A deeper look into the diversity of Phyllium leaf insects from Indonesia: seven new species and two unique egg morphologies (Phasmatodea, Phylliidae)

Abstract

Leaf insects of the genus Phyllium Illiger, 1798 are primarily distributed across Southeast Asia, with most species known from the Philippines, Malaysia, and Indonesia. Subsequent to a morphological and phylogenetic review of all available Indonesian Phyllium, seven previously unknown species were identified and are described herein as Phyllium boislardi sp. nov., from northern Kalimantan; Phyllium cayabyabi sp. nov., from northern Kalimantan; Phyllium crapulatum sp. nov., from western Kalimantan; Phyllium hennemanni sp. nov., from Sulawesi; Phyllium illusorium sp. nov., from Buton; Phyllium morganae sp. nov., from Yapen; and Phyllium ouelleti sp. nov., from Obi.

In addition to describing seven new species, two previously undescribed egg morphotypes are identified within Phylliidae, bringing the total number of recognized phylliid egg morphotypes to 13. The twelfth morphotype, found in Phyllium cayabyabi sp. nov., is characterized by spatulate pinnae and hollow, columnar pinnae covering the entire egg surface. The thirteenth, observed in Phyllium hennemanni sp. nov., is unique among phylliids in possessing lateral flaps that are held slightly away from the egg capsule.

Due to the pronounced sexual dimorphism in phylliids, and the importance of establishing new species within a phylogenetic context, as well as correctly matching male and female specimens, a comprehensive phylogenetic tree was constructed based on nearly all currently described Phyllium species. Furthermore, the conditions outlined in Article 23.9. 1 of the International Code of Zoological Nomenclature 1999 (ICZN), specifically sub-articles 23.9.1.1 and 23.9.1.2, have been satisfied regarding the binomen Phyllium longicorne Latreille, 1802.

This name is herein designated as nomen oblitum, in favor of the junior synonym Pulchriphyllium bioculatum (Gray, 1832), nomen protectum. Therefore, the name Pulchriphyllium bioculatum (Gray, 1832) is considered valid and protected in accordance with the International Code of Zoological Nomenclature article 23.9. 2.