Alloperla joosti Zwick, 1972

Judson, Sarah W. & Nelson, C. Riley, 2012, 3541, Zootaxa 3541, pp. 1-118 : 24-25

Alloperla joosti Zwick, 1972

SYNONYMY

Alloperla joosti Zwick, 1972

TYPE LOCALITY: Mongolia: Arkhangai aimag, Somon Chencher at Urd-Tamir Gol .

DIAGNOSIS: This species characterized by reduced pigementation, with only a prominent dorsal abdominal stripe originating on segment 1 and continuing through segment 7 ( Fig. 96). The majority of Chloroperlidae of Mongolia, including A. rostellata ( Fig. 104) and A. mediata ( Fig. 100), possess this abdominal stripe but usually have additional pigmentation. In A. joosti , the meso- and metanota have only faint pigmentation at their periphery and, similar to A. deminuta , A. joosti lacks pigmentation on the pronotum. The epiproct of A. joosti is recurved anteriorly, the anteriorly directed portion is slightly swollen at its base and after a brief constriction, is uniformly narrow ( Fig. 97), with the length approximately four times the width. The apex of the epiproct is rounded ( Fig. 97), whereas it is pointed in all other Alloperla ( Fig. 93, 101). The epiproct of A. joosti has spines along the ventral margin (best seen laterally), similar to A. rostellata ( Fig. 104) and A. mediata ( Fig. 100), but which A. deminuta lacks entirely. The female subgenitial plate of A. joosti ( Fig. 98) is often difficult to discern due to lack of contrasting pigmentation. The plate gradually slopes to an abrupt point, forming a triangle with a broad base, and extends only slightly over sternum 8. The nymphs are readily distinguishable to the generic level and we did not have enough material to attempt species separation.

DISTRIBUTION—Global: East Palearctic— Regional: AOB- Aimag: AR, BU^, KhG^, OV^, SE^, TO^, UB, ZA.

DISCUSSION: This species was originally described from Mongolia (Zwick 1972) and has been documented throughout the eastern Palearctic (Teslenko & Bazova 2009), including additional collections in Mongolia (Zhiltzova 1982). Among Mongolian Chloroperlidae , the epiproct of A. joosti superficially resembles that of Alaskaperla longidentata ( Fig. 111), but the epiproct of Ala. longidentata has no swollen base, is upturned, and very smooth on all sides especially lacking ventral spines.