The Guardian notes
Almost six centuries after most of them converted to Christianity, a rabbinical court has declared that descendants of a “lost tribe” from the Spanish island of Mallorca can once more be considered Jews.
A decision by the ultra-orthodox rabbi Nissim Karelitz recognises that the Chuetas of Mallorca, who were persecuted by the Spanish Inquisition and remained a distinct group within Mallorcan society until the 1970s, had the right to call themselves Jews.
Today’s Chuetas are descendants of Jews who are considered to have been forcibly converted in the early 15th century, decades before Spain formally expelled its Jews in 1492.
More at the Guardian link above. I’m not sure ‘lost tribe’ is a very good term. It implies that the folk in question can be identified with a specific ‘Israelite tribe’ which seems not only unlikely but impossible. Jews, perhaps. Israelites? Not exactly since, strictly speaking, there were no Israelites after the destruction of the Kingdom of Israel. Now, there are Israelis (but that is not the same thing at all).