Cultures of a bacterial species were incubated on the shelf of a refrigerator (5°C), on a lab benchtop (25°C), on the shelf of a 37°C incubator, and on the shelf of a 50°C incubator. After incubation, there was no growth at 37°C or 50°C, slight growth on the benchtop, and abundant growth at refrigeration. What term could be used for this species?