Assertion: duck | /r/HasProperty | divided among several subfamilies
Facets:
value: in the family anatidae
type: OTHER
Source sentences:
text: Ducks are divided among several subfamilies in the family Anatidae; they do not represent a monophyletic group (the group of all descendants of a single common ancestral species) but a form taxon, since swans and geese are not considered ducks.