''Dlusskyidris'' is an extinct

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nom ...

ant Ants are eusocial insects of the family Formicidae and, along with the related wasps and bees, belong to the order Hymenoptera. Ants evolved from vespoid wasp ancestors in the Cretaceous period. More than 13,800 of an estimated total of ...

in the Formicidae subfamily

Sphecomyrminae Sphecomyrminae is an extinct subfamily of ants in family Formicidae known from a series of Cretaceous fossils found in North America, Europe, and Asia. Sphecomyrminae contains eight genera, divided into two tribes Sphecomyrmini and Zigrasimec ...

, and is one of the five genera placed in the tribe Sphecomyrmini. The genus contains a single described species, ''Dlusskyidris zherichini'', and is known from three

Late Cretaceous The Late Cretaceous (100.5–66 Ma) is the younger of two epochs into which the Cretaceous Period is divided in the geologic time scale. Rock strata from this epoch form the Upper Cretaceous Series. The Cretaceous is named after ''creta'', ...

fossils which have been found in

northern Russia Russian North (russian: Русский Север) is an ethnocultural region situated in the northwestern part of Russia. It spans the regions of Arkhangelsk Oblast, the Republic of Karelia, Komi Republic, Vologda Oblast and Nenets Autonomous ...

History and classification

The three males of ''Dlusskyidris'' have been identified from adults that are preserved as inclusions in Taymyr amber. The ambers of the peninsula occur in the upper levels of the Kheta Formation, which is exposed in a number of locations in the Taimyr region. Age estimates of the Kheta Formation are between the Coniacian and

Santonian The Santonian is an age in the geologic timescale or a chronostratigraphic stage. It is a subdivision of the Late Cretaceous Epoch or Upper Cretaceous Series. It spans the time between 86.3 ± 0.7 mya (million years ago) and 83.6 ± 0.7 mya. ...

, and the ambers are found consistently in the uppermost units, giving a Santonian age range for the inclusions. The ''Dlusskyidris'' adults were collected from the Yantardakh locality, which is approximately upstream from the confluence of the Maimecha River with the

Kheta River The Kheta (russian: Хета) is a river in Krasnoyarsk Krai in Russia, left composite of the Khatanga River. The river is long. The area of its drainage basin is . Course The Kheta is formed by the confluence of the Ayan and Ayakli, both of ...

, on the bank of the Maimecha. Based on the flora and fauna of the

Ledyanaya Ledyanaya (russian: Ледяная, meaning "Icy"), is a peak in the Koryak Mountains. Administratively it is part of the Kamchatka Krai, Russian Federation.Google Earth This high mountain is the highest point of the Koryak Mountains. It is a ...

and Mutino formations which surround the Kheta Formation, the paleoforest likely has a humid and warm temperate climate with the trees growing along river banks. While the resin producing trees have not been identified, the resins were likely dropped into the river systems and buried quickly in deltaic sediments. The three males were first studied by Russian paleoentomologist Gennady Dlussky, who published the genus and species description in a 1975 paper. In that paper Dlussky named the genus "''Palaeomyrmex''" and the species "''Palaeomyrmex zherichini''". However the genus name ''Palaeomyrmex'' had already been used over a hundred years earlier by

Oswald Heer Oswald Heer (or Oswald von Heer) (31 August 1809 – 27 September 1883), Swiss geologist and naturalist, was born at Niederuzwil in Canton of St. Gallen and died in Lausanne. Biography Oswald Heer was educated as a clergyman at Halle an ...

for '' Palaeomyrmex prodromus''. Due to the name being preoccupied, the species was moved to the new genus name ''Dlusskyidris'' in 1994 by Barry Bolton. Russian paleoentomologist K. S. Perfilieva re-examined the holotype and paratype fossils 2011. Perfilieva noted that the visibility of the wings and the refractive index of the amber had been altered due to years of storage in

castor oil Castor oil is a vegetable oil pressed from castor beans. It is a colourless or pale yellow liquid with a distinct taste and odor. Its boiling point is and its density is 0.961 g/cm3. It includes a mixture of triglycerides in which about ...

. The oil had seeped into the amber, filling in air bubbles and making the wings nearly invisible under light microscope examination.

Description

The ''Dlusskyidris'' males are distinguished from other Sphecomyrminae males based on several features. There are spurs present on the tibias of the hind and mid legs. The

tergite A ''tergum'' (Latin for "the back"; plural ''terga'', associated adjective tergal) is the dorsal ('upper') portion of an arthropod segment other than the head. The anterior edge is called the 'base' and posterior edge is called the 'apex' or 'mar ...

of the end abdominal segment is triangular in shape, as is the subgenital plate. There are well developed cerci on the abdomen, the parameres are narrow with slight curving in the middle and pointed tips. In Dlussky's original description, he considered the wing venation primitive and similar to that of Armaniidae genera with complete cells 1r+2r, 3r and 2rm. Perfilieva noted however that two different versions of the venation were presented by Dlussky.

References

{{Taxonbar, from=Q18102432 Sphecomyrminae Cretaceous insects Fossil ant genera Fossil taxa described in 1975 Fossil taxa described in 1994 Cretaceous insects of Asia Taimyr amber