Phyllium (Phyllium) Illiger, 1798

Hennemann, Frank H., Conle, Oskar V., Gottardo, Marco & Bresseel, Joachim, 2009, On certain species of the genus Phyllium Illiger, 1798, with proposals for an intra-generic systematization and the descriptions of five new species from the Philippines and Palawan (Phasmatodea: Phylliidae: Phylliinae: Phylliini) 2322, Zootaxa 2322 (1), pp. 1-83 : 61-62

Phyllium (Phyllium) Illiger, 1798

As can be seen from table 10 above this subgenus differs from Pulchriphyllium (s. str.) by: the lack of exterior lobes on the tibiae of both sexes; ± round cross-section of antennomeres IV–VIII of ♀; longer tegmina which at least reach to abdominal segment III and ventrally unarmed antennomeres of ♂♂, as well as the raised hairy, umbrella- or feather-like structures, flat operculum and lack of longitudinal lamellae in the eggs. Based on morphological features of the insects and eggs two distinct species-groups of closely related species can be recognized within this subgenus.

1. Siccifolium species-group. Already Rehn & Rehn (1933: 414) have suggested a “ geryon speciesgroup” within the genus to comprise Ph. (Ph.) geryon as well as the three newly described Ph. jacobsoni Rehn & Rehn, 1993 , Ph. woodi Rehn & Rehn, 1993 and Ph. pusillulum Rehn & Rehn, 1993 . The first two species are here attributed to the less strictly defined siccifolium species-group, while the latter belongs in the genus Microphyllium Zompro, 2001 and is here transferred (n. comb.).

Members of this species-group, which contains a large bulge of the species known, are characteristic for the very narrow exterior lobe on the profemora in ♂♂, which always is distinctly narrower than the interior lobe, and ♀ lacking alae. The eggs are well characterized by the flat operculum and long hairy, umbrella- or feather-like appendices on the operculum and along the longitudinal carinae of the capsule, which only develop when the egg gets in contact with water. These features well distinguish the 17 species contained from the following group, the celebicum species-group, and the subgenus Pulchriphyllium (s. str.).

Species, which upon these features, belong into this group are: Ph. bilobatum Gray, 1834 [ Philippines], Ph. caudatum Redtenbacher, 1906 [New Guinea], Ph. drunganum Yang, 1995 (rev. stat.) [S-China], Ph. elegans Grösser, 1991 [New Guinea], Ph. gantungense n. sp. [Palawan], Ph. geryon Gray, 1843 [ Philippines], Ph. hausleithneri Brock, 1999 [Peninsular Malaysia & Singapore], Ph. jacobsoni Rehn & Rehn, 1933 [Java], Ph. mabantai n. sp. [ Philippines], Ph. mamasaense Grösser, 2008 [Sulawesi], Ph. mindorense n. sp. [ Philippines], Ph. monteithi Brock & Hasenpusch, 2003 [NE-Australia], Ph. palawanense Grösser, 2001 [Palawan], Ph. philippinicum n. sp. [ Philippines], Ph. siccifolium (Linné, 1758) [ Moluccas], Ph. woodi Rehn & Rehn, 1933 [ Philippines] and Ph. zomproi Grösser, 2001 [New Guinea].

The New Guinean Ph. caudatum and Ph. elegans are remarkable for having a distinct blunt prosternal spine, actually a feature which distinguishes the genus Chitoniscus Stål, 1875 from Phyllium . The eggs of the two closely related Ph. monteithi from NE-Australia and New Guinean Ph. zomproi have a knob-like to roundly conical operculum and would, based on this feature alone rather fall into the celebicum species-group. Features such as the entire outer margin of the exterior lobe of the profemora, just very small apical outer elevation of the protibiae and slender abdomen place Ph. drunganum from S-China in the subgenus Phyllium , hence is here re-transferred from Pulchriphyllium Griffini, 1898 (rev. stat.).

2. Celebicum species-group. This group is meant to provisionally comprise all those species which have developed alae in ♀. Members are furthermore characteristic and distinguished from species of the previous species-groups by the rather broad, often angular abdomen (♀ in particular) and large exterior lobe of the profemora. The latter is at least equal in width or conspicuously wider than the interior lobe. With the exception of Ph. ericoriai n. sp. from the Philippines the eggs have a conically raised operculum and exhibit only short, moss-like appendices on the capsule and operculum. For a more detailed discussion and keys to the eight species contained see discussion of the celebicum species-group below .