GC content of microsatellite repeats found in the studied Cnidarian species (panel A and B). PGS species include Leiopathes (n =628count/Mbp), Tanacetipathes (n =364), Eunicea (n =85), Plumarella (n =308), Corynactis (n =106), Amplexidiscus (n =103), Metridium (n =532), Millepora (n =117). Analysis of variance testing for differences in GC content among microsatellite repeat types in PGS was non-significant (p = 0.06). WGS species include Nematostella (n =1042), Hydra (n =1666), A. digitifera (n =1210). Analysis of variance testing for a difference in GC content among microsatellite repeats types in WGS was non-significant (p =0.10). The lowest boundary of the box indicates the 25th percentile, the upper boundary indicates the 75th percentile. Lines within the box indicate the mean (dashed line) and the median (solid line). Whiskers indicate the 10th and 90th percentiles; the filled circles are outliers.