Polyphyly

[1] The term is often applied to groups that share similar features known as homoplasies, which are explained as a result of convergent evolution.

[6] In recent research, the concepts of monophyly, paraphyly, and polyphyly have been used in deducing key genes for barcoding of diverse groups of species.

[7] The term polyphyly, or polyphyletic, derives from the two Ancient Greek words πολύς (polús) 'many, a lot of', and φῦλον (phûlon) 'genus, species',[8][9] and refers to the fact that a polyphyletic group includes organisms (e.g., genera, species) arising from multiple ancestral sources.

By comparison, the term paraphyly, or paraphyletic, uses the ancient Greek preposition παρά (pará) 'beside, near',[8][9] and refers to the situation in which one or several monophyletic subgroups are left apart from all other descendants of a unique common ancestor.

[10] Species have a special status in systematics as being an observable feature of nature itself and as the basic unit of classification.

In this phylogenetic tree , the blue and red groups (which are both monophyletic ) do not share an immediate common ancestor. If they are grouped together because they share characteristics which appear to be similar, then their combination forms a polyphyletic group .
Cladogram of the primates , showing a monophyly (the simians, in yellow), a paraphyly (the prosimians, in cyan, including the red patch), and a polyphyly (the night-active primates, the lorises and the tarsiers , in red).
Phylogenetic groups: A monophyletic taxon (in yellow, the clade Sauropsida grouping "reptiles and birds") contains a common ancestor and all of its descendants. A paraphyletic taxon (in cyan, the "reptiles") contains its most recent common ancestor, but does not contain all the descendants of that ancestor. A polyphyletic taxon (in red, the group Haemothermia containing warm-blooded tetrapods ) does not contain the most recent common ancestor of all its members.