Stigmella tripartita Diškus & Stonis, 2016

Stonis, Jonas R., Diškus, Arūnas, Remeikis, Andrius, Gerulaitis, Virginijus & Karsholt, Ole, 2016, Leaf-mining Nepticulidae (Lepidoptera) from record high altitudes: documenting an entire new fauna in the Andean páramo and puna, Zootaxa 4181 (1), pp. 1-94 : 36

Stigmella tripartita Diškus & Stonis, 2016

( Figs 1, 2 , 17 , 27 , 88–92 )

Stigmella tripartita Diškus & Stonis, in Stonis et al. 2016b: 110 –112.

Material examined. 2 Ƌ (holotype and paratype), ECUADOR, 15 km SW Cajabamba , Chimborazo Province, 1°45'41"S, 78°48'51"W, elevation 3870 m, mining larvae on Baccharis buxifolia (Lam.) Pers . 19.ii.2007, field card no. 4874, A. Diškus & J. R. Stonis, genitalia slide nos AD622Ƌ holotype, AD624Ƌ paratype (ZMUC) (see Remarks).

Diagnosis. In the male genitalia, the set of three very large cornuti distinguishes S. tripartita from all other Stigmella species; the host-plant ( Baccharis buxifolia ) also makes this species distinctive.

Male ( Fig. 89 ). Forewing length about 3.0 mm; wingspan about 6.5 mm. Head: palpi cream; frontal tuft brown to brown cream; scape cream to yellowish cream; antenna longer than half the length of forewing; flagellum with approx. 26 segments, grey.Thorax and tegula dark grey-brown to fuscous. Forewing dark brown-grey to fuscous, with slightly postmedian fascia; fascia wide to narrow, whitish grey or grey cream; terminal and tornal cilia pale grey-brown. Abdomen dark grey to fuscous (also see Remarks).

Female. Unknown.

Male genitalia ( Figs 39–43 ). Capsule short (230–295 µm) but wide (235–240 µm). Vinculum with very small (25–30 µm), triangularly shaped lateral (anterior) lobes; ventral plate of vinculum short. Uncus 85–90 µm wide, with two small lobes, each bearing one or two papillae. Gnathos stout, with two caudal processes widening basally; central plate of gnathos large to very large, 85 µm wide, in the form of a trapezium ( Fig. 41 ). Valva ( Fig. 39 ) 180 µm long, 80–85 µm wide, with two apical processes (ventral process short and pointed); inner lobe almost straight or slightly bulged; transtilla with rounded sublateral processes or without processes, rounded at corners. Juxta membranous, distinctly triangular, widening caudally. Phallus ( Fig. 90 ) very short (145–200 µm) but wide (120 µm); vesica with a set of three very large (up to 100 µm long) cornuti; no small spinose cornuti developed.

Bionomics. Larva mines in leaves. Host-plant: Baccharis buxifolia (Lam.) Pers. (Asteraceae) ( Fig. 88 ). Larva yellow to pale yellow; mines in February. Contorted gallery of mine with central line of dark brown to black frass (approximately resembling the mines of the European S. myrtilella (Stt.)) . Larval exit slit on upper side of the leaf. Cocoon grey-beige to grey-ochre; length 2.6–3.2 mm, maximal width 1.3–1.8 mm. Adults emerged in March.

Distribution ( Fig. 1, 2 , 17 , 27 ). This species occurs high in the equatorial Andes ( Ecuador: Chimborazo Province) at altitudes between 3800–3870 m, mostly along roadsides.

Etymology. The species name is derived from Latin tripartita (consisting of three parts) in reference to the set of tree cornuti in the male genitalia.

Remarks. This distinctive species, associated with Baccharis buxifolia as a host-plant and possessing three large cornuti in the male genitalia was described from the genitalia slides dissected from adults still enclosed within the pupa shell.

Figures

FIGURE 27. Distribution map of the high-Andean Nepticulidae with height records.

FIGURES 1 – 5. Habitats: grass páramo near volcano Chimborazo (Ecuador: Chimborazo Province) at altitudes about 3980 – 4000 m. 1, 2, habitat of Stigmella gynoxyphaga sp. n. and S. tripartita Diškus & Stonis, 1 ° 31 ' 20 " S, 78 ° 50 ' 27 " W; 3 – 5, habitat of S. lachemillae sp. n. and S. calceolariae sp. n., 1 ° 45 ' 41 " S, 78 ° 48 ' 51 " W.

FIGURES 16 – 17. Distribution of high altitude Stigmella species in the Ecuadorian Andes. 16, habitat of Stigmella paramica sp. nov. and S. confertae Diškus & Stonis, 3700 – 3800 m, 0 ° 21 ' 45 " S, 78 ° 11 ' 35 " W; 17, distribution map.

FIGURES 88 – 92. Stigmella tripartita Diškus & Stonis. 88, host-plant Baccharis buxifolia (Lam.) Pers. (Asteraceae); 89, male forewing, reconstructed from adult still enclosed within the pupa shell; 90, male genitalia, paratype, genitalia slide no. AD 624; 91, same, holotype, genitalia slide no. AD 622, capsule without phallus, dorsal view; 92, same, ventral view (ZMUC).

FIGURES 39 – 43. Genitalia of Stigmella paramica Diškus & Stonis, sp. nov. 39, male genitalia, uncus and gnathos, holotype, temporary mount in glycerol no. AD 611; 40, same, phallus, paratype, permanent genitalia slide in Euparal no. AD 612; 41, same, capsule without phallus, holotype, permanent genitalia slide no. AD 611, ventral view; 42, same, paratype, genitalia slide no. AD 620; 43, female genitalia, paratype, slide no. AD 619 (ZMUC).