Han Zhuochen, Jia Hui, Meng Xiangning, Ferguson David K, Luo Mingyue, Liu Ping, Wang Junjie, Quan Cheng
School of Earth Sciences and Engineering Xi'an Shiyou University, Xi'an 710065, China.
Shaanxi Key Lab of Petroleum Accumulation Geology, Xi'an Shiyou University, Xi'an 710065, China.
Biology (Basel). 2022 Oct 1;11(10):1442. doi: 10.3390/biology11101442.
Both L. and the extinct Miki are aquatic plants in the family Lythraceae, with abundant fossil records in Eurasia and North America in the Cenozoic. However, documented materials are mainly based on fruit and pollen grains without reliable leaf fossils. Here, we report fossil leaves, fruit, and roots of and fruit of from the late Eocene of Weinan, the Weihe Basin of central China. The fossil leaves are identified as a new species, Z. C. Han et H. Jia sp. nov., which represents the earliest known record of a leaf fossil. It is remarkably similar to extant species of , mostly due to the unique inflated petiole structures found in both of them. While displaying prominent intergeneric differences, the incomplete fossil fruits are assigned to sp. indet. and sp. indet. The former is the earliest fossil fruit record of , and the latter represents the earliest fossil record of found in Asia. These new fossil discoveries suggest that the divergence of and occurred at least by the late Eocene. It is believed that modern most likely originated in China. Furthermore, this unexpected aquatic plant fossil assemblage indicates that central China was warm and humid, with freshwater ponds or lakes, in the late Eocene and not as arid as previously thought.
L. 和已灭绝的Miki均为千屈菜科的水生植物，在新生代的欧亚大陆和北美拥有丰富的化石记录。然而，文献资料主要基于果实和花粉粒，缺乏可靠的叶片化石。在此，我们报道了来自中国中部渭河盆地渭南晚始新世的L. 的化石叶片、果实和根以及Miki的果实。这些化石叶片被鉴定为一个新物种，Z. C. Han et H. Jia sp. nov.，这是已知最早的L. 叶片化石记录。它与现存的L. 物种极为相似，主要是因为两者都具有独特的膨大叶柄结构。尽管不完全的化石果实显示出显著的属间差异，但它们被分别归类为L. sp. indet. 和Miki sp. indet.。前者是L. 的最早化石果实记录，后者是在亚洲发现的Miki的最早化石记录。这些新的化石发现表明，L. 和Miki的分化至少在晚始新世就已发生。据信，现代L. 最有可能起源于中国。此外，这一意外的水生植物化石组合表明，中国中部在晚始新世温暖湿润，有淡水池塘或湖泊，并非如之前所认为的那样干旱。
