Siderus bisignatus Faynel, Ramirez & Robbins 2024, sp. nov.
Creators: name: Faynel, Christophe
name: Fåhraeus, Christer
name: Ramirez, Juan-Jose
name: Robbins, Robert K.
Publisher: name: Zenodo
Year: 2024
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Lepidoptera
Lycaenidae
Siderus
Siderus bisignatus

description: Siderus bisignatus Faynel, Ramírez & Robbins sp. nov.
(Figures 10, 17, 18, 22, 30)
Diagnosis and description. Male mean FW length: 14.3 mm (n = 5). Siderus bisignatus sp. nov. is a strange Siderus species that differs from its congeners by possessing a small oblique white line at the base of VHW in Sc+R1-Rs (Fig. 10) and by its male genitalia (Figs 17, 18, 22). Males are dark iridescent blue dorsally with a broad black apex. The DFW androconial spot consists of an oval scent patch in the discal cell and a triangular scent pad at the base of forewing vein M1. The ventral wing pattern is reminiscent of S. athymbra (Figs 13, 14, 18), especially the dark brown basal part of both wings, which is one of the reasons for an initial placement in the genus Siderus. Male genitalia: valvae without tapered terminal part as in other species but with a central constriction; very long saccus and a stout penis with an enlarged posterior part. The female remains unknown (see DISCUSSION).
Type material. Holotype ♂ (Fig. 10): “ GUYANE // St Laurent du Maroni // Route d’Apatou // 17. X. 2012 // Mohamed BENMESBAH leg.” [white rectangular label, printed in black], “C. FAYNEL // n° 2338” [white square label, printed in black], “Genitalia CF n° 611” [white rectangular label, printed in black], “CF-LYC-524” [orange rectangular label, printed in black], “Holotype ♂ // Siderus bisignatus // Faynel, Ramírez & Robbins, 2024” [red rectangular label, printed in black]. Will be deposited in MNHN. The approximative GPS data of the type locality are 5°29′ N, 54°02′ W.
Paratypes: PERU. Loreto. 1♂, El Milagro — km 21, carretera Iquitos — Nauta, X.2010, J.J. Ramírez leg., Coll. C.F. n° 15676, DNA CF-LYC-407 (CF); 1♂, El Milagro — km 21 route Iquitos — Nauta, VIII.2011, J.J. Ramírez leg., Coll. C.F. n° 15784, DNA CF-LYC-1119, Genitalia CF n° 612 (CF); 1♂, El Milagro, XI. 2013, 03°57´S, 73°22´W, J.J. Ramírez leg., Coll. C.F. n° 16302 (CF); 1♂, Tierra Hermosa, 140m, XI.2023, 03°20´S, 73°19´W, J.J. Ramírez leg., DNA CF-LYC-2187 (CF); 1♂, Loreto, Agua Blanca, 0356/ 7328, 130m, 6.IX.2005, J.J. Ramírez (MUSM). BRAZIL. Pará. 1♂, M. de Mathan leg., Ex Oberthür Coll., Brit. Mus. 1927-3, genitalia No. 1990: 65♂, R.K. Robbins (NHMUK015203858, on loan USNM).
Distribution. French Guiana, Peru (LO), Brazil (PA).
Natural history. This uncommon species is known from lowland rainforests.
Etymology. The latinized name ‘bisignatus’ comes from the VHW basal marks. The name is masculine, in accordance with the genus Siderus considered as masculine.
Systematic Placement. The specimens from different countries (French Guiana, Brazil, Peru) have been recognized as belonging to the same species because they are the only Eumaeini having a ventral wing pattern with the white comma at the base of VHW. Moreover, the specimens from Peru and French Guiana share the same sequence BIN (ACK3174), i.e., they are recognized as a single species by the clustering algorithm with only 0.7% divergence (pairwise p-distance). S. bisignatus sp. nov. shows differences in male androconia and genitalia with the other Siderus species, and comes out as sister to the rest of the Siderus (Figs 33, 34). However, we believe it is best placed in Siderus since it is sharing a long branch with the rest of Siderus, separating it from all the members of the outgroup.
Genitalic Variability. Besides being distinctive, the male genitalia show variation in the structure of the valvae, saccus and terminal penis (Figs 17, 18, 22) unlike that reported before in the Eumaeini. In lateral view, the holotype from French Guiana (Fig. 22 on the left) has a spine at the ventral terminal part of the penis (arrow a) and a ventral step at the ventral edge of the valvae (arrow b), absent in the other two. The specimen from Brazil (Fig. 22 on the right) has a squared posterior end of the valvae (arrow c), while the others have rounded ones and the end of its penis (arrow a) forms a bump and bears two cornuti while the other have no bump and only one cornutus. Length of the saccus (arrow d) and penis vary also. A hypothesis explaining this variation could be that they represent more than one species. However, for now, we consider it to be intraspecific because of the small study sample (4 dissected specimens) and the limited genetic information with moderate distance divergence (3 barcodes only).
description: Published as part of Faynel, Christophe, Fåhraeus, Christer, Ramirez, Juan-Jose & Robbins, Robert K., 2024, The genus Siderus (Lepidoptera: Lycaenidae) in French Guiana: four newly discovered species and conspicuous male genitalia polymorphism, pp. 38-58 in Zootaxa 5519 (1) on pages 47-49, DOI: 10.11646/zootaxa.5519.1.2, http://zenodo.org/record/13915424