Thereus tierralinda Faynel & Fåhraeus, 2023

Faynel, Christophe & Fåhraeus, Christer, 2023, Two new Thereus species from Peru, with notes on ecological niche partitioning (Lepidoptera: Lycaenidae: Theclinae), Zootaxa 5315 (4), pp. 301-314 : 303-306

Thereus tierralinda Faynel & Fåhraeus , sp. nov.

( Figures 1 , 10 , 15 , 23 )

Type material. Holotype ♁ ( Fig. 1 ): “ Pérou - Cusco // Carretera Manu, Km 89 // Chontachaca , 772 m // Réserve Tierra Linda // Poste 10h20 // S 13°00.172’ - O 71°27.849’ // 7.VIII.2019 C. Faynel leg” (white rectangular label, black printed); “LYC 1021” (orange rectangular label, black printed); “Diss. n° 654 // 19.IX.2019 // C. Faynel ” (white rectangular label, black printed); “HOLOTYPE ♁ // Thereus tierralinda // Faynel & Fåhraeus, 2023” (red rectangular label, black printed). Currently in CF, will be deposited in MUSM.

Paratypes: 1♁, same data as holotype, DNA sample ID LYC 1023 ( CF) ; 1♁, same locality as holotype, 4.VIII.2021, 10:10 am ( CF) ; 2♁, same locality as holotype, 22.IX.2021, 9:33 am & 9:35 am, DNA sample ID CFCA01836 & CFCA01835 ( FILS) . Paratypes have the following label: “ Thereus tierralinda // Faynel & Fåhraeus, 2023 // Paratype ♁” (blue rectangular label, black printed).

Diagnosis. Thereus tierralinda sp. nov. is placed in Thereus because males possess secondary sexual structures including DFW double androconia (scent patch and pad), as well as a pair of small ventro-lateral brush organs in addition to the huge pair of dorsal ones attached to an anterior process of the vinculum ( Fig. 15 ). Males of T. tierralinda sp. nov. have an external morphology similar to the sympatric T. columbicola . They differ from T. columbicola and other Thereus species by: (1) the size of the double androconial spot on DFW with a large black scent patch that occupies almost the entire discoidal cell, similar to the patch in T. columbicola , and a huge brown scent pad centered on the discocellular veins that is much larger than in any other species of the Thereus eryssus species group ( Figs 10–14 ); (2) very dark ventral wing patterns with a VFW dark brown postmedian band wider than in its congeners ( Figures 1, 2, 3, 5, 7 ); (3) the shape of the valvae in ventral view ( Figs 15–19 ); (4) a mean genetic distance (COI sequence) of 3.6% with the nearest species, T. columbicola , in the distance matrix (Table 3, respective BIN AEB9489 and ACK2912). The five males examined are also larger than all the males of T. columbicola , T. eryssus , and T. illex we have examined in collections, with a wing span range from 9 to 20% larger depending on the species (see Figs 1–8 ).

Description. Male ( Fig. 1 ). FW length: 18.9 mm (SD = 0,57, n = 5). Head: Brown eyes sparsely pilose with white circumference; black antennae ringed with white, orange nudum; labial palps with grey scales, white at base. Thorax: dark brown with blue scales dorsally, brown and hairy ventrally; legs brown and white. Abdomen: grey brown dorsally, brown ventrally, with a thin cream-colored line. Wings: DFW: blue basal part, distal half of wing black; scent patch black, oval inside cell; scent pad oval of the same size, dark brown, centered on discocellular veins and seemingly covering scent patch on its distal part ( Fig. 10 ). VFW: brown ground color; costa reddish orange at its base. Broad postmedian band, of the same hue but darker, going from coast to CuA 2 bordered externally by some white scales. Submarginal band, also darker but finer and more diffuse, going from R 3 to 2A. DHW: mostly blue (between veins M 1 and 2A) with black costal margin and beige grey anal border covered with light grey bristles. VHW: brown ground color, even darker than on FW; postmedian and submarginal band darker but less visible than on FW. Postmedian and submarginal bands bordered by white, externally and internally respectively. Small CuA 1 –CuA 2 red orange spot with black pupil, tornus perfectly imitating false head with black spot (eye) surrounded by white scales (as around eye) and red orange line like base of costa. Brown fringe on outer margin of both wings. Tails at the end of CuA 1 short (1 mm) and CuA 2 long (4 mm), both brown with white tips. Male genitalia ( Fig. 15 ): uncus subrectangular, narrow and setose; gnathos curved but not bent; tegumen with a ventral pointed projection; vinculum with a dorso-lateral process supporting long dorsal brush organs (secondary sexual organ) with another pair of shorter brush organs attached to the lateral part of vinculum, just before saccus; valvae short (two fifths of genitalia length) and hemispherical with rounded posterior margin in ventral view; saccus short and pointed. Aedeagus with two cornuti situated at the dorsally curved posterior end. Eighth tergite with anterior border modified in W-shape ( Fig. 23 ), often characteristic of species with brush organs which increase eighth tergite length (Faynel pers. obs.). Female. Unknown.

Etymology. Tierra Linda is a private voluntary reserve created by Jose Vicens and Pilar Diez Hurtado that welcomes volunteers and researchers in ecology. It now belongs to Kety Paredes. This reserve is located not far from the Chontachaca village, in the valley of the Rio Cosñipata ( Peru, Cusco). The name of this species is a noun in the nominative singular standing in apposition to the generic name, not Latinized.

Ethology. Males exhibit a territorial behavior in the morning around 10:00 in a sunny forest clearing at around 5 m from the ground ( Table 1 ). They chase conspecific males and butterflies from other families that have transgressed into their territory with a powerful flight. Usually, the fighting remains in the flight zone, having a 3 to 5 meter radius from the perch ( Fig. 24 ), but sometimes two males leave the flight zone and fly away, circling perhaps more than 30 meters into the air before returning and landing on top of the vegetation. Only a small number of males of T. tierralinda sp. nov. were observed flying at the same time, generally two but occasionally three, a pattern also seen for T. columbicola .

Distribution and bionomics. This species is only known from the type-locality ( Fig. 9 ). This old-growth secondary rainforest was well conserved until 2019. In 2021, unfortunately, large areas were cut for coca cultivation and construction of new lodges.

Figures

FIGURE 9. Type locality of Thereus tierralinda sp. nov., with the Manu Road going through Chontachaca on the North along the Cosñipata river (source: Google Earth).

FIGURE 23. Male eighth tergite in ventral view.Anterior border (at bottom) W-shape on Thereus tierralinda sp. nov. (left) and subrectangular on T. vicens sp. nov. (right).

FIGURE 24. Flight zone of T. tierralinda sp. nov. in 2019 and 2021 (higher oval) and the approximate flight zone of T. columbicola in 2017 and 2018 (lower oval) from a riverside clearing adjacent to the Tierra Linda Reserve camp (picture taken in 2021). Arrows indicate the preferred location for the observation posts.

FIGURES 1–8. Adults of Thereus, dorsal view at left. 1.♁ T. tierralinda sp. nov. (HT, Peru, MUSM). 2. ♁ T. illex (Colombia, MNHN). 3. ♁ T. vicens sp. nov. (HT, Peru, MUSM). 4. ♀ T. vicens sp. nov. (Peru, FILS). 5. ♁ T. columbicola (Peru, CF). 6. ♀ T. columbicola (Peru, CF). 7. ♁ T. eryssus (Brazil, CF). 8. ♀ T. eryssus (Brazil, CF).

FIGURES 10–14. Male DFW androconia. 10. Thereus tierralinda sp. nov. 11. T. illex. 12. T. columbicola. 13. T. eryssus. 14. T. vicens sp. nov.

FIGURES 15–19. Male genitalia, ventral view (on right), left lateral view (at left). 15. Thereus tierralinda sp. nov. (HT, Peru, MUSM). 16. T. illex (Colombia, MNHN). 17. T. columbicola (Peru, CF). 18. T. eryssus (Brazil, CF). 19. T. vicens sp. nov. (HT, Peru, MUSM).