matthew_bettelheim's Identifications

A Southwestern Pond Turtle (Actinemys marmorata pallida), photographed in the canal leading from Moffett Channel to Salt Pond A4 in northern Santa Clara County, CA. This canal is located just north of the Sunnyvale Water Pollution Control Plant (SWPCP).

Note the smooth, outer edge of the scutes on the rear of this turtle's carapace. For a melanistic Red-eared Slider (Trachemys scripta elegans), which can look rather similar, the outer edge of the scutes on the rear of the carapace is scalloped or serrated. Also note that the pattern to the turtle's head is mottled, which seems to be typical of Southwestern Pond Turtles. Red-eared Sliders usually have stripey heads with a bright, red patch on their ears, or black heads with that red patch, or unmarked black heads. I haven't been able to find any examples of Red-eared Sliders with mottled heads on iNaturalist or elsewhere.

Also note that, according to California Herps (www.californiaherps.com/turtles/turtles.html), Actinemys marmorata pallida is the only subspecies of Western Pond Turtle (Actinemys marmorata) present in the southern half of the San Francisco Bay Area, where I found this turtle; consequently, I have identified it to subspecies on that basis.