Fossil Pinus from the Cenozoic of Thailand

A novel seed cone of Pinus from the Miocene of coastal Southeast China indicates kinship with Southeast Asian pines

“…As stated by Klaus (1980) , the southeastern Asian P. merkusii and P. latteri and eastern Asian P. thunbergii have a cone with annular bulges surrounding the umbo ( Fig. 5 B; Grote and Srisuk, 2021 : Plate III, 2). Unexpectedly, our extensive investigations suggest that P. thunbergii lacks this key character.…”

“…As discussed above, the sister species P. latteri and P. merkusii are native to mountainous areas of tropical southernmost China (Hainan, Guangxi and Guangdong) and the Indochinese Peninsula, and Sumatra, Luzon and Mindoro Islands, respectively ( Fig. 6 ; Businský, 2014 ; Grote and Srisuk, 2021 ). Surprisingly, P. merkusii has colonized a few lands just south of the equator in central Sumatra, western Indonesia ( Fig.…”

“…P. latteri is a species in tropical Mainland Southeast Asia and closely related to Sumatran pine P. merkusii and, thus, both were occasionally treated as conspecifics by some publications ( Grote and Srisuk, 2021 ). These two low-latitude species differ from the present fossil cones in more prominent apophyses with well-developed umbo fields and radial ridges ( Table 2 ; Fu et al., 1999 ; Plate III, 2 in the Grote and Srisuk, 2021 ). Overall, these aforementioned species, except P. merkusii and P. latteri , can also be discriminated from the present fossil specimen with annular bulges ( P. shengxianica sp.…”

“…and Pinus taiwanensis Hayata (subgenus Pinus subsection Pinus ), grow in Zhejiang ( Zhang and Zhang, 1986 ), while there are only three species native to Southeast Asia, i.e., Pinus kesiya Royle ex G. Gordon, and P . latteri and P. merkusii ( Grote and Srisuk, 2021 ).…”

“…Although recent schemes at the intra-subgeneric level to a great degree focus on gene sequencing data ( Zeb et al., 2020 ; Jin et al., 2021 ), these phylogenetically updated circumscriptions within the two subgenera also show a considerable number of trait variations ( Cheng et al., 1978 ; Klaus, 1980 ; Price et al., 1998 ; Gernandt et al., 2005 ), which contribute to the recognition of fossils within the extant taxonomic framework ( Fig. 1 B; Grote and Srisuk, 2021 ; Jin et al., 2021 ). The systematic taxonomy of pine fossils can provide evidence that attests to the evolutionary events of this conifer hypothesized by molecular botany.…”