Most early and not a few later checklists contain a very high proportion of entirely spurious entries, and a considerable number of described species are now considered invalid – either because they are homonyms, non-binomial or for some other reason.

[3] Paleobiogeographical considerations suggest the rate of evolution of the mitochondrial 12S rRNA gene is 1.0-1.6% per million years for the last dozen million years or so in the present genus[4] and ntDNA evolution rate has been shown to vary strongly even between different population of T. hermanni;[5] this restricts sequence choice for molecular systematics and makes the use of molecular clocks questionable.

Arguably, T. horsfieldii belongs in a new genus (Agrionemys) on the basis of the shape of its carapace and plastron,[6] and its distinctness is supported by DNA sequence analysis.

[7] Likewise, a separate genus Eurotestudo has recently been proposed for T. hermanni; these three lineages were distinct by the Late Miocene as evidenced by the fossil record.

The genus Chersus has been proposed to unite the Egyptian and marginated tortoises which have certain DNA sequence similarities,[4] but their ranges are (and apparently always were) separated by their closest relative T. graeca and the open sea and thus, chance convergent haplotype sorting would better explain the biogeographical discrepancy.

[10] Mating involves a courtship ritual of mechanical, olfactory and auditory displays elicited from the male to coerce a female into accepting copulation.

[11] These are considered honest signals that are then used to influence pre- and post-copulatory choice, as females are the choosy sex.

[10] Female mate choice offers no direct benefits (such as access to food or territory or parental care).