''Pseudectatomma'' 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

ant Ants are Eusociality, eusocial insects of the Family (biology), family Formicidae and, along with the related wasps and bees, belong to the Taxonomy (biology), order Hymenoptera. Ants evolved from Vespoidea, vespoid wasp ancestors in the Cre ...

s in the formicid subfamily

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 described in 2003 when Barry Bolton divided the Ponerinae Ponerinae, the ponerine a ...

described by 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 ...

. The genus contains two species dating from the Eocene, ''Pseudectatomma eocenica'' and ''Pseudectatomma striatula''.

History and classification

When described, ''Pseudectatomma'' was known from four 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 ''Pseudectatomma'' specimens were collected from layers of the

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 ...

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 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

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 ...

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 ...

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 both species named in it. The genus name is a combination of the ant genus ''

Ectatomma ''Ectatomma'' is a Neotropical realm, Neotropical genus of ants in the subfamily Ectatomminae. The genus contains 17 described extant species and one extinct species. Distribution and habitat ''Ectatomma'' is one of the most common genera in the ...

'' and the

Greek Greek may refer to: 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 of all kno ...

word ''pseudo'', meaning false. 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 ...

"eocenica" is derived from the Eocene age of the fossil, while the name "striatula" is based on the

Latin Latin ( or ) is a classical language belonging to the Italic languages, Italic branch of the Indo-European languages. Latin was originally spoken by the Latins (Italic tribe), Latins in Latium (now known as Lazio), the lower Tiber area aroun ...

''striatulus'', meaning "marked by parallel lines".

Description

In both species the

pronotum The prothorax is the foremost of the three segments in the thorax of an insect, and bears the first pair of legs. Its principal sclerites (exoskeletal plates) are the pronotum (dorsal), the prosternum (ventral), and the propleuron (lateral) on e ...

has an upper front surface that is rounded and not angular, lacking a tooth. The petiole is node shaped, separating it from the extinct genus '' Electroponera'' that has a much more angular petiole. The rear side of the metatibiae do not have a median tooth, as seen in modern Ectatomminae genera. The gaster is different from the modern ''

Gnamptogenys ''Gnamptogenys'' is a genus of ants in the subfamily Ectatomminae. The genus has a wide distribution. It is known to occur in the Nearctic, Neotropic, Indomalayan and Australasian realms. Camacho et al, 2022 revised this genus, significantly redu ...

'' and '' Rhytidoponera'' in that the trapezoid shaped second segment is not notably rounded as in the modern genera.

Species

As of 2024, ''Pseudectatomma'' contains two valid species, both of which are

. *'' Pseudectatomma eocenica'' *'' Pseudectatomma striatula''

''Pseudectatomma eocenica''

The type fossil for ''P. eocenica'' is a female gyne that was preserved as a lateral imprint in the matrix. Overall the body length as preserved is with forewings that are long. The eyes, funicular segment, tibial spurs and pretarsal claws are all missing or not preserved in the only known fossil. The head capsule is longer than wide, and The scape is 1.5 times as long as the head capsule, extending beyond the occipital margin. Over half of the head length is composed of the mandibles, which are triangular in outline, with no tooth dentition preserved.

''Pseudectatomma striatula''

''P. striatula'' is known from both lateral and dorsal imprints of reproductive females. The dorsal imprint is not fully preserved but the length is estimated between . Unlike ''P. eocenica'', the head capsule is nearly the same length as it is wide. The eyes are preserved and show the compound eyes placed just to the rear of the heads midpoint and there are three

ocelli A simple eye or ocellus (sometimes called a pigment pit) is a form of eye or an optical arrangement which has a single lens without the sort of elaborate retina that occurs in most vertebrates. These eyes are called "simple" to distinguish the ...

placed into a triangle. The scape is about as long as the head and protrudes beyond the posterior margin. The mandibles are just over half the heads length, with at least five teeth on each. There are notable distinct parallel longitudinal lines on the head.

References

External links

* {{Taxonbar, from=Q21358016

† A dagger, obelisk, or obelus is a typographical mark that usually indicates a footnote if an asterisk has already been used. The symbol is also used to indicate death (of people) or extinction (of species or languages). It is one of the mo ...

Fossil taxa described in 2012 Hymenoptera of Europe Fossil ant taxa Prehistoric life of Europe Ant genera Eocene insects