''Formica biamoensis'' is an

extinct Extinction is the termination of a kind of organism or of a group of kinds (taxon), usually a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and ...

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

of formicid in the ant subfamily

Formicinae The Formicinae are a subfamily within the Formicidae containing ants of moderate evolutionary development. Formicines retain some primitive features, such as the presence of cocoons around pupae, the presence of ocelli in workers, and little ...

known from fossils found in eastern Asia.

History and classification

''Formica biamoensis'' is known from a single ant found in Russia. The specimen was described from a

compression fossil A compression fossil is a fossil preserved in sedimentary rock that has undergone physical compression. While it is uncommon to find animals preserved as good compression fossils, it is very common to find plants preserved this way. The reason fo ...

preserved in

diatomite Diatomaceous earth (), diatomite (), or kieselgur/kieselguhr is a naturally occurring, soft, siliceous sedimentary rock that can be crumbled into a fine white to off-white powder. It has a particle size ranging from more than 3 μm to le ...

deposits of the Bol’shaya Svetlovodnaya site. Located in the

Pozharsky District Pozharsky District (russian: Пожа́рский райо́н) is an administrativeLaw #161-KZ and municipalLaw #191-KZ district (raion), one of the twenty-two in Primorsky Krai, Russia. It is located in the northern and northwestern parts of t ...

, on the Pacific Coast of Russia, the fossil-bearing rocks preserve possibly

Priabonian The Priabonian is, in the ICS's geologic timescale, the latest age or the upper stage of the Eocene Epoch or Series. It spans the time between . The Priabonian is preceded by the Bartonian and is followed by the Rupelian, the lowest stage of t ...

plants and animals which lived in a small lake near a volcano. The site has been attributed to either the Maksimovka or Salibez Formations and compared to the Bembridge Marls and

Florissant Formation The Florissant Formation is a sedimentary geologic formation outcropping around Florissant, Teller County, Colorado. The formation is noted for the abundant and exceptionally preserved insect and plant fossils that are found in the mudstones and ...

, both of which are Priabonian in age. At the time of description, the

holotype A holotype is a single physical example (or illustration) of an organism, known to have been used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of several ...

specimen, number PIN 3429/1141 was preserved in the A. A. Borissiak Paleontological Institute collections, part of the

Russian Academy of Sciences The Russian Academy of Sciences (RAS; russian: Росси́йская акаде́мия нау́к (РАН) ''Rossíyskaya akadémiya naúk'') consists of the national academy of Russia; a network of scientific research institutes from across t ...

. The fossil was first described by the trio of paleomyrmecologists Gennady Dlussky,

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 ...

and Ksenia Perfilieva. In the type description, Dlussky, Rasnitsyn and Perfilieva named the species ''F. biamoensis'', with the

specific epithet In taxonomy, binomial nomenclature ("two-term naming system"), also called nomenclature ("two-name naming system") or binary nomenclature, is a formal system of naming species of living things by giving each a name composed of two parts, bot ...

derived from "Biamo", the older name for the type locality. ''F. biamoensis'' is similar in overall appearance to the

Baltic amber The Baltic region is home to the largest known deposit of amber, called Baltic amber or succinite. It was produced sometime during the Eocene epoch, but exactly when is controversial. It has been estimated that these forests created more than 1 ...

species '' Formica flori'' and '' Formica gustawi'', but differs in the eyes and petiole size. Comparison to other species is complicated however, by the other fossil workers being described from

amber Amber is fossilized tree resin that has been appreciated for its color and natural beauty since Neolithic times. Much valued from antiquity to the present as a gemstone, amber is made into a variety of decorative objects."Amber" (2004). In Ma ...

specimens and not compression fossils like ''F. biamoensis''. At the time of description the authors noted that it was not possible to tell if the ''F. biamoensis'' workers and the ''

Formica paleosibirica ''Formica paleosibirica'' is an extinct species of formicid in the ant subfamily Formicinae known from fossils found in eastern Asia. History and classification ''F. paleosibirica'' is known from a group of ants found in Russia. The specimens ...

'' males described in the same paper were separate species.

Description

The holotype worker is approximately with a slender mesosoma, weakly rounded pronotum and a thick petiole node. The side of the node facing the gaster is bowed outwards forming a curved profile and the top of the node is rounded. The head has oval compound eyes that are placed towards the back end and are small compared to other ''Formica'' species. While the chewing edges of the mandibles are not preserved enough to determine the presence of teeth, the ends of the chewing margins each have an acute tooth. The preserved antennae segments are all longer than they are wide.

References

{{Taxonbar, from=Q24668307 Priabonian insects Fossil ant taxa Fossil taxa described in 2015 Cenozoic insects of Asia biamoensis