Hylister obliquus, Do Nascimento, Jeane M. C. & Salles, Frederico F., 2013

Do Nascimento, Jeane M. C. & Salles, Frederico F., 2013, New species of Hermanella complex (Ephemeroptera: Leptophlebiidae) from Brazilian Atlantic Forest, Zootaxa 3718 (1), pp. 1-27 : 12-16

Hylister obliquus sp. nov.

(Figs. 8–12)

Diagnosis. Male imago: (1) fore-wing hyaline, brown at base (Figs. 8A, B and 9A, B); (2) subgenital plate yellowish brown, with pointed projection near inner base of forceps (Figs. 8D and 9D); (3) penes divided on distal 1/3 (Fig. 9D); (4) penis lobe with ventral, short, narrow, posteromedially directed spine (Fig. 9D); (5) abdomen with contrasting color pattern (segments II–VI translucent, segment I dark brown, and terga VII–X reddish brown) (Figs. 8A, B). Nymph: (1) clypeus with lateral margin slightly concave, without anteromedial projection; (2) galealacinia with a prominent tusk on inner apical angle (1/3 the apical width of galea-lacinia) ( Fig. 11 C); (3) tarsal claws with subapical denticle much larger than others ( Fig. 12 D).

Male imago. Length: body, 6.8–8.5 mm; forewing, 6.2–7.5 mm; hind wing, 1.0– 1.3 mm.

Head. Dorsal region orangish yellow with brown marks; ventral region dark brown. Upper portion of compound eye orangish brown, lower portion black; ocelli whitish, surrounded by dark brown. Antenna. Scape and pedicel dark brown, flagellum translucent white.

Thorax. Pronotum yellowish brown, with medial strip, submedial mark and lateral margin black; mesonotum brown, medioparapsidal, mediolongitudinal and anterolateral parapsidal sutures yellow, scuto-scutellar impression whitish, scutellum blackish brown; metanotum yellowish brown with brown areas; pleurae brown, with sclerites dark brown, membranous region lighter; sterna dark brown, prosternal carina narrow (Fig. 8C). Wings (Figs. 8A, B and 9A–C). Membrane hyaline, brown at base. Forewing with longitudinal veins light yellow and cross veins translucent; hind wing with longitudinal and cross veins translucent, vein C brown in basal third. Legs. Coxae and trochanters brown washed with black. Leg I: femur orangish brown; tibia dark orange with a basal slender brown band and an apical slender black band; tarsomeres white, with apical black band. Legs II and III: whitish, femora with apical orangish brown band, tibiae with a small apical brown band.

Abdomen. Tergum I dark brown washed with black, terga II–VI translucent, posterior margin orangish brown; terga VII–X reddish brown, terga VII and IX with submedial white mark. Abdominal sternum I brown, sterna II– VI translucent, medial region with gray mark; VII–IX reddish brown. Genitalia (Figs. 8D and 9D). Subgenital plate yellowish brown, with pointed projection near inner base of forceps. Forceps. Forceps whitish, segment II 0.17 length of segment I, 1.5 length of segment III. Penis divided on distal 1/3, each lobe with a ventral, short, narrow and posteromedially directed spine (Figs. 8D and 9D); penis lobe whitish; spine orangish brown. Caudal filaments white, with apical margin of each segment black.

Female subimago. Length: body, 7.0– 7.8 mm; fore wing, 8.0– 8.5 mm; hind wing, 1.0– 1.8 mm. Color pattern similar to male imago except for the color ligther. Abdomen completely orangish brown, without the male contrasting color pattern. Sternum IX cleft apically.

Mature Nymph. Length: body, 4.8–7.9 mm; antenna, 2.7–3.4 mm; cerci, 6.0– 8.2 mm; terminal filament, 9.3– 13.5 mm. General coloration dark orangish brown, female lighter ( Figs. 10 A, B).

Head. Yellowish orangish brown, with black marks. Upper portion of male compound eye dark brown, lower portion black. Eye of female black. Antenna yellowish white. Clypeus without a anteromedial projection, lateral margin strongly concave, maximum width of labrum 1.3 times maximum width of clypeus. Mouthparts ( Figs. 11 A–E). Labrum ( Fig. 11 A) brown, U-shaped anteromedial emargination; with dorsal proximal row of 27–29 long setae interrupted medially; numerous ventral setae directed obliquely to sagittal plane. Mandible ( Fig. 11 B) brown, except for central region translucent; outer margin strongly curved, forming a right angle; with 3–4 thick and short setae near to basal articulation. Maxilla ( Fig. 11 C). Galea-lacinia with a prominent tusk on inner apical angle (1/3 the apical width of galea-lacinia). Hypopharynx as in figure 11D. Labium as in figure 11E.

Thorax. Terga orangish brown, irregularly washed with gray; pronotum with a dark gray submedial stripe, apico-lateral angle with 2–3thick setae; pleura bownish, washed with gray; sterna whitish yellow. Legs. General coloration brown. Leg I ( Fig. 12 A). Femur with yellowish translucent marks in dorsal region, proximal region gray, outer margin with long and short thick spatulate setae, long spine-like setae and few thin setae; tibia with a medial translucent mark and apical black band, with few setae along outer margins and short spine-like setae in inner margin; tarsi with three apical black bands. Legs II and III ( Figs. 12 B, C). Femora yellowish translucent with a basal and subapical brown bands. Outer and inner margin and dorsal region with long and short thick spatulate setae, outer margin with few thin setae, absent in femur III. Tibia yellowish translucent with medial brown band; tibia II with few short thick spatulate setae in dorsal surface and numerous thin setae in outer margin, tibia III with short thick spatulate setae along outer and inner margin and few long spatulate setae along outer margin. Tarsal claws ( Fig. 12 D) with subapical denticle much larger than others, 4–6 median denticles subequal in size, without accessory denticles.

Abdomen. Terga dark orangish brown, with a submedial yellow spot. Sterna orangish yellow. Gills ( Fig. 10 C) gray, with marks and apical region translucent; plate-like, with apex excavated, bearing long slender processes. Caudal filaments yellowish brown.

Life cycle association. Reared.

Etymology. From the Latin word obliquus , oblique; a reference to the inner margin of the apex of the gills, which is obliquely excavated.

FIGUREs 8. Hylister obliquus , sp. nov., male imago. A) lateral view; B) dorsal view; C) prosternum; D) male genitalia, ventral view.

FIGUREs 9. Hylister obliquus , sp. nov., male imago. A) forewing; B) hind wing; C) enlarged hind wing; D) male genitalia, ventral view.

Material examined. Holotype: Male imago (reared), Brazil, Espírito Santo, Sooretama, Rio São José (S 19°07'33.1'', W 40°14'26.1''), 24m, 09/ix/2010, FF Salles, JMC Nascimento cols. (INPA). Paratypes: one male imago (reared), three male imagos (light trap), three female (reared), 12 nymphs same date of holotype (two male, one female, four nymphs at CZNC; one male, one female, four nymphs at IBN; one male, one female, four nymphs at INPA), five male imago, three female 14/ii/2011 (one male, one female at CZNC; one male, one female at IBN; three male, one female at DZRJ).

Comments. The imago of Hy. obliquus sp. nov. appears very similar to Hy. chimaera Kluge, 2007 , sharing with this species the same pattern of coloration on body and wings. However, both species can be distinguished by the styliger plate, which has a pair of pointed projections near base of forceps in the new species and a pair of large protuberances, each bearing a very small non-sclerotized point on its apex, in Hy. chimaera . The nymphs can be distinguished based on the presence, in the new species, of a subapical denticle much larger than others in the tarsal claw. Besides that, nymphs of the new species possess a unique gill shape. While in Hy. plaumanni Domínguez & Flowers, 1989 and Hy. chimerae the apex is truncate, bearing long slender processes, on the new species the apex also bears these processes, but it is excavate rather than truncate.

Figures

FIGURE 10. Hylister obliquus, sp. nov. A) and B) habitus of nymph; C) gill IV.

FIGURE 11. Hylister obliquus, sp. nov., nymphal mouthparts. A) labrum: left: dorsal view, right: ventral view; B) mandible; C) maxilla; D) hypopharynx; E) labium: right: ventral view, left: dorsal view.

FIGURE 12. Hylister obliquus, sp. nov., nymph. A) fore leg; B) middle leg; C) hind leg; D) tarsal claw.