Messelepone Leptogenoides Paratype SMFMEI7198
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''Messelepone'' 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 ...
genus of ants in the formicid subfamily Ponerinae described from fossils found in
Europe Europe is a large peninsula conventionally considered a continent in its own right because of its great physical size and the weight of its history and traditions. Europe is also considered a Continent#Subcontinents, subcontinent of Eurasia ...
. ''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 or 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 is sometimes referred to as the Midd ...
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 (geology), rock that are formed by the accumulation or deposition of mineral or organic matter, organic particles at Earth#Surface, Earth's surface, followed by cementation (geology), cementation. Sedimentati ...
rock. Along with other well preserved insect fossils, the ''Messelepone'' specimens were collected from layers of the Lutetian Messel pit
World Heritage Site A World Heritage Site is a landmark or area with legal protection by an international convention administered by the United Nations Educational, Scientific and Cultural Organization (UNESCO). World Heritage Sites are designated by UNESCO for h ...
. The formation is composed of brown coals, oil shales, and
bituminous shale Oil shale is an organic-rich fine-grained sedimentary rock containing kerogen (a solid mixture of organic chemical compounds) from which liquid hydrocarbons can be produced. In addition to kerogen, general composition of oil shales constitute ...
, which preserved numerous insects, fish, birds, reptiles, and terrestrial mammals as a notable lagerstätten. The area is a preserved
maar lake A maar is a broad, low-relief volcanic crater caused by a phreatomagmatic eruption (an explosion which occurs when groundwater comes into contact with hot lava or magma). A maar characteristically fills with water to form a relatively shallow ...
which initially formed approximately 47 million years ago as the result of volcanic explosions. 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 ...
queen Queen or QUEEN may refer to: Monarchy * Queen regnant, a female monarch of a Kingdom ** List of queens regnant * Queen consort, the wife of a reigning king * Queen dowager, the widow of a king * Queen mother, a queen dowager who is the mother ...
and paratype 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 ''Ponera'' is a genus of ponerine ants. The name is the Latinized form (') of the Ancient Greek ' (, 'wicked, wretched'). Description Workers are very small to small in size (1–4 mm); queen are similar to workers but winged. This genus ...
'' and Messel after the type locality. 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 ...
was derived from the modern ant genus name ''
Leptogenys ''Leptogenys'' is a genus of ants in the subfamily Ponerinae. ''Leptogenys'' is the most diverse ponerine ant genus in the world; it is widespread throughout tropical and subtropical regions and there are over 260 extant species described. Most ...
'', 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 ''Cephalopone'' is an extinct genus of ants in the formicid subfamily Ponerinae described from fossils found in Europe. There are two described species placed into the genus, ''Cephalopone grandis'' and ''Cephalopone potens''. ''Cephalopone'' ...
'', ''
Cyrtopone ''Cyrtopone'' is an extinct genus of ants in the formicid subfamily Ponerinae described from fossils found in Europe. There are four described species placed into the genus, ''Cyrtopone curiosa'', ''Cyrtopone elongata'', ''Cyrtopone microcephal ...
'', and ''
Protopone ''Protopone'' is an extinct genus of ants in the formicid subfamily Ponerinae described from fossils found in Europe and Asia. There are seven described species placed into the genus, ''Protopone? dubia'', ''Protopone germanica'', ''Protopone m ...
'' are also placed in Ponerinae. The genus ''
Casaleia ''Casaleia'' is an extinct genus of ants in the formicid subfamily Amblyoponinae described by Pagliano & Scaramozzino in 1990 from fossils found in Europe. The genus contains four species dating from the Eocene to Miocene, ''Casaleia eocenica'' ...
'' is placed in
Amblyoponinae Amblyoponinae is a subfamily of ants in the poneromorph subfamilies group containing 13 extant genera and one extinct genus. The ants in this subfamily are mostly specialized subterranean predators. Adult workers pierce the integument (non letha ...
, while the last genus '' Pseudectatomma'' is in
Ectatomminae Ectatomminae is a subfamily of ants in the poneromorph subfamilies group containing four extant and three extinct genera in two tribes. The subfamily was created in 2003 when Barry Bolton divided the Ponerinae subfamily into six subfamilies. ...
.


Description

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. In hymenopterans of t ...
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 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. '' P. eocenica'' and '' P. lutzi'') a ...
'' 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 anatomy, the mandible, lower jaw or jawbone is the largest, strongest and lowest bone in the human facial skeleton. It forms the lower jaw and holds the lower tooth, teeth in place. The mandible sits beneath the maxilla. It is the only movabl ...
s are well developed and opposable, a feature that separates ''M. leptogenoides'' males from those of ''Pachycondyla'' species.


References


External links

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