''Pseudectatomma'' 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

ant Ants are eusocial insects of the family Formicidae and, along with the related wasps and bees, belong to the order Hymenoptera. Ants evolved from vespoid wasp ancestors in the Cretaceous period. More than 13,800 of an estimated total of ...

s in the formicid subfamily

Ectatomminae Ectatomminae is a subfamily of ant Ants are eusocial insects of the family Formicidae and, along with the related wasps and bees, belong to the order Hymenoptera. Ants evolved from vespoid wasp ancestors in the Cretaceous period. More t ...

described by 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 ...

. 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 that are formed by the accumulation or deposition of mineral or organic particles at Earth's surface, followed by cementation. Sedimentation is the collective name for processes that cause these particles ...

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 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 ...

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-preserved ...

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 ...

. 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 constitut ...

, 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 shallo ...

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 seve ...

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 nor a syntype). O ...

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 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 Neotropical regio ...

'' 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 ''pseudo'', meaning false. 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, bo ...

"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 a dialect spoken in the lower Tiber area (then known as Latium) around present-day Rome, but through ...

''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'' and ''

Rhytidoponera ''Rhytidoponera'' is a large genus of ants in the subfamily Ectatomminae. The genus is known from Australia and Melanesia, with New Caledonia as the most eastern limit. Some ''Rhytidoponera'' species have both winged alate Alate (Latin ''āl� ...

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

''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 fore-wings 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'' 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 (sometimes called a pigment pit) refers to a form of eye or an optical arrangement composed of a single lens and without an elaborate retina such as occurs in most vertebrates. In this sense "simple eye" is distinct from a multi-l ...

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). It is one of the modern descendan ...

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