The third aeschnidiid dragonfly genus and species from the Lower Cretaceous Crato Formation (Odonata, Anisoptera)

International audienceThe family Aeschnidiidae is a speciose fossil dragonfly clade currently encompassing 33 genera. Representatives of this family were distributed worldwide between the Late Jurassic and the latest Cretaceous (Fleck and Nel 2003; Nel 2021). Recent studies indicate that the family seems to die out during the Cretaceous-Cenozoic (K-Pg) crisis, and not during the mid-Cretaceous floristic and faunal turnover as previously supposed by Fleck et al. (1999). However, the effect of the K-Pg crisis on insects appears to be soft and poorly quantified (Condamine et al. 2016; Schachat and Labandeira 2021) suggesting that the family may be present during the Palaeocene, even if not recorded from Palaeocene deposits (e.g., Nel and Jouault 2022). The Aeschnidiidae were apparently extremely diversified in the Lower Weald Clay (Hauterivian), in the UK, but less diverse in the Lower Cretaceous of Spain (Las Hoyas and Montsec) (e.g., Nel and Martínez-Delclòs 1993; Fleck and Nel 2003). In China, the family is known by a few genera, some of them being very frequent in the Lower Cretaceous of Liaoning (e.g., Huang and Nel 2010). Interestingly, several species are known from the Southern Hemisphere with specimens known from Australia, Brazil, and Colombia (e.g., Martill and Nel 1996; Fleck and Nel 2003; Gómez-Cruz et al. 2011; https://paleobiodb.org/). This ”worldwide” distribution during the Cretaceous suggests that the family was perhaps present on the Gondwana masses during the Jurassic and not only restricted to the northern hemisphere, as evidenced by their current fossil record. They were possibly not found due to the scarcity of Gondwanan Jurassic insect assemblages. The family could also have rapidly dispersed from Laurasia to Gondwana during the earliest Cretaceous (Nel and Jouault 2021). The Brazilian Lagerstätte of the Crato Formation is worldwide known for its abundant and perfectly preserved fossils of insects, and odonatan specimens are not an exception. This rich entomofauna encompasses two aeschnidiid species, viz. Santanoptera gabbotti Martill and Nel, 1996 and Leptaeschnidium araripina (Carle and Wighton, 1990) (originally in the genus Wightonia Carle and Wighton, 1990). The latter genus is known from numerous specimens while the former is known by only one specimen.Here, we describe a new genus and species from this formation, superficially resembling the species Leptaeschnidium araripina, but showing a unique combination of characters. This discovery confirms that the odonatan diversity of the Crato Formation is really impressive (Bechly 2007)