Asthenopus magnus, Molineri, Carlos, Salles, Frederico F. & Peters, Janice G., 2015

Molineri, Carlos, Salles, Frederico F. & Peters, Janice G., 2015, Phylogeny and biogeography of Asthenopodinae with a revision of Asthenopus, reinstatement of Asthenopodes, and the description of the new genera Hubbardipes and Priasthenopus (Ephemeroptera, Polymitarcyidae), ZooKeys 478, pp. 45-128 : 88-89

Taxon classification Animalia Ephemeroptera Polymitarcyidae

Asthenopus magnus sp. n. Figs 4C, 14C, E, G, I–J, 15 A–D, 16 C–D, 17G, 18 E–F

Asthenopus curtus , Domínguez 1989: 173; Domínguez et al. 2006: 561 (missidentification).

Material.

Holotype (IBN) male imago from Ecuador, Napo Province, Laguna Limon Cocha, 250 m, 6.iv.1984, E. Domínguez col.(aprox. S 0°24' − W 76°38'). Paratypes, same data as holotype, separated in 16 vials including: 1 nymph dissected (parts in alcohol), 2 male imagos (parts on slides: IBN-2-64ED, IBN-2-70ED), 1 male imago (IBN-2-67ED), 2 nymphs/3 exuviae/1 pharate male, 1 pharate male subimago and nymphal cuticle (IBN483CM), 1 male imago (IBN481CM), 3 nymphal exuviae (IBN640CM, IBN641CM), 7 nymphal exuviae (1 at FAMU, 1 at CZNC), 5 female adults (used for SEM); 7 male imagos (used for the description; 1 at FAMU, 1 at CZNC), 20 male subimagos, 10 female adults, 1 male and 8 female subimagos, 10 female adults, 9 female adults (1 at FAMU, 1 at CZNC), 1 female adult (IBN-2-71ED). All the material is deposited in IBN except otherwise indicated.

Diagnosis.

Asthenopus magnus , known from all the stages, can be distinguished from other species in the genus by the following combination of characters (also see the six autapomorphies in Appendix 2): 1) male FW 9.0-10.1, female FW 16.0-17.5; 2) forelegs of male 0.69-0.73 × the length of FW; 3) pronotum width/length ratio: 1.7-2.4 (male), 2.0-2.2 (female); 4) FW (Fig. 16C) with 6-14 relatively short marginal intercalaries (21-28 in female), hind wings with 2-4 (5-7 in female) marginal intercalaries; 5) male FW with 0 to 2 (2-3 in female) cross veins between Rs and MA basal to Rs fork; 6) forceps relatively slender, ratio length/basal width 6.1-6.2 (Fig. 17G); 7) penes tubular and robust, with well developed thumb, curved ventro-medially, with apex projecting medially as a distal spine, furrow separating penis lobe from thumb reduced; median remnant of styliger plate subrectangular, pedestals subrectangular to subovate, relatively large (Fig. 17G); 8) female sternum VIII with reduced, not distinguishable female sockets, but with a long anteromedian keel (Fig. 18F); 9) eggs (Fig. 18E) ratio maximum width of egg/maximum width of PC 1.2-1.3, cap formed by 4-5 filaments, chorionic plates separated by smooth chorion; 10) nymph, ratio total length of mandible/mandibular tusk length 1.4-1.5; 11) inner margin of left mandibular tusk with subbasal and submedian tubercles well separated (Fig. 14C, E).

Male imago. Length (mm): body, 9.0-10.5; FW, 9.0-10.1; HW, 4.0-4.8; leg I, 6.5-7.4; cerci, 37.0. General coloration yellowish light brown. Head whitish shaded black dorsally on pale median mark on hind margin and along inner margin of eyes; frons pale except paired submedian black lines. Antennae: whitish shaded diffusely with gray on scape and apex of pedicel; length (mm): scape 2.25, pedicel 1.5, flagellum 7.25. Thorax. Pronotum yellowish translucent shaded with black dorsally except at pale median membrane between both pronotal rings, on mediolongitudinal line and along margins; the black shading presents many scattered and small pale spots. Pronotum width/length: 1.7-2.4. Meso- and metanotum yellowish shaded with grayish on carinae, posteromedian triangular mark (on mesonotum), and scutellum (both). Thoracic pleurae and sterna paler, shaded gray on pleural sclerites. Legs yellowish white, shaded gray on all coxae. Leg I shaded gray almost completely, stronger on femur and tibia, paler on tarsal segments (Fig. 20J). Legs II–III shaded with black dorsally on apex of femora and entire dorsum of tibiae, rest pale. Wings (Fig. 16 C–D). Membrane hyaline shaded grayish near costal margin on basal half, more whitish apically; all veins translucent completely shaded gray; 1-3 cross veins between MA and R, basad to R stem. Abdomen yellowish white shaded with gray and black dorsally except on median and lateral zones and intersegmental membranes. Median pale areas on terga II–IX are oval and are surrounded by darker pigments, a delicate mediolongitudinal black line is present but sometimes is only visible on tergum IX. Sterna whitish turning yellowish laterally and on sternum IX, shaded gray on paraproct and basally to terminal filament. Genitalia (Fig. 17G): forceps whitish, penes yellowish white. Cerci whitish very slightly shaded with gray.

Female imago. Length (mm): body, 15.5-19.5; FW, 16.0-17.5; HW, 5.2-7.8; cerci, 3.5-5.0. Pronotum width/length: 2. Morphologically very similar to Asthenopus curtus and Asthenopus angelae , the last is described elsewhere ( de Souza and Molineri 2012). Color pattern similar to male but more strongly marked, exceptions follows: pale median mark on occiput longer, reaching median ocellus; wing membrane tinged with yellowish near costal margin and base, all veins shaded brown; shading on abdominal terga more extended, shaded widely gray except medially, tergum VIII–IX (sometimes also II–VII) with a black line in the pale median zone; medial margins of gill sclerites on abdominal sterna II-VII and lateral margins of sterna VIII–IX grayish; Sternum VIII with keel as in Fig. 18F. Cerci yellowish, 0.3-0.4 the length of FW.

Eggs (Fig. 18E). Length, 250-285 µ; width, 145-160 µ. Two polar caps (maximum width, 115-135 µ), formed by 4-5 very long coiled threads. Chorionic surface smooth with relatively large subcircular chorionic plates, the plates are regularly spaced and some of them are divided in two or three subequal parts.

Nymphs. Length of male (mm): body, 10.0-11.0 mm; cerci, 7.0-8.0; terminal filament, 5.0-5.5. Length of female (mm): body, 17.0-20.0 mm; cerci, 4.0-5.0; terminal filament, 5.0. General coloration brownish. Head (Fig. 14 I–J) yellowish brown extensively shaded with grayish brown, darker on a band between ocelli, occiput with a profuse netted grayish pattern, except on paler median zone and along inner margin of eyes; paler areas also present basally to antennae and around median ocellus. Antennae yellowish white, length (mm): scape (0.5), pedicel (0.28), flagellum (2.0). Mandibular tusks with relatively large space between large basal tubercle and smaller subdistal tubercle, not C-shaped as in Asthenopus curtus but in the form of broad “C” or bracket-shaped (Fig. 14C, E, G). Thorax. Anterior ring of pronotum (collar) blackish; posterior ring shaded gray except on mediolonitudinal line and a pair of sublateral pale marks; pronotal membranes whitish. Mesonotum brownish, lighter toward apex of wingpads. Thorax ventrally whitish. Legs (Fig. 15 A–D) whitish yellow shaded with gray on coxae, apex of femora and along tibiae; foretarsal claw with 20 (male) to 31 (female) denticles in a marginal row, increasing in size distally; distal region of hind femur with a group of ca. 60 (male) to ca. 100 (female) stout spines. Abdomen. Terga shaded gray dorsally, except on paler median band, a thin black median line is present inside this pale area on tergum IX–X; lateral zones of terga below gills, pale. Gills whitish almost completely shaded with gray, darker on outer (exposed) zones. Sterna whitish shaded with gray on lateral margins of sterna VIII–IX, and with grayish black on paraprocts (Fig. 15E). Caudal filaments yellowish.

Etymology.

From Latin “magnus” meaning “large”, noun in apposition. The name alludes to the general size of the individuals, mainly the female adults.

Distribution.

Only known from the type locality in Napo (Ecuador).

Discussion.

The type series described here as Asthenopus magnus were previously treated as Asthenopus curtus ( Domínguez 1989: 173; Domínguez et al. 2006: 561), and used to record the latter species in Ecuador. As a result of our study we found some characters distinguishing these specimens as a new species, and thus Asthenopus curtus is no more considered to be present in that country. Nymphs and adults of both sexes were associated by nymphal exuviae and adults caught at the moment of emergence.