GEOMETRINI

Geometra, the type genus of this tribe, its subfamily and family, and its junior synonym, Hipparchus (both with papilionaria as type species), have been used in the past to describe a number of species that were later split amongst several sections or subgenera on the basis of wing shape and features of the palpus and antenna by Prout (1912, 1920–41). Most subgenera were later synonymized with Geometra, with the exception of Neohipparchus and Chloroglyphica, which were placed in Sections C and D of Hipparchus in Prout (1920 –41).

Prout (1912–16, 1920–41) stated that Tanaorhinus is scarcely more than a subgenus of Hipparchus (Geometra), with a more or less strongly falcate apex. Section C of Tanaorhinus (as Timandromorpha), Geometra smaragdus (Butler) and G. sinoisaria Oberthür are to some extent intermediate. The species of section B of Tanaorhinus belong to Mixochlora. Prout’s statements and treatment indicated a close relationship among Geometra, Tanaorhinus, Mixochlora, Neohipparchus, Chloroglyphica and Timandromorpha.

Inoue (1961) included Geometra, Tanaorhinus and Mixochlora in Geometrini for the Japanese fauna based on the absence of abdominal crests, the separated CuA 1 and M 3, and the structure of the male genitalia. Holloway (1996) followed Inoue’s tribes, emphasizing the distinctive ovipositor lobes of the Geometrini, which are smoother, more sclerotized and more elongated than those of other tribes. He also noted that Timandromorphini, Neohipparchini and Aracimini are perhaps related to Geometrini. Hausmann (1996) provided a wider concept of Geometrini, including Paramaxates (Aracimini), Neohipparchus (Neohipparchini), Chlororithra, Iotaphora, Ornithospila, Sphagnodela, Mixochlora and Tanaorhinus in addition to the type genus Geometra, and synonymized Neohipparchini with Geometrini. Han & Xue (2011a) first placed Chlorozancla into Geometrini, due to the similar wing shape and male genitalia, but they also noted that a developed, collarlike colliculum in the female genitalia is absent in Chlorozancla but present in Geometra, Tanaorhinus and Mixochlora.

In the present concept of Geometrini, Mixochlora and Chlorozancla constitute a monophyletic clade, which is sister to the clade embracing Geometra and Tanaorhinus. Han, Galsworthy & Xue (2009) stated that the monophyly of Geometra is highly questionable and that a full phylogenetic revision would probably entail splitting the genus. Those authors also split Geometra into two species-groups (smaragdus group and papilionaria group) based on the male genitalia, with three species, glaucaria Ménétriés, rana (Oberthür) and sigaria (Oberthür), not placed in any group. The authors mentioned that on the basis of the male genitalia, some species in Tanaorhinus centred around kina Swinhoe are similar to the smaragdus group of Geometra, whereas another group centred around Tanaorhinus rafflesii (Moore) is similar to the papilionaria group. This opinion was validated in this study, in which Tanaorhinus kina is clustered with Geometra fragilis (Oberthür), G. sinoisaria and G. smaragdus (smaragdus -group of Geometra) with full support and Tanaorhinus reciprocata confuciaria (Walker) (type species of Tanaorhinus), T. viridiluteata (Walker) and T. luteivirgatus Yazaki & Wang are clustered with most species of the papilionaria group with full support. Although not all species of Geometra and Tanaorhinus were sampled, we propose, on the basis of the combination of morphological characters and molecular analysis, that T. kina, G. fragilis, G. sinoisaria, G. smaragdus and most likely G. burmensis and T. tibeta Chu (Han et al., 2009: fig. 2: L–O; Han & Xue, 2011a: fig. 161; Orhant, 2014: photograph 6) should be placed in a separate genus. The genus Loxochila Butler stat. rev., which was established based on Tanaorhinus smaragdus Butler, was treated as a subgenus of Hipparchus by Prout (1912, 1920–41) but as a valid genus by Fletcher (1979) and is listed as a synonym of Geometra by Scoble (1999). Here, we revive its generic status and transfer the species mentioned above to it as L. smaragdus stat. rev., L. kina comb. nov., L. fragilis comb. nov., L. sinoisaria comb. nov., L. burmensis comb. nov. and L. tibeta comb. nov. We also tentatively speculate that Tanaorhinus reciprocata (Walker), T. viridiluteata and perhaps T. celebensis Yazaki, T. dohertyi Prout, T. rafflesii, T. unipuncta Warren, T. waterstradti Prout, T. philippinensis Yazaki and T. luteivirgatus should be combined into Geometra. However, further molecular studies, including additional taxa, are needed to confirm this hypothesis.