An unexpectedly abundant new genus of black flies (Diptera, Simuliidae) from Upper Cretaceous Taimyr amber of Ugolyak, with discussion of the early evolution of birds at high latitudes

Ugolyakia kaluginae gen. et sp. nov. is described from Ugolyak (Santonian Taimyr amber), based primarily on its unbranched Rs and developed katepisternal sulcus. It is attributed to the tribe Simuliini, although it lacks calcipala and spiniform seta on the costal vein characteristic of most genera of the tribe. Possession of a claw with a large subbasal tooth and absence of significant sclerotization of the sternites suggest that U. kaluginae females were blood-sucking avian parasites. Black flies make up 3% of all insect inclusions and 5% of all identifiable dipterans in Ugolyak amber. Only two Late Cretaceous black fly specimens were previously known: a poorly preserved female from Yantardakh (Santonian Taimyr amber) and a complete one from Turonian New Jersey amber. Feathers found at nearly all Cretaceous black fly sites (and at all formations with records of Simuliini) were younger than the Hauterivian. Ugolyak black flies are thought to have inhabited the same environments as Cretaceous ornithurine birds and most likely fed on them. These insects can then be used as an indicator of this bird community, allowing a better understanding of the Late Cretaceous forest ecology of Northern Asia. The inferred presence of Ornithuromorpha at high latitudes by the Early Cretaceous implies that their high growth rate may have evolved as an adaptation to a short yearly period of productivity (probably as a compensation for the poor flight ability of their young). This further implies that advanced ornithuromorphs might have originated at higher latitudes: later, aquatic ornithuromorphs occupied niches in lower latitude regions with tropical climates such as the Chinese Jehol biota, to which they were preadapted. The inferred seasonality at higher latitudes during cold spells of the Early Cretaceous could further be viewed as a prerequisite for the evolutionary origin of the granivory. (C) 2018 Elsevier Ltd. All rights reserved.