The lands of the Cannanites are described in parashat Noach 10:19:
And the border of the Canaanites was from Sidon as you come to Gerar, until Gaza, as you come to Sodom and Gomorrah, and Admah and Zeboiim, until Lasha.
וַיְהִי גְּבוּל הַכְּנַעֲנִי מִצִּידֹן בֹּאֲכָה גְרָרָה עַד עַזָּה בֹּאֲכָה סְדֹמָה וַעֲמֹרָה וְאַדְמָה וּצְבוֹיִם עַד לָשַׁע׃
Four of the last 5 places are the cities that were destroyed in the Sodom incident. I would expect that when those four cities are named, the fifth city (Tzoar or Bela) would also be named.
If Lasha is the same as Tzoar/Bela , why the name change? Is there anything else I should know about Lasha?