Orthocladius pedestris Kieffer, 1909

Bruno Rossaro & Carlotta Casalegno, 2001, Description of the pupal exuviae of some species belonging to Orthocladius s. str. van der Wulp, 1874 (Diptera: Chironomidae: Orthocladiinae), with a new key to species of West Palaearctic region, Zootaxa 7, pp. 1-20 : 11

Orthocladius pedestris Kieffer, 1909

O. pedestris Kieffer, 1909

O. tubicola Kieffer, 1909 ( Langton & Cranston 1991, a questionable synonym)

Orthocladius Pe 10 Langton, 1984: 158 ( Langton 1991: 191; Langton & Cranston 1991)

O. rhyacobius Kieffer, 1911 sensu Langton, 1984: 158 ( Langton & Cranston 1991)

DESCRIPTION. See Potthast (1915: 271­272), Langton & Cranston (1991, Fig. 1 c, 2c, 4c). Frontal warts often greatly developed, frontal setae present on small cephalic tubercles. Thorax heavily rough. Thoracic horn 360­450 m long, with strong spines and clearly bent at apex. Apical part of abdominal segments with large brown blotches on sternites and on tergites extended laterally to apical points (Fig. 1.2), “Die Intersegmentalstreifen sind mit dunklen, runden Flecken betupft (Fig. 26). Dieses etwa mosaik­artige Aussehen ist besonders auffallend an den ventralen und den spitzenfreien dorsalen Streifen” ( Potthast 1915: 272). Fields of points very extended on T II­VI, well beyond the antero­lateral adhesion marks, grading in size from posterior and central to anterior and lateral areas. S I­VII with "Gruppen­shagreen". Abdominal segment VIII with five strong lateral setae. Anal lobes with 2 or more taeniate extensions of cuticle, with the shape of brown and sturdy chitinised spurs, often fused at base; one or more lighter extensions also often present, simulating a small fringe of lateral setae. Anal macrosetae 160­210 m long, hooked at tip, anal lobes 300­360 m long, 375­430 m wide.

COMMENTS. The examination of type material (a female pupal exuviae) deposited at the Zoologische Staatssammlung (München) showed that O. pedestris is identical with specimens collected in Italy in northern Apennines and it is quite different from specimens collected in other European rivers (Loira, Garonna, Ticino, Brembo etc.) which were (erroneously) assigned to pedestris . These specimens belong to O. obumbratus or to O. ticinoi . O. pedestris can be easily separated from O. obumbratus because of the presence of large brown blotches on the apical part of abdominal segments III­VI.

MATERIAL EXAMINED. Holotype, GERMANY Westfalia, ZSM (Zoologische Staatssammlung der Bayerische State, München). ITALY: EMILIA ROMAGNA: Tributary of Taro river, Bedonia, 15/5/2001, 12 Pex; Case Nicola, 24/4/2001, 1 Pex; Taro river, Borgo val di Taro, 3/5/2000, 2 Pex; Reno river, P.te della Venturina, 4/4/1987, 4 Pex.

Figures

FIGURE 1. Ventral view (sternite) on the left, dorsal view (tergite) on the right. 1.1: O. marchettii: tergite III with anterior, median, posterior and apical point fields; 1.2: O. pedestris: tergite III with anterior, median, posterior and apical point fields