The Celtici were an ancient celtic tribe akin to the Lusitanians and Calaicians or Gallaeci, living in what today is the province of Alentejo in modern Portugal. This article is about the European people. ... The Lusitanians were a tribe, or various tribes, from the western Iberian peninsula, who spoke a Lusitanian language until the conquest of their territory by the Romans. ... Gallaecia or Callaecia was the name of a Roman province that comprised a territory in the north-west of Hispania (approximately the current Galicia of Spain and the north of Portugal). ... Alentejo is a south-central region of Portugal. ...
Turduli movement in red, Celtici in brown and Lusitanian in blue.
The Celtici (Latin for "Celts") were an ancient Celtic tribe of Lusitania, akin to the Lusitanians and Gallaecians, living in what today are the provinces of Alentejo and the Algarve in Portugal, though some migrated north alongside the Turduli.
Their presence was the result of a third or even fourth wave of migrations of Celts (or other speakers of Indo-European languages) into the Iberian peninsula (which the Romans called Hispania).
As to the fact that the Celtici were not Proto-Celts, ok, we all agree, but maybe calling them "True Celts" is a bit old fashioned...
But I probably would have added the tag even without that, just because there seems to be a certain fashion for claiming Celtic tribes all over the map of Europe, without actually verifying that (1) the tribe actually existed or (2) the tribe is verifiably Celtic.
And even for the Celtici, if there isn't linguistic or at least archaeological evidence that they were Celtic, we shouldn't boldly claim that they were just because of their name.