Dragonflies and Damselflies from the Middle Miocene Satovcha Palaeolake of southwest Bulgaria.

The Satovcha Graben (depression formed by extension, as two geological blocks draw apart causing the ground between to thin and slump) forms a basin roughly 7 km in length and 1.5 km in width in the western Rhodopes Mountains of southwest Bulgaria. During the Miocene-Oligocene this depression was filled by a lake, and surrounded by subtropical evergreen forests similar to those found in Southeast Asia today. These deposits have produced a diverse range of Plant fossils preserved in freshwater diatomites (sedimentary rocks made up of the tests, or shells, of tiny planktonic Algae called Diatoms). The site is also known to produce Insect fossils, including Beetles, Coleoptera, Bugs, Hemiptera, Caddisflies, Trichoptera, Earwigs, Dermaptera, Ants and Bees, Hymenoptera, Flies including Mosquitoes, Gnats and Midges, Diptera, Cockroaches and Termites, Dictyoptera, a Grasshopper and Crickets, Orthoptera, and Dragonflies and Damselflies, Odonata; though to date these Insects have never been formally described or studied in any organized way.

In a paper published in the journal Palaeontologica Electronica in September 2016, Andre Nel of thr Institut de Systématique,Évolution, Biodiversité at the Muséum national d’Histoirenaturelle, Nikolay Simov of the National Museum of Natural History in Sofia, Vladimir Bozukov of the Institute of Biodiversity andEcosystem Research at the Bulgarian Academy of Sciences, and Milen Marinov of the Plant Health & Environment Laboratory of the Ministry for Primary Industries in Auckland, New Zealand, describe two new species of Dragonfly and a species of Damselfly from the Middle Miocene Sivik Formation of the Satovcha Graben.

The first Dragonfly species described is placed in the genus Oligaeschna, which has previously been described from other locations of similar age, and given the specific name bulgariensis, meaning 'from Bulgaria'. The species is described from two specimens, though both of these comprise the forewing only, one specimen preserved as part and counterpart on s split block, the second as part only. Insects in most groups can be identified to species level using the venation on the their forewings, so it is not unusual to describe new fossil species using isolated forewings.

Oligaeschna bulgariensis. (1) First specimen (part); (2) Second specimen (counterpart); (3) Second specimen. Scale bars represent 5 mm in all figures. Nel et al. (2016).

The second new Dragonfly species described is placed in the genus Stenolestes, which has previously been described from the Middle Oligocene to Early Miocene of Europe and Siberia, making this potentially the youngest example of the genus, and given the specific name rhodopensis, meaning 'from Rhodopes'; in reference both to the Rhodopes Mountains and the mythical Thracian queen Rhodope. The species is described from an isolated forewing preserved as part and counterpart, plus a largely intact insect compressed in lateral (side) view.

Stenolestes rhodopensis, whole Insect. Scale bar is 1 cm. Nel et al. (2016).

The new Damselfly species is placed in the genus Primorilestes, which has previously been used to describe species from the Early Oligocene of Primorye Territory in Russia and Early Eocene of Denmark, and is given the specific name magnificus, in reference to the quality of preservation on the frst specimen. The species is described from two specimens, a forewing preserved as part and counterpart, and an isolated wing-tip.

Primorilestes magnificus, first specimen (part). Scale bar is 5 mm. Nel et al. (2016).

See also...

A new species of Clubtail Dragonfly from Malaysian Borneo.                                                    Clubtail Dragonflies, Gomphidae, are a group of small-to-medium-sized Dragonflies related to Damselflies which get their name from a widening the end...

A new species of Damselfly from the La Montaña de Corazal Cloud Forest of Honduras.                                         Damselflies (Zygoptera) are members of the Dragonfly order (Odonta), though generally smaller...

A Dragonfly from the Late Jurassic of Central Poland.                                                 Dragonflies are one of the oldest groups of insects with a fossil record that dates back to the...

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A new species of Hawkweed from Bulgaria.

Hawkweeds (Hieracium spp.) are herbaceous flowering plants in the Aster Family (Asteraceae), closely related to Dandelions. There are numerous species in Europe, Africa, Asia, and North and South America, though the precise number of species is open to dispute, as most Hawkweeds are triploid (have three sets of chromosomes, which means that they cannot reproduce sexually (which requires an even number of chromosomes sets, which can then divide and recombine); the plants instead produce seeds asexually that are genetically identical to the parent plant. These triploid species are thought to have arisen by hybridization of diploid species (i.e. species with two sets of chromosomes that can reproduce sexually). This has led to some dispute over the classification of Hawkweeds, with American botanists tending to regard only the diploid, sexual, species as truly valid taxa with other plats regarded as hybrids of these, while in Europe botanists have tended to recognize the triploid, asexual, varieties as species as well, arguing that they may be of hybrid origin, and incapable of reproducing sexually, but are clearly successful organisms capable of sustaining large stable populations and competing against diploid plants.

In a paper published in the journal Phytotaxa on 20 May 2013, Zbigniew Szeląg of the Institute of Botany at Jagiellonian University, and Vladimir Vladimirov of the Department of Plant and Fungal Diversity and Resources at the Institute of Biodiversity and Ecosystem Research at the Bulgarian Academy of Sciences, describe a new species of Hawkweed from the central Rhodopes Mountains of southern Bulgaria.

Specimen of Hieracium crinitopannosum from by the road from Devin town to Mihalkovo village in the central Rhodopes Mountains of southern Bulgaria. Szeląg & Vladimirov (2013).

The new species is named Hieracium crinitopannosum; it is thought to be a hybrid between Hieracium crinitum and Hieracium petrovae, two diploid species found in the Rhodopes Mountains (Hieracium petrovae) and nearby Vacha River valley (Hieracium crinitum). Hieracium crinitopannosum is a 25-55 cm robust Hawkweed that flowers (pointlessly) in July and August and sets seeds in September. It is found growing in open spaces on eroded and rocky slopes in stands of a several dozen to a few hundred in the central Rhodopes Mountains of southern Bulgaria; Szeląg & Vladimirov suggest that it is likely that it is also found across the border in northern Greece.

The approximate location of the area where Hieracium crinitopannosum was discovered. Google Maps.

See also New species of Daisy from Brazil and Protests against hydraulic fractionation across Bulgaria.

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