cetaceans 0.06: marine carnivores 0.04: echinoids 0.01: brachiopods 0.001 genera extinctions per million genera per year
||De Vos JM, Joppa LN, Gittleman JL, Stephens PR, Pimm SL. Estimating the normal background rate of species extinction. Conserv Biol. 2015 Apr29(2):452-62. doi: 10.1111/cobi.12380. p.454 left column 5th paragraphPubMed ID25159086
||Harnik PG et al., Extinctions in ancient and modern seas. Trends Ecol Evol. 2012 Nov27(11):608-17. doi: 10.1016/j.tree.2012.07.010.PubMed ID22889500
||P.454 left column 5th paragraph: "Alroy (1996) estimated 0.165 extinctions of genera per million genera years for Cenozoic mammals. Most paleontological studies assess genera, not species (Flessa & Jablonski 1985). Harnik et al. (primary source) examined marine taxa. Their extinction rate is a dimensionless extinction fraction, the natural logarithm of the fractional survival of genera measured over an average stage length of 7 million years. Converting these fractions to their corresponding rates yields values for the last few million years of 0.06 genera extinctions per million genera for cetaceans, 0.04 for marine carnivores, and from 0.001 (brachiopods) to 0.01 (echinoids) for a variety of marine invertebrates. Put another way, 1% of echinoid genera are lost per million years."