Macunahyphes pemonensis, Molineri, Carlos, Grillet, Maria-Eugenia, Nieto, Carolina, Dominguez, Eduardo & Guerrero, Edmundo, 2011

Molineri, Carlos, Grillet, Maria-Eugenia, Nieto, Carolina, Dominguez, Eduardo & Guerrero, Edmundo, 2011, New species and records for the mayfly families Caenidae, Leptohyphidae and Coryphoridae (Ephemeroptera, Pannota) from Venezuelan Guayana’s Uplands, Zootaxa 2750, pp. 39-50 : 45

Macunahyphes pemonensis sp. nov.

( Figs. 7–8 , 14–16 )

Material. Venezuela, Estado Bolívar: 2 3 imagos (slide 364) from Aponwao, N 5° 51' 2" – W 61° 27' 52", 1340 m, 20/XI/2005, EG, AMO, CA and MEG cols.; 1 3 (slide 515) and 1 & imagos from Mareman-Paru, N 5° 44' 49" – W 61° 24' 6", 1308 m, 28/VI/2007, EG, AMO, CA and MEG cols. Holotype 3 imago and allotype Ƥ in MLBV, 2 paratype 3 imagos in IML.

Male imago ( Fig. 14 ). Length (mm): body, 2.9–3.0 mm; fore wings, 3.1; fore leg, 1.6; cerci, 6.8; terminal filament, 9.0. General coloration whitish yellow. Head yellowish shaded heavily with gray except on two pale transversal strikes and a median blotch between lateral ocelli; antennae whitish, not shaded; venter of head pale, shaded gray on vestiges of submentum. Thorax. Prothorax yellowish translucent completely shaded with black. Meso- and metathorax yellowish orange shaded widely with gray, darker on carinae, anterolateral corners of mesonotum, and pleural membranes; sterna paler. Legs yellowish white shaded with gray on coxa, tibia and tarsus of forelegs. Wings, only fore wings present ( Fig. 16 ), hyaline, membrane tinged with gray on basal half of C and Sc regions and basally to vein A; longitudinal veins blackish, cross veins grayish; vein CuP absent. Abdomen whitish translucent shaded heavily with black on terga 3–7, and with gray on 8–10 ( Fig. 14 ); intersegmental membranes and median line not shaded, translucent; pleural folds 3–7 with black dashes; sterna not shaded. Genitalia ( Figs. 7–8 ) with yellowish white styliger and orangeish penes, forceps absent; styliger plate very slightly projected posteriorly as a columnar base for each forceps with a pair of sublateral acute projections on hind margin (pps in Figs. 7–8 ); penes long and slender with apical furrow and a somewhat protruded ventral structure (vs in Figs. 7–8 ). Caudal filaments translucent very slightly shaded with gray.

Female imago ( Fig. 15 ). Length (mm): body, 3.0 mm; fore wings, 3.1; cerci, 1.0; terminal filament, 1.7. Similar to male except more widely shaded with gray, including thoracic and abdominal sterna, and apex of hind femur. Sternum 9 projected slightly, apically blunt. Caudal filaments whitish.

Etymology. The name of the species, pemonensis , include the voice "Pemon" (meaning "people", according to the Pemon indigenous group from La Gran Sabana) and the Latin suffix "-ensis" (denoting place).

Discussion. This and the following described species are extremely rare, only few specimens are known from different collections. All male adults lack forceps, that may have been present and lost, or more likely their absence is a natural characteristic defining both species in a separate clade. We include the species in Macunahyphes Dias et al. because they show a ventral structure on the penes, a diagnostic character of that genus ( Dias et al. 2005). Other important character defining Macunahyphes is in the shape of forceps, feature obviously impossible to check in the new species described here. All the other characters including wing venation and even color pattern are similar to Macunahyphes australis , the only previously known species. The main difference between the two new species here described and M. australis are: 1) the stronger development of the sublateral processes on the hind margin of the styliger, 2) the slender penes and 3) the absence of spines and the general smaller size of the ventral structure of the penes.

Diagnosis. Macunahyphes pemonensis sp. nov. can be distinguished from all other species in the family by the following combination of characters: 1) eyes similar in both sexes, undivided ( Figs. 14–15 ); 2) fore wings with well developed CU-A lobe, especially in males; longitudinal vein CuP absent in both sexes ( Fig. 16 ); 3) hind wings absent in both sexes; 4) membranous filaments of mesoscutellum absent; and 5) styliger plate very slightly projected posteriorly as a columnar base, forceps absent ( Figs. 7–8 ); 6) penes heavily sclerotized, wide basally and narrowing distally, with a smooth (without spines) ventral projection along their entire length ( Figs. 7–8 ).

Ecology. Imagos were collected along the river margins, at night, and during the rainy season (June 2007 and November 2005). Rivers flow through the upland savanna ecosystem (~ 1308–1340 m) and were non shaded, bedrock bottom rivers with acidic waters (pH=5). Mareman-Parú is a medium river (30 m wide, Fig. 25 ), whereas Aponwao is a large (100 m wide,> 4th order) river ( Fig. 26 ).

Figures

FIGURES 5 – 9. Caenis teipunensis sp. nov.: 5, male genitalia, v. v. (a = apophysis, cs = central sclerite, sc = styliger sclerite, st = small tubercles, vg = ventral groove); 6 a-f, variations in forceps. Macunahyphes pemonensis sp. nov.; 7, male genitalia, l. v.; 8, same, v. v. Macunahyphes incognitus: 9, male genitalia, v. v. (pps = posterior projection of styliger, vs = ventral structure of penes).

FIGURES 14 – 22. Macunahyphes pemonensis sp. nov.; 14, male imago; 15, female imago; 16, male fore wing. Macunahyphes incognitus: 17, male fore wing. Tricorythopsis yucupe: 18, female imago; 19, nymph, l. v. (at = abdominal tubercle, mk = mesonotal keel); 20, styliger and forceps of pharate male adult (sp = styliger projections, f 1 = forceps segment 1, f 2 = forceps segment 2); 21, penes of pharate male; 22, operculate gill, d. v. (tl = transverse line).

FIGURES 23 – 26. Study sites: 23, Kaku Parú; 24, Kavanayén; 25, Mareman Parú; 26, Aponwao.