Unless I missed something, the word “telomeres” doesn’t occur in the article or its source paper—rather, it discusses the rate of DNA methylation.

IMO, the key passage in the paper is this:

However, any genetic regulation for a species may potentially be a secondary factor as there may be other environmental selective pressures. This may be the case with species which have lifespans post reproductive age and therefore, there may be non-genetic factors that may be more predictive of their maximum lifespan.

I suspect that the methylation rate is actually tracking the end of the reproductive stage of the lifecycle, rather than the length of the lifecycle as a whole.