ἐξ ὀνύχων λέοντα τεκμαίρεσθαι → judge by the claws, judge by a slight but characteristic mark, small traits give the clue to the character of a person, deduce something from a small indication, identify a lion from its claws
Spießchen, hastula (kleine Lanze). – veruculum (kleiner Bratspieß, auch als Zeichen der Kritik).