bilineata vs trilineata

[Bri]

'scuse my ignorance but can someone tell me the difference between bilineata and trilineata ? They look exactly the same to me !!!

[robpilley]

bilineata is more closely related to L. viridis than it is to trilineata.
Originally the Green Lizard of western, central and eastern Europe was called L. viridis. This range has recently been split into L. bilineata (in the west of Europe as far east as Croatia) and L. viridis from Croatia eastwards into the Ukraine and south into Greece.
L. trilineata is not closely related to either of them, occuring from southern Greece and Croatia eastwards to Turkey.
L. viridis and bilineata look very similar (and do form intergrades along their transition line), typically green males and greenish brown females with varying degrees of 2 or 4 dorsal stripes along the back/ flanks plus other dorsal markings. Males usually have bright blue throats in the breeding season (although some southern Italian ssp. of bilineata do not have bue throated males) and so do some of the females. They are up to 40cm total length.
L. trilineata is generally larger (up to 50cm) and more chunkier than bilineata/viridis, usually with 8 rows of ventral scales (viridis and bilineata usually only have 6) plus trilineata has 15-20 evenly sized supratemporal scales (scales between the eye and the eardrum) whereas bilineata and viridis usually have less than 15, several of which are quite large.
There is lots of variation between between the colours and markings of ssp. of trilineata, some populations have males with blue chins and others dont. Some are bright green all over, others grey brown, others have orange dorsal stripes and blue flanks!
The main difference between bilineata/ viridis and trilineata are the scale counts mentioned above, thats the only way to properly ID what you have in hand, plus an idea of the animals origins.

Incidentally, a lot of the animals that have appeared on the market in the recent few years are imports from Ukraine/ Russia and so are composed of L. viridis (as well as other Lacertids like L. agilis exigua, L agilis chersonensis, L. strigata, L. praticola).

Good luck

Rob

[Bri]

Thanks for that Rob.
That has helped clear up a bit of my confusion.