Agroecomyrmex

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Agroecomyrmex
Temporal range: Lutetian
Agroecomyrmex duisburgi BMNHP18831 01.jpg
Close-up of the head of Agroecomyrmex duisburgi
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Agroecomyrmecinae
Tribe: Agroecomyrmecini
Genus: Agroecomyrmex
Wheeler, 1910
Species:
A. duisburgi
Binomial name
Agroecomyrmex duisburgi
(Mayr, 1868)
Synonyms
  • Myrmica duisburgi Mayr, 1868

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. [1]

Contents

History and classification

When described Agroecomyrmex was known only from five separate fossils, the holotype worker, number 639/10246 plus three paratype workers and a single paratype female, which are fossilized as inclusions in transparent chunks of Baltic amber. [1] 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 evidence supporting relatives of either an Agathis relative or a Pseudolarix relative. [2] All the type specimens were collected over 125 years ago, and when first described were part of the University of Königsberg amber collection. The fossils were first studied by Austrian entomologist Gustav Mayr who placed the species in the living genus Myrmica . Mayr's 1868 type description of the new species was published in the journal Beitrage zur Naturkunde Preussens . [1] The species was moved to the new genus Agroecomyrmex in a short note in 1910 by William Morton Wheeler. Wheeler expanded upon and gave a full description of the new genus in his 1915 paper The ants of the Baltic amber. [1] In the description Wheeler recognized the very distinct morphology of the species, and that it was not closely related to the Myrmica species. Since its description two other related genera have been described, the late Eocene genus Eulithomyrmex from the Florissant Formation of Colorado, and the living genus Tatuidris from Central and South America. [3] Placement of the group has changed several times, with the genera being placed in the Myrmicinae tribe Agroecomyrmecini from 1930 until 2003. [4] The placement of the tribe was challenged in 2003 by Barry Bolton who suggested a closer relationship between the group and the "poneromorph" subfamilies. in addition to the suggested relationship, Bolton moved the tribe from Myrmicinae to a new subfamily, Agroecomyrmecinae. [3]

Description

The new genus was described from a full alate female and four workers, all of the workers being preserved in a curled up position, obscuring details. Overall it is estimated the female would have been around 5.5 millimetres (0.22 in) long while the workers range between 4 and 5 millimetres (0.16 and 0.20 in). A. duisburgi individuals have heads which are nearly square, being just slightly longer than wide, and slightly wider behind than in front. Individuals have small, very convexly shaped eyes which are placed near the back edge of the head capsule and completely lack ocelli. The mandibles are short and rounded, and have 5 unequal teeth. The antennae are composed of thirteen segments, the terminal three forming a distinct club shape. The head and thorax have a strongly reticulated structuring to the exoskeleton and having an overall black coloration. [1] Agroecomyrmex can be separated from Eulithomyrmex based on the features of the head, with Agroecomyrmex displaying larger mandibles and a smaller antennal club. [4]

Related Research Articles

<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.

Avitomyrmex is an extinct genus of bulldog ants in the subfamily Myrmeciinae which contains three described species. The genus was described in 2006 from Ypresian stage deposits of British Columbia, Canada. Almost all the specimens collected are queens, with an exception of a single fossilised worker. These ants are large, and the eyes are also large and well-developed; a sting is present in one species. The behaviour of these ants may have been similar to extant Myrmeciinae ants, such as foraging solitarily for arthropod prey and never leaving pheromone trails to food sources. Avitomyrmex has not been assigned to any tribe, instead generally being regarded as incertae sedis within Myrmeciinae. However, its identity as an ant has been challenged, although it is undoubtedly a hymenopteran insect.

<span class="mw-page-title-main">Prionomyrmecini</span> Tribe of ants

Prionomyrmecini is an ant tribe belonging to the subfamily Myrmeciinae established by William Morton Wheeler in 1915. Two members are a part of this tribe, the extant Nothomyrmecia and the extinct Prionomyrmex. The tribe was once considered a subfamily due to the similarities between Nothomyrmecia and Prionomyrmex, but such reclassification was not widely accepted by the scientific community. These ants can be identified by their long slender bodies, powerful stingers and elongated mandibles. Fossil Prionomyrmecini ants were once found throughout Europe, possibly nesting in trees and preferring jungle habitats. Today, Prionomyrmecini is only found in Australia, preferring old-growth mallee woodland surrounded by Eucalyptus trees. Nothomyrmecia workers feed on nectar and arthropods, using their compound eyes for prey and navigational purposes. Owing to their primitive nature, they do not recruit others to food sources or create pheromone trails. Nothomyrmecia colonies are small, consisting of 50 to 100 individuals.

<span class="mw-page-title-main">Agroecomyrmecinae</span> Subfamily of ants

Agroecomyrmecinae is a subfamily of ants containing two extant and two fossil genera. The subfamily was originally classified in 1930 by Carpenter as Agroecomyrmecini, a Myrmicinae tribe. Bolton raised the tribe to subfamily status in 2003, suggesting that Agroecomyrmecinae might be the sister taxon to Myrmicinae. It has since been discovered to be one of the earliest lineages of ants, a clade from the basal polytomy for all ants. In 2014, the subfamily was expanded to two tribes. The tribe Ankylomyrmini was moved from the subfamily Myrmicinae to Agroemyrmecinae.

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<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.

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

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

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

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<i>Yantaromyrmex</i> Genus of ants

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

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References

  1. 1 2 3 4 5 Wheeler, W. M. (1915). "The ants of the Baltic amber". Schriften der Physikalisch-Okonomischen Gesellschaft zu Konigsberg. 55 (4): 56–59.
  2. 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.
  3. 1 2 Donoso, D. A. (2012). "Additions to the taxonomy of the armadillo ants (Hymenoptera, Formicidae, Tatuidris)" (PDF). Zootaxa . 3503: 61–81. doi:10.11646/zootaxa.3503.1.5.
  4. 1 2 Carpenter, F. M. (1930). "The fossil ants of North America" (PDF). Bulletin of the Museum of Comparative Zoology. 70: 1–66.