''Cyrtopone'' 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 Ponerinae 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 replaced the queen as the fun ...

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 ...

. There are four described species placed into the genus, ''Cyrtopone curiosa'', ''Cyrtopone elongata'', ''Cyrtopone microcephala'', and ''Cyrtopone striata''. ''Cyrtopone'' is one 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, ''Cyrtopone'' was known from four 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 ''Cyrtopone'' specimens were collected from layers of the Lutetian

Messel pit The Messel pit (german: Grube Messel) is a disused quarry near the village of Messel ( Landkreis Darmstadt-Dieburg, Hesse) about southeast of Frankfurt am Main, Germany. Bituminous shale was mined there. Because of its abundance of well-preserv ...

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 which initially formed approximately 47 million years ago as the result of volcanic explosions. At the time of description, the four

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 ...

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 the genus and four 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 the

Greek Greek may refer to: Greece Anything of, from, or related to Greece, a country in Southern Europe: *Greeks, an ethnic group. *Greek language, a branch of the Indo-European language family. **Proto-Greek language, the assumed last common ancestor ...

word ''cyrtos'', meaning curved. ''Cyrtopone'' 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'' ...

'', ''

Messelepone ''Messelepone'' is an extinct genus of ants in the formicid subfamily Ponerinae described from fossils found in Europe. ''M. leptogenoides'' is the only species assigned to the genus, which is one of several Lutetian Ponerinae genera. History ...

'', 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 ''Pseudectatomma'' is an extinct genus of ants in the formicid subfamily Ectatomminae described by from fossils found in Europe. The genus contains two species dating from the Eocene, ''Pseudectatomma eocenica'' and ''Pseudectatomma striatula'' ...

'' is in Ectatomminae.

Description

The ''Cyrtopone''

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 ...

s from Messel are described as having approximate body lengths ranging between . Species have heads that are 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 about 2 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.

''C. curiosa''

The only ''C. curiosa'' fossil is of a wingless gyne preserved in profile view with a body about long. The head is slightly rectangular and 1.8 times shorter than the mesosoma. The sides are mostly straight, while the back corners are rounded the back edge is convex and the eyes are placed just behind the middle point of the head. The antennae have a scape which reaches just past the back edge of the head. The

frons Insect morphology is the study and description of the physical form of insects. The terminology used to describe insects is similar to that used for other arthropods due to their shared evolutionary history. Three physical features separate insec ...

stretches across a quarter of the head front. The mesosoma is massive, and 3.2 times longer than the

scutum The ''scutum'' (; plural ''scuta'') was a type of shield used among Italic peoples in antiquity, most notably by the army of ancient Rome starting about the fourth century BC. The Romans adopted it when they switched from the military formati ...

. The species name "curiosa" is derived from the Latin ''curiosus'' which means funny.

''C. elongata''

The described ''C. elongata'' fossil is the only queen preserved as dorsal impression. The body length of the winged queen is approximately long with a node shaped petiole and a mesosoma that is double the length of the head. As with ''C. curiosa'', the head has nearly parallel sides rounded back corners and a convex back margin, though the head in ''C. elongata'' is distinctly rectangular. The oval eyes are placed just to the front of the heads midpoint and the

gena Gena (Amharic: ገና) or qarsa (ቃርሳ) is a traditional field hockey game popular in the Ethiopian highlands. It is a game played in the space between villages but with no defined boundaries. It is played among two teams who attempt to throw ...

are bigger than the maximum eye width. The antennae have a scape which reaches the back edge of the head, while the segments gradually thicken from scape to tip. but they do not form a distinct club at the tip. Each of the antenna segments are about the same width as they are long. 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 approximately 45% to 50% the length of the head. Dlussky and Wedmann coined the species name ''elongata'' from the Latin "elongates" meaning elongated.

''C. microcephala''

''C. microcephala'' is known from a single fossil, a winged gyne preserved in profile view. The body has an approximate length of with an essentially square head. The head is 1.5 times shorter than the mesosoma and has a sculpturing of small pits. The clypeus has a trapazohedral shape to the lower edge, and the eyes are placed at the middle point of the head. The antennae have segments that are 2 times as long as they are wide, with a scape which reaches to the back edge of the head. The mandibles are small, being under half the head length and each chewing side is toothed. The species name is taken from the Greek "microcephalos", which translates to "with a small head".

''C. striata''

The largest of the ''Cyrtopone'' species, ''C. striata'' has a body length of about and has the biggest difference between head and mesosoma, the head being 2.5 times shorter. The winged gyne is a dorsal impression showing distinct sculpturing on the head and scutum made of longitudinal ridges. The eyes are small, placed near the center of the head, and the gena below them are nearly one and a half times longer than the eye diameter. The scape is longer than in the other species with one third of its length extending past the back margin of the head. The metatibiae shows two spurs, a simple and a pectinate one.

References

External links

* * {{Taxonbar, from=Q21334474 †Cyrtopone Fossil taxa described in 2012 Hymenoptera of Europe Fossil ant genera Prehistoric life of Europe Eocene insects