Thereus geminus Faynel & Fåhraeus, 2025

Faynel, Christophe, Huertas, Blanca, Crom, Jean-François Le, O’Brien, Richard & Fåhraeus, Christer, 2025, Diagnostic male secondary sexual structures and wing patterns in the Thereus genena species group (Lepidoptera: Lycaenidae: Theclinae) with the description of nine new species from Colombia, Peru, Brazil and French Guiana, Zootaxa 5728 (2), pp. 201-246 : 214-215

publication ID	https://doi.org/10.11646/zootaxa.5728.2.1
publication LSID	lsid:zoobank.org:pub:2E6171E0-E7A7-430E-BCC0-2C583209A94F
persistent identifier	https://treatment.plazi.org/id/F8303331-AF1F-EA2E-ABEF-FB819A43EEA4
treatment provided by	Plazi
scientific name	Thereus geminus Faynel & Fåhraeus
status	sp. nov.

Treatment

Thereus geminus Faynel & Fåhraeus sp. nov.

LSIDurn:lsid:zoobank.org:act: E21118A2-180D-43D8-B1E0-ABF1E564C629

Figures 4, 5 View FIGURES 2–17 , 35 View FIGURES 34–49 , 51 View FIGURES 50–59 , 67 View FIGURES 66–77 , 87 View FIGURES 86–87

Type material. Holotype male ( Fig. 4 View FIGURES 2–17 ), FW: 16.26 mm, labelled as “Iquitos, Peru, // February 1932. // G. Klug ” (white rectangular label, black printed); “Rothschild // Bequest // B.M.1939-1.” (white rectangular label, black printed); “ Thereus cf. endera ” (white rectangular label, black printed); “NHMUK015201071” (white rectangular label, black printed); “Gen. prep. K. Florczyk // NHMUK015201071” (green rectangular label, black printed); “ Holotype ♂ // Thereus geminus // Faynel & Fåhraeus, 2025 ” (red rectangular label, black printed). Iquitos is in Loreto department. The approximative GPS data are 03°45'S, 73°15'W. The holotype is held at NHMUK collections. GoogleMaps

Paratype ( 1♀ illustrated on Fig. 5 View FIGURES 2–17 ). PERU. Loreto. 1♀, San Juan de Poli, rio Momón , 120m, 03° 37′ S, 73° 25′ W, xii.2018, J.J. Ramírez leg., CF-LYC-1612*, gen. prep. K. Florczyk CFCF029 ( RCCF). The paratype has the following labels “ Paratype ♀ // Thereus geminus // Faynel & Fåhraeus, 2025 ” (blue rectangular label, black printed) GoogleMaps .

Diagnosis and description. Thereus geminus sp. nov. is distinguishable from T. endera , the most closely related species in the phylogenetic tree ( Fig. 1 View FIGURE 1 ), by: (1) bluer male dorsal coloration; (2) VFW postmedian line almost straight, not slightly convex like in T. endera ; (3) VHW postmedian line lacking (or being less pronounced) the characteristical disjunction at M 1 present in T. endera ; (4) 3.47% mean genetic divergence ( Table 3). T. geminus sp. nov. is also close to Thereus cacao sp. nov. but differs by: (1) different blue extents on the dorsal forewings (reduced in T. geminus sp. nov.); (2) valvae less wide at their base, longer and tapered at their end; (3) 2.99% mean genetic divergence ( Table 3). Male ( Fig. 4 View FIGURES 2–17 ). FW length: 16.26 mm, n=1. Wings. Similar to T. endera but dorsally shinier blue, and not blue grey like T. endera . Male genitalia ( Fig. 51 View FIGURES 50–59 ). Holotype dissected. In lateral view, the dorsal brush organs are longer, the ventral edge of the valvae has no step, compared to T. endera . Eighth tergite subrectangular, anterior border convex with a small depression in the center, posterior one concave. Female ( Fig. 5 View FIGURES 2–17 ). FW length: 18.18 mm, n=1. Wings. Similar to T. endera but straighter VHW postmedian line without the disjunction in M 1. Female genitalia ( Fig. 67 View FIGURES 66–77 ). One female dissected. The ductus bursae is 1.5 times longer than in T. endera and the ostium bursae is wider in ventral view. Similar to other species in the group. Larger ductus bursae in ventral view. No signum observed in the corpus bursae, and no sclerotized element in between the papillae anales. Eighth tergite subrectangular, anterior border convex, posterior one concave. The association of the sexes was based on similar type locality, similar ventral wing patterns, the same COI sequence and hence the same BIN (AEL2838).

Sympatry. Thereus geminus sp. nov. and T. endera , are sympatric in Loreto, Peru while T. geminus sp. nov. and T. cacao sp. nov. have allopatric distributions regarding the actual known data.

Known distribution ( Fig. 87 View FIGURES 86–87 ). Only known from Peru (LOR).

Etymology. The name geminus is the Latin word for twin. This refers to its close relationship with T. endera . It is used in a masculine sense and agrees in gender with the generic name Thereus .