|Wood turtle (Glyptemys insculpta)
Previously known as: Clemmys insculpta, Testudo insculpta and Emys speciosa
The wood turtle probably derives both its Latin and common names from the deep concentric growth rings and grooves known as ‘annuli' that mark the somewhat raised carapacial scutes, which give the shell a ‘sculpted' appearance as if carved from wood. In immature specimens (up to the age of 15 or even up to 20), roughly one ring is produced per year so that the annuli count can give a rough estimate of age, usually accurate within a couple of years. Once they approach adulthood, however, accuracy drops off quickly. The back edge of the carapace is serrated and a prominent keel runs down the centre, also adding to its sculpted appearance. The carapace is typically brown or greyish-brown, sometimes with ray-like yellow streaking. The upper head is usually black, and upperparts of the limbs and tail are grey to greyish-brown, or even black with yellow spots. By contrast, the vividly-coloured underparts range from yellow in specimens from western (Great Lakes) parts of the species' range, to orangish-yellow or orange in the central part of its range, to orange-red or ‘salmon-red' in the northeast. Hatchling turtles have flat, non-sculpted, almost circular carapaces, and lack any of the adult yellow, orange or red pigment. The yellow plastron is also distinctive, with its pattern of dark blotches along the outside edge of each scute.