''Archencyrtus'' 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 ...

wasp A wasp is any insect of the narrow-waisted suborder Apocrita of the order Hymenoptera which is neither a bee nor an ant; this excludes the broad-waisted sawflies (Symphyta), which look somewhat like wasps, but are in a separate suborder. ...

in the Chalcidoidea family

Encyrtidae Encyrtidae is a large family of parasitic wasps, with some 3710 described species in about 455 genera. The larvae of the majority are primary parasitoids on Hemiptera, though other hosts are attacked, and details of the life history can be variab ...

. The genus contains a single described species, ''Archencyrtus rasnitsyni'' known from a

Middle Eocene The Eocene ( ) Epoch is a geological epoch that lasted from about 56 to 33.9 million years ago (mya). It is the second epoch of the Paleogene Period in the modern Cenozoic Era. The name ''Eocene'' comes from the Ancient Greek (''ēṓs'', "da ...

fossil that was found in Eastern Asia.

History and classification

When first described, ''Archencyrtus'' was known from a single fossil insect included in a transparent chunk of Sakhalin amber. While being studied the fossil was part of the amber collections housed in the

Paleontological Institute, Russian Academy of Sciences The Paleontological Institute, Russian Academy of Sciences (PIN; russian: Палеонтологический институт РАН) in Moscow is among the world's largest paleontological institutes. An affiliate of the Russian Academy of Scienc ...

. Sakhalin amber is recovered from fossil bearing rocks in the Sakhalin region of Eastern Russia. At the time of description the amber, which originates from the Lower Due Formation, was estimated to be of Middle Eocene age. The amber fossil specimen was first studied by paleoentomologist S. A. Simutnik of the Russian Academy of Sciences, with his 2014

type description A species description is a formal description of a newly discovered species, usually in the form of a scientific paper. Its purpose is to give a clear description of a new species of organism and explain how it differs from species that have be ...

for the genus and species being published in the ''Paleontologicheskii Zhurnal''. The genus name was coined as a combination of the Encyrtidae genus name '' Encyrtus'', and the Greek word ''archaios'' that translates as "ancient". The species name is a patronym that was chosen to honor the Russian paleoentomologist

Alexandr Rasnitsyn Alexandr Pavlovich Rasnitsyn (Russian: Александр Павлович Расницын) is a Russian entomologist, expert in palaeoentomology, and Honored Scientist of the Russian Federation (2001). His scientific interests are centered on ...

. Among the features distinguishing ''Archencyrtus'' from other genera is the antennae with five funicular segments, the other described fossil Encyrtidae genera have four segments, while the major portion of the living genera have six segments.

Description

In females of ''A. rasnitsyni'' the head has a rounded rear margin and the mouth is shifted under the lower edge. The antennae have a pedicel, five segments and a apical club formed from three to four additional segments. The first three segments after the pedicel are ring shaped and very small while the next two are larger. Unlike some other members of Encyrtidae, ''A. rasnitsyni'' has a body that is elongated rather than flattened. The metasoma is a little longer than the mesosoma, but details of the body are not discernible due to the preservation conditions of the amber. The transparent wings are long, with the tips reaching notably farther back than the abdomen tip. There is an elongate setae free section on the wing, the linea calva, which is bordered on the basal side by long setae. The wing setae also from a short fringe along the margin of the forewings. The legs show spurs present on the protibia and mesotibia, while the tarsi have five segments each.

References

{{Taxonbar, from=Q24885497 Encyrtidae Eocene insects Fossil taxa described in 2014 Hymenoptera of Asia Sakhalin amber Prehistoric insects of Asia