About Thermonectus marmoratus (Gray, 1831)
Adult Thermonectus marmoratus, commonly called the sunburst diving beetle, measure 0.8–1.5 cm (0.31–0.59 in) in length, and females are slightly larger than males. This species has a streamlined black carapace marked with bright yellow or golden spots, and each of a male’s forelegs bears a suction disk. Sunburst diving beetles are distributed across the extreme south of California, United States (mostly in the Peninsular Ranges), plus southern Utah, Arizona, New Mexico, and Texas, where they were first recorded in 1996; they also live in Mexico. They occupy a variety of slow-moving freshwater habitats, particularly shallow, temporary or intermittent pools and creeks called arroyos that have little to no aquatic vegetation. If their current water source dries out, they fly to a new freshwater habitat.
