Structural Monophyly Analysis Allows Estimation of Self-Sustainability at the Supraspecific Level over 88 Million Years in Mosses

A new method of macroevolutionary analysis—high-resolution phylogenetics, integrating both morphological and molecular traits—has revealed well-supported evidence of complexity-based processes generating and controlling biodiversity. A novel technique of using evolutionary rates following a strict morphological clock, at least approximately, may allow detailed information on speciation and extinction events across geologic time. Branching series of minimally monophyletic genera are used to characterize in detail the branching lineage of the widely distributed moss family Streptotrichaceae. A strict morphological clock is calibrated by timing of genera new to recently exposed islands, molecular scaling against fossil taxa, and fossil evidence of the origin of the modern bryoflora. The numbers of genera generated in each 22-million-year interval are similar, while only one genus is inferred as extinct. The general outline of the phylogeny is tadpole-shaped because cumulative extinction is less than cumulative speciation, thus sustaining the family over vast time spans. Extant species per genus increase significantly over time, not through the proliferation of secondary descendants (i.e., more than four species per ancestral node), but through the selective preservation of lineages via extinction. Ancient traits are preserved throughout the lineage. It is hypothesized that descendant species are protected from coeval competition through bursts of speciation. This study supports a complexity-based explanation of the interaction of major evolutionary processes resulting in sustainability.