Which entries are these?
it is somewhat a matter of interpretation, but for normal people, i expect those quotes would suggest specialist roles:
http://ufoai.ninex.info/wiki/index.php/Aliens/Ortnok"Ortnoks do not seem to serve in many specialist capacities; they are never used as technicians according to our camera observations, and usually busy themselves handling perimeter security for the Tamans when not engaged in combat."
well, this one does not say they do have specialist roles, it just says they don't, which is, technically, correct.
as we know very little about aliens, this kind of assumption might be treated the same way as 'bug becomes a feature'.
http://ufoai.ninex.info/wiki/index.php/Aliens/Taman"Besides serving as soldiers, they fill many specialist roles in the alien war machine, positions in which Tamans seem to be the most numerous."
this one could be interpreted in the context of being able to wield more complicated weapons, and therefore tamans could fill specialist roles in tactical combat.
but in the ortnoks description there is text about specialist roles in the sense of technicians.
could be misleading, and end up in disaster for the player, and devs might get sued maybe and that could be annoying even if there is a technically correct interpretation.
heh, one more, this time it also includes a suggestion about hierarchy, however nebulous.
so, every single organic alien description includes something about specialist roles.
http://ufoai.ninex.info/wiki/index.php/Aliens/Shevaar"The Shevaar seem to be located between Tamans and Ortnoks in the nebulous alien hierarchy, in that they sometimes fill specialist or command roles, unlike Ortnoks, but these tasks are still usually taken by Tamans whenever the two races are deployed together."