7. Potamocloeon (Aquaediva) freitagae (Gattolliat, 2001)

Figures 10b, 13, 14

Potamocloeon freitagae: Gattolliat 2001a: figs 13-19.

Diagnose.

Nymph. Following combination of characters: A) labrum on dorsal surface with a long, simple submedian seta and a submarginal arc of simple setae; B) both mandibles with long, stout setae between prostheca and mola, incisors blade-like; C) labial palp without protuberance at segment II; D) legs stocky with tibia and tarsus almost fused; tibia and tarsus with subproximal arc of long, fine, simple setae; claw short, without denticles.

Complementary description.

Nymph (Figs 10b, 14). Body length 3.8-4.8 mm (up to 5.5 mm according to Gattolliat 2001a). Cerci: ca. 2/3 of body length. Paracercus: ca. 3/4 of cerci length. Antenna: approx. 1.5 × as long as head length.

Colouration (Fig. 10b). See also Gattolliat 2001a, colouration may be altered due to long storage of nymphs in alcohol. Head, thorax and abdomen dorsally brown, abdominal segments V and VI darker; head, thorax and abdomen ventrally light brown. Legs light brown, caudalii light brown.

Right mandible (Fig. 14a, b). Incisor and kinetodontium partly fused. Incisor blade-like; kinetodontium with three denticles. Prostheca stick-like, apically with two long and several short denticles. Margin between prostheca and mola straight, with long, stout setae. Tuft of setae at apex of mola present.

Left mandible (Fig. 14c, d). Incisor and kinetodontium partly fused. Incisor blade-like; kinetodontium with three denticles. Prostheca robust, apically with small denticles and comb-shaped structure. Margin between prostheca and mola straight, with long, stout setae. Subtriangular process long and slender, above level of area between prostheca and mola. Denticles of mola apically constricted. Tuft of setae at apex of mola absent.

Hind protoptera (Fig. 14e) vestigial or absent.

Gills (Fig. 14f-l). Present on segments I-VII. Tracheae extending to inner and outer margins. Gill I as long as segment II; gill IV as long as segments V, VI and VII combined; gill VII nearly reaching bases of cerci.

Distribution

(Fig. 13). Comoros (Anjouan), Madagascar.

Biological aspects.

The specimens were collected at altitudes of 600 m and 750 m, together with A. bicorne and N. richardi sp. nov.. The characteristics and environmental conditions of the sampling sites in the Comoros (Anjouan: Riv. Tatinga, Riv. Santsa) are described in Starmühlner (1979: pp. 651, 652): river width 0.5-8 m, depth 2-50 cm, water temperature 22 °C-24 °C, bottom substrata consisted of basaltic rock, boulders, gravel and sand.

Material examined.

Comoros • 5 nymphs; Anjouan, Riv. Tatinga, upper course, near Dindri; 600 m; 11.03.1974; leg. F. Starmühlner; 4 on slides; GBIFCH00592753, GBIFCH00515707, GBIFCH00592725, GBIFCH00592709, GBIFCH00592712, GBIFCH00592710; 1 in alcohol; GBIFCH00515659; MZL, FAMU • 2 nymphs; Anjouan, Riv. Santsa, upper course, near Adda-Douéni; 750 m; 21.03.1974; leg. F. Starmühlner; 1 on slide; GBIFCH00592754; 1 in alcohol; GBIFCH00515660; MZL, FAMU .