Thermonectus zimmermani is a species of diving beetle native to western Mexican states of Jalisco, Colima, and Morelos. T. zimmermani reaches a total length of and has variable bright yellow and black markings similar to that of T. marmoratus. However, T. marmoratus has a spotted pattern of yellow circles, T. zimmermani has an irregular, blotched pattern. T. zimmermani head has a V-shaped medial black marking that has been reduced. References Dytiscidae Beetles of North America Beetles described in 1981