Tvetenia paucunca (Saether)

Namayandeh, Armin, Bilyj, Bohdan, Beresford, David V., Somers, Keith M. & Dillon, Peter J., 2012, 3324, Zootaxa 3324, pp. 1-65 : 52

Tvetenia paucunca (Saether)

Figs 42A–F

Diagnosis. Head capsule, including posterior margin pale; and premandible as in Fig. 42A; SI seta divided; premandible with single tooth; antenna ( Fig. 42B) 5-segmented with segment 3 slightly shorter than segment 4 ( Fig. 42C); mandible ( Fig. 42D) with 2 short inner serrations; mentum ( Fig. 42E) with bifid median tooth and 5 lateral teeth; VM plate narrow, curved distally and connecting basally to a dark circular plate; abdomen ( Fig. 42F) with long setae, about half the length of respective segment; procercus well developed, twice as long as wide; anal tubules short, about half the length of posterior parapods.

Notes. In our specimens the antennal segment 3 is not as short as indicated in Epler (2001) and segment 5 is attenuated apically giving the appearance of a 6 th segment. The ventromental plates are connected basally to dark circular plates as shown in Bode (1983: 15, upper right figure).

Ecology and habitat. Based on Berg & Hellenthal (1991) this species has an asynchronous life history with indistinguishable overlapping cohorts. This species is common in mountain streams and coastal plains ( Epler 2001). Larvae of T. paucunca are reported as collector-gatherer and tolerant of organic pollution ( Fiorentino 2005).

Sampling sites. Massasauga Provincial Park

Nearctic distribution. Canada: NWT, Yukon, Alberta, Manitoba , and Ontario. USA: Georgia, Michigan, Ohio, North Carolina, South Carolina .