Ithome tamarugensis Vargas, 2020

Espinoza-Donoso, Sebastian, Bobadilla, Dante, Huanca-Mamani, Wilson, Vargas-Ortiz, Marcelo & Vargas, Hector A., 2020, A new species of Ithome Chambers (Lepidoptera, Cosmopterigidae, Chrysopeleiinae) from the Atacama Desert revealed by morphology and DNA barcodes, ZooKeys 912, pp. 125-138 : 125

Ithome tamarugensis Vargas sp. nov. Figures 2 , 3 , 4

Ithome sp. ( Vargas et al. 1986; Vargas and Bobadilla 2000)

Ithome concolorella ; misidentification ( Artigas 1994)

Type locality.

Chile, Tarapacá Region, Tamarugal Province, La Tirana village, 20°20'S, 69°39'W.

Type material.

Holotype male, pinned, genitalia slide HAV-1307. Original labels: "Chile, Tamarugal, La Tirana, emerged October, 2019, H.A. Vargas coll.", "ex-larva inflorescence Prosopis tamarugo , collected September, 2019", "Holotype / Ithome / tamarugensis / Vargas" [red handwritten label] (MNNC).

Other material.

Paratypes (Five males, five females). One male (genitalia slide HAV-1309), two females (genitalia slides HAV-1308, 1310), same data as for holotype (MNNC). Four males (genitalia slides HAV-1311, 1313, 1315, 1317), three females (genitalia slides HAV-1312, 1314, 1316), same data as for holotype (IDEA).

Diagnosis.

The mainly shiny black adults of I. tamarugensis resemble those of I. tiaynai , the only other Chilean congeneric. In addition, the genitalia of the two species are outstandingly similar. However, the male of I. tamarugensis has the phallus dorsally excavated in the middle, slightly broadened subapically, and with a deep cleft apically. In contrast, the phallus of I. tiaynai is parallel sided in the middle, slightly straightening subapically, and with a small cleft apically. The female of I. tamarugensis has a short cylindrical antrum and coiled ductus bursae. In contrast, the female of I. tiaynai has a mainly undifferentiated antrum and conic ductus bursae. Although signa were not mentioned in the original description of I. tiaynai , recent observations have revealed the presence of two signa similar to those found in I. tamarugensis .

Description.

Male (Fig. 2 ). Forewing length 4.4-4.6 mm.

Head. Shiny dark grey on face, shiny black dorsally. Haustellum shiny dark grey. Labial palpus shiny black. Antenna shiny black, filiform, about 3/4 wing length; pecten formed by a dark brown scale placed near base of scape.

Thorax. Shiny black dorsally, brownish grey laterally. Foreleg mainly shiny black; coxa brownish grey laterally; brownish grey at middle and apex of tibia and apex of tarsomeres. Midleg mainly shiny black; two brownish grey tibial spurs; brownish grey at apex of tarsomeres. Hindleg mainly shiny black laterally, brownish grey medially; tibia with longitudinal stripe of short, hair-like, yellowish-grey scales dorsally; four brownish-grey tibial spurs; tarsomeres mainly brownish grey with a few darker areas. Forewing shiny black with slightly differentiated (or sometimes absent) brownish-grey transverse stripe subapically; fringe brownish grey. Hindwing shiny black on basal half, brownish grey on distal half; fringe brownish grey.

Abdomen (Fig. 3a ). Mainly brownish grey; shiny black on terga I-IV; lateral membrane of segment VII with a pocket of yellowish-brown, hair-like scales exceeding slightly the posterior margin of tergum VIII. Tergum VII mainly not modified, posterior margin broadly convex. Sternum VII modified, well-sclerotized margins, a transverse stripe close to the posterior margin divides the sternum into a square-shaped anterior part and a posterior transverse band; anterolateral margin slightly convex; posterior part of lateral margin laterally projected, posterior margin slightly convex. Tergum VIII hood-shaped; anterior margin broadly concave, posterior margin broadly convex, slightly excavated in the middle; narrow, sclerotized rod medially, anterior end bifurcated. Sternum VIII strongly modified, partially overlapped with sternum VII; longitudinally divided by a sharp posterior excavation that reaches the anterior margin; two narrow sclerotized rods medially in the middle of anterior margin, length similar to rod of tergum VIII; two finger-like posterior projections of similar length, with right one slightly narrower; both projections with an inward spine of differing length; the left projection with a short, robust, and tapering spine medially near middle, the right projection with a long, narrow, and straight spine medially, bent near base.

Male genitalia (Fig. 3b-f ). Uncus short, slightly shorter than the left spine on sternum VII, narrow, parallel sided, apex suddenly pointed. Tegumen narrow, somewhat forceps-like, slightly broadened ventrally. Saccus about 1.5 times length of uncus, with a longitudinal ventral carina and a pair of convex lateral projections. Subscaphium as a narrow stripe, slightly sclerotized, and with a few small setae on the membrane near base of subscaphium. Valvae asymmetrical; left valva lobular (Fig. 3b , arrow), a slightly curved pointed hook distally (Fig. 3d ), a few short setae near apex of hook; right valva lobular without hook. Phallus (Fig. 3c ) cylindrical, dorsally excavated at middle (Fig. 3e , arrow), slightly broadened subapically; apex with a deep cleft and a knife-like projection. Vesica with a conic cornutus (Fig. 3f ), similar in size to apical cleft of phallus.

Female. Similar to male in size and coloration. Hindwing brownish grey; fenulum with three acanthae. Abdomen brownish grey. Separation between VI and VII segments slightly differentiated.

Female genitalia (Fig. 4a-e ). Papillae analis well sclerotized, fused medially, forming a triangular plate with serrated lateral margin (Fig. 4b ). Intersegmental membrane between papillae and segment VIII with triangular spinules (Fig. 4c ). Posterior apophysis rod-shaped, narrow, elongated, about three times length of tergum VIII. Anterior apophysis rod-shaped, about 2/3 length of posterior apophysis. Tergum VIII slightly more sclerotized and with a few long setae posterolaterally. Lamella postvaginalis as a small semicircular plate in middle of posterior margin of sternum VII (Fig. 4d ). Ostium bursae as a narrow longitudinal slit on middle of sternum VII. Antrum cylindrical, apex rounded. Ductus bursae arising subapically on antrum, membranous, coiled. Corpus bursae pear-shaped, membranous, with two small conical signa close to the base (Fig. 4e ).

Geographic distribution.

Ithome tamarugensis is known from the Pampa del Tamarugal (Fig. 5a ), Atacama Desert of northern Chile.

Host plants.

All the specimens of I. tamarugensis examined in this study were reared from larvae collected on P. tamarugo (Fig. 5b, c ). This tree is the main host plant of I. tamarugensis , although its larvae also feed on inflorescences of at least two other species of Prosopis , P. alba Griseb. var. alba and P. strombulifera (Lam.) Benth. var. strombulifera ( Vargas and Bobadilla 2000).

Etymology.

The specific epithet is derived from the Pampa del Tamarugal, where the type locality of I. tamarugensis , La Tirana village, is located.

Figures

Figure 2. Holotype of Ithome tamarugensis Vargas sp. nov. in dorsal view. Scale bar: 1 mm.

Figure 3. Male genitalia and pregenital abdominal segments of Ithome tamarugensis Vargas, sp. nov. A Abdominal segments VII and VIII B genitalia in ventral view, phallus removed, asterisk shows the right valva C phallus in lateral view D apex of the hook of the left valva (marked with arrow in B) E apex of phallus, arrow shows the dorsal excavation F cornutus. Scale bar: 0.1 mm.

Figure 4. Female genitalia of Ithome tamarugensis Vargas, sp. nov. A Female genitalia in ventral view B papillae analis C ornamentation of intersegmental membrane between papillae and segment VIII D lamella postvaginalis E signum. Scale bar: 0.1 mm.

Figure 5. Habitat and host plant of Ithome tamarugensis Vargas, sp. nov. in the Atacama Desert. A Habitat near La Tirana village, Pampa del Tamarugal, northern Chile B a tree of tamarugo, Prosopis tamarugo (Fabaceae) C inflorescences of P. tamarugo at bud and flowering stages.