Synargis attilius ( Stichel, 1925 ) Zhang & Cong & Shen & Song & Grishin, 2024

Zhang, Jing, Cong, Qian, Shen, Jinhui, Song, Leina & Grishin, Nick V., 2024, Taxonomic advances driven by the genomic analysis of butterflies, The Taxonomic Report of the International Lepidoptera Survey 11 (7), pp. 1-43 : 17-18

Synargis attilius ( Stichel, 1925) is a species distinct from Synargis regulus (Fabricius, 1793)

Genomic analysis of two syntypes of Nymula regulus attilius Stichel, 1925 (type locality in Brazil: Rio de Janeiro; sequenced as NVG-21119F06 and NVG-21119F07) reveals that, together with other specimens from Southeast and South Brazil ( Fig. 15 blue), they are sister to and genetically differentiated from Synargis regulus (Fabricius, 1793) ( Fig. 15 olive) at the species level, e.g., their COI barcodes differ by 6.7% (44 bp). Therefore, we propose that Synargis attilius ( Stichel, 1925) stat. nov. is a species distinct from Synargis regulus (Fabricius, 1793) .

Zimsen (1964) did not specify repositories of S. regulus syntypes, which were from the Drury collection. We are not aware of their whereabouts and are researching this question. Presently, short of a neotype designation if no syntypes can be located, our identification of this species is based on the Jones’ illustration (Oxford University Museum of Natural History 2021), which shows a comparatively large female with broad pale-yellow markings and a ventral hindwing brown border without a pair of yellow marginal spots inside it. According to our analysis, only one species of the S. regulus complex lacks these yellow spots. It is a Southeast Brazilian species, where it may be sympatric with S. attilius .

We identify the “ holotype ” of an infrasubspecific name Nymula regulus regulus forma ingens Stichel, 1925 (from Brazil: Espirito Santo, sequenced as NVG-21119F08) referring to a “giant form” of the species ( Stichel 1925) as S. regulus , in agreement with Stichel. However, not all S. regulus specimens are that large, and NVG-21119F08 is smaller than an average S. attilius . Besides the absence of yellow marginal spots inside the brown ventral hindwing marginal area, males of S. regulus can be distinguished from S. attilius by a more concave outer edge and more convex inner edge of the postbasal yellow band near the inner margin of the dorsal hindwing (i.e., more crescent-shaped postbasal dorsal hindwing band). In addition to S. regulus and S. attilius being distinct species, the genomic analysis revealed five more species in the S. regulus complex ( Fig. 15). All five are new and they are described below.