Extended Data Fig. 2: Magnitude, direction and the number of descendents for shifts in sperm length in each phyla.

The magnitude of each of the 108 shifts (change in theta (evolutionary optima, θ) along a branch) in sperm length plotted by phyla. The number and average magnitude of positive (+) and negative (−) shifts in each phylum is summarized under the phylum name. The direction and magnitude of each shift is indicated with an arrow, and the start (circle) and end (arrowhead) locations of the arrow show the initial and ending theta value (evolutionary optima, θ) of the shift, respectively. The vertical dashed line shows the root value of theta (θ = 4.12) estimated by bayou. The size of the circle indicates the number of descendant species (species downstream of a shift). Red symbols indicate shifts in sperm length that followed an evolutionary transition to internal fertilization (for example all species downstream of these shifts were internally fertilizing species). Blue symbols indicate shifts in sperm length all species downstream were external fertilizers. Purple symbols indicate shifts in sperm length that occurred before transitions to external fertilization and where most species were spermcasters.