Canonical variate analysis of the core groups (with sample sizes of n > 4 in both males and females) in the Trimeresurus albolabris, septentrionalis, and insularis groups (excluding mensural and colour pattern characters). Populations that can definitively be assigned to the nominate species are enclosed in a coloured ellipse (T. albolabris: blue, T. septentrionalis: red, T. insularis: green). While these are distinguished from each other, many intervening populations clearly fall outside these clusters.