Capniidae

Judson, Sarah W. & Nelson, C. Riley, 2012, 3541, Zootaxa 3541, pp. 1-118 : 17

Capniidae

COMMON NAME: Small Winter Stoneflies.

SIZE: Small (5–10 mm).

FEEDING GROUP: Shredders.

TOLERANCE VALUE: 1 (Low).

DIAGNOSIS: Adults are usually dark brown to black in color, though some species are golden brown or faintly colored. Although wing reduction ( Fig. 48) is common in this family, the majority of Mongolian species are macropterous. The adults, with the exception of the genus Eucapnopsis , have long many –segmented cerci with ≤16 cercomeres. The male epiproct is either very long and thin as in Isocapnia ( Fig. 51), or short and wide as in Capnia ( Fig. 33) or Eucapnopsis ( Fig. 44). The female subgenital plate is usually little produced but heavily sclerotized in characteristic patterns. The nymphs are slender and elongate with the pronotum only slightly wider than the abdomen. Nymph abdominal segments 1–9 are separated by a membranous pleural fold ( Fig. 15). The nymphal mouthparts exhibit the following combination of characters: mentum not covering the base of the lacinia (Zwick 2004), the paraglossa subequal to the glossa, and robust labial palps ( Fig. 7).

DISCUSSION: Capniid nymphs are most common in small streams, including temporary streams and springs. The nymphs are relatively cryptic and often inhabit the hyporheic zone. When they inhabit the main stem of the stream, they are usually located in gravel or detritus in sections of fast or moderate flow. Most capniid stoneflies emerge during cold months. The adults are often visible on snow due to their dark color. Some species are found in temporary streams where they spend dry months burrowed down in the wetted substrate. The ecology of capniids in Mongolia is not well known and many species have only been documented in late July at higher elevations.