Short-winged Golden Stone
Claassenia sabulosa
Key Identification Characters - nymph: 3
- Two stout tails at least as long as abdomen.
- Thick filamentous gill tufts at base of each leg and between tails
- Body light brown with dark markings on abdomen and thorax, similar to Calineuria californica.
- Body length of mature nymphs (excluding tails) 20-30mm.
Similar nymphs: 3
Claassenia sabulosa closely resembles Calineuria californica in body color and size, but has gills tufts between the tails as in Hesperoperla pacifica. Skwala americana. also resembles C. sabulosa, but S. americana lacks all gill tufts at base of legs and between tails.
Key Identification Characters - adult 3
- Two stout tails as long as abdomen.
- All four wings short and non-functional
- Body color brown with dark markings.
- Remnants of gills present at base of legs.
- Body length (excluding tails) 20-30mm.
Similar adults: 3
While similar in appearance to golden stone adults, especially Calineuria californica, Claassenia sabulosa have two characteristics distinct from golden stones. First, the wings are clearly short and are non-functional. As a result adults can’t fly. Second, C. sabulosa emerges in the late summer and fall, well after the emergence of C. californica is finished.
Habitat & Distribution: 3
The short-winged golden stone is distributed throughout the Rocky Mountains and the Pacific Northwest, with the best populations found in larger rivers. It lives in the same habitat used by golden stones.
In Oregon C. sabulosa is found on both sides of the Cascade Mountains, but appears to be more abundant east of the mountain range in rivers like the Deschutes and John Day. It never seems to reach the same level of abundance as golden stones.
Life Cycle - Emergence: 3
Claassenia sabulosa, besides similar appearance, also has similar behavior and life cycle to golden stones. Nymphs require 2-3 years to reach maturity, and then migrate towards shore where they crawl out after dark onto shoreline rocks or debris for emergence. While adults are unable to fly, they are fast runners and very active along the shore. Females often run out onto the water to lay their eggs. Adults appear to be most active at dusk and after dark.
In Oregon C. sabulosa is found in a variety of large streams across the state, but its abundance never appears to be large.
Oregon Emergence Period: mid August - late September
Metolius: Abundant. ?
McKenzie: Small numbers. Emerge late August-September.
Necanicum/Nehalem: ?
Sources and Credits
- (c) Jerry Schoen, all rights reserved, uploaded by Jerry Schoen
- (c) Bob Henricks, some rights reserved (CC BY-NC), http://www.flickr.com/photos/aquaticinsects_of_central_virginia/6095043732/
- (c) Jerry Schoen, some rights reserved (CC BY-SA)
