Punctuated equilibria remains the dominant pattern of morphospecies origin in the fossil record: an analysis using the “persistence of ancestor” criterion

• Published in: Paleobiology pp. 1 - 15
• Main Authors: Anderson, Brendan Matthew, Allmon, Warren D.
• Format: Journal Article
• Language: English
• Published: 01.08.2025
• ISSN: 0094-8373; 1938-5331
• DOI: 10.1017/pab.2025.10051

Punctuated equilibria (PE) was presented 50 years ago as an alternative to the widespread assumption that most evolution proceeds by gradual phyletic change within lineages. Unfortunately, PE has been widely misunderstood, misrepresented, and unfairly dismissed since this first publication. We argue that much of this misunderstanding centers around a misinterpretation of the meaning of “mode” in evolution, and its significance, properly understood, for how we understand macroevolutionary processes. PE proposed that most morphospecies do not show significant anagenetic trends through their stratigraphic ranges, and that most new morphospecies that are recognized arise via cladogenesis. To the degree that this is true, most exploration of disparity space must be associated with cladogenesis. We surveyed a sample of the recent paleontological literature to assess the frequency with which new morphospecies appear in the fossil record via anagenesis versus cladogenesis using a persistence of ancestor criterion and found the overwhelmingly dominant mode of species origin to be cladogenesis. This is a valuable but underutilized approach to this problem, which could be exploited with more studies of species-level phylogenies of fossil taxa. Combined with the conclusions of other studies that stasis or nondirectional change is common, this finding of the dominance of cladogenesis affirms that PE is very much alive and of substantial significance for understanding macroevolutionary patterns.