Eumerus druk: A new species of Hoverfly from Bhutan.

Hoverflies, Syrphidae, are often large and attractively coloured Insects that are frequently found on flowers and play a vital role in ecosystem services as pollinators. In contrast to other members of the group, the majority of the species from the very genus Eumerus are inconspicuously dark coloured, sometimes with metallic bronze-green or even golden luster or bluish sheen, and they are more often than not found on the ground or on rocks. With the wings folded over the abdomen, the metallic luster is obscured when in rest. For the same reason, the bright-red abdomen of some species is less conspicuous when in rest. The genus is widespread in the Old World and Australia and introduced to the Americas.

In a paper published in the journal ZooKeys on 27 January 2020, John Smit and Theo Zeegers of the Naturalis Biodiversity Center, and Phurpa Dorji of the Gross National Happiness Commission, and the Bhutan Royal Society for Protection of Nature, describe a new species of Eumerus from Bhutan.

The new species is named Eumerus druk, where 'druk' means 'dragon' in Dzongkha, the Sino-Tibetan language spoken in Bhutan, and refers to the official name of the kingdom: 'Druk yul' (country of the Dragon people, or the Land of the Thunder Dragon). It is is only known from the type series collected at the Royal Botanical Garden in Thimphu, Bhutan, but it likely has a wider distribution in the Himalayas.

The body of Eumerus druk is a coppery-gold colour with a dense coating of black hairs, the five males found are 7.5-8.5 mm in length with a wing length of 5.5-6.5 mm, while the only known female is 7 mm long with a wing length of 6 mm. Eyes are black and holoptic (meet along the median dorsal line of the head), covering much of the exterior surface of the head, these have a thin covering of white hairs, areas of the head not covered by the eyes have a thicker coating of white hairs. The males of Eumerus druk have tufts of long while hairs on their third and fourth thoracic segments, something not known in any other species of Eumerus.

Eumerus druk, specimens in lateral view. (A) Male and (F) female. Smit et al. (2020).

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Oligopipiza quadriguttata: A new species of Pipizine Hoverfly from the Middle Oligocene of France.

Hoverflies, Syrphidae, are one of the most successful groups of True Flies, Diptera, alive today, found on all landmasses except Antarctica, Spitzbergen and some remote oceanic islands. They play a significant ecological role, both as adult pollinators and as voracious predators during their larval stages, and are thought to have appeared during the Middle Cretaceous, around the time when Angiosperms (Flowering Plants) were rapidly diversifying and coming to dominate most terrestrial ecosystems. Despite this success, the fossil record of Hoverflies is rather sparse, with only 106 fossil species described, the most recent of which was identified in 2005.

In a paper published in the journal Acta Palaeontologica Polonica on 20 July 2018, Valentin Nidergas of the Institut Systématique Evolution Biodiversité at the Muséum national d’Histoire naturelle, Jiří Hadrava of the Department of Zoology at Charles University, Romain Garrouste, also of the Institut Systématique Evolution Biodiversité at the Muséum national d’Histoire naturelle, Jakub Prokop, also of the Department of Zoology at Charles University, and Thomas Schubnel and André Nel, again of the Institut Systématique Evolution Biodiversité at the Muséum national d’Histoire naturelle, describe a new species of Hoverfly from the Middle Oligocene clay-limestone laminites of the National Geological Reserve of Lubéron at Cereste in France.

The new species is named Oligopipiza quadriguttata, where ‘Oligopipiza’ derives from ‘Oligocene’ and ‘Pipiza’ a modern genus which the new Hoverfly resembles, and ‘quadriguttata’ means ‘four drops’ in reference to the markings on the abdomen of this species. Oligopipiza quadriguttata is named from four male and four female specimens, obtained by splitting the laminites with a hammer and a spatula. These specimens are 6.8-8.1 mm in length, with hairy abdomens, thoraxes and legs, with two pairs of yellow, drop-shaped markings on the abdomens; these vary in size but are always present. 

Pipizine hoverfly Oligopipiza quadriguttata, male. Rupelian, Céreste, France. Nidergas et al. (2018).

Many of the specimens assigned to the species were covered in what appeared to be Pine pollen. This is surprising, as while modern Hoverfly’s are significant pollinators, no there are no recorded instances of modern Pines being pollinated by Hoverflies, or indeed any other Insect, the group being entirely wind-pollinated today. However, the Lubéron deposits are thought to have been laid down in a mixed Pine/broadleaf forest, a similar habitat to that occupied by many European Pipizine Hoverflies today, with macrofossils of Pine fragments being quite common, but no previously recorded Pine pollen. This is curious, as (wind-pollinated) Pines usually produce copious amounts of pollen, which is likely to be preserved in any local deposits preserving other fossils. The presence of a Pine species reliant on Insect pollination might help to explain this, as such as species could produce far less pollen, and would not need to shed it so freely into the environment.

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