Zanchius Distant, 1904

Genus Zanchius Distant, 1904 View in CoL View at ENA

Zanchius Distant, 1904: 477. Type species: Zanchius annulatus Distant, 1904. View in CoL

Zonodorus Distant, 1909: 522 (syn. Carvalho 1952: 79).

Uzeliella Poppius, 1911: 31 (syn. Carvalho 1952: 79).

Poppiella Bergroth, 1911: 188 (new name for Uzeliella Poppius, 1911).

Habrocoris Wagner, 1951: 153 (syn. Linnavuori 1964: 329).

Diagnosis.

Differs from other orthotyline genera by dorsum being generally greenish, shiny, spindle-shaped, sparsely or normally covered with shiny setae (vs dorsum being gradually widened caudad; Latizanchius Liu & Zheng, 2001 ); head short and vertical; frons convex; clypeus not or only barely visible dorsally; compound eyes protuberant, set forward on head, removed from anterior pronotal margin; first antennal segment distinctly short, shorter than head width across eyes; exposed part of mesoscutum wide; hemelytra hyaline or subhyaline, wide and rounded; cuneus somewhat small relative to corium (updated from Schuh (1974) and Yasunaga (1999)).

Discussion.

The genus Zanchius has traditionally been diagnosed based on external morphology, particularly its greenish dorsum and head structure with compound eyes that are conspicuously set forward. Species exhibiting these characters have been assigned to Zanchius within Orthotylini . However, the diversity in pygophore structure and the male and female genitalia (e. g. Figs 2 View Figure 2 , 3 View Figure 3 ) within Zanchius raises questions regarding its monophyly.

Additionally, Liu and Zheng (2001) established the genus Latizanchius , primarily distinguishing it from Zanchius based on differences in body shape and the ratio between the first antennal segment and head width. Notably, the genital structures of Latizanchius also exhibit significant variation ( Liu and Zheng 2001).

Zanchius is a species-rich group within Orthotylini , and the female genitalia are scarcely studied. As the need for monophylogical assessment has already been emphasized for other genera of Orthotylinae (e. g. Pseudoloxops Kirkaldy, 1905 ; see Yasunaga et al. 2022; Kim et al. 2024), a similar evaluation is required for Zanchius . Future studies should test the monophyly of Zanchius and its allied genera, as well as reassess the placement of species currently assigned to Zanchius .

After the recognition of natural groups within Orthotylinae (e. g. the Falconia , Zanchius groups) by Schuh (1974), it has been proposed that the Zanchius group should be upgraded to a new tribal level, as it possesses distinct morphological characters that differentiate it from the traditional Orthotylini (e. g. a dorsally flattened head with small, anteriorly directed eyes set apart from the pronotum, delicate and often semitransparent forewings; Yasunaga and Duwal 2017).

Recently, Bolshakova and Konstantinov (2022) provided a molecular phylogeny of the Orthotylinae , revealing that the Zanchius group is indeed monophyletic and separated from other Orthotylini members. Additionally, Bolshakova and Konstantinov (2022) presented the morphological characters of its representatives.

In our study, we conducted a review of the genus Zanchius in Vietnam, providing not only previously known morphological features but also new insights into the largely unstudied female genitalia. Notably, the interramal lobe extends far beyond the interramal sclerite (Fig. 3 B, D View Figure 3 ), a character shared with other members of the Zanchius group (e. g. Malacocoris Fieber, 1858 and Filicicapsus Bolshakova & Konstantinov, 2022; see Bolshakova and Konstantinov 2022: fig. 6 b, d). Although further examination of female genitalia from a greater number of species within Zanchius is necessary given the genus’s size, these data will serve as a foundation for the potential elevation and diagnosis of the Zanchius group at the tribal level.