Assertion: hoatzin's relationship | /r/HasProperty | difficult to resolve
Facets:
value: because of the misidentification of some finds
type: CAUSE
value: formerly
type: TEMPORAL
value: because of a poor fossil record
type: CAUSE
Source sentences:
text: Relationships between various tern species, and between the terns and the other Charadriiformes, were formerly difficult to resolve because of a poor fossil record and the misidentification of some finds.
text: Prior to the availability of molecular data, the relationships within this clade were difficult to resolve due to the extreme morphological diversity of its members and the scarcity of apomorphic morphological characters .