Macabeemyrma

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Macabeemyrma
Temporal range: Ypresian, 51  Ma
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Macabeemyrma ovata head.svg
Reconstruction of Macabeemyrma ovata head capsule
Scientific classification Red Pencil Icon.png
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Myrmeciinae
Genus: Macabeemyrma
Species:
M. ovata
Binomial name
Macabeemyrma ovata

Macabeemyrma is an extinct genus of bulldog ants in the subfamily Myrmeciinae containing the single species Macabeemyrma ovata, described in 2006 from Ypresian stage (Early Eocene) deposits of British Columbia, Canada. Only a single specimen is known; a holotype queen found preserved as a compression fossil. The specimen had no wings and small portions of its legs and eyes were faintly preserved. It was a large ant, reaching 25 millimetres (0.98 in) in length. This ants' behaviour would have been similar to that of extant Myrmeciinae ants, such as foraging singly in search for arthropod prey and nesting in soil or in trees. Macabeemyrma shows similarities to extinct ants in the genus Ypresiomyrma , and to the living Nothomyrmecia macrops , but has not been conclusively assigned to any tribe, instead generally regarded as incertae sedis within Myrmeciinae. However, the sole specimen lacks definitive traits, and its classification in Myrmeciinae, and even its identity as an ant, has been challenged.

Contents

History and classification

McAbee Fossil Beds, British Columbia. Type locality of Macabeemyrma McAbee Fossil Beds, British Columbia.jpg
McAbee Fossil Beds, British Columbia. Type locality of Macabeemyrma

Macabeemyrma ovata is known only from a single fossil specimen: a mostly complete adult queen, preserved as a compression fossil in fine-grained shale. [2] The shale is from fossiliferous outcrops at the McAbee Fossil Beds, part of an unnamed bed in the Kamloops group Tranquille Formation which outcrops east of Cache Creek in British Columbia, Canada. [3] The holotype specimen was collected by an unknown person and donated to Thompson Rivers University in 2002. [4] [5] The specimen was described by Bruce Archibald, Stefan Cover and Corrie Moreau of Harvard University's Museum of Comparative Zoology, with their 2006 type description of the genus and species. The generic name Macabeemyrma is a toponym of the type locality at McAbee [lower-alpha 1] combined with the Greek myrmex, meaning "ant". The specific epithet ovata, from the Latin "ovatus" meaning "egg shaped", refers to the shape of the head capsule. [6]

Archibald and colleagues originally classified Macabeemyrma as incertae sedis (Latin for "of uncertain placement") within the ant subfamily Myrmeciinae, as it could not be confidently placed into any ant tribe. However, in a 2008 paper, Cesare Baroni Urbani of the University of Basel, Switzerland, noted that the specimen shares some traits found in other ant subfamilies and some wasps, and lacks key diagnostic traits (synapomorphies) of the ant family, Formicidae, and thus argued Macabeemyrma could only be confidently classified as incertae sedis within the order Hymenoptera. [7] [8] A subsequent report describing new fossil myrmecines accepted the classification of Archibald and colleagues without comment on the views of Baroni Urbani. [3]

The following cladograms generated by Archibald and colleagues show two possible phylogenetic positions of Macabeemyrma among some ants of the subfamily Myrmeciinae; the cladogram on the right included three additional extinct genera compared to that on the left. [9] They suggest that Macabeemyrma ovata and other extinct ants such as Avitomyrmex and Ypresiomyrma may be closely related to the living Nothomyrmecia macrops . [10]

Myrmeciinae

Myrmecia

Prionomyrmex janzeni

Prionomyrmex longiceps

Macabeemyrma

Nothomyrmecia

Myrmeciinae

Archimyrmex

Myrmecia

Prionomyrmex janzeni

Prionomyrmex longiceps

Macabeemyrma

Avitomyrmex

Ypresiomyrma

Nothomyrmecia

Description

The overall body of the ant is poorly preserved and much of it is indistinct. [5] Macabeemyrma ovata is about 25 millimetres (0.98 in) long with a distinct elongated oval head capsule that is about 1.5x longer than wide. The holotype is missing the wings and some portions of the legs while the eyes are very faintly preserved. It could not be confirmed whether its eyes were compound or not, but if it was to be confirmed they would share similar eye characteristics to Myrmecia . The exact shape of the mandibles cannot be properly determined, but they are elongated and not subtriangular which is normal for other members of Myrmeciinae except the genus Myrmecia. [8] [11] Its elongated head and mandibles distinguish this species from those in the genus Ypresiomyrma, which are otherwise thought to have a close phylogenetic relationship due to similarities. The waist consists of a single segment, and whether or not the ant has a sting cannot be fully determined due to the condition of the specimen collected. [11]

Ecology

Archibald and colleagues suggested the life habits of Macabeemyrma ovata may have been similar to extant Myrmeciinae ants. [12] The ant is large with long legs and elongated mandibles. It presumably had large eyes that were used to hunt for prey and navigation, and the ant was possibly equipped with a sting. Colonies most likely nested in the soil like most other Myrmeciinae, but like some Myrmecia species it is possible they were an arboreal nesting species. Workers were solitary foragers, foraging on the ground or onto vegetation while preying on arthropods. Workers most likely did not recruit other ants to food sources or lay down pheromone trails. [12]

Notes

  1. In accordance with the International Code of Zoological Nomenclature recommendations, the locality name was spelled Macabee.

Related Research Articles

Myrmeciinae Subfamily of ants

Myrmeciinae is a subfamily of the Formicidae, ants once found worldwide but now restricted to Australia and New Caledonia. This subfamily is one of several ant subfamilies which possess gamergates, female worker ants which are able to mate and reproduce, thus sustaining the colony after the loss of the queen. The Myrmeciinae subfamily was formerly composed of only one genus, Myrmecia, but the subfamily was redescribed by Ward & Brady in 2003 to include two tribes and four genera: An additional three genera, one form genus, and 9 species were described in 2006 from the Early Eocene of Denmark, Canada, and Washington.

<i>Nothomyrmecia</i> Genus of ants

Nothomyrmecia, also known as the dinosaur ant or dawn ant, is a rare genus of ants consisting of a single species, Nothomyrmecia macrops. These ants live in South Australia, nesting in old-growth mallee woodland and Eucalyptus woodland. The full distribution of Nothomyrmecia has never been assessed, and it is unknown how widespread the species truly is; its potential range may be wider if it does favour old-growth mallee woodland. Possible threats to its survival include habitat destruction and climate change. Nothomyrmecia is most active when it is cold because workers encounter fewer competitors and predators such as Camponotus and Iridomyrmex, and it also increases hunting success. Thus, the increase of temperature may prevent them from foraging and very few areas would be suitable for the ant to live in. As a result, the IUCN lists the ant as Critically Endangered.

<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. Two additional species, S. canadensis and S. mesaki, were described in 1985 and 2005, 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>Ypresiomyrma</i> Extinct genus of ants

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.

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.

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

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.

Prionomyrmecini 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.

Agroecomyrmecinae 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.

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

Haidomyrmodes is an extinct genus of ant in the formicid subfamily Haidomyrmecinae, and is one of only nine genera placed in the subfamily Haidomyrmecinae. The genus contains a single described species, Haidomyrmodes mammuthus. Haidomyrmodes is known from several Middle Cretaceous fossils which have been found in Europe.

Acanthognathus poinari is an extinct species of ant in the subfamily Myrmicinae known from a single possibly Miocene fossil found on Hispaniola. A. poinari is the first species of the ant genus Acanthognathus to have been described from fossils found in Dominican amber and is one of several species of Acanthognathus found in the Greater Antillies.

<i>Anochetus corayi</i> Extinct species of ant

Anochetus corayi is an extinct species of ant in the subfamily Ponerinae known from one possibly Miocene fossil found on Hispaniola. A. corayi is one of eight species in the ant genus Anochetus to have been described from fossils found in Dominican amber and is one of a number of Anochetus species found in the Greater Antillies.

<i>Myrmecia piliventris</i> Species of ant

Myrmecia piliventris is an Australian ant which belongs to the genus Myrmecia. This species is native to Australia. The Myrmecia piliventris is distributed Australia wide, but they're not too common in the western regions of Australia.

<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>Myanmyrma</i> Extinct genus of ants

Myanmyrma is an extinct genus of ants not placed into any Formicidae subfamily. Fossils of the single known species, Myanmyrma gracilis, are known from the Middle Cretaceous of Asia. The genus is one of several ants described from Middle Cretaceous ambers of Myanmar.

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

Camelomecia is an extinct genus of stem-group ants not placed into any Formicidae subfamily. Fossils of the single known species, Camelomecia janovitzi, are known from the Middle Cretaceous of Asia. The genus is one of several ants described from Middle Cretaceous ambers of Myanmar.

Gesomyrmex macrops is an extinct species of formicid in the ant subfamily Formicinae known from a fossil found in eastern Asia.

Gesomyrmex incertus is an extinct species of formicid in the ant subfamily Formicinae known from a fossil found in eastern Asia.

Klondikia is an extinct hymenopteran genus in the ant family Formicidae with a single described species Klondikia whiteae. The species is solely known from the Early Eocene sediments exposed in northeast Washington state, United States. The genus is currently not placed into any ant subfamily, being treated as incertae sedis.

References

  1. Johnson, Norman F. (19 December 2007). "Macabeemyrma Archibald, Cover & Moreau". Hymenoptera Name Server version 1.5. Columbus, Ohio, USA: Ohio State University . Retrieved 1 April 2015.
  2. Archibald, Cover & Moreau 2006, p. 488.
  3. 1 2 Dlussky, G. M. (May 2012). "New fossil ants of the subfamily Myrmeciinae (Hymenoptera, Formicidae) from Germany" (PDF). Paleontological Journal. 46 (3): 288–292. doi:10.1134/S0031030111050054. S2CID   83891156.
  4. Archibald, Cover & Moreau 2006, p. 489.
  5. 1 2 Archibald, Cover & Moreau 2006, p. 500.
  6. Archibald, Cover & Moreau 2006, p. 498.
  7. AntWeb. "Genus: †Macabeemyrma Archibald, Cover & Moreau, 2006". The California Academy of Sciences. Retrieved 12 April 2015.
  8. 1 2 Baroni Urbani, Cesare (2008). "Orthotaxonomy and parataxonomy of true and presumed bulldog ants (Hymenoptera, Formicidae)" (PDF). Doriana (Suppl. To Annali del Museo Civico di Storia Naturale Giacomo Doria). 8 (358): 1–10. ISSN   0417-9927.
  9. Archibald, Cover & Moreau 2006, p. 512.
  10. Archibald, Cover & Moreau 2006, p. 511.
  11. 1 2 Archibald, Cover & Moreau 2006, p. 508.
  12. 1 2 Archibald, Cover & Moreau 2006, p. 513.

Cited text

Archibald, S.B.; Cover, S. P.; Moreau, C. S. (2006). "Bulldog Ants of the Eocene Okanagan Highlands and History of the Subfamily (Hymenoptera: Formicidae: Myrmeciinae)" (PDF). Annals of the Entomological Society of America. 99 (3): 487–523. doi: 10.1603/0013-8746(2006)99[487:BAOTEO]2.0.CO;2 .