Sphaenogona Butler, 1870

Zhang, Jing, Cong, Qian, Shen, Jinhui, Opler, Paul A. & Grishin, Nick V., 2019, Changes to North American butterfly names, The Taxonomic Report of the International Lepidoptera Survey 8 (2), pp. 1-12 : 3

Sphaenogona Butler, 1870 and Lucidia Lacordaire, 1833 are subgenera of Abaeis Hübner, [1819] and not of Eurema Hübner, [1819] , new placement

Previously junior subjective synonyms of Eurema Hübner, [1819] (type species Papilio delia Cramer, [1780] , a junior subjective synonym of Pieris daira Godart, 1819 ), Sphaenogona Butler, 1870 (type species Terias bogotana C. & R. Felder, 1861, which is treated as a subspecies of Terias mexicana Boisduval, 1836 ) and Lucidia Lacordaire, 1833 (type species Papilio albula Cramer, 1775 ) are not monophyletic with Eurema , but are instead in the same clade with Abaeis Hübner, [1819] (type species Papilio nicippe Cramer, 1779 ) ( Fig. 2 ). This genomic tree shows notable genetic divergence among Abaeis , Sphaenogona and Lucidia that is only slightly less than the divergence between Eurema and Pyrisitia Butler, 1870 (type species Papilio proterpia Fabricius, 1775) suggesting that Sphaenogona and Lucidia are not synonyms, but can be treated as subgenera of Abaeis . As a result, we use the following new or revised combination for the US species: Abaeis (Sphaenogona) boisduvaliana (C. Felder & R. Felder, 1865) , Abaeis (Sphaenogona) mexicana (Boisduval, 1836) , Abaeis (Sphaenogona) salome (C. Felder & R. Felder, 1861) , and Abaeis (Lucidia) albula (Cramer, 1775) . Consequently, only a single US species remains in Eurema , the type species of the genus: Eurema daira . Our proposed changes keep the number of genera in this group at 3 ( Eurema , Abaeis , and Pyrisitia ), and simply rearrange species between these genera. This rearrangement agrees with wing pattern characters on the dorsal side, making identification of the genus in the US easier. Both Eurema and Pyrisitia lack darker expanded area near forewing tornus and their males possess darker scaling along the outer margin of hindwing, at least by the veins. Eurema males can be distinguished by a long dark bar near forewing inner margin, which Pyrisitia species lack. Males of Abaeis species either have a dark forewing tornus (forewing mostly orange with a dark cell spot in the nominal subgenus and yellower, without the cell spot in the subgenus Sphaenogona ), or lack dark scaling by the hindwing outer margin ( USA only) and wings are mostly white with variable extent of dark margins (subgenus Lucidia ). Although it is tempting to unite all these medium-sized white-yellow-orange butterflies in a single genus Eurema , their genetic divergence is very large ( Fig. 2 ), and the group is divided into two prominent clades ( Eurema + Pyrisitia and Abaeis ), one of which splits into two more ( Eurema and Pyrisitia ). Therefore, we keep the three-genus arrangement of the group. Moreover, Abaeis as defined here is a broad and diverse genus. Comprehensive sequencing of the worldwide fauna of the group is likely to substantiate further splits rather than lumps.

Figures

Fig. 2. Eurema, Abaeis, Sphaenogona, and Lucidia.