Cladistic Classification Neglects Paraphyly

Cladistics does not allow reference of paraphyletic assemblage as ‘groups’ because they present non-evolutionary events, and the character traits derived from the common ancestors are mere inferences and not observations. Paraphyletic groups also appear problematic in taxonomic studies as they do not precisely distinguish between phylogenetic relationships, character traits, and extinction among species. Hence paraphyletic classifications are sometimes ruled out due to the rise of the clade system of classification. 

The only negative aspect of using the cladistic approach is the disregard for evolutionary data in constructing branching patterns. Cladistic principles impose on a restrictive hypothesis, with data from synapomorphy being given importance while data from autapomorphies are discarded as non-informative.