Habaek, Murányi & Hwang, 2023

Murányi, Dávid & Hwang, Jeong Mi, 2023, A new genus and species of Perlodinae (Plecoptera: Perlodidae) from Korea, Zootaxa 5249 (1), pp. 138-150 : 139

Habaek gen. n.

Diagnosis: Medium sized, dark brown Perlodinae with contrasting pale pattern on wings and rather long appendages; vestigial submental and thoracal gills present, furcal pit anteriorly connected to mesosternal ridge. Wings with enlarged costal field in both sexes, and unbranched Radial vein in the female. Male: sterna lack vesicle, terga lack sensilla basiconica, tergum X widely divided into triangular hemiterga; epiproct with large basal anchor and lateral arm, large paragenital plate and ventral projection, small lateral stylet and densely setose cowl, large and complex epiproct tip that is not connected with wide lever arm. Aedeagus displays a distinct pattern of golden scales. Female: subgenital plate reduced.

Type species: Habaek koreanus sp. n., by monotypy.

Affinities: The present tribal concept of the subfamily Perlodinae recognizes three tribes, based mainly on larval and egg characters and a few distinct characters of the male terminalia ( Stark & Szczytko 1984, 1988). The lack of finger-like male hemiterga preclude the new genus from the tribe Arcynopterygini , while the lack of male sternal vesicle preclude it from Diploperlini. Consequently, we classify it in the Perlodini . However, discovery of the larva and matured egg may require modification of this classification. The spherical shape of immature eggs found in the paratype females already suppose classification in Arcynopterygini , since, with few exceptions, Perlodini species have eggs triangular in cross section, but it cannot be excluded that eggs become triangular when fully matured. The anteriorly connected furcal pit and mesosternal ridge is unique among Perlodini , while usual in Arcynopterigini ( Arcynopteryx , Frisonia Ricker, 1943 , Megarcys , Neofilchneria Zwick, 1973 , Pseudomegarcys Kohno, 1946 , Skwala Ricker, 1952 ) and rare in Diploperlini ( Osobenus Ricker, 1952 and Stavsolus ). Probably more important, and supportive of the new genus being classified in Perlodini , is the presence of fully divided but widely rounded hemiterga that lacks sensilla basiconica. This type of hemiterga occur only in the Perlodini : Tadamus Ricker, 1952 and an unnamed genus sensu Inada (1996) and Shimizu et al. (2005) from Japan, Malirekus Ricker, 1952 , Oconoperla Stark & Stewart, 1982 and Yugus Ricker, 1952 from the eastern Nearctic, and Susulus Bottorf, Stewart & Knight, 1989 from California. The arrow-like apex of the epiproct tip is another character shared in only a few Perlodini genera ( Dictyogenus Klapálek, 1904 , Hydroperla Frison, 1935 and Isogenoides Klapálek, 1912 ) and not known in the Arcynopterygini and Diploperlini. The extreme reduction of the female subgenital plate is unique among the Perlodinae , though poorly produced subgenital plate is characteristic for the Pacific East Asian Megaperlodes and the Californian Salmoperla Baumann & Lauck, 1987 . The presence of thoracic gills is characteristic for the Arcynopterygini . The new genus is the only Perlodini where thoracic gills are documented; however, gill vestiges are small and can be easily overlooked. Submental gills may both be present or lacking in all three tribes. In the Perlodini , more or less developed submental gills are present in Helopicus Ricker, 1952 , Hydroperla , Isogenoides , Malirekus , Susulus , Tadamus , Yugus and the new genus. There are four genera of Perlodidae that are characterized by an entirely dark head and pronotum: Hemimelaena Klapálek, 1907 , Levanidovia , Tadamus Ricker, 1952 and the new genus. Surprisingly, three of these are restricted to the southern temperate Pacific area of Asia and classified in the Perlodini , though they are apparently not closely related. Contrasting dark and pale wing pattern is rare among the Asian Perlodidae ; besides the new genus, patterned wings are known for Megaperlodes tiunovi Teslenko, 2015 and Filchneria zhouchangfai ( Chen, 2020) , both of which belong to the Perlodes genus group sensu Zwick (1997). The enlarged costal field and unbranched Radial vein of both fore- and hindwings are unique among Perlodidae , and can be regarded as apomorphies. The enlarged costal area (and unusually large, rounded anal field of hindwing) is reminiscent of the Antarctoperlarian family Eustheniidae , but it surely does not reflect on phylogenetic relations with that basal family. The unbranched Radial vein of the female is unique among the Plecoptera .

Etymology: The new genus is named after the Korean water god Habaek . Used as a noun, gender masculine.