Extreme global warming and environmental changes associated with the Toarcian (Lower Jurassic) Oceanic Anoxic Event (T-OAE, ~183 Mya) profoundly impacted marine organisms and terrestrial plants. Despite the exceptionally elevated abundance of fossil insects from strata of this age, only assemblages from Germany and Luxembourg have been studied in detail. Here, we focus on the insect assemblage found in strata recording the T-OAE at Alderton Hill, Gloucestershire, UK, where <15% of specimens have previously been described. We located all known fossil insects (n = 370) from Alderton Hill and used these to create the first comprehensive taxonomic and taphonomic analysis of the entire assemblage. We compared the Alderton Hill assemblage with the only other significant T-OAE assemblage insect assemblage in the UK at Strawberry Bank, Somerset UK. All insects from Alderton Hill, in addition to those from the coeval palaeoentomofauna of Strawberry Bank, Somerset, UK within the collections at the Natural History Museum, London, UK, were photographed. Well-preserved specimens from the smaller collections at seven other museums were also photographed. Most of the Strawberry Bank insects are at the Somerset Heritage Centre, Taunton, UK, and are poorly preserved so they were not photographed. The best-preserved specimens within each taxon (n = 39) from Alderton Hill are presented as figures 3-5 in the associated publication, and the remainder of the specimen photographs (n = 300) from Alderton Hill and Strawberry Bank are presented here. We show that Alderton Hill has a diverse palaeoentomofaunal assemblage, comprising 12 orders, 21 families, 23 genera, and 21 species. The palaeoentomofauna from Strawberry Bank, Somerset is less diverse with 9 orders, 12 families, 6 genera, and 3 species.

Additionally, 386 rock specimens, which possessed fossilised insects from Strawberry Bank, Somerset, UK, were also located within four museum and institutional collections. While the majority (n = 359) of the Strawberry Bank insects are housed within the collections at Somerset Heritage Centre, Taunton, UK (TTNCM), additional specimens (n = 27) from Strawberry Bank were also discovered during this study within the collections of NHMUK (n = 18), Sedgwick Museum, Cambridge, UK (CAMSM, n = 8) and Bristol Museum & Art Gallery, Bristol, UK (BRSMG, n = 1).

Through direct observation and high-resolution photographs, the taxonomy of each specimen from Alderton Hill was revised to the finest taxonomic resolution possible. The Strawberry Bank insect material, originally identified by Williams et al. 2015, was also re-examined, and in some cases, the taxonomy was also refined. All of the insect material from Alderton Hill and Strawberry Bank, including the revised taxonomy, specimen numbers, museum/institution, types, name of the original collectors, and references were compiled into databases. These two databases have been uploaded as part of this dataset.

 All of the Alderton Hill and Strawberry Bank insects within the collections at NHMUK were photographed using a Canon EOS 5DS R with a single headlight source with an adjacent reflector in order to best capture the preserved wing venation. Within the smaller museum collections (CHAGM, BRSMG, BGS, CAMSM), the insect material was often poorly preserved and fragmentary, and therefore only well-preserved specimens were photographed (using a Nikon D3200 with Nikon Micro-Nikkor 40mm F/2.8 macro lens). All of these photographs are included in the zip file, aside from those from CHAGM (due to the cost of copyright and reproduction). The four insect specimens from Alderton Hill, documented as being held at WARMS, in addition to the single specimen from the NMW, could not be re-examined or photographed, as the collections were inaccessible at the time of this study. The specimen held within the collections at PALE could not be re-examined in person but can be viewed on the ‘MCZBASE: The Database of the Zoological Collections’ [Accessible from: https://mczbase.mcz.harvard.edu/Specimens.cfm].

The Strawberry Bank insects at TTNCM were not photographed due to the poor and fragmentary preservation of the majority of the material (see Williams et al. 2015 for the best-preserved examples). Within the smaller museum collections (BRSMG and CAMSM), the Strawberry Bank insects were again poorly preserved and fragmentary, and therefore only selected better-preserved specimens were photographed. These photographs are included in the zip file.

 This dataset is comprised of:

(1) Two spreadsheets, one detailing all fossil insect specimens from Alderton Hill, Gloucestershire, UK, and the other detailing all fossil insect specimens from Strawberry Bank, Somerset, UK collated for this study. Each spreadsheet provides a revised taxonomy, specimen numbers, museum/institution, and abbreviation, whether it is a type specimen, name of original collector, references, and whether the photograph is part of a figure in the publication or part of the zip file.  

(2) Photographs (excluding those featured in Figs 3 – 5 of the associated publication) of each insect specimen within the NHMUK collection from Alderton Hill recorded for this study. Additionally, the best-preserved specimens from BRSMG, BGS, and CAMSM are also included. Photographs of the Strawberry Bank insects discovered during this study within the collections of NHMUK, in addition to the best-preserved specimens from BRSMG and CAMSM, are also included here. 

Note: for the photographs, the total length of the smaller scale bar (used in the majority of the photographs) is equal to 1 cm, each tick is 1 mm, while the total length of the larger scale bar (with individual values on, only used for larger specimens) is equal to 5 cm.

References

Williams M, Benton MJ, Ross A. 2015. The Strawberry Bank Lagerstätte reveals insights into early Jurassic life. Journal of the Geological Society. 172: 683-692. doi:10.1144/jgs2014-144.