Editing Phylogenetic tree (section)

=== Spindle diagram ===
[[File:Spindle diagram.jpg|thumb|upright=1.35|A spindle diagram, showing the evolution of the [[vertebrate]]s at class level, width of spindles indicating number of families. Spindle diagrams are often used in [[evolutionary taxonomy]].]]
A spindle diagram, or bubble diagram, is often called a romerogram, after its popularisation by the American palaeontologist [[Alfred Romer]].<ref name="palaeos">{{cite web |url=http://palaeos.com/systematics/evolutionary/spindle_diagram.html |title=Evolutionary systematics: Spindle Diagrams |date=2014-11-10 |website=Palaeos.com |access-date=2019-11-07 }}</ref>
It represents taxonomic diversity (horizontal width) against [[Geologic time scale|geological time]] (vertical axis) in order to reflect the variation of abundance of various taxa through time.
A spindle diagram is not an evolutionary tree:<ref name="3lbmonkeybrain">{{cite web |url=https://3lbmonkeybrain.blogspot.com/2007/11/trees-bubbles-and-hooves.html |title= Trees, Bubbles, and Hooves |date=2007-11-21 |website=A Three-Pound Monkey Brain — Biology, programming, linguistics, phylogeny, systematics ... |access-date=2019-11-07 }}</ref> the taxonomic spindles obscure the actual relationships of the parent taxon to the daughter taxon<ref name="palaeos"/> and have the disadvantage of involving the [[paraphyly]] of the parental group.<ref name="Podani2019">{{Cite journal|last=Podani|first=János|date=2019-06-01|title=The Coral of Life|journal=Evolutionary Biology|language=en|volume=46|issue=2|pages=123–144|doi=10.1007/s11692-019-09474-w|issn=1934-2845|doi-access=free|bibcode=2019EvBio..46..123P |hdl=10831/46308|hdl-access=free}}</ref>
This type of diagram is no longer used in the form originally proposed.<ref name="Podani2019"/>