Electromyrmex

Last updated

Electromyrmex
Temporal range: Middle Eocene
Electromyrmex klebsi IGRBA010 profile.jpg
E. klebsi worker close-up view
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Myrmicinae
Tribe: incertae sedis
Genus:† Electromyrmex
Species:
†E. klebsi
Binomial name
†Electromyrmex klebsi
Wheeler, 1910

Electromyrmex is an extinct genus of ants in the formicid subfamily Dolichoderinae. The genus contains a single described species, Electromyrmex klebsi and is known from a group of Middle Eocene fossils which were found in Europe.

Contents

History and classification

Electromyrmex is known from several fossil specimens of adult workers. A worker was first discovered preserved as an inclusion in a transparent chunk of Baltic amber, [1] and additional workers have been identified from Baltic amber found in Lithuania. [2] Workers of an undescribed species labeled as "Electromyrmex sp A" have been found in Bitterfeld amber. [3] [4]

Baltic amber is approximately forty six million years old, having been deposited during Lutetian stage of the Middle Eocene. There is debate on what plant family the amber was produced by, with macrofossil and microfossil evidence suggesting a Pinus relative, while chemical and spectroscopic evidence suggests Agathis or Sciadopitys . [5] [6] The paleoenvironment of the Eocene Baltic forests where the P. eocenicum lived was that of humid temperate to subtropical islands. The forests were composed of mostly Quercus and Pinus species, while the lower sections of the forests had paratropical plant elements, such as palms. [5]

The genus and species were first mentioned by entomologist William Morton Wheeler in 1908 and again in 1910. However neither the 1908 or 1910 publications were accompanied by a description of the genus or species, rather they were noted as to be described later. [7] [8] Wheeler published a formal description for Electromyrmex in his 1915 work The ants of the Baltic amber, seven years after first publishing the name. When first examined and described, the type worker was in the private collection of Professor Richard Klebs of Königsberg University, who first interested Wheeler on working with Baltic amber ant specimens. [1] Sometime after the 1910 type description, the specimen, along with parts of the Klebs collection, was moved to the Georg-August University Geoscientific Center. [2] An additional two fossils in the University of Rennes 1 collections have been identified as E. klebsi workers. [2]

Wheeler placed the genus into the Myrmicinae tribe Myrmicini, and this placement was unchanged until 1988. In a paper discussing the early evolution of ants, the genus was treated as incertae sedis in Myrmicinae, with no tribal assignment. [9] Based on the slender nature of the body and appendages, combined with large forward placed eyes, Wheeler suggested an arboreal habit similar to the living genera Pseudomyrma and "Sima" (now called Tetraponera ). [1]

Description

closeup of head showing mandibles, eyes, and antennae Electromyrmex klebsi IGRBA012 head.jpg
closeup of head showing mandibles, eyes, and antennae

The worker described by Wheeler is estimated to be about 5.5 mm (0.22 in). The exoskeleton is a mix of smooth and ridged textures, with longitudinal ridges on the head, petiole and postpetiol, while the mesopleurae and epinotum have transverse ridges. In contrast the gaster, pronotum and mandibles plus clypeus are shining and smooth. The overall coloration of the workers is black, with a silvery luster present on most of the body. The large head is rectangular, narrowing to a prominent concave rear margin. The eyes are large and positioned near the front of the head, while there are no ocelli visible on the head. The mandibles are elongated, slightly curved near the bases, and narrow. They are separated into distinct base and masticatory areas, with very small uniform teeth populating the whole length of the chewing edge. [1]

The thorax forms a slender neck from the prothorax, on which the head is connected, and the remainder of the thorax is narrower in width than the head. The upper surface of the thorax is divided by a distinct constriction between the mesonotum and epinotum. Two small spines rise from the rear edge of the epinotum. [1] The petiole is thin with no teeth on the underside and only a slight thickening into a node on the upper surface. The abdominal segment connected to the petiole is modified into a postpetiole that is thicker and a little shorter than the petiole, and which has a distinct convex curve to the upper surface. Of similar size as the head, the gaster has a notably enlarged first segment and in the holotype specimen the remaining abdominal segments are withdrawn into it. [1]

Related Research Articles

<i>Sphecomyrma</i> Extinct genus of ants

Sphecomyrma is an extinct genus of ants which existed in the Cretaceous approximately 79 to 92 million years ago. The first specimens were collected in 1966, found embedded in amber which had been exposed in the cliffs of Cliffwood, New Jersey, by Edmund Frey and his wife. In 1967, zoologists E. O. Wilson, Frank Carpenter and William L. Brown, Jr. published a paper describing and naming Sphecomyrma freyi. They described an ant with a mosaic of features—a mix of characteristics from modern ants and aculeate wasps. It possessed a metapleural gland, a feature unique to ants. Furthermore, it was wingless and had a petiole which was ant-like in form. The mandibles were short and wasp-like with only two teeth, the gaster was constricted, and the middle and hind legs had double tibial spurs. The antennae were, in form, midway between the wasps and ants, having a short first segment but a long flexible funiculus. Three additional species, S. canadensis, S. mesaki and S. nexa, were described in 1985, 2005, and 2024, respectively.

<i>Prionomyrmex</i> Extinct genus of ants

Prionomyrmex is an extinct genus of bulldog ants in the subfamily Myrmeciinae of the family Formicidae. It was first described by Gustav Mayr in 1868, after he collected a holotype worker of P. longiceps in Baltic amber. Three species are currently described, characterised by their long mandibles, slender bodies and large size. These ants are known from the Eocene and Late Oligocene, with fossil specimens only found around Europe. It is suggested that these ants preferred to live in jungles, with one species assumed to be an arboreal nesting species. These ants had a powerful stinger that was used to subdue prey. In 2000, it was suggested by Cesare Baroni Urbani that the living species Nothomyrmecia macrops and a species he described both belonged to Prionomyrmex, but this proposal has not been widely accepted by the entomological community. Instead, scientists still classify the two genera distinctive from each other, making Nothomyrmecia a valid genus.

<i>Eulithomyrmex</i> Extinct genus of ants

Eulithomyrmex is an extinct genus of ant in the formicid subfamily Agroecomyrmecinae. The genus contains two described species, Eulithomyrmex rugosus and Eulithomyrmex striatus. Eulithomyrmex is known from a group of Late Eocene fossils which were found in North America.

<i>Agroecomyrmex</i> Extinct genus of ants

Agroecomyrmex is an extinct genus of ants in the formicid subfamily Agroecomyrmecinae, for which it is the type genus. The genus contains a single described species, Agroecomyrmex duisburgi. Agroecomyrmex is known from a group of Middle Eocene fossils which were found in Europe.

Pristomyrmex rasnitsyni is an extinct species of ant in the genus Pristomyrmex. The species is known from a single Late Eocene fossil which was found in Europe.

<i>Aphaenogaster sommerfeldti</i> Extinct species of ant

Aphaenogaster sommerfeldti is an extinct species of ant in the subfamily Myrmicinae known from a group of Middle Eocene fossils found in Europe. A. sommerfeldti is one of three species in the ant genus Aphaenogaster to have been noted from fossils found in Baltic amber by William Morton Wheeler.

<i>Aphaenogaster oligocenica</i> Extinct species of ant

Aphaenogaster oligocenica is an extinct species of ant in the subfamily Myrmicinae known from a pair of Middle Eocene fossils found in Europe. A. oligocenica is one of three species in the ant genus Aphaenogaster to have been noted from fossils found in Baltic amber by William Morton Wheeler.

<i>Aphaenogaster mersa</i> Extinct species of ant

Aphaenogaster mersa is an extinct species of ant in the subfamily Myrmicinae known from a pair of Middle Eocene fossils found in Europe. A. mersa is one of three species in the ant genus Aphaenogaster to have been noted from fossils found in Baltic amber by William Morton Wheeler.

<i>Archimyrmex</i> Extinct genus of ants

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.

<i>Asymphylomyrmex</i> Extinct genus of ants

Asymphylomyrmex is an extinct genus of ants in the formicid subfamily Formicinae. The genus contains a single described species, Asymphylomyrmex balticus and is known from a group of Middle Eocene fossils which were found in Europe.

<i>Yantaromyrmex</i> Genus of ants

Yantaromyrmex is an extinct genus of ants first described in 2013. Members of this genus are in the subfamily Dolichoderinae of the family Formicidae, known from Middle Eocene to Early Oligocene fossils found in Europe. The genus currently contains five described species, Y. constrictus, Y. geinitzi, Y. intermedius, Y. mayrianum and Y. samlandicus. The first specimens were collected in 1868 and studied by Austrian entomologist Gustav Mayr, who originally placed the fossils in other ant genera until the fossils were reviewed and subsequently placed into their own genus. These ants are small, measuring from 4 to 6 mm in length and can be characterized by their trapezoidal shaped head-capsules and oval compound eyes that are located slightly to the rear of the capsules midpoint, with no known ocelli present.

<i>Zherichinius</i> Genus of ants

Zherichinius is an extinct genus of ants in the subfamily Dolichoderinae known from fossils found in amber from the Middle Eocene of Sakhalin island Far eastern Russia and Bitterfeld, Germany. At the time of description the species Zherichinius horribilis and Zherichinius rapax were two of eight ant species known from Sakhalin fossils.

<i>Paraneuretus</i> Genus of ants

Paraneuretus is an extinct genus of formicid in the ant subfamily Aneuretinae known from fossils found in Asia and Europe. The genus contains three middle to late Eocene age species, Paraneuretus dubovikoffi, Paraneuretus longicornis, and Paraneuretus tornquisti.

Formica biamoensis is an extinct species of formicid in the ant subfamily Formicinae known from fossils found in eastern Asia.

Aneuretellus is an extinct genus of ant in the formicid subfamily Aneuretinae, and is one of eight genera of the subfamily. The genus contains a single described species Aneuretellus deformis and is known from one Middle Eocene fossil which was found in Sakhalin in the Russian Far East.

<i>Bradoponera</i> Extinct genus of ants

Bradoponera is an extinct genus of ant in the Formicidae subfamily Proceratiinae, and is one of four genera of the subfamily. The genus contains four described species Bradoponera electrina, Bradoponera meieri, Bradoponera similis, and Bradoponera wunderlichi. The species are known from several Middle Eocene amber fossils which were found in Europe.

<i>Aphaenogaster dlusskyana</i> Extinct species of ant

Aphaenogaster dlusskyana is an extinct species of ant in the subfamily Myrmicinae known from a single Middle Eocene fossil found in amber on Sakhalin. At the time of description A. dlusskyana was one of eight ant species known from Sakhalin fossil.

<i>Pachycondyla succinea</i> Extinct species of ant

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.

<i>Odontomachus pseudobauri</i> Extinct species of ant

Odontomachus pseudobauri is an extinct species of ant in the subfamily Ponerinae known from one possibly Miocene fossil found on Hispaniola. O. pseudobauri is one of two species in the ant genus Odontomachus to have been described from fossils found in Dominican amber and is one of a number of Odontomachus species found in the Greater Antilles.

<i>Nylanderia pygmaea</i> Extinct species of ant

Nylanderia pygmaea is an extinct species of formicid in the ant subfamily Formicinae known from fossils found in the Prussian Formation of the Baltic region.

References

  1. 1 2 3 4 5 6 Wheeler, W. M. (1915). "The ants of the Baltic amber" (PDF). Schriften der Physikalisch-Okonomischen Gesellschaft zu Konigsberg. 55 (4): 55–56.
  2. 1 2 3 "Species: †Electromyrmex klebsi". antweb.org. AntWeb . Retrieved 31 July 2017.
  3. ↑ Dlussky, G. M.; Rasnitsyn, A. P. (2009). "Ants (Insecta: Vespida: Formicidae) in the Upper Eocene Amber of Central and Eastern Europe" (PDF). Paleontological Journal. 43 (9): 1024–1042. Bibcode:2009PalJ...43.1024D. doi:10.1134/S0031030109090056. S2CID   84191149.
  4. ↑ Perkovsky, E. E. (2016). "Tropical and Holarctic ants in Late Eocene ambers" (PDF). Vestnik Zoologii. 50 (2): 116. doi:10.1515/vzoo-2016-0014. S2CID   89013805.
  5. 1 2 Weitschat, W.; Wichard, W. (2010). "Chapter 6: Baltic amber". In Penney, D. (ed.). Biodiversity of Fossils in Amber from the Major World Deposits. Siri Scientific Press. pp. 80–115. ISBN   978-0-9558636-4-6.
  6. ↑ Henderickx, H.; Tafforeau, P.; Soriano, C (2012). "Phase-contrast synchrotron microtomography reveals the morphology of a partially visible new Pseudogarypus in Baltic amber (Pseudoscorpiones: Pseudogarypidae)". Palaeontologia Electronica. 15 (2, 17A, 11p): 1–11.
  7. ↑ Wheeler, W.M. (1908). "Comparative Ethnology of the European and North American Ants". Journal für Psychologie und Neurologie. 13: 404–435.
  8. ↑ Wheeler, W.M. Ants: Their Structure, Development and Behavior (PDF). Columbia University Biological Series. Vol. 9. Columbia University Press.
  9. ↑ Dlussky, G. M.; Fedoseeva, E. B. (1988). "Origin and early stages of evolution in ants.". In Ponomarenko, A. G. (ed.). Cretaceous biocenotic crisis and insect evolution. Moskva: Nauka. pp. 70–144.
This page is based on this Wikipedia article
Text is available under the CC BY-SA 4.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.