Longtail Tadpole Shrimp

T. longicaudatus is the most widespread notostracan species, and may be found in western North America, South America, Japan, South Korea, and several Pacific Islands. It is most active at a temperature of approximately 20 °C (68 °F), and is usually found scratching the mud at the bottom of pools, searching for benthic food. Triops collect food particles by straining the water with hairs on their limbs. Loose food particles are collected in a groove running down the underside of the body lengthwise, and held together by a sticky secretion until they are swallowed by their very small (2 mm wide) mouth. The tiny mouth is deep in its underbelly, and while the animal is capable of breaking up plant roots or dead fish, it is incapable of chasing down and eating prey larger than it is.

Diet. Tadpole shrimps are omnivorous and may eat algae, insects, and other organic debris; they are known to chase very small fry, tadpoles, and oligochaete worms. In general, they eat anything organic that is smaller than they are, which even may include their siblings (they are cannibalistic). In turn, Triops longicaudatus are eaten by frogs and birds.

Interaction with humans. The species is considered a human ally against the West Nile virus, as the individuals consume Culex mosquito larvae. They also are used as a biological pest control agent in Japan, eating weeds in rice paddies. …

The feeding method of tadpole shrimps is similar to that proposed for the ancestral crustacean. The anterior appendages (second pair to tenth pair) stir sediments and swirl muddy water into the wide, midventral food groove. The gnathobases (inward-facing lobes at the base of the leg) guide food anteriorly to the mouth. The large flat exopods (outward-facing lobes at the end of the leg) stir and lift the sediments. Fine silt particles and water escape easily, but large, coarse food particles are torn into smaller pieces by the blade-like, inward-facing lobes called endopods at the end of the leg.

The genus name Triops comes from Ancient Greek τρία (tría), meaning "three", and ὄψ (óps), meaning "face" or "eye". The specific name longicaudatus comes from Latin longus, meaning "long", and caudatus, meaning "tailed", referring to its long tail structures.