C. parkeri in adult stage is a very small, black (sometimes with large reddish spots on elytra), non-swimming beetle living on rocks, sand and gravel in riffles. Body is cylindrical, legs long with large claws, and moderately long antennae. Adults range in size from 2.15-2.75 mm long and 0.85-1.1 mm wide. Larvae are very small, brown, hard, elongate, and roughly triangular in cross section; about 6.0 mm long and live in riffles. The body is NOT covered in dense, short hair.
For riffle beetles in general, the body is usually dark brown or red-brown, with color patterns or various metallic tints. There are numerous longitudinal rows of very small indentations, such as would be made by the point of a needle, on the hardened front of the wings. The antennae ranges from 1-8 mm. In general for the larvae, the body length is usually 3-8 mm and may range up to 16 mm. The body is elongate, cylindrical and hard. They are usually dark brown or red-brown. The legs have four segments (not counting the claws). There is one claw on the end of each leg. The abdomen has nine segments. Abdomen segment nine has a cavity that is covered by a hinged lid, and there is a tuft of filamentous gills that can be withdrawn into this cavity (Voshell 2002).
According to McKown, only known habitat for C. parkeri occurs Yavapai County, Arizona, in spring fed Roundtree Canyon in Bloody Basin within the Tonto National Forest. R. Johnson (1992) states that it also occurs in Tangle Creek, also located in Bloody Basin.
Both adults and larvae feed on periphyton, algae, moss and vegetable material, and inhabit permanent, clean, slow moving small streams, with loose gravelly substrate and very little sand.
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