Massartella alegrettae Ulmer, 1943

Souto, Paula Malaquias, Da-Silva, Elidiomar Ribeiro & Nessimian, Jorge Luiz, 2013, Description of the nymph of Massartella alegrettae Ulmer, 1943 (Ephemeroptera: Leptophlebiidae: Atalophlebiinae) with a key to Massartella Lestage, 1930 nymphs, Zootaxa 3681 (5), pp. 583-588 : 584-587

Massartella alegrettae Ulmer, 1943

Ulmer 1943: 21; Peters & Edmunds 1972: 1404; Hubbard 1982: 265; Pescador & Peters 1990: 148; Domínguez et al. 2006: 415.

Material examined. Brazil, SP: São José do Barreiro, Parque Nacional da Serra da Bocaina, Córrego das Posses, 1308 m, 22°46’06.40’’S /44°36’35.80’’, 02.IX.2012, De-Souza, M.R., Nessimian, J.L., Queiroz, F.A. & Souto, P.M. leg. 1 male nymph dissected (DZRJ—Ephemeroptera 2361); same data, 12 female nymphs (DZRJ— Ephemeroptera 2362 ); same data, 1 male nymph (DZRJ—Ephemeroptera 2363); same data, 1 male nymph (DZRJ—Ephemeroptera 2365); same data, 1 male nymph (DZRJ—Ephemeroptera 2366); same data, 1 male nymph (DZRJ—Ephemeroptera 2367); same location, 01.IX.2012, same collectors, 3 males subimagos (DZRJ— Ephemeroptera 2364 ).

Diagnosis. The nymph of M. alegrettae can be distinguished from its congeners by the following combination of characteristics: 1) labrum with broad anteromedian emargination with five rounded denticles ( Fig. 2 ); 2) mandibles with short row of 5–10 setae of circa 0.25 mm length on external margin ( Figs. 4–5 ); 3) segment II of maxillary palp with spine-like setae ( Fig. 3 ); 4) segment III of maxillary palp without peg-like setae ( Fig. 3 ); 5) abdominal terga and sterna with characteristic pattern of black maculae ( Fig. 14 ); 6) abdominal sterna glabrous ( Fig. 4 ); 7) posterolateral projections on abdominal segments short, equal or shorter than 1/2 maximum median length of segment ( Fig. 12 ); 8) gills on segments I–V; 9) gills with membrane dark gray without apical processes ( Fig 8 ).

Mature nymph. Length of body: 13–15mm; caudal filaments, 12mm; general coloration dark with characteristic abdominal color pattern ( Figs. 12–14 ); legs brown with dark brown band on femora and tibiae.

Head ( Figs. 1–7 , 12 ): Head dark brown with lateral margin stramineous; epicranial suture stramineous. Eyes and ocelli black; frontal area between the eyes and the base of antennae, including the lateral ocelli, stramineous; turbinated portion dark brown. Scape and pedicel brown; flagella stramineous. Labrum dark brown at base, lightning to apex; labrum with broad anteromedian emargination with five rounded denticles; presence of apical and subapical rows of stramineous setae; dorsal surface covered with short curved setae and punctuations. Mandibles dark brown at base up to median region and whitish at apical third; presence of a short row of 5–10 setae of circa 0.25 mm length on external margin; incisors detached; prostheca well-developed. Outer incisor of right mandible with three apical denticles; inner incisor with two apical denticles; tuft of translucent setae next to molars. Incisors of left mandible with three unequal apical denticles. Maxillae stramineous with median region dark brown; apical margin light brown with row of long and dense light brown setae and a subapical transverse row of shorter setae; inner margin with fringe of long setae; first segment of maxillary palpi light brown with median dark brown maculae and thin setae on outer margin; second segment with spine-like setae; third segment with long and thin setae. Hypopharynx overall whitish except at apex of superlingua, superlingua light brown with long light brown setae on apical margin; lingua whitish and glabrous. Labium light brown with dark brown maculae; glossae, apical half of paraglossae and inner margin of first segment of labial palpi heavily covered with long brown setae; paraglossae with median dark brown maculae; first segment of labial palpi with median dark brown maculae and covered by dense fine setae on inner margin and thicker setae on outer margin; second segment of labial palpi with median dark brown maculae; second and third segment of labial palpi covered by thicker and less dense setae than on paraglossae and glossae.

Thorax ( Fig. 12 ): Nota brown with some dark brown and black maculae. Wing pads brown with dark brown venation. Sternites light brown.

Legs ( Fig. 9–12 ): Legs yellowish brown. Coxae and trochanters brown shaded in dark brown. Femora of all legs with two transversal dark brown bands. Tibiae and tarsi of all legs lighter than other segments. Coxae with long and thin setae. Coxae and trochanters with short spine-like setae dorsally. Femora, tibiae and tarsi with spinelike setae on ventral and dorsal margins. Tibiae of all legs with two transversal dark bands. Tarsi of all legs with one median band. Femora I and II with claviform setae on dorsal and ventral surfaces, more abundant on inner region; tibiae with claviform setae on dorsal surface, being more restricted on inner surface and less abundant than on femora. Tarsal claws with circa 12 small denticles being the apical denticle much larger than others, and the basal denticles are greatly reduced.

Abdomen ( Figs. 8 , 13, 14 ): abdominal sterna glabrous. Tergites and sternites brown. Abdominal terga and sterna with color pattern of dark brown maculae similar to adults. Posterolateral projections on abdominal segments short, equal or shorter than half maximum length of respective segment. Lateral margin of terga with row of short setae. Gills dark gray, on segments I–V; gills without apical process on dorsal lamellae; black trachea with inconspicuous branches. Caudal filaments yellowish brown expressing the pigmented subimaginal hypoderm of black annulations, visible through nymph cuticle.

Remarks. The nymphs were collected in riffle litter in high speed flow areas of second order stony bottom streams. Mature nymphs and subimagines were collected in early September, indicating that in the study area adults should emerge around late winter and early spring.

Figures

FIGURES 1 – 11. Massartella alegrettae, mature nymph. 1. Labrum, dorsal view (scale: 0.5 mm); 2. Detail of the anterior margin of labrum, dorsal view (scale: 0.5 mm); 3. Maxilla, dorsal view (scale: 0.5 mm); 4. Left mandible, dorsal view (scale: 0.5 mm); 5. Right mandible, dorsal view (scale: 0.5 mm); 6. Hypopharynx, dorsal view (scale: 0.5 mm); 7. Labium (left—dorsal, right—ventral); 8. Gill I, dorsal view (scale: 1.0 mm); 9. Foreleg, dorsal view (scale: 1.0 mm); 10. Detail of two types of setae at foreleg, spine-like at margin and spatulated at surface (scale: 0.1 mm); 11. Fore tarsal claw (scale: 0.1 mm).

FIGURES 12 – 14. Massartella alegrettae, nymph and male subimago. 12. Mature nymph, overall aspect; 13. Abdominal color pattern from male subimago (left—sterna, right—terga); 14. Abdominal color pattern from mature male nymph (left—sterna, right—terga).