Stigmella humboldti Remeikis & Stonis

Remeikis, Andrius & Stonis, Jonas R., 2015, First discovery of Quercus- feeding Nepticulidae (Lepidoptera) in South America, with description of new species and designation of the S. nigriverticella complex in the S. saginella group, Zootaxa 4057 (3), pp. 409-429 : 412-413

Stigmella humboldti Remeikis & Stonis , sp. nov.

( Figs 42–53 )

Type material. Holotype: ♀, Colombia, Cundinamarca Department, San Antonio del Tequendama municipality, Parque Chicaque, 4°36'21"N, 74°18'24"W, cloud forest, elevation 2550 m, mining larvae on Quercus humboldtii , 18.ii.2013, leg. A. Remeikis & J. R. Stonis, genitalia slide no. RA607 (PUJ).

Diagnosis. Externally, Stigmella humboldti sp. nov. is most similar to Central American S. aurifasciata Diškus & Stonis which belongs to the saginella species group and are illustrated in Stonis et al. 2013b. However, in contrast to S. aurifasciata , the golden yellowish area of forewing of the new species is distinctly widened along tornus. In female genitalia, the new species is highly distinctive from all known Quercus- feeding and other Stigmella : the new species possesses two large oval signa comprising numerous large and acute spines. Because this unique character, S. humboldti sp. nov. is not included to any species group of Stigmella (also see Discussion). From the other species, also feeding on Quercus humboldtii in Colombia but belonging to the S. nigriverticella complex and S. saginella group ( S. robleae sp. nov.), it differs by the dark grey hindwing and two black fascia of forewing (see Fig. 56 ), and the specific, broadly oval signa composed by numerous large and acute spines (not lamellar signa as in S. robleae ).

Male. Unknown.

Female ( Figs 48, 49 ). Forewing length 1.8 mm; wingspan 4.2 mm. Head: palpi yellowish cream; frontal tuft entirely orange-ochre; scape yellowish cream; collar ochre-yellow, large; antenna about 1/3 of forewing; flagellum with 19 segments, fuscous on upper side, yellowish cream on underside. Thorax and tegulae yellow-ochre, without darkenings. Forewing with two black fasciae with some purple iridescence: sub-basal and three times broader apical one; apical fascia strongly and abruptly narrowed at tornal margin ( Fig. 49 ); cilia grey except forewing apex where it remains ochre-yellow to yellow cream; underside of forewing dark grey to blackish, with very weak purple iridescence and pale yellow spot on apex. Hindwing (depending on angle of view) dark grey to black-grey on under side and upper side, with some purple iridescence but without spots or androconia; cilia dark grey. Legs glossy, golden cream, with grey to fuscous darkenings on upper side, except midlegs (which remain entirely golden cream). Abdomen fuscous on upper side, dark grey on underside, anal tufts cream.

Female genitalia ( Figs 51–53 ). Total length 605 µm. Apophyses anteriores distinctly shorter than apophyses posteriores ( Fig. 53 ). Distal, slender part of apophyses anteriores 50–55 µm long; length of slender part of a. posteriores 105–110 µm. Vestibulum narrow, without sclerites. Accessory sac small, rounded. Corpus bursae oval, 415 µm long, covered with numerous pectinations and with two large, oval signa on both sides; signa comprise numerous large acute spines; signa not fully symmetrical: one larger (240 µm long, 100 µm broad), the other slightly smaller (190 µm long, 95 µm broad); they are overlapping in figs 52, 53.

Bionomics ( Figs 43–47 , 50 ). Mines in leaves ( Figs 43, 45–47 ). Host-plant: Quercus humboldtii Bonpl (section Lobatae) ( Figs 23–25 ). Egg on upper side of the leaf. Larvae mine in January and early February (in February most of leaf-mines are already empty). Sinuous gallery of mine filled with black frass, very narrow unfilled (clear) margins left only in final part of the track ( Figs 46, 47 ). Larva bright green, with dark green to pale brown intestine. Larval exit slit on upper side of the leaf. Cocoon ( Fig. 50 ) beige cream; length 2.2 mm, maximal width 1 mm. Adults emerged in March.

Distribution ( Fig. 42 ). Currently known from single locality in Colombia (Parque Chicaque, SW Bogotá), in cloud forest at elevation 2550 m ( Fig. 44 ).

Etymology. As its host-plant ( Quercus humboldtii ), this new species of leaf-miner is named after Friedrich Wilhelm Heinrich Alexander von Humboldt (1769–1859), famous naturalist, geographer and explorer, who travelled extensively in Latin America and laid the foundation for the science of biogeography.

Remarks. Although descriptions of new species based on single specimens are generally not recommended, in our opinion the report (description) of this taxon has some merit due to several unique features and its endemic host-plant.

Figures

FIGURES 56. Comparison of the species of the Stigmella nigriverticella complex.

FIGURES 42 – 47. Distribution and bionomics of Stigmella humboldti sp. nov. 42, distribution map; 43, 45 – 47, leaf-mines on Quercus humboldtii Bonpl (section Lobatae); 44, habitat, cloud forest at elevation 2550 m, 4 ° 36 ' 21 " N, 74 ° 18 ' 24 " W, Parque Chicaque, Colombia.

FIGURES 48 – 53. Stigmella humboldti sp. nov., holotype. 48, 49, female adult; 50, cocoon; 51; female genitalia, slide no. RA 607, abdominal tip; 52, same, signa; 53, same, general view (currently in LEU, with ultimate deposition in PUJ).

FIGURES 22 – 28. Bionomics of Stigmella robleae sp. nov. 1, habitat, montane mixed forest at elevation 2000 m, 5 ° 02 ' 04 " N, 75 ° 28 ' 41 " W, Manizales, Colombia; 23 – 25, host-plant Quercus humboldtii Bonpl (section Lobatae); 26 – 28, leaf-mines.