Actually, this is more difficult to answer. For example, after the Tang dynasty, it experienced troubled times-five Hu sixteen countries, five dynasties and ten dynasties. For example, when the Southern Tang Dynasty was founded, "Tang" was taken as the country name, and Wang Ke was regarded as the ancestor.

Li Ke (6 19-653), the third son of Li Shimin and the daughter of Yang Di.

In the third year after Qi Tang Prince Li Zhi ascended the throne, Sun Chang Wuji found a reason to destroy Li Ke. His descendants Li Ren (Li), Li Kun and Li Kun were all exiled.

Therefore, from this perspective, it is hard to say whether the Tang direct line is still there, because there is no textual research. Some famous family tributaries may be destroyed.

Then, after Tang Jianguo at that time, names were given one by one. Causing the Li family to be huge. It's hard to be surnamed Li who has really passed down to this day. Real nobles are basically anonymous in order to preserve their blood after national subjugation.

So I can only give you this non-answer.