The semi-aquatic pondweed bugs of a Cretaceous swamp

Abstract

Pondweed bugs (Hemiptera: Mesoveliidae), considered a sister group to all other Gerromorpha, are exceedingly rare as fossils. Therefore, each new discovery of a fossil mesoveliid is of high interest, giving new insight into their early evolutionary history and diversity and enabling the testing of their proposed relationships. Here, we report the discovery of new mesoveliid material from Spanish Lower Cretaceous (Albian) amber, which is the first such find in Spanish amber. To date, fossil records of this family only include one species from French Kimmeridgian as compression fossils, two species in French amber (Albian-Cenomanian boundary), and one in Dominican amber (Miocene). The discovery of two males and one female described and figured as Glaesivelia pulcherrima Sánchez-García & Solórzano Kraemer gen. et sp. n., and a single female described and figured as Iberovelia quisquilia Sánchez-García & Nel, gen. et sp. n., reveals novel combinations of traits related to some genera currently in the subfamily Mesoveliinae. Brief comments about challenges facing the study of fossil mesoveliids are provided, showing the necessity for a revision of the existing phylogenetic hypotheses. Some of the specimens were studied using infrared microscopy, a promising alternative to the systematic study of organisms preserved in amber that cannot be clearly visualised. The new taxa significantly expand the fossil record of the family and shed new light on its palaeoecology. The fossils indicate that Mesoveliidae were certainly diverse by the Cretaceous and that numerous tiny cryptic species living in humid terrestrial to marginal aquatic habitats remain to be discovered. Furthermore, the finding of several specimens as syninclusions suggests aggregative behaviour, thereby representing the earliest documented evidence of such ethology.

Fly palaeo-evo-devo: immature stages of bibionomorphan dipterans in Baltic and Bitterfeld amber

“…The preservation of a large number of immature of Mycetobia is in line with recent research on the entrapment bias in amber. This research (Sánchez-García et al, 2017; Solórzano Kraemer et al, 2018) has shown that the taphonomic window of amber deposits is positively selecting towards fauna associated with tree trunks, while negatively selecting against species from the certain other habitats, i.e., hygropetric water films (aquatic habitats formed by the thin layers of water seepagin from the soil) and true aquatic habitats (Sánchez-García et al, 2017).…”