New fossils in Cenomanian Burmese amber shed light on the high disparity of early Leptosaldinae (Hemiptera, Heteroptera, Leptopodidae)

Abstract

The shore bug subfamily Leptosaldinae is relict with only one monospecific living genus, but it is well documented in the Cenozoic and Mesozoic of America and Eurasia. Based upon three well-preserved adult shore bugs trapped in mid-Cretaceous Kachin amber of northern Myanmar, two new leptosaldine genera along with three new species (Parvilepta jinghuiae Yu, Zhuo and Chen, gen. et sp. nov., P. jingyuanae Yu, Zhuo and Chen, gen. et sp. nov., and Macrolepta chenchenae Yu, Zhuo and Chen, gen. et sp. nov.) are described in the present study. The new taxa reported herein plus other known Cretaceous leptosaldines display the combination of plesiomorphies and derived characteristics and the mixed features of Saldoidea: Saldidae and Leptopodoidea: Leptopodidae, confirming the view that Leptosaldinae represents one of basal groups of the infraorder Leptopodomorpha. In addition, our new genera and species show some unusual autapomorphies, such as the pronotal collar distinctly contractive (Parvilepta Yu, Zhuo and Chen, gen. nov.), the rostrum reaching to pygofer (Macrolepta Yu, Zhuo and Chen, gen. nov.), and the very large body size compared to most leptopodomorphans (Macrolepta Yu, Zhuo and Chen, gen. nov.). The high morphological disparity of Mesozoic Leptosaldinae reveals that early leptosaldine shore bugs diversified multi-dimensionally and so possibly had evolved to occupy a wider range of ecotypes compared to their Cenozoic descendants, who share relatively similar body size and habitus as well.