Callibaetis (Abaetetuba) fasciatus (Pictet) 1843

(Figs 5–8)

Cloe fasciata Pictet 1843: 262 .

Callibaetis trifasciatus Esben-Petersen 1912: 339 . (syn. by Gillies 1990) Callibaetis fasciatus: Eaton 1883: 197; Gillies 1990: 23; Domínguez et al. 2006: 113; Cruz et al. 2014: 20.

Known stages. Male and female imagoes, nymph

Diagnoses. Male imago: 1) turbinate eyes with oval dorsal portion (Fig. 5 A); 2) dorsal portion of turbinate eyes, in lateral view, without constriction; 3) turbinate portion of compound eyes (in lateral view) with anterior and posterior margins divergent; 4) forewing with three or four transverse pigmented bands (Fig. 5 F); 5) marginal intercalary veins paired (Fig. 5 F); 6) hind wing with small dashes of pigmentation (Fig. 5 G); 7) hind wing with a small pointed costal projection (Fig. 5 G); 8) marginal intercalary veins on hind wing present (Fig. 5 G); 9) anterior margin of abdominal terga with a transversal mark (Fig. 5 A); 10) abdominal sterna with strongly pigmented medioanterior and medioposterior sigilla (Fig. 5 B); 11) forceps segment I wide at base (Fig. 57 in Cruz et al. 2014); 12) segment III of forceps elongated and oval (Fig. 57 in Cruz et al. 2014).

Female imago: 1) forewing with three or four transverse bands of pigmentation (Fig. 5 H); 2) marginal intercalary veins paired; 3) hind wing with small dashes of pigmentation (Fig. 5 I); 4) hind wing with a small pointed costal projection (Fig. 5 I); 5) marginal intercalary veins on hind wing present (Fig. 5 I); 6) abdominal sterna with strongly pigmented medioanterior and medioposterior sigilla (Fig. 5 D); 7) abdominal sterna I–IX with one pair of lateral black mark (Fig. 5 D).

Mature nymph: 1) distal margin of labrum with short, robust and pectinate setae medially (Fig. 6 B); 2) maxillary palp 1.3× length of galea-lacinia (Fig. 6 E); 3) one row of setae on basal part of inner-dorsal row of maxilla (Figs 6 E and similar to 21C); 4) paraglossa with rounded apex (Fig. 6 G); 5) paraglossa with one tuft of thin setae (Fig. 6 G); 6) inner margin of labial palp segment III not tapering towards the base (Fig. 6 G); 7) metanotum without spines; 8) anterior surface of foretarsus with one row stout setae (Fig. 7 A).

Description. Mature nymph. Length: body, 6.5 mm; cerci, 2.54 mm; paracercus, 2.35 mm (n=1). Head light brownish yellow; turbinate portion of male compound eyes yellowish brown. Antenna with spines and thin setae on flagellum (Fig. 6 A). Labrum (Fig. 6 B) maximum length about 1.3× minimum length; anterolateral margins with long and stout setae; distal margin with short, robust and pectinate setae medially; dorsal surface with numerous long and thin setae; dorsal surface, near distal margin, with three robust and long setae; distal margin with one row of stout setae ventrally; ventral surface with short and stout setae near lateral margin. Right mandible (Fig. 6 D) with 4+3 denticles; margin between prostheca and mola convex; basal half with short and thin setae and pores scattered over dorsal surface. Left mandible (Fig. 6 C) with 4+3 denticles; margin between prostheca and mola straight; basal half with short, thin setae and pores scattered over dorsal surface. Lingua of hypopharynx (Fig. 6 F) with apical lobe covered with small setae; short and thin setae scattered over distal margin of lingua and superlingua. Maxilla (Fig. 6 E) with one row of setae on basal part of inner-dorsal row (similar to Fig. 21 C); medially, on inner margin, with 1+6 stout setae. Maxillary palp short, 1.3× length of galea-lacinia; palp segment II 1.2× length of segment I; outer margin of segment I covered with long and thin setae; inner margin of segment II with thin setae. Labium (Fig. 6 G) with glossae shorter in length than paraglossae; inner margin of glossae with 7 stout setae; apex with 3–5 long and stout setae; near outer margin with one row of long and stout setae; dorsal surface with one tuft of setae at apex. Paraglossae with rounded apex, with one row of stout setae and with one tuft of setae on inner margin; dorsal surface with numerous long and stout setae; distal margin with two rows of long and stout setae; outer margin with one row of long and stout setae. Labial palp with segment I 0.8× length of segments II and III combined; segment I with micropores; inner margin of segment II with four robust, short and stout setae, and few thin and short setae (Fig. 6 G); dorsally with row of six short and stout setae; inner margin of labial palp segment III not tapering towards the base; whole margin of labial palp segment III, on dorsal surface, with one row of long and stout setae; inner margin of labial segment III, on ventral surface, with four long and stout setae. Thorax light brownish yellow. Metanotum without spines (Fig. 8 B). Foreleg (Fig. 7 A) with black spots at base of femur; ratio 1.5:(0.62 mm):0.8:0.5. Forefemur length about 4.3× maximum width; dorsal margin with one row of short and stout setae; apex of femur with two stout setae; length of setae on dorsal margin about 0.1× maximum width of femur; ventral margin without setae; anterior and posterior surface covered with stout setae; near ventral margin with two rows of stout setae, one trifid and one simple; near dorsal margin with one row of stout setae. Ventral margin of tibia with one row of stout setae; anterior surface with one row of short and stout setae. Ventral margin of tarsus with one row of trifid stout setae (Fig. 7 C); anterior and posterior surface with one row of stout setae. Claw 0.7× length of tarsus. Hind leg similar to foreleg except femur without trifid setae and claw denticles smaller than foreclaw denticles (Fig. 7 B). Abdomen (Fig. 8 C) light brownish yellow. Posterior margin of terga with regular spines (Fig. 8 A). Surface of sterna with thin setae. Gill I about 1.5 × length of segment II, with two folds. Gill IV as long as length of segments V to VI combined, with two folds. Gill VII as long as length of segment VIII and half of segment IX combined, with one fold. Paraproct (Fig. 8 D) with 28 marginal spines; surface with micropores and short, thin setae. Paracercus (Fig. 8 G) with long spines every two segments. Cerci (Figs 8 E, 8F) with spines on all segments, basal half with long spines every two segments.

Comments. The nymph of C. (Ab.) fasciatus is similar to the nymph of C. (Ab.) sellacki, they can be distinguished by the absence, in C. (Ab.) fasciatus, of spines on posterior margin of metanotum.

Material examined. Three male imagoes, BRAZIL, Rio Grande do Sul, Derrubadas, 27°15’58.76”S / 53°51’50.62”W, lake, 25.x.2008, E. Raimundi coll., INPA ; one male imago, BRAZIL, Paraná, Rio Branco do Sul, 25°11’42.20”S / 49°18’50.44”W, Gruta de Lancinha, 31.v.1987, DZRJ ; one male imago reared (with larval and subimaginal exuviae) and one nymph, BRAZIL, Mato Grosso do Sul, Bonito, Balneário municipal de Jardim Rio Prata, 21°25'04.3"S / 56°23'24.0"W, 15.iii.2012, P. V. Cruz coll., INPA ; three female imagoes, BRAZIL, Mato Grosso do Sul, Bonito, Ponte na BR-178, Rio Mimoso, 20°58'21.43"S / 56°32'49.74"W, 15.iii.2012, P. V. Cruz coll., INPA ; one male and one female imagoes, ARGENTINA, Prov. Corrientes, Parque Nacional Mburucuyá, casca central estancia, 12–14.xii.1999, C. Molineri coll.; three female and one male imagoes, ARGENTINA, Missiones, Parque Prov . Uruguai, Uruzú, Ruta Prov. 19, 7-11.xii.1999, C. Molineri coll.; three female subimagoes ( C. trifasciatus), ARGENTINA, La Plata, 27.x.1920, Navás det., MZB ; one male imago ( C. trifasciatus), ARGENTINA, Prov. Buenos Aires Navás det., MZB .

Distribution. Argentina: Corrientes; Missiones; La Plata; Buenos Aires. Uruguay: Maldonado. Brazil: Rio Grande do Sul; Paraná; Mato Grosso do Sul.