Saturday 14 June 2014

Winter Crane Flies from the Middle Jurassic Jiulongshan Formation of Inner Mongolia.

Winter Crane Flies (Trichoceridae) are large True Flies (Diptera) with a (slightly erroneous) reputation for being tolerant of cold conditions. In fact a few species are capable of remaining active in winter, with some even mating and laying eggs beneath snow cover, but other members of the group are no more tolerant of cold conditions than most insects.

In a paper published in the journal ZooKeys on 28 May 2014, Fei Dong, Chungkun Shih and Dong Ren of the College of Life Sciences at Capital Normal University, describe two new species of Winter Crane Fly from the Jiulongshan Formation of Inner Mongolia, both of which are placed in the previously described genus Eotrichocera, which has previously been used to describe fossils from the Middle Jurassic of Inner Mongolia and south-central Siberia.

The Jiulongshan Formation outcrops around Daohugou Village, and has produced a large number of exceptionally well preserved Insects from what is commonly known as the Daohugou Lagerst├Ątte, part of the Yanliao Biota. The fossils are thought to be late Middle Jurassic in origin, from the boundary between the Bathonian and Callovian eras, making them about 165 million years old. This provides a valuable insight into insect diversity in the Jurassic, before the appearance and rapid rise to dominance of Angiosperms (Flowering Plants), an event which radically reshaped Insect faunas.

The first species is named Eotrichocera longensis, in reference to its long legs. It is described from two female specimens about 13 mm in length.

Eotrichocera longensis, both specimens. Scale bars are 1 mm. Fei et al. (2014).

The second species is named Eotrichocera amabilis, meaning ‘lovely’ in Latin. It is described from two specimens, one female and one of uncertain sex, about 5.8 mm in length.

Eotrichocera amabilis, both specimens. Scale bars are 1 mm. Fei et al. (2014).

See also…

Non-biting Midges (Chironomidae) are small Flies closely related to the Biting Midges, Solitary Midges and Blackflies. They closely resemble Mosquitoes, but despite their appearance and relationships...

Axymyids are medium sized, stout bodied, True Flies (Diptera) related to the Gnats, Midges, Mosquitoes and Crane Flies. They have a fossil record going beck to the Jurassic, but are rare today, with only six described species.

Mosquitoes are small Flies notorious for their habit of sucking blood. Only the females do this, the males tend to feed on pollen, nectar or plant sap. The larvae of Mosquitoes are aquatic carnivores, the adults emerging from the water to mate, lay eggs and die. This is clearly a successful lifestyle; Mosquitoes are found on every continent except Antarctica and have a fossil record dating back to the Middle...

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