Pulchriphyllium Griffini, 1898

Cumming, Royce T., Le Tirant, Ste ́ phane, Linde, Jackson B., Solan, Megan E., Foley, Evelyn Marie, Eulin, Norman Enrico C., Lavado, Ramon, Whiting, Michael F., Bradler, Sven & Bank, Sarah, 2023, On seven undescribed leaf insect species revealed within the recent " Tree of Leaves " (Phasmatodea, Phylliidae), ZooKeys 1173, pp. 145-229 : 145

Pulchriphyllium Griffini, 1898

Type species.

Pulchriphyllium pulchrifolium (Audinet-Serville, 1838).

Historically, many Pulchriphyllium populations have been the subject of repeated taxonomic adjustments, oftentimes without being properly assessed or clearly defined. Originally, many of the populations were treated as distinct species, but eventually, as phylliids became better known and more common in museums, authors started to assume phylliids were species-poor with wide geographic ranges ( Brock 1999; Größer 2008; Brock et al. 2022). Several taxa have been treated as forms, subspecies, or synonyms by past authors ( Giglio-Tos 1910; Brock 1995; Hennemann et al. 2009), and it was only recently that authors have begun to split certain lineages into distinct species again ( Seow-Choen 2017). The Pulchriphyllium are only found Northwest of Wallace’s line of faunal balance ( Huxley 1868) and range as far north as Bangladesh/northeastern India, and as far west as the Seychelles islands (Fig. 15A ). The area with the highest Pulchriphyllium diversity appears to be the biogeographical region of Sundaland, an area which was recovered as the likely geographic ancestral range for this clade ( Bank et al. 2021).

Within the Pulchriphyllium there appear to be several recurring, leaf-shape mimicry patterns; broad leaf (like in Pulchriphyllium giganteum ), boxy leaf (like in Pulchriphyllium pulchrifolium ), and tapered leaf (like in Pulchriphyllium bioculatum Gray, 1832). Of particular difficulty to differentiate are the numerous species where females have a tapered abdominal shape and males have rounded/ovoid abdomen, herein referred to as " Pulchriphyllium bioculatum -like species". These " Pulchriphyllium bioculatum -like species" are a subset of the " Pulchriphyllium bioculatum species group", the only species group within the Pulchriphyllium proposed by Hennemann et al. (2009) which has not been taxonomically adjusted (the other three species groups proposed within that work have either been transferred to a different genus (such as the " frondosum species group" which were transferred to the Nanophyllium by Cumming et al. 2020d), or have since been described as their own genera (like the " brevipenne species group" which is now Acentetaphyllium Cumming & Le Tirant, 2022 and the " schultzei species group" which is now Rakaphyllium Cumming & Le Tirant, 2022).

The " Pulchriphyllium bioculatum -like species" are difficult to morphologically differentiate, have wide-ranging geographic distributions (Fig. 15A ), and coupled with the fact that the holotype of Pulchriphyllium bioculatum lacks a precise collection locality, has made this group of similar-looking species difficult to clearly define. Based upon the type specimen morphology, the population considered true " Pulchriphyllium bioculatum " is the species centered around Sundaland and mainland Asia (Fig. 15A ; Hennemann et al. 2009). This leaves the numerous populations once considered subspecies or synonyms of Pulchriphyllium bioculatum (but now recognized as independent species; Fig. 15A ) in need of clarification. Thanks to extensive review of historic type specimen morphology, modern specimen morphology, geographic distribution, and molecular analyses, the " Pulchriphyllium bioculatum -like species" are now beginning to be clarified.

Figures

Figure 15. Distribution map for the herein discussed Pulchriphyllium species with known records plotted. For data on the distribution points used for this map, see Suppl. material 1 A distribution of the " Pulchriphyllium bioculatum - like species " B distribution of the Pulchriphyllium species from mainland Asia with a boxy abdominal shape (inset outline in A). Abbreviations: KH, Cambodia; LA, Laos; TH, Thailand; VN, Vietnam.