Isostenosmylus bifurcatus Ardila-Camacho, Martins & U. Aspöck, 2016

Martins, Caleb Califre, Ardila-Camacho, Adrian & Aspöck, Ulrike, 2016, Neotropical osmylids (Neuroptera, Osmylidae): Three new species of Isostenosmylus Krüger, 1913, new distributional records, redescriptions, checklist and key for the Neotropical species, Zootaxa 4149 (1), pp. 1-66 : 14-16

Isostenosmylus bifurcatus Ardila-Camacho, Martins & U. Aspöck n. sp.

( Fig. 7 )

Holotype, ³, Colombia: Meta, San Martín , Vda. El Merey, Fca. Los Sabanales 3°42’46.85’’N −73°38’42.32’’W, 250 m, 22.ii.2014, A. Reyes (UNAB).

Holotype condition. Pinned, wings partially destroyed, lacking antennae, male terminalia dissected and cleared, stored in a microvial with glycerin.

Distribution ( Fig. 43 ). Colombia (Meta).

Diagnosis. This species is apparently closely related to I. fasciatus Kimmins , but it is distinguished by having weakly pigmented wings and the nygmata inconspicuous. The male ectoproct is rhomboid with two lobes, one posterodorsal, widened and elongated, bilobed at the apex, in lateral view each apical lobe slightly acuminate and blunt in dorsal view; the other one is located posteroventrally, shorter and mammilliform. Ninth gonocoxites with medial lobe straight posteromedially, and slightly emarginate posterolaterally in ventral view.

Head ( Fig. 7 B). Labrum light brown, subrectangular with anterior edge concave, covered with yellowish setae; clypeus light brown, slightly protuberant; frons mainly light brown, with two amber spots beneath antennal sockets. Maxilla light brown, palpi five-segmented, the first four articles light brown, the last brown, galea amber suffused. Labial palpi with the first two articles light brown, the third dark brown. Antennae filiform and composed of 38 articles, scape and pedicel light brown, flagellomeres light brown, densely covered with brown setae.Vertex slightly elevated, rough textured, light brown; peripheral surface of ocelli dark brown suffused, and covered with long setae. Occiput light brown, rugous. Genae amber, postgenae brown.

Thorax ( Figs. 7 A, B). Prothorax, length 2 mm; pronotum greyish brown, with two pairs of dark amber spots laterally, entire surface with numerous setae arising from protuberant bases, some of these dark brown pigmented.

Pleural region of prothorax, anteriorly with a dark brown lobe, densely covered with long setae. Pterothorax, length 3 mm. Mesonotum greyish brown, anterolaterally with three pairs of semicircular amber spots, anterior edge with several amber setae, the remainder surface with scattered yellow setae. Mesonotum greyish brown, scutum laterally with brown spots. Pteropleura greyish brown, with brown spot near wing bases, entire surface densely covered with yellowish setae.

Legs ( Fig. 7 A). Foreleg with elongated coxa, but shorter in mid- and hindlegs. Femora and tibiae mainly pale yellow and covered with setae of the same color, dorsal surface with brown spots at base. Apex of tibiae amber. Tibial spurs short, light amber. Tarsi light brown and covered with yellowish setae, five-segmented, the first tarsomere as long as the following three together, the fifth as long as the second and third together, all covered with pale brown setae. Tarsal claws light brown, arolium present.

Wings ( Fig. 7 A). Forewing, length 26.5 mm, maximum width 9.38 mm; wing veins alternating brown and pale yellow, covered with setae of the same color as cuticle. Wing margin with trichosors. Costal field wide, 53 costal cross-veins, some of these forked near Sc vein. Pterostigma, length 3 mm, slightly marked with mottled color pattern consisting in a mixture of greyish brown and pale yellow. Nine crossveins in the costal field beyond of the pterostigma. Subcostal field hyaline with single crossvein basally. Radial field with 25 crossveins. Rs with 11 or 12 branches. Five presectoral crossveins. Wing membrane barely pigmented, with maculae on crossveins of radial field, Rs, MP and between CuA and CuP. Small amber spot near the posterior margin of wing at the level of the first Rs branch. Nygmata barely perceptible. CuP abruptly curved posterad at the level of the third Rs branch. Branches of the 1A forked, with forks not sinuate. Hindwing, length 21.5 mm; wing membrane hyaline, veins mainly pale yellow with some regions alternating greyish brown. Radial field with 21 crossveins, two or three presectoral crossveins. CuP pectinate, with branches forked, not sinuate. Pterostigma weakly marked with color pattern similar to forewing.

Abdomen ( Figs 7 C, E). Tergites mainly brown, sternites pale yellow, all segments covered with long pale yellow setae.

Male genitalia ( Figs 7 C–F). Eighth and ninth tergites fused, the fusion line inconspicuous, eighth tergite elongated in dorsal view. Ectoproct rhomboidal in lateral view, posterodorsally with a prominent process, the process bilobed at apex, each of these lobes slightly acuminate. In dorsal view with the lobes blunted at apex. Ninth sternite densely setose; in ventral view emarginated posteromedially and rounded. Ninth gonocoxites in ventral view with medial lobe straight posteromedially and with long setae at margin, posterolaterally slightly emarginate. Ninth gonapophysis S-shaped in lateral view, with widened apex. Complex of tenth gonocoxites laterally flattened, like plates joined together, curved in lateral view, posteriorly widened and with two apical processes, one of them posteroventrally located, widened, another posterodorsally located, narrow. Hypandrium internum triangular in ventral view.

Etymology. The name bifurcatus comes from the Latin bi = two and furcatus = forked, in reference to the bilobed process of ectoproct.

Female unknown.

Remarks. Isostenosmylus bifurcatus n. sp., is distinguished from other species previously described from Colombia by the morphology of the male genital structures, wing pigmentation and venation. It is similar to I. septemtrionalandinus in having numerous costal crossveins forked and a weak coloration pattern of wings, but unlike this, Isostenosmylus bifurcatus , has the forks of costal crossveins nearest to the Sc vein, similar to I. contrerasi . This species has 1A branches straight. It differs from I. contrerasi by wing color pattern, morphology of the ectoproct processes and male internal genitalia. Moreover the new species can be differentiated from Isostenosmylus sp., a phenon which has been described as morphospecies of Isostenosmylus by Ardila - Camacho & Noriega (2014), by the shape of costal crossveins and the nygmata being nearly imperceptible. Regarding of the distribution of Isostenosmylus bifurcatus , it is the only Colombian species of Osmylidae found in lowlands (about 250 m); it is distributed in the department of Meta, in the Orinoco basin. In contrast, Isostenosmylus sp. is distributed in the high Andean forest of the western slope of the Eastern Cordillera (Cudinamarca department).

Figures

FIGURE 7. Holotype of Isostenosmylus bifurcatus n. sp., male. A) Habitus dorsal; B) Head and thorax, dorsal view; C – D) Terminalia, lateral view; E – F) Terminalia, ventral view. ect (ectoproct), gcx IX (ninth gonocoxite), gcx X (tenth gonocoxite), gph IX (ninth gonapophysis), S VII (seventh sternite), S VIII (eighth sternite), S IX (ninth sternite), T VII (seventh tergite), T VIII (eighth tergite), T IX (ninth tergite).

FIGURE 43. Distribution of Neotropical Osmylidae species. 1) white star, I. contrerasi; cross, Isostenosmylus sp.; red star, I. bifurcatus n. sp.; white triangle, I. septemtrionalandinus; white circle, I. fasciatus; red triangle, I. irroratus n. sp. 2) asterisk, I. nigrifrons; cross, I. morenoi; red circle, I. julianae n. sp.; star, I. fusciceps; white circle, I. fasciatus. 3) circle, I. pulverulentus; red star, G. adspersus. 4) white star, K. digoniostigma; white circle, K. tjederi; green circle, K. falcatus; red triangle, K. crenatus; cross, Ph. caprorum.