However, in the loose delimitation (which incorporates about 30 species) the genus is not monophyletic but an evolutionary grade, as has long been suspected due to its lack of characteristic apomorphies.

For instance, the black rock skink is a species who can perform kin discrimination based on scent and form monogamous pair-bonds and a nuclear family structure.

It may still be, however, that the intelligent behaviour is a homoplasy that evolved several times in the Egernia genus-group; the fact that Corucia is a monotypic and rather distinct genus makes it impossible to decide at present.

[1] Egernia species are mid-sized to large skinks, adult snout-to-vent length (SVL) 10–24 cm (3.9–9.4 in), with a bulky, usually somewhat flattened body and small eyes.

Cladistic analysis of NADH dehydrogenase subunit 4, 12S rRNA, c-mos and β-fibrinogen intron 7 DNA sequence data delimits 3 clades, Bellatorias, Liopholis, and Lissolepis in Egernia sensu lato, which are best regarded as separate genera — as had already been often proposed in former times, as early as the 19th century.