Thereus ramirezi Faynel, Huertas & Fåhraeus sp. nov.

LSIDurn:lsid:zoobank.org:act: 494FB4F7-0F5E-4795-8D3F-CCADCA4C2025

Figures 15, 43, 59, 88

Type material. Holotype male (Fig. 15), FW: 15.4 mm, labelled as “Holo- // type” (white disc surrounded by red, black printed); “ Pérou // Moyobamba // M. de Mathan // 1er Sem. 1887” (white rectangular label, black printed); “Oberthur // Bequest // BMNH // 1927-3” (white rectangular label, black printed); “ thecla endera ? // Hew. pl. 42 // fig. 156. 157.” (white rectangular label, black handwritten); “ ‘Thecla’ pseudoendera // B. D’Abrera m/s Holotype ” (white rectangular label, red handwritten, see Remarks); “ Thereus sp. ” (white rectangular label, black printed); “ NHMUK 015201088 ” (white rectangular label, black printed); “Gen. prep. K. Florczyk // NHMUK015201088” (green rectangular label, black printed); “Holotype ♂ // Thereus ramirezi // Faynel, Huertas & Fåhraeus, 2025 ” (red rectangular label, black printed). Moyobamba is the capital city of the San Martín Region in northern Peru. The holotype is found in NHMUK collections .

Paratype (1♂). PERU. San Martín. 1♂, Tarapoto, San Antonio de Cumbaza, 450m, 6°24′33″ S, 76°24′22″ W, xi-2022, A. Passerieux leg., CF-LYC-2175 * (Collection Passerieux). The paratype has the following labels “Paratype ♂ // Thereus ramirezi // Faynel, Huertas // & Fåhraeus, 2025” (blue rectangular label, black printed) .

Diagnosis and description. In the ML tree (Fig. 1), Thereus ramirezi sp. nov. is sister to T. chontachaca sp. nov., to which it is externally most similar. It differs from it by: (1) bigger male DFW scent patch and scent pad; (2) male genitalia with wave-shaped dorsal edge of vinculum (character unique in the genus) supporting dorsal pair of brush organs half as short as in T. chontachaca sp. nov.; (3) 2.77 % mean genetic distance divergence with T. chontachaca sp. nov. (Table 3). Male (Fig. 15). FW length: 15.4 mm (n = 1). Wings. The male holotype of Thereus ramirezi sp. nov. is 20% larger than T. chontachaca sp. nov. DFW blue covering two-thirds of the wing. Ventral postmedian line farther from the external margin, compared to T. chontachaca sp. nov. Male genitalia (Fig. 59). Holotype male dissected. Wave-shaped dorsal edge of the fused tegumen/vinculum with two dorsal projections (black arrow on Fig. 59) visible in lateral view, that does not appear in any other species of the genena species group, the posterior one supporting short dorsal brush organs; penis straighter than in Thereus chontachaca sp. nov.; eighth tergite suboval with anterior and posterior edges convex. Female. Unknown.

Ethology. The male from Tarapoto was found near a river.

Sympatry. According to the known distribution (Fig. 88), T. ramirezi sp. nov. is allopatric from both its sister species T. chontachaca sp. nov. and the more distantly related T. borbaensis sp. nov.

Known distribution (Fig. 88). Only known from Peru (San Martín).

Etymology. This rare species is named to honour local biologist Juan José Ramírez (Universidad Nacional de la Amazonía Peruana, Iquitos, Peru) who has worked with the Peruvian butterfly fauna for more than 30 years.

Remarks. Thereus ramirezi sp. nov. was recognized as a different species from T. endera 30 years ago by D’Abrera (1995) who put a manuscript label under the specimen but did not formally describe it when he published his book.