Freshwater planarian

Dugesia tigrina

ORDER

Tricladida

FAMILY

Dugesiidae

TAXONOMY

Dugesia tigrina (Girard, 1847), New Jersey, United States.

OTHER COMMON NAMES None known.

PHYSICAL CHARACTERISTICS

Body lanceolate with auricles laterally on head, light to dark brown in color with some forms having a stripe down its midline, light spots on a dark background or dark spots on a light background; pharynx large in middle of body, gut with two posterior and one anterior directed branch as others in order.

DISTRIBUTION

Widespread in North America and has scattered distribution in Europe, where it may have been introduced with aquatic plants.

HABITAT

Under rocks, plants, and debris in clear freshwater ponds, streams, and springs.

BEHAVIOR

Tends to hide under rocks during day. When hunting, will swing head side to side to better sense sources of chemicals coming from food or prey.

FEEDING ECOLOGY AND DIET

Carnivorous, feeds on various invertebrates, including mosquito larvae.

REPRODUCTIVE BIOLOGY

Asexual reproduction by transverse fission. Transverse fission may be more common method of reproducing since sexual organs have not been observed in some populations. It has strong capacity to regenerate. Following mating, several egg capsules are deposited per worm. Development is direct and juveniles hatch from eggs.

CONSERVATION STATUS

Not threatened.

SIGNIFICANCE TO HUMANS

Studied intensively as a model to better understand regeneration of cells in humans and other animals. ♦

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