First fossil true water bugs (Heteroptera, Nepomorpha) from Upper Jurassic strata of North America (Morrison Formation, southeastern Utah)

ABSTRACT

The first fossil hemipteran from the Late Jurassic of North America, Morrisonnepa jurassica n. gen. et n. sp., is reported and described from the Morrison Formation, Jurassic Salad Bar locality, San Juan County, Utah, USA. The new specimen is characterised and illustrated, showing morphological characters similar to nepomorphs such as forewing well-developed and folded flat on the abdomen, oval abdomen shape, and the presence of a short pair of appendages. The taxonomic allocation close to members of the Nepomorpha is discussed. Morrisonnepa jurassica n. gen. et n. sp. was collected with abundant plants, spinicaudatan carapaces, and a small amphibian from a finely laminated shale that overlies a coarser plant debris bed, supporting the presence of a possible oxbow lake or pond, environments developed within the greater ecosystem of the Morrison Formation during the Late Jurassic. In this context, we analyse the taphonomic and palaeoecological implications of the presence of aquatic insects. Besides providing morphological information on Jurassic nepomorphs, the new fossil helps illustrate how the aquatic insect assemblage was integrated during the Jurassic in North America.

KEYWORDS:

• Heteroptera
• Nepomorpha
• Late Jurassic
• Morrison Formation
• North America (Utah)

Acknowledgments

Fieldwork conducted under Bureau of Land Management (BLM) paleontological resources use permit UT18-003E to the Utah Field House, with special thanks to Greg McDonald and the Monticello Field Office. Initial assistance in the field with the UGS included Don DeBlieux and Scott Madsen under BLM permit UT07-003S-SW. Thanks also to Christy Bills and the Natural History Museum of Utah for donation of the specimen of Lethocerus to the Utah Field House. Technical reviews by Don DeBlieux, Grant Willis, and Stephenie Carney are appreciated. The authors also thanks to Dr Jacek Szwedo (University of Gdańsk, Poland) for comments on the specimen. We sincerely thank Dr Gareth Dyker (Editor) and two anonymous reviewers, for their useful comments on the first version of this paper.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the Bureau of Land Management with match by Utah Geological Survey (J.I.Kirkland) and Museum of Moab, Utah (J.R.Foster), and Utah Field House, Utah (J.R.Foster, T.F.Howells).