 666303, China
E-mail: sutao@xtbg.org.cn
Published: 22 March 2024
