Cretaceous winged stick insects clarify the early evolution of Phasmatodea

Area of Science:

• Paleontology
• Entomology
• Evolutionary Biology

Background:

• Modern stick insects exhibit reduced wings, contrasting with most extinct species possessing fully developed wings.
• The evolutionary relationship between extinct winged and extant wingless/short-winged stick insects remains debated.
• Previous studies highlight morphological differences and similarities between extinct and extant Phasmatodea.

Purpose of the Study:

• To describe three new male winged stick insects from mid-Cretaceous Burmese amber.
• To establish a new family, Pterophasmatidae fam. nov., for these fossil specimens.
• To investigate the phylogenetic position of these fossils within the Phasmatodea.

Main Methods:

• Morphological analysis of tegmina venation and body features.
• Comparative anatomy focusing on phallic organ structures.
• Phylogenetic analyses incorporating fossil and extant taxa.

Main Results:

• Three male winged stick insects were identified and assigned to the new family Pterophasmatidae fam. nov.
• Pterophasmatidae fam. nov. exhibit transitional features, linking extinct winged forms (Susumanioidea) with extant Phasmatodea.
• Distinct symmetric phallic organs in Pterophasmatidae differ from all extant stick insect groups.

Conclusions:

• Extinct winged taxa, including Pterophasmatidae, represent stem groups of modern stick and leaf insects (Phasmatodea).
• Morphological diversification of winged and wingless stick insects occurred by the mid-Cretaceous.
• The discovery provides crucial insights into the early evolution and diversification of Phasmatodea.