Description:Pseudacris illinoensis can reach a maximum size of 48 mm. It is the largest of the chorus frogs, with a stout, toadlike body and forearms. This frog has a dark stripe through its eyes from snout to shoulder, dark spots along the side of the body, dark blotches on the dorsum (back), a white belly, and yellow or orange-yellow pigmentation on the groin. Coloration may be gray, brown, olive, or green in the subspecies P. streckeri streckeri, but the dorsum is never green in the subspecies P. illinoisensis. Most have a dark spot below the eye. They can be distinguished from all other chorus frogs within its range by its lack of a continuous light line along the upper lip. During the breeding season, the vocal pouch of the male becomes dark.
Habitat: Basically terrestrial. Sand prairies and cultivated fields, open sandy areas of river lowlands. Burrows into soil using forelimbs. Eggs and larvae develop in flooded fields, ditches, sloughs, small ponds, or other temporary bodies of water.
Range: Disjunct populations in west-central and southwestern Illinois, southeastern Missouri and adjacent Arkansas. .
Diet: Metamorphosed frogs eat small terrestrial arthropods obtained from ground surface or in soil. Larvae eat suspended matter, organic debris, algae, and plant tissue.
Reproduction: Lays clutch of up to several hundred eggs divided among many clusters. Breeds in late winter or early spring in Midwest, from as early as late January through mid-April in Arkansas. In Missouri, breeding begins in late February or early March, continues into early April. Breeds in March in Illinois. Aquatic larvae metamorphose into terrestrial form in about 2 months (late spring in Illinois).
Status: Continued draining and clearing of bottomlands, and housing developments and other land uses, have greatly reduced the habitat in southeastern Missouri, where there also is concern over the effects of pesticides in the environment. In Illinois, habitat has been lost to drainage of breeding sites and cultivation. Possible threats include highway construction, water contamination, and chemical spills. Bullfrogs and fish are also threats to breeding ponds.
Disclaimer: ITIS taxonomy is based on the latest scientific consensus available, and is provided as a general reference source for interested parties. However, it is not a legal authority for statutory or regulatory purposes. While every effort has been made to provide the most reliable and up-to-date information available, ultimate legal requirements with respect to species are contained in provisions of treaties to which the United States is a party, wildlife statutes, regulations, and any applicable notices that have been published in the Federal Register. For further information on U.S. legal requirements with respect to protected taxa, please contact the U.S. Fish and Wildlife Service.
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