むねしろてんじゃなかったです
胸白貂じゃなかったです
muneshirotenjanakattadesu

Noun
Desu Copula

The polite, past negative form of むなじろてん

1. Was not a beech marten.; Was not a white-chested marten.

Past/Perfective
Negative
Polite
Casual Register
Usually Written in Kana