The quinarian system was a method of zoological classification which was popular in the mid 19th century, especially among British naturalists. It was largely developed by the entomologist

William Sharp Macleay William Sharp Macleay or McLeay (21 July 1792 – 26 January 1865) was a British civil servant and entomologist. He was a prominent promoter of the Quinarian system of classification. After graduating, he worked for the British embassy in Par ...

in 1819. The system was further promoted in the works of Nicholas Aylward Vigors, William John Swainson and Johann Jakob Kaup. Swainson's work on

ornithology Ornithology is a branch of zoology that concerns the "methodological study and consequent knowledge of birds with all that relates to them." Several aspects of ornithology differ from related disciplines, due partly to the high visibility and th ...

gave wide publicity to the idea. The system had opponents even before the publication of

Charles Darwin Charles Robert Darwin ( ; 12 February 1809 – 19 April 1882) was an English naturalist, geologist, and biologist, widely known for his contributions to evolutionary biology. His proposition that all species of life have descended ...

's ''

On the Origin of Species ''On the Origin of Species'' (or, more completely, ''On the Origin of Species by Means of Natural Selection, or the Preservation of Favoured Races in the Struggle for Life''),The book's full original title was ''On the Origin of Species by Me ...

'' (1859), which paved the way for

evolution Evolution is change in the heritable characteristics of biological populations over successive generations. These characteristics are the expressions of genes, which are passed on from parent to offspring during reproduction. Variation ...

ary trees.

Classification approach

Quinarianism gets its name from the emphasis on the number five: it proposed that all taxa are divisible into five subgroups, and if fewer than five subgroups were known, quinarians believed that a missing subgroup remained to be found. Presumably this arose as a chance observation of some accidental analogies between different groups, but it was erected into a guiding principle by the quinarians. It became increasingly elaborate, proposing that each group of five classes could be arranged in a circle, with those closer together having greater affinities. Typically they were depicted with relatively advanced groups at the top, and supposedly degenerate forms towards the bottom. Each circle could touch or overlap with adjacent circles; the equivalent overlapping of actual groups in nature was called osculation. Another aspect of the system was the identification of ''analogies'' across groups: Quinarianism was not widely popular outside the United Kingdom (some followers like William Hincks persisted in Canada); it became unfashionable by the 1840s, during which time more complex "maps" were made by

Hugh Edwin Strickland Hugh Edwin Strickland (2 March 1811 – 14 September 1853) was an English geologist, ornithologist, naturalist and systematist. Through the British Association, he proposed a series of rules for the nomenclature of organisms in zoology, known as ...

and Alfred Russel Wallace. Strickland and others specifically rejected the use of relations of "analogy" in constructing natural classifications. These systems were eventually discarded in favour of principles of genuinely natural classification, namely based on

ary relationship.

References

{{reflist, 28em History of biology Biological classification Obsolete biology theories