''Messelepone'' is an

extinct Extinction is the termination of an organism by the death of its Endling, last member. A taxon may become Functional extinction, functionally extinct before the death of its last member if it loses the capacity to Reproduction, reproduce and ...

genus of ants in the formicid subfamily

Ponerinae Ponerinae, the ponerine ants, is a subfamily of ants in the Poneromorph subfamilies group, with about 1,600 species in 47 extant genera, including '' Dinoponera gigantea'' - one of the world's largest species of ant. Mated workers have replac ...

described from fossils found in

Europe Europe is a continent located entirely in the Northern Hemisphere and mostly in the Eastern Hemisphere. It is bordered by the Arctic Ocean to the north, the Atlantic Ocean to the west, the Mediterranean Sea to the south, and Asia to the east ...

. ''M. leptogenoides'' is the only species assigned to the genus, which is one of several

Lutetian The Lutetian is, in the geologic timescale, a stage (stratigraphy), stage or age (geology), age in the Eocene. It spans the time between . The Lutetian is preceded by the Ypresian and is followed by the Bartonian. Together with the Bartonian it ...

Ponerinae genera.

History and classification

When described, ''Messelepone'' was known from two fossil insects which are compression-impression fossils preserved in layers of soft

sedimentary Sedimentary rocks are types of rock formed by the cementation of sediments—i.e. particles made of minerals (geological detritus) or organic matter (biological detritus)—that have been accumulated or deposited at Earth's surface. Sedime ...

rock. Along with other well preserved insect fossils, the ''Messelepone'' specimens were collected from layers of the Lutetian

Messel pit The Messel Formation is a Formation (geology), geologic formation in Hesse, central Germany, dating back to the Eocene Epoch (geology), epoch (about 47 Ma). Its geographic range is restricted to the Messel pit. There it unconformably overlie ...

World Heritage Site World Heritage Sites are landmarks and areas with legal protection under an treaty, international treaty administered by UNESCO for having cultural, historical, or scientific significance. The sites are judged to contain "cultural and natural ...

. The formation is composed of brown coals, oil shales, and bituminous shale, which preserved numerous insects, fish, birds, reptiles, and terrestrial mammals as a notable lagerstätten. The area is a preserved maar lake which initially formed approximately 47 million years ago as the result of volcanic explosions. At the time of description, the

holotype A holotype (Latin: ''holotypus'') is a single physical example (or illustration) of an organism used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of s ...

queen Queen most commonly refers to: * Queen regnant, a female monarch of a kingdom * Queen consort, the wife of a reigning king * Queen (band), a British rock band Queen or QUEEN may also refer to: Monarchy * Queen dowager, the widow of a king * Q ...

and

paratype In zoology and botany, a paratype is a specimen of an organism that helps define what the scientific name of a species and other taxon actually represents, but it is not the holotype (and in botany is also neither an isotype (biology), isotype ...

male specimens were preserved in the Senckenberg Research Station Messel fossil collections. The fossils were described by Gennady Dlussky and Sonja Wedmann in a 2012 paper on the poneromorph ants of Messel, with both the genus and species named in it. The genus name is a combination of the ant genus '' Ponera'' and Messel after the type locality. The

specific epithet In Taxonomy (biology), taxonomy, binomial nomenclature ("two-term naming system"), also called binary nomenclature, is a formal system of naming species of living things by giving each a name composed of two parts, both of which use Latin gramm ...

was derived from the modern ant genus name '' Leptogenys'', which ''M. leptogenoides'' has similarities to. ''Messelepone'' is one of five extinct genera from three subfamilies which have species described from Messel Formation fossils by Dlussky and Wedmann in 2012. Three of the other genera '' Cephalopone'', '' Cyrtopone'', and ''

Protopone ''Protopone'' is an extinct genus of ants in the Formicidae, formicid subfamily Ponerinae described from fossils found in Europe and Asia. There are seven described species placed into the genus, ''Protopone? dubia'', ''Protopone germanica'', '' ...

'' are also placed in Ponerinae. The genus '' Casaleia'' is placed in Amblyoponinae, while the last genus '' Pseudectatomma'' is in Ectatomminae.

Description

Messelepone leptogenoides paratype SMFMEI7198

The ''Messelepone'' queen was described as having an approximate body length of with a head that is distinctly small, the

mesosoma The mesosoma is the middle part of the body, or tagma, of arthropods whose body is composed of three parts, the other two being the prosoma and the metasoma. It bears the legs, and, in the case of winged insects, the wings. Wasps, bees and a ...

being almost two times greater in length. The subtriangular mandibles are up to one half the head length and have toothed chewing faces. Like ''Protopone'' species, the antennae sockets are widely placed on the head, in contrast to those seen in ''

Pachycondyla ''Pachycondyla'' is a Ponerinae, ponerine genus of ants found in the Neotropics. Distribution ''Pachycondyla'' is currently distributed from southern United States to northern Argentina, but some fossil species (e.g. ''Pachycondyla eocenica, P. ...

'' which are close together. The node-shaped petiole is shorter than the height, with a helcium that projects of the front face of the gasteral segment. Both the queen and male have a distinct petiole, rectangular in side view, similar to some species of ''Leptogenys''. Both genders also have a gaster with the first segment shorter than the second segment. The queen has eyes that are oval in shape and placed slightly forward from the heads midpoint. The gena below the eyes are a little shorter than the eyes are wide. The rectangular petiole lacks a peduncle between it and the mesosoma. The male is smaller than the gyne, with an estimated body length of . The eyes are round and the gena only half as long as the eyes are wide. The thirteen segmented antennae have a filifrom morphology and the scape is short. The second antenna segment is nearly the same length as wide, contrasting the next segment which is 3.5 times longer than wide. The

mandible In jawed vertebrates, the mandible (from the Latin ''mandibula'', 'for chewing'), lower jaw, or jawbone is a bone that makes up the lowerand typically more mobilecomponent of the mouth (the upper jaw being known as the maxilla). The jawbone i ...

s are well developed and

opposable The thumb is the first digit of the hand, next to the index finger. When a person is standing in the medical anatomical position (where the palm is facing to the front), the thumb is the outermost digit. The Medical Latin English noun for thumb ...

, a feature that separates ''M. leptogenoides'' males from those of ''Pachycondyla'' species.

References

External links

* * {{Taxonbar, from1=Q21334029, from2=Q21319060 †Messelepone Fossil taxa described in 2012 Hymenoptera of Europe Prehistoric life of Europe Monotypic fossil ant genera Eocene insects