Cremastobombycia socoromaensis, Vargas, 2024

Vargas, Héctor A., 2024, Cremastobombycia socoromaensis sp. nov., the first South American representative of the micromoth genus Cremastobombycia Braun (Lepidoptera, Gracillariidae, Lithocolletinae), ZooKeys 1218, pp. 333-342 : 333-342

Cremastobombycia socoromaensis sp. nov.

Figs 1 , 2 , 3 , 4

Type locality.

Chile, Parinacota Province, Socoroma (18°17'22"S, 69°35'12"W), 3400 m elevation on the western slope of the Andes.

Type material.

Holotype. Chile • ♂; Parinacota, Socoroma ; June, 2023; H. A. Vargas leg.; ex-larva; Baccharis tola ; May, 2023; “ HOLOTYPE Cremastobombycia socoromaensis Vargas ” [red handwritten label]; IDEA-LEPI-2024-09 ; HAV-1811 [genitalia slide] ( IDEA) . Paratypes. Chile • 2 ♂ 2 ♀; same data as for the holotype; IDEA-LEPI-2024-10 to IDEA-LEPI-2024-13 ; HAV-1639 , 1719, 1806, 1807 [genitalia slides] ( IDEA) .

Diagnosis.

Among the currently described Cremastobombycia species, C. socoromaensis sp. nov. is recognized based on wing pattern and genitalia morphology. Male forewing (length 3.6–3.7 mm) is brownish-orange and bears poorly defined creamy-white markings: a short longitudinal sub-basal streak and three costal and two dorsal oblique strigulae. Although female forewing (length 3.0– 3.1 mm) is also brownish-orange with a sub-basal streak similar to that of the male, the four well-defined creamy-white transverse fasciae and three well-defined dark brown spots differ from the forewing pattern of the male. Male genitalia of C. socoromaensis sp. nov. resemble those of C. chromolaenae Davis, 2013 from Florida, United States. However, the poorly defined longitudinal sub-basal streak on the forewing of the former clearly contrasts with the conspicuous white longitudinal streak along the basal third on the forewing of the latter ( Davis et al. 2013, figs 2, 3). Furthermore, the posterior projection of the tegumen, the straight margin between the lobes of the transtilla, the vesica with a cornutus in the male genitalia, and the diamond-shaped signum with a transverse fold in the female genitalia allow the recognition of C. socoromaensis sp. nov.; as in the male genitalia of C. chromolaenae the tegumen lacks a posterior projection, the margin between the lobes of the transtilla is concave, and the vesica lacks a cornutus ( Davis et al. 2013, figs 6, 8), and the female genitalia have a strongly bilobed signum ( Davis et al. 2013, figs 9–12). The transverse fold of the signum in the female genitalia of C. socoromaensis sp. nov. resembles that of C. lantanella ( De Prins et al. 2019, fig. 436). However, in clear contrast with the male genitalia of the former, those of C. lantanella lack a posterior projection of the tegumen, have the saccus shorter than the vinculum width, and lack a cornutus on the vesica ( De Prins et al. 2019, fig. 374).

Description.

Male (Fig. 1 A ). Head. Vertex with narrow, elongate, raised scales, mostly brownish-orange and a few dark brown; frons with narrow, elongate, smooth brownish-orange scales. Antenna filiform, slightly shorter than forewing, silvery-gray, scape with pecten. Labial palpus straight, drooping, silvery-gray. Thorax (forewing length 3.6–3.7 mm). Mostly brownish-orange with scattered creamy-white dorsally; silvery-gray ventrally; legs silvery-gray. Forewing brownish-orange with poorly defined creamy-white markings, including a short longitudinal sub-basal streak and three costal and two dorsal oblique strigulae; first two costal strigulae arising before the middle, third one arising near the apex; dorsal strigulae arising near the middle; scattered dark brown scales between the two dorsal strigulae and between the second dorsal and the third costal strigulae; fringe brownish-orange. Hindwing uniformly gray with gray fringe. Abdomen. Mostly gray with scattered creamy-white scales; sternum VIII flap-like, elongate. Male genitalia (Fig. 2 ). Tegumen with narrow arms slightly widened on dorsal half, with flat, somewhat triangular posterior projection bearing eight elongate setae near apex. Vinculum U-shaped. Saccus a narrow, elongate, slightly sinuous rod. Subscaphium a narrow, poorly sclerotized longitudinal stripe ending in a broad patch of microtrichiae. Juxta a broad, poorly sclerotized plate joined to posterior margin of vinculum by a narrow stripe. Transtilla well-differentiated with two widely separated lobes on anterior margin. Valva elongate, slender, length about 1.5 times the saccus; dorsal margin slightly convex near tip; ventral margin mostly straight; apex widely rounded; median surface with dense patch of stout setae on distal third. Phallus cylindrical, straight, about twice the saccus length; coecum about a third the phallus length; a narrow cleft on distal third with two small spine-like projections on opposed margins; vesica with a narrow, elongate cornutus; ductus ejaculatorius with a ring-shaped sclerite near the tip of the coecum.

Female (Fig. 1 B ). Mostly similar to male, except for forewing length (3.0– 3.1 mm) and maculation pattern; mostly brownish-orange with a poorly defined, short creamy-white longitudinal sub-basal streak and four well-defined creamy-white transverse fasciae, the first one convex, the three other straight; a small dark brown spot on the middle of the outer margin of the first fascia; a great dark brown spot between the outer margin of the second and the inner margin of the third fasciae and between the outer margin of the third and the inner margin of the fourth fasciae; a small dark brown spot on the outer margin of the fourth fascia. Female genitalia (Fig. 3 ). Papillae anales flattened, bearing long setae mostly near posterior margin. Posterior apophyses straight, slightly longer than posterior margin of papillae anales. Anterior apophyses dorsally curved, length similar to posterior apophyses. Ostium near the posterior margin of sternum VII. Ductus bursae membranous, narrow, about three times the posterior apophyses length; ductus seminalis arising near the posterior third of ductus bursae. Corpus bursae membranous, oval, about half the length of ductus bursae; signum a slightly sclerotized diamond-shaped plate on posterior half of corpus bursae with a well-sclerotized semicircular serrated transverse fold near the middle.

Etymology.

The specific epithet is derived from the type locality.

Distribution

(Fig. 4 A ). The currently documented range of C. socoromaensis sp. nov. is restricted to the type locality in the surroundings of Socoroma Village, at about 3400 m elevation on the western slope of the Andes in the Parinacota Province of northern Chile.

Host plant

(Fig. 4 B ). Baccharis tola is the only host plant currently recorded for C. socoromaensis sp. nov. This shrub, native to Argentina, Bolivia, Chile and Peru ( POWO 2024), is used for medicinal purposes ( Villagrán et al. 2003). In northern Chile, B. tola inhabits the highlands of the Andes between about 2000–4800 m elevation ( Rodriguez et al. 2018).

Natural history

(Fig. 4 C – E ). Eggs of C. socoromaensis sp. nov. are laid individually mainly on the adaxial surface of the leaf. Larva and pupa are endophytic. The hypermetamorphic larval development includes early sap-feeding and later tissue-feeding forms. The bulged, elongate mature mine occupies a large proportion of the leaf. The last instar tissue-feeding larva constructs a loose, smooth, cylindrical silk cocoon for pupation attached to the mine by anterior and posterior ends. The cocoon and the mine surface are pierced by the frontal process of the pupa to allow the adult emergence.

Figures

Figure 1. Habitus of Cremastobombycia socoromaensis sp. nov. (Lepidoptera, Gracillariidae) A holotype, male B paratype, female. Scale bars: 1 mm.

Figure 2. Male genitalia and sternum VIII of Cremastobombycia socoromaensis sp. nov. (Lepidoptera, Gracillariidae) A male genitalia, phallus removed B phallus C sternum VIII D tegumen apex E phallus apex. Scale bars: 0.2 mm (A, B); 0.1 mm (C – E).

Figure 3. Female genitalia of Cremastobombycia socoromaensis sp. nov. (Lepidoptera, Gracillariidae) A female genitalia B signum. Scale bars: 0.2 mm (A); 0.1 mm (B).

Figure 4. Natural history of Cremastobombycia socoromaensis sp. nov. (Lepidoptera, Gracillariidae) A habitat at the type locality B host plant Baccharis tola (Asteraceae) C leaf mine (red arrow) on B. tola D pupal exuvium (red arrow) attached to the mine after adult emergence E artificially opened leaf mine showing a pupal cocoon (red arrow). Scale bars: 5 mm.