A phylogenetic tree: both blue and red groups are monophyletic. The green group is paraphyletic: it is missing a monophyletic subgroup – the blue group – that shares a common ancestor with itself (that being the vertical stem at the root of the green group). In this form, monophyletic means "no sideways stems leaving the group".
A cladogram of the primates, showing a monophyletic taxon: the simians (in yellow); a paraphyletic taxon: the prosimians (in cyan, including the red patch); and a polyphyletic group: the night-active primates, i.e., the lorises and the tarsiers (in red).
A cladogram of the vertebrates showing phylogenetic groups. A monophyletic taxon (in yellow): the group of "reptiles and birds", contains its most recent common ancestor and all descendants of that ancestor. A paraphyletic taxon (in cyan): the group of reptiles, contains its most recent common ancestor, but does not contain all the descendants (namely Aves) of that ancestor. A polyphyletic "group" (in red): the group of all warm-blooded amniotes (Aves and Mammalia), does not contain the most recent common ancestor of all its members; this group is not seen as a taxonomic unit and is not considered a taxon by modern systematists.

In biological cladistics for the classification of organisms, monophyly is the condition of a taxonomic grouping being a clade – that is, a grouping of taxa which meets these criteria:

  1. the grouping contains its own most recent common ancestor (or more precisely an ancestral population), i.e. excludes non-descendants of that common ancestor
  2. the grouping contains all the descendants of that common ancestor, without exception

Monophyly is contrasted with paraphyly and polyphyly as shown in the second diagram. A paraphyletic grouping meets 1. but not 2., thus consisting of the descendants of a common ancestor excepting one or more monophyletic subgroups. A polyphyletic grouping meets neither criterion, and instead serves to characterize convergent relationships of biological features rather than genetic relationships – for example, night-active primates, fruit trees, or aquatic insects. As such, these characteristic features of a polyphyletic grouping are not inherited from a common ancestor, but evolved independently.

Monophyletic groups are typically characterised by shared derived characteristics (synapomorphies), which distinguish organisms in the clade from other organisms. An equivalent term is holophyly.[1]

The word "mono-phyly" means "one-tribe" in Greek.

These definitions have taken some time to be accepted. When the cladistics school of thought became mainstream in the 1960s, several alternative definitions were in use. Indeed, taxonomists sometimes used terms without defining them, leading to confusion in the early literature,[2] a confusion which persists.[3]

The first diagram shows a phylogenetic tree with two monophyletic groups. The several groups and subgroups are particularly situated as branches of the tree to indicate ordered lineal relationships between all the organisms shown. Further, any group may (or may not) be considered a taxon by modern systematics, depending upon the selection of its members in relation to their common ancestor(s); see second and third diagrams.


The term monophyly, or monophyletic, derives from the two Ancient Greek words μόνος (mónos), meaning "alone, only, unique", and φῦλον (phûlon), meaning "genus, species",[4][5] and refers to the fact that a monophyletic group includes organisms (e.g., genera, species) consisting of all the descendants of a unique common ancestor.

Conversely, the term polyphyly, or polyphyletic, builds on the ancient Greek prefix πολύς (polús), meaning "many, a lot of",[4][5] and refers to the fact that a polyphyletic group includes organisms arising from multiple ancestral sources.

By comparison, the term paraphyly, or paraphyletic, uses the ancient Greek prefix παρά (pará), meaning "beside, near",[4][5] and refers to the situation in which one or several monophyletic subgroups are left apart from all other descendants of a unique common ancestor. That is, a paraphyletic group is nearly monophyletic, hence the prefix pará.


On the broadest scale, definitions fall into two groups.

The concepts of monophyly, paraphyly, and polyphyly have been used in deducing key genes for barcoding of diverse group of species.[12]

See also


  1. ^ Allaby, Michael (2015). A Dictionary of Ecology (5 ed.). Oxford: Oxford University Press. ISBN 9780191793158.
  2. ^ a b Hennig, Willi (1999) [1966]. Phylogenetic Systematics. Translated by Davis, D.; Zangerl, R. (Illinois Reissue ed.). Board of Trustees of the University of Illinois. pp. 72–77. ISBN 978-0-252-06814-0.
  3. ^ a b Aubert, D. 2015. A formal analysis of phylogenetic terminology: Towards a reconsideration of the current paradigm in systematics. Phytoneuron 2015-66:1–54.
  4. ^ a b c Bailly, Anatole (1 January 1981). Abrégé du dictionnaire grec français. Paris: Hachette. ISBN 978-2010035289. OCLC 461974285.
  5. ^ a b c Bailly, Anatole. "Greek-french dictionary online". www.tabularium.be. Retrieved 7 March 2018.
  6. ^ Colless, Donald H. (March 1972). "Monophyly". Systematic Zoology. 21 (1): 126–128. doi:10.2307/2412266. JSTOR 2412266.
  7. ^ Envall, Mats (2008). "On the difference between mono-, holo-, and paraphyletic groups: a consistent distinction of process and pattern". Biological Journal of the Linnean Society. 94: 217–220. doi:10.1111/j.1095-8312.2008.00984.x.
  8. ^ Ashlock, Peter D. (March 1971). "Monophyly and Associated Terms". Systematic Zoology. 20 (1): 63–69. doi:10.2307/2412223. JSTOR 2412223.
  9. ^ a b Simpson, George (1961). Principles of Animal Taxonomy. New York: Columbia University Press. ISBN 978-0-231-02427-3.
  10. ^ Carr, Steven M. "Monophyletic, Polyphyletic, & Paraphyletc Taxa". www.mun.ca. Retrieved 23 February 2018.
  11. ^ Stamos, D.N. (2003). The species problem : biological species, ontology, and the metaphysics of biology. Lanham, Md. [u.a.]: Lexington Books. pp. 261–268. ISBN 978-0739105030.
  12. ^ Parhi J., Tripathy P.S., Priyadarshi, H., Mandal S.C., Pandey P.K. (2019). "Diagnosis of mitogenome for robust phylogeny: A case of Cypriniformes fish group". Gene. 713: 143967. doi:10.1016/j.gene.2019.143967. PMID 31279710. S2CID 195828782.((cite journal)): CS1 maint: multiple names: authors list (link)