Four new species of the genus Anomala Samouelle, 1819 (Coleoptera: Scarabaeidae: Rutelinae) from South-East Asia and a key to the species with the similar elytral sculpture

Four new species of the genus Anomala Samouelle, 1819 from the continental South-East Asia are described. Anomala paramychodes sp. n. from Laos, Myanmar and South China and A. sinifrater sp. n. from South China are externally indistinguishable from A. amychodes Ohaus, 1914 but differ from this species in the structure of the aedeagus. Anomala levilinea sp. n. from Northern Vietnam is also similar to the aforementioned species but besides the structure of the aedeagus it can be distinguished by the presence of the glabrous longitudinal stripe on the pronotal disc. Anomala triformis sp. n. from northern Myanmar, Laos and Northern Vietnam belongs to the spiloptera species-group and can be easily distinguished from other members of this group by the presence of the lateral plate-like expansions of the parameres. A key to species of Anomala of Vietnam, Laos and the neighbouring territories having the strongly costate and deeply sulcate elytra and the indistinct punctures in the punctate rows is presented. Differential diagnosis of A. paramychodes sp. n. The new species belongs to the members of Anomala having the strongly costate and deeply sulcate elytra with the points of the punctate rows inseparable from the puncturation of the interstices. Within this complex of species, the new species can be attributed to the amychodes species-group characterizing by the strongly carinate abdominal ventrites 1–4 and the characteristic aedeagus with the short deep semi-tube-shaped and strongly asymmetrical parameres. The new species is very similar to and externally inseparable from A. amychodes (Sa Pa and Tam Dao mountain areas in Northern Vietnam) and A. sinifrater sp. n. (South China), but can be easily distinguished from these species in the structure of the aedeagus. Besides, the new species differs from A. levilinea sp. n. (Northern Vietnam) by the absence of the impunctate longitudinal stripe on the pronotum, and from A. bidoupensis Prokofiev, 2015 (Dalat Highlands in Central Vietnam) by the absence of the setosity on the pronotum and elytra. Differential diagnosis of A. sinifrater sp. n. The new species is externally indistinguishable from A. amychodes and A. paramychodes sp. n., but differs from these species in the shape of the parameters. Differential diagnosis of A. levilinea sp. n. The new species belongs to the amychodes species-group but differs from the other members of the group by the presence of the glabrous longitudinal stripe on the pronotal disc (vs. absent in A. amychodes, A. bidoupensis, A. paramychodes sp. n. and A. sinifrater sp. n.) and by the shape of parameres. Differential diagnosis of Anomala triformis sp. n. The new species belongs to the members of Anomala having the strongly costate and deeply sulcate elytra with the points of the punctate rows inseparable from the puncturation of the interstices. Within this agglomeration of species, the new species can be attributed to the spiloptera species-group characterizing by the presence of the wide wrinkled membrane connecting the parameres dorso-basally. By external characters the new species is indistinguishable from A. spiloptera Burmeister, 1855 and A. recordata Zorn, Kobayashi et Wada, 2017. The new species is most similar to A. recordata и A. jeanvoinei Benderitter, 1929 by the strucrure of the aedeagus, but can be easily distinguished from these and other species of the group by the presence of the plate-like lateral expansions of the parameres. It further differs from A. jeanvoinei by the elytra strongly transversely striolate and by the presence of the transverse band on the elytra, at least in a form of a few small isolated spots.