I have no idea if they are recent arrivals in Nigeria (I find it difficult to believe they are) but tontines are quite common across Africa and have been for some time. The chances of finding a rotating credit association anywhere on our planet where there are poor people are pretty good, actually.
We've always had cooperatives, we call them esusu down here. The Church getting fully into the business means that there is likely to be more honesty and better adherence.