Letter: Letters: Forked only once

From J. FRENCH

Vincent Kiernan in ‘Intimate secrets of the snake’s forked tongue’ (This
Week, 26 March) suggests that the forked tongue independently evolved twice,
perhaps four times, by snakes and one, possibly three, groups of lizard.

But snakes, monitors and heloderms must have had joint ancestry (back
in early Jurassic or in Triassic), which in turn derived from skinks. Thus
there is a strong possibility that all of the above had a single common
ancestry, derived from skinks, in which the forked tongue was evolved –
once only.

Snakes and lizards should each be a subclass, and skinks with their
lizard derivatives should be classed as a separate order of lizards.

J. French Watford, Hertfordshire