Biting midges (Diptera: Ceratopogonidae) as indicators of biostratigraphy, ecological reconstructions and identification of amber deposits

Abstract

Biting midges (Diptera: Ceratopogonidae) are a large family of flies that commononly appear in Lower Cretaceous to Miocene strata, with over 280 fossil species (4.3 % of the family), belonging to 49 genera (26 extant; 23 extinct). Morphological characters used in the identification of fossil genera and species are identical to those used in studies of extant Ceratopogonidae and, as a result, their potential indicative value is reliable. Two relictual extant genera, Leptoconops and Austroconops, reported from Lower Cretaceous Lebanese amber, are at least 125 million years old. Certain ceratopogonid genera are indicative for the Lower Cretaceous, Upper Cretaceous, Eocene or Miocene. A morphological character indicative for the Upper Cretaceous and Cenozoic is macrotrichia on the wing membrane of adults. Indicator species and genera are reviewed for all amber deposits. Eocene Baltic amber contains the best known fauna of biting midges, with 109 named species. Some genera are indicative of aquatic and semiaquatic habitats (predaceous genera, subfamily Ceratopogoninae), forests with rotting trees (Forcipomyia), sandy sea shore habitats (Leptoconops), a cold boreal climate (Ceratopogon) or warm climates (Nannohelea, Austroconops, Leptoconops, Meunierohelea, Metahelea). Females require a protein-rich meal and are well known for feeding on the blood of vertebrates, but many feed on other things, so this information can help with the interpretation of palaeoenvironments. Washingtonhelea taimyrica Szadziewski, 1996, described from Siberian amber, is transferred to the fossil genus Palaeobrachypogon: P.taimyricus (Szadziewski, 1996), comb. nov. For Serromyia alphea, mistakenly redescribed and illustrated from Eocene Bitterfeld amber (= Baltic amber) by Szadziewski (1993), a new name – Serromyiaerrata Szadziewski, nom. nov. – is proposed.

The Phylogenetic Relationships of Cretaceous Biting Midges, with a Key to All Known Genera (Diptera: Ceratopogonidae)

“…The Ceratopogonidae have one of the most diverse and abundant fossil records of any family of insects, with 283 species known from throughout the Tertiary Era and Cretaceous Period (Borkent, 2016). Because the phylogenetic relationships among many genera, and espe¬ cially those of extant basal lineages, are well established, many of these fossils are particularly informative regarding the diversification of the family in time and space (Borkent, 2000a;Szadziewski, 2017). In this paper, some problematic Cretaceous genera are discussed, a number of species reassigned generically, and a phylogenetic interpretation of those with identifiable synapomorphies is provided.…”

“…Identifying the phylogenetic position of various fossil genera of Ceratopogonidae is fun¬ damental to proper interpretation of their historical zoogeography and palaeoecology, includ¬ ing features such as the likely hosts of adult females, adult activity times, and larval habitats, features that have already been at least partially interpreted (Borkent, 1995(Borkent, , 1996Borkent and Craig, 2004;Szadziewski, 1996). As their fossil record continues to be described, these genera will also become increasingly valuable as indicators of stratigraphy and the dating of fossil deposits (Borkent, 1995(Borkent, , 2000aPerez-de la Fuente et al, 2011;Szadziewski, 1996Szadziewski, , 2008Szadziewski, , 2017.…”

The Lower Cretaceous male ofLebanoculicoides daheri– belonging to the earliest lineage of biting midges (Diptera: Ceratopogonidae)

“…The extant earliest lineages of each of the families of Culicomorpha (Diptera) live in small aquatic habitats and feed on microorganisms (Borkent and Craig 2004;Borkent 2012a). The earliest extant lineage of Ceratopogonidae is the Leptoconopinae, with two extant genera, Austroconops Wirth and Lee and Leptoconops Skuse, both of which were present during the Lower Cretaceous (Borkent 2000;Szadziewski 2017). The specific natural aquatic habitat of Austroconops is unknown (Borkent and Craig 2004), but the immatures of Leptoconops are present in wet sand (marine or freshwater) or in cracked clay, or halomorphic calcareous soils.…”

Synchrotron-radiation computed tomography uncovers ecosystem functions of fly larvae in an Eocene forest

“…Among such crucial questions are the main avenues of matter and energy transfer in Eocene forests, as well as the nature of the whole biome beyond those commonly preserved organisms with hard external or internal skeletons. Amber provides a unique peek into these aspects of Eocene ecosystems by preserving small soft-bodied organisms, absent from other fossil deposits, but playing vital roles in the functioning of the environment (Andersen et al, 2009;Peñalver et al 2012, 2018, Ramirez et al, 2017Cai et al 2018).…”

“…Owing to the specificity of the ecological requirements, flies are often used to reconstruct habitats and climatic conditions based on the occurrence of particular groups in a deposit (e.g., Walker, 2001;Brooks, 2006;Rolland et al, 2008). While adult flies are most often used for this purpose (e.g., Moe et al, 2005;Grund, 2006;Szadziewski, 2018), they are short-lived (days to weeks) and frequently do not feed, serving solely as the dispersive and reproductive stage (Marshall, 2012). Fly larvae, in contrast, are tightly associated with certain types of habitat and perform most ecosystem functions and are therefore the stage that provides the greatest direct linkage between the fly and its specific environment (Baranov et al, 2019a(Baranov et al, , 2019b.…”