NITELLOPSIS (CHAROPHYTA) FROM THE MIOCENE OF NORTHERN THAILAND

Charophyte gyrogonites from two Miocene sites in northern Thailand are studied and compared for population variation. Morphometrical differe nces between the two populations, determined as Nitellopsis merianii a nd N. merianii globula, correspond to variation at the interpopulation level and do not justify the distinction of two separate species as m ade by previous authors. The first exhaustive synonymy for both taxa i s listed. Morphological differences can be attributed to environmental differences as reflected by distinct lithologies of the samples conce rned. The eurasian character of N. merianii is underlined through its biogeographical distribution in China The flora is in accordance with the early Middle Miocene age(16-14 My) previously published for verteb rate faunas from the same sites.