| Liometopum imhoffii | |
|---|---|
 | |
| L. imhoffii queen | |
Scientific classification  | |
| Kingdom: | Animalia |
| Phylum: | Arthropoda |
| Class: | Insecta |
| Order: | Hymenoptera |
| Family: | Formicidae |
| Subfamily: | Dolichoderinae |
| Genus: | Liometopum |
| Species: | †L. imhoffii |
| Binomial name | |
| †Liometopum imhoffii (Heer, 1849) | |
| Synonyms | |
| |
Liometopum imhoffii is an extinct species of ants in the dolichoderine genus Liometopum . The species was described from a number of Early Miocene fossils found in what is now Croatia.
The original group of fossils that the type species, and three other species, were described from are preserved as compression fossils in sedimentary rock from the Radoboj area of what is now Croatia. The deposits are the result of sedimentation in an inland sea basin, possibly a shallow lagoon environment, during the Burdigalian of the Early Miocene. Along with L. imhoffii a diverse assemblage of several hundred species of insects have been preserved in the sediments, along with fish and algae. [1] The fossil impressions are preserved in micrite limestones, resulting in low quality preservation of fine details. The insect fossils were first studied by Oswald Heer, then a professor with the University of Zürich, who placed the fossils in four new ant species in two different genera, "Formica imhoffii", "Formica schmidtii", "Ponera fuliginosa radobojana", and "Ponera affinis". Based on the petiole structure and wing venation, Heer subsequently moved the four species to the new genus "Poneropsis" in 1867 as "Poneropsis affinis", "P. fuliginosa", "P. imhoffii", and "P. schmidtii". He also described three new species, "P. livida", "P. lugubris", and "P. morio". In the same year, entomologist Gustav Mayr of Vienna examined a number of fossils from Radoboj, some being the type specimens, others being identified by Heer but not types. Later in 1907 Anton Handlirsch revisited the work of Mayr and Heer in a monograph of fossil ants. In 2014 a series of 21 specimens, many of the type specimens plus additional fossils, were reexamined and redescribed by paleoentomologists Gennady Dlussky and Tatyana Putyatina. [1]
Mayr examined eight of the Radoboj specimens belonging to the species "F. imhoffi" and "F. schmidtii", noting the similarity between the males of the two species, and that they likely belonged to the genus Liometopum. Following on Mayr's suggestion Handlirsch formally synonymized the two species, giving "P. imhoffii" seniority over "P. schmidtii", and moved the species to Liometopum. [1]
Heer based the species "P. fuliginosa" on fossils from both Radoboj and Öhningen, Germany. When Mayr examined several of the specimens, he interpreted them to show a two segmented petiole, and moved both "P. fuliginosa" and "P. livida" to the genus Aphaenogaster . In contrast, Heer in 1867 moved the two species to his new genus "Poneropsis", a move that was followed by William Morton Wheeler in 1911 when he designated "P. fuliginosa" the type species of the genus. The single type specimen of "P. affinis" was preserved with a distorted head and wing proportions, from which Heer differentiated the species from "P. fuliginosa". Neither Mayr or Handlirsch were able to study the fossil, so they did not comment on the species status. However Dlussky and Putyatina concluded that the specimen did not differ from "P. fuliginosa" when the distortion of the fossil was accounted for, and included it as a junior synonym of L. imhoffii. [1]
Following the research of Mayr and Handlirsch, Dlussky and Putyatina agreed with the placement in Liometopum. Based on examination of one of the "P. fuliginosa" type queens, and on Heer's illustrations, they also concluded "P. fuliginosa" was a junior synonym of L. imhoffii. Of all the species named, Dlussky and Putyatina were not able to examine the type specimens for "F. livida" and "P. morio", only other specimens looked at and identified by Heer. In both species, the examined fossils do not match the descriptions published by Heer, and either belong to other species, or are not well enough preserved to identify at all. Based on Heer's 1867 descriptions and illustrations Dlussky and Putyatina concluded that both are synonyms of Liometopum imhoffii. [1]
Heer named L. imhoffii for his friend Ludwig Imhoff of Basel, Switzerland. [2]
The queens of L. imhoffi range between 11.5–13.3 mm (0.45–0.52 in) in length with rectangular heads that are slightly wider than long. The sides of the head are convex in outline, while the rear margin curves inwards near the middle. The mesosoma is wider than the maximum width of the head and thick in construction, while the fore section of the mesonotum is large and the legs are robust and short. The petiole has a wide scale on the node and connects to an oval gaster. [1]
The males are smaller than the queens, ranging between 8.5–9.5 mm (0.33–0.37 in) in length and having a much smaller head. The legs are longer and thinner than those of the queen, while the mesosoma is wider than the head, as in the queens. The males have a petiole that is low and triangular in outline, the node being only 1.5 times as high as long. Unlike the oval gaster of the queens the males have a more elongated egg shaped gaster. [1]
Ypresiomyrma is an extinct genus of ants in the subfamily Myrmeciinae that was described in 2006. There are four species described; one species is from the Isle of Fur in Denmark, two are from the McAbee Fossil Beds in British Columbia, Canada, and the fourth from the Bol’shaya Svetlovodnaya fossil site in Russia. The queens of this genus are large, the mandibles are elongated and the eyes are well developed; a stinger is also present. The behaviour of these ants would have been similar to that of extant Myrmeciinae ants, such as solitary foraging for arthropod prey and never leaving pheromone trails. The alates were poor flyers due to their size, and birds and animals most likely preyed on these ants. Ypresiomyrma is not assigned to any tribe, and is instead generally regarded as incertae sedis within Myrmeciinae. However, some authors believe Ypresiomyrma should be assigned as incertae sedis within Formicidae.
Myrmeciites is an extinct form genus of bulldog ants in the subfamily Myrmeciinae of the family Formicidae, which contains three described species and two fossils not placed beyond the genus level. Described in 2006 from Ypresian stage deposits, all three of the described species and one unplaced fossil are from British Columbia, Canada, while the second unplaced fossil is from Washington State, USA. These ants were large, with the largest specimens collected reaching 3 centimetres (1.2 in). The behaviour of these ants would have been similar to extant Myrmeciinae ants, such as solitary foraging, nesting either in the soil or trees, and leaving no pheromone trail to food sources. Due to the poor preservation of these ants, their phylogenetic position among Myrmeciinae is unclear, and no type species has been designated. These ants are classified as incertae sedis in Myrmeciinae, but some writers have classified it as incertae sedis within the insect order Hymenoptera. This reclassification, however, has not been accepted; instead, Myrmeciites remains in Myrmeciinae.
Archimyrmex is an extinct genus of ant in the formicid subfamily Myrmeciinae, described by palaeoentomologist Theodore Cockerell in 1923. The genus contains four described species, Archimyrmex rostratus, Archimyrmex piatnitzkyi, Archimyrmex smekali and Archimyrmex wedmannae. Archimyrmex is known from a group of Middle Eocene fossils which were found in North America, South America, and Europe. The genus was initially placed in the subfamily Ponerinae, but it was later placed in Myrmeciinae; it is now believed to be the ancestor of the extant primitive genus Myrmecia from Australia. Despite this, Archimyrmex is not a member to any tribe and is regarded as incertae sedis within Myrmeciinae. However, some authors believe Archimyrmex should be assigned as incertae sedis within Formicidae. These ants can be characterised by their large mandibles and body length, ranging from 13.2 to 30 mm. They also have long, thin legs and an elongated mesosoma (thorax) and petiole.
Attopsis is an extinct genus of ants in the formicid subfamily Formicinae. While formerly containing a number of species, the genus is currently monotypic; the type species, Attopsis longipennis, is known from a single Early Miocene fossil found in what is now Croatia.
Emplastus is an extinct morphogenus of ants in the subfamily Dolichoderinae, known from fossils found in Asia and Europe. The genus contains twelve species described from sites in England, Eastern Europe and Far Eastern Russia.
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, Casaleia inversa, Casaleia longiventris, Casaleia orientalis.
Liometopum brunascens is an extinct species of Miocene ant in the genus Liometopum. Described by Heer in 1867, the fossils were found and described from Croatia.
Liometopum crassinervis is an extinct species of Miocene ants in the genus Liometopum. Described by Heer in 1849, fossils of the species were found in Switzerland.
Liometopum croaticum is an extinct species of Miocene ant in the genus Liometopum. Described by Heer in 1849, the fossils were found in Croatia.
Liometopum escheri is an extinct species of Miocene ant in the genus Liometopum. Described by Heer in 1867, fossils of the species were found in Switzerland.
Liometopum globosum is an extinct species of Miocene ant in the genus Liometopum. Described by Heer in 1849, the fossils were found in Switzerland.
Liometopum longaevum is an extinct species of Miocene ant in the genus Liometopum. Described by Heer in 1849, the fossils were found in Switzerland.
Liometopum pallidum is an extinct species of Miocene ant in the genus Liometopum. Described by Heer in 1867, the fossils were found in Croatia.
Liometopum stygium is an extinct species of Miocene ants in the genus Liometopum. Described by Heer in 1867, fossils of the species were found in Switzerland.
Liometopum venerarium is an extinct species of Miocene ants in the genus Liometopum. Described by Heer in 1864, fossils of the species were found in Switzerland.
Liometopum ventrosum is an extinct species of Miocene ants in the genus Liometopum. Described by Heer in 1849, fossils of the species were found in Switzerland.
Pachycondyla? messeliana is an extinct species of ants in the formicid subfamily Ponerinae described by from a fossil found in Europe. P.? messeliana is one of six Lutetian Pachycondyla species.
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 is one several Lutetian Ponerinae genera.
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.
Pachycondyla succinea is an extinct species of ant in the formicid subfamily Ponerinae described from fossils found in Europe. P. petrosa is one of three middle Eocene Pachycondyla species found in Baltic amber.
Media related to Liometopum imhoffii at Wikimedia Commons