Monday, July 3, 2023

[PaleoEntomology • 2021] Panorpidium spica • The First Orthopteran Fossils from the Lower Cretaceous (Albian) Jinju Formation of Korea: Ethological Implications for Elcanids


Panorpidium spica 
Kim, Lee, Nam & Park, 2021

artwork by Do-Yoon Kim
 
Abstract
The lower Albian Jinju Formation has produced various trace fossils and body fossils of vertebrates, as well as the fossils of diverse invertebrates which must have served as prey for many vertebrates. Of them, insect fossils of the Jinju Formation have remained understudied, and especially, orthopteran fossils have never been described from the Jinju Formation. Here we describe a new species of the Elcanidae (Orthoptera: Elcanoidea), Panorpidium spica sp. nov. based on three specimens from the Jinju Formation. Notably, we have applied Wavelength Dispersive Spectrometer (WDS) analysis for the first time on insect fossils, and discovered that the carbon elemental maps are helpful in recognizing crucial morphology. The presence of pterostigmata in forewing supports that elcanids evolved a unique flight mechanism distinct from other extant orthopterans. Based on a detailed morphological comparison with the paddles of the extant tridactylids, it is inferred that the leaf-shaped spurs on the metatibiae of elcanids were used for jumping on the water, although other possible functions cannot be ruled out. Diving into the water and jumping on the water surface must have been an effective way of escaping from predators, both for the flightless nymphs and the short-range flying adults.

Keywords: Jinju Formation, Elcanidae, WDS analysis. pterostigmaspur, Tridactyloidea

The holotype of Panorpidium spica sp. nov., GNUE212001.



Artistic reconstruction of Panorpidium spica sp. nov., escaping towards the water from a theropod predator (artwork by Do-Yoon Kim).

Panorpidium spica sp. nov. 

Conclusions: 
Panorpidium spica sp. nov. is described from the Lower Cretaceous (Albian) Jinju Formation, Korea. The Wavelength Dispersive Spectrometer (WDS) analyses have produced carbon elemental maps that are helpful in recognizing crucial features, such as pterostigma, forewing venations, and abdominal structures. The pterostigma in the wings suggest that elcanids had a unique mode of flight, distinct from extant orthopterans. The well-preserved dorsal spurs on the metatibiae are considered to have been...



 Do-Yoon Kim, Mirinae Lee, Gi-Soo Nam and Tae-Yoon S. Park. 2021. The First Orthopteran Fossils from the Lower Cretaceous (Albian) Jinju Formation of Korea: Ethological Implications for Elcanids. Cretaceous Research. 104843, In Press.  DOI: 10.1016/j.cretres.2021.104843 
1억년 전 한반도 메뚜기, 물 박차고 날아올랐다