Nepidae
Guides
Nepa
water scorpion
Nepa is a genus of aquatic true bugs in the family Nepidae, commonly known as water scorpions. These insects inhabit freshwater environments and are characterized by their elongated bodies, raptorial forelegs adapted for capturing prey, and a long respiratory siphon extending from the abdomen. The genus belongs to the subfamily Nepinae and is distinguished from related genera primarily by morphological features of the pronotum and respiratory siphon structure.
Nepoidea
Nepoidea is a superfamily of aquatic true bugs comprising two families: Belostomatidae (giant water bugs) and Nepidae (water scorpions). These are the largest-bodied members of the infraorder Nepomorpha and function as top predators in freshwater ecosystems. A distinctive morphological trait is the reduction and concealment of antennae in grooves behind the eyes, an adaptation to submerged aquatic life. The antennal sensilla exhibit remarkable structural diversity, with 11 morphological types identified including mechanosensilla, thermo-hygrosensilla, and olfactory sensilla that facilitate environmental sensing and prey detection.
Ranatra
water stick-insect, water scorpion, water mantis
Ranatra is a genus of slender aquatic predatory insects in the family Nepidae, commonly called water stick-insects or water scorpions. The genus contains over 140 species distributed across freshwater habitats worldwide, with highest diversity in South America and Asia. These insects are sit-and-wait predators that use raptorial forelegs to capture prey. They possess a distinctive long caudal siphon for breathing while submerged.
Ranatra brevicollis
Western Waterscorpion
Ranatra brevicollis is a species of waterscorpion in the family Nepidae, first described by Montandon in 1910. It is distributed across Central America and North America. The species belongs to a genus of aquatic predatory insects commonly known as waterscorpions due to their elongated, scorpion-like appearance. It is recognized by the common name Western Waterscorpion.
Ranatra buenoi
waterscorpion
Ranatra buenoi is a species of waterscorpion in the family Nepidae, described by Hungerford in 1922. It occurs in North America. Waterscorpions in this genus are aquatic predatory insects characterized by elongated bodies and raptorial forelegs. The specific epithet honors an individual, though the source context does not clarify the namesake.
Ranatra drakei
Ranatra drakei is a species of water scorpion in the family Nepidae, described by Hungerford in 1922. Like other members of the genus Ranatra, it is an aquatic predatory insect with raptorial forelegs adapted for capturing prey. The species is known from North America, though specific ecological details remain poorly documented in published literature.
Ranatra fusca
brown water scorpion, brown waterscorpion
Ranatra fusca is a predatory aquatic bug in the family Nepidae, commonly called the brown water scorpion. Native to North America, it inhabits freshwater environments where it hunts small invertebrates using raptorial forelegs. Adults reach 3.2–4.2 cm in length and possess a long respiratory siphon for breathing at the water surface. The species is most active from spring through autumn.
Ranatra montezuma
Montezuma waterscorpion
Ranatra montezuma is a waterscorpion species endemic to Montezuma Well, a thermally constant, fishless spring in Yavapai County, Arizona. It was described by J. Polhemus in 1976 and represents a highly localized population with specific dietary adaptations to its unique aquatic environment. The species exhibits nocturnal foraging behavior and maintains high population densities supported by abundant endemic prey.
Ranatra nigra
Ranatra nigra is a waterscorpion species in the family Nepidae, occurring in aquatic environments of the Mobile/Tensaw Delta. The species has been documented in association with the water mite Hydrachna magniscutata, which exhibits temporal distribution patterns linked to R. nigra. As a member of the genus Ranatra, it possesses the elongated body form and raptorial forelegs characteristic of waterscorpions.
Ranatra quadridentata
waterscorpion
Ranatra quadridentata is a species of waterscorpion described by Stål in 1862. As a member of the family Nepidae, it is an aquatic predatory insect that inhabits freshwater environments. The species has been documented in Central America and North America, with 188 observations recorded on iNaturalist.