did i miss something or are the alternian trolls the biological ancestors?

so ive seen people debate which trolls ectobiologically make which others, and ive always seen beforus->alternian. however, alternia is post scratch, and in the kids post scratch, the roles of the ancestors and descendants switched, same as what happed in the troll sessions according to DoC SCRATCH,. so shouldnt the original, pre-scratch version be alternian-> beforan?