A new genus of dance fly (Diptera: Empidoidea: Hybotidae) from Cretaceous Spanish ambers and introduction to the fossiliferous amber outcrop of La Hoya (Castellón Province, Spain)

Abstract

Hybotidae fly species, also known as dance flies, in Cretaceous ambers have been described from Lebanon, France, Myanmar, Russia, and Canada. Here we describe Grimaldipeza coelica gen. et sp. n., and recognize another two un-named species, in Spanish amber from the middle Albian El Soplao and lower Cenomanian La Hoya outcrops. The fore tibial gland is present in the new genus, which is characteristic of the family Hybotidae. We compare Grimaldipeza coelica gen. et sp. n. with the holotypes of Trichinites cretaceus Hennig, 1970 and Ecommocydromia difficilis Schlüter, 1978, and clarify some morphological details present in the latter two species. Further taxonomic placement beyond family of the here described new genus was not possible and remains incertae sedis within Hybotidae until extant subfamilies are better defined. We provide new paleoecological data of the hybotids, together with paleogeographical and life paleoenvironmental notes. A table with the known Cretaceous Hybotidae is provided. Furthermore, the La Hoya amber-bearing outcrop is described in detail, filling the information gap for this deposit.

Taphonomy and palaeoenvironmental interpretation of a new amber-bearing outcrop from the mid-Cretaceous of the Maestrazgo Basin (E Iberian Peninsula)

“…The vegetation of the terrestrial areas was probably analogous to that of the late Albian environments inferred for the Maestrazgo Basin, mainly composed of ferns and angiosperms in humid places, conifers in coastal areas, arid woodlands, and salt marshes (Barrón et al, 2023). The FTIR spectrum of La Dehesa amber shows similar characteristics to spectra of other ambers from the Maestrazgo Basin (Peñalver et al, 2007;Álvarez-Parra et al, 2021;Solórzano-Kraemer et al, 2023), pointing to similar resin-producing trees (Araucariaceae) and diagenetic conditions, although a gas chromatography-mass spectrometry analysis is required to link the amber with a resin source. According to Abbink et al (2004), a high percentage of Mesozoic Araucariaceae pollen might be related to plants that grew near seashores.…”

“…Exocyclic methylenic bands are absent at 1640 cm −1 and 880 cm −1 , indicating a high degree of maturation. The FTIR spectrum from La Dehesa amber has less intense bands, but it does not show significant differences in comparison with the spectra of the other ambers from the Maestrazgo Basin (Peñalver et al, 2007;Álvarez-Parra et al, 2021;Solórzano-Kraemer et al, 2023). Interestingly, some amber pieces show evidence of interaction between organisms and resin in the palaeoenvironment.…”

“…The most studied amber-bearing outcrops are Ariño, El Soplao, Peñacerrada I and II, and San Just Álvarez-Parra et al, 2021). Regarding the Maestrazgo Basin, bioinclusions have been found in ambers from four outcrops related to the Escucha Formation and Utrillas Group Álvarez-Parra et al, 2021;Barrón et al, 2023;Solórzano-Kraemer et al, 2023): Ariño (early Albian), San Just (late Albian), Arroyo de la Pascueta (late Albian), and La Hoya (earliest Cenomanian). Here, we present a new amber-bearing outcrop from the Cretaceous of the Maestrazgo Basin called La Dehesa, in Estercuel (Teruel, Aragón, Spain).…”

New Cretaceous empidoids and the Mesozoic dance fly revolution (Diptera: Empidoidea)

“…Among empidoids, a three‐articled stylus occurs only in a few Atelestidae (e.g. Meghyperus Loew, Acarteroptera Collin) and in the Cretaceous Turonempis Grimaldi and Cumming (the apparently three‐segmented stylus of Trichinites Hennig is a preservation artefact; see Solórzano‐Kraemer et al., 2023). In half of the Electrochoreutes species, vein M 1 + 2 is proximally upcurved (e.g.…”