hey.. apparently they are Basque fairies...
here, this is all i could find:
www.pantheon.org/articles/l/laminak.html

as i say, my wife mother is also a lamina..... ;)

agur bero bat iparraldetik

I remember going to a forest in Guipuzkoa where they had a film of a 'Lamina' explaining why her kind were dying and going away since the industrialization and disregard of the basoa.

They are very much like faeries- but not as much as the little winged Victorian era ones- more like the Fae of irish myth. There are stories about men marrying Lamina, children born with half blood of a lamina...

They are beautiful women, whose feet are often those of a horse or a bird, and they hide their feet because of this. They comb their hair and sit by streams (they are always connected to water)- often with bridges.

They will often give you rewards if you can guess their age accurately. They show obeisance to Mari and her court, and are also tied to her sons, Atarrabi and Mikelats, and to Gaueko.

Some say they're tied to snakes as well, being female versions of the snake spirits- the males being dragons and spirits like Maju and Sugaar (who are often considered the same), or being at the very least the daughters of such spirits.

Basque mythology is very intriguing~