Myanmyrma

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Myanmyrma
Temporal range: Earliest Cenomanian
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Myanmyrma gracilis AMNH-BU014 holotype 01.jpg
M. gracilis holotype
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily:† Sphecomyrminae
Genus:† Myanmyrma
Species:
†M. gracilis
Binomial name
†Myanmyrma gracilis
Engel & Grimaldi, 2005

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. [1]

Contents

History and classification

Myanmyrma is known from three total adult fossils, the holotype, specimen number "AMNH Bu-014", and two additional fragmentary adults not designated as paratypes. At the time of the genus description, the three specimens were residing in the American Museum of Natural History, in New York City. [1] All the described specimens are of worker caste adult females which have been preserved as inclusions in transparent chunks of Burmese amber. The amber specimen was recovered from deposits in Kachin State, 100 kilometres (62 mi) west of Myitkyina in Myanmar. Burmese amber has been radiometrically dated using U-Pb isotopes, yielding an age of approximately 98.79 ± 0.62  million years old, close to the Aptian  – Cenomanian boundary, in the earliest Cenomanian. [2] [3]

The fossil was first studied by paleoentomologists Michael Engel and David Grimaldi, both of the American Museum of Natural History. [1] Engel and Grimaldi's 2005 type description of the new genus and species was published in the journal American Museum Novitates. [1] The genus name Myanmyrma was coined as a combination of the suffix "myrma" which is commonly used in ant genus names, and Myanmar, in recognition of the country of origin. The specific epithet gracilis was based from the Latin word "gracilis" meaning slender, a reference to the elongated nature of the legs and body. [1] Myanmyrma is one of several ant genera described from Burmese amber the others being Burmomyrma , Haidomyrmex , Sphecomyrmodes , and Zigrasimecia . [3]

In the type description, Engel and Grimaldi described Myanmyrma as a poneriod genus based on the constriction of the metasoma, with a possible relationship to either Ponerinae or Myrmeciinae. The large body size and slender nature of the genus was likened to the extant genera Leptomyrmex and Oecophylla which are both arboreal. As such Engel and Grimaldi suggested a similar habitat for Myanmyrma. [1] The myrmeciine affinities were suggested to be unlikely by Archibald, Cover and Moreau in a 2006 paper on fossils of that subfamily. The length of the scape is notably short, a feature seen only in the Cretaceous ant subfamily Sphecomyrminae and the ant family relatives in Armaniidae. [4] The short scape was again noted as a puzzling feature that prevented subfamily placement by Ward in a 2007 paper on the phylogeny of ants. [5]

Description

Myanmyrma has very long mandibles that near the same length as the head. [1] Each mandible has only two large teeth, one blunt subapical, one sharp apical and the right mandible is notably longer than the left. The clypeus is modified with two large lobes, one on each genal margin and having about fourteen denticles. Occeli are not detectable on the holotype, but the presence of them was not ruled out due to the position of the specimen. The twelve segmented antennae are long, being approximately 7.2 millimetres (0.28 in), and have a notably short scape. The second flagellomere is elongated, a trait shared with other Cretaceous ants, possibly due to convergent evolution. The antennae sockets point the antenna nearly vertically off the head and there are several groups of spines on ridges and the frons. The metapleural gland has a small opening which shows on the mesosoma above the rear leg. The gaster is attached to the petiole with a narrow connection on the second metasomal segment, while the petiole is narrow and tall. A large sting is present and partly extended from the gaster tip. The pygidium has a fine covering of setae. [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. 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>Astreptolabis</i> Extinct genus of earwigs

Astreptolabis is an extinct genus of earwig in the Dermaptera family Pygidicranidae known from a group of Cretaceous fossils found in Myanmar. The genus contains two described species, Astreptolabis ethirosomatia and Astreptolabis laevis and is the sole member of the subfamily Astreptolabidinae.

<i>Brownimecia</i> Cretaceous ant genus described from amber fossils

Brownimecia is an extinct genus of ants, the only genus in the tribe Brownimeciini and subfamily Brownimeciinae of the Formicidae. Fossils of the single identified species, Brownimecia clavata, are known from the Middle Cretaceous of North America. The genus is one of several ants described from Middle Cretaceous ambers of New Jersey. Brownimecia was initially placed in the subfamily Ponerinae, until it was transferred to its own subfamily in 2003; it can be distinguished from other ants due to its unusual sickle-like mandibles and other morphological features that makes this ant unique among the Formicidae. The ant is also small, measuring 3.43 millimetres (0.135 in), and a stinger is present in almost all of the specimens collected. The morphology of the mandibles suggest a high level of feeding specialization.

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

Zigrasimecia is an extinct genus of ants which existed in the Cretaceous period approximately 98 million years ago. The first specimens were collected from Burmese amber in Kachin State, 100 kilometres (62 mi) west of Myitkyina town in Myanmar. In 2013, palaeoentomologists Phillip Barden and David Grimaldi published a paper describing and naming Zigrasimecia tonsora. They described a dealate female with unusual features, notably the highly specialized mandibles. Other features include large ocelli, short scapes, 12 antennomeres, small eyes, and a clypeal margin that has a row of peg-like denticles. The genus Zigrasimecia was originally incertae sedis within Formicidae until a second species, Zigrasimecia ferox, was described in 2014, leading to its placement in the subfamily Sphecomyrminae. Later, it was considered to belong to the distinct subfamily Zigrasimeciinae.

<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.

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

Haidomyrmex is an extinct genus of ants in the formicid subfamily Haidomyrmecinae, and is one of nine genera placed in the subfamily Haidomyrmecinae. The genus contains three described species Haidomyrmex cerberus, Haidomyrmex scimitarus, and Haidomyrmex zigrasi. All three are known from single Late Cretaceous fossils which have been found in Asia. H. cerberus is the type species and Haidomyrmex the type genus for the subfamily Haidomyrmecinae.

<i>Burmomyrma</i> Genus of ants

Burmomyrma is an extinct genus of aculeate hymenopteran, suggested to be an ant. The genus contains a single described species, Burmomyrma rossi. Burmomyrma is known from a single Middle Cretaceous fossil which was found in Asia.

<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.

Armaniidae was a name formerly given to a group of extinct ant-like hymenopterans known from a series of Cretaceous fossils found in Asia and Africa. Armaniidae has been suggested by several authors to belong to the family Formicidae as one of the stem-group subfamilies, Armaniinae; however, this position has not been taken up by myrmecologists. The family contained seven described genera and thirteen described species. An analysis of fossil ants based on antenna structure in 2017 resulted in three of the family being broken up with some genera being moved to Sphecomyrminae and other genera being relegated to incertae sedis in Formicidae or Aculeata.

Zigrasolabis is an extinct genus of earwig in the family Labiduridae known from Cretaceous fossils found in Myanmar. The genus contains a single described species, Zigrasolabis speciosa.

Toxolabis is an extinct genus of earwig in the dermapteran family Anisolabididae known from a Cretaceous fossil found in Burma. The genus contains a single described species, Toxolabis zigrasi.

Cananeuretus is an extinct genus of ant in the Formicidae subfamily Aneuretinae, and is one of two Cretaceous genera of the subfamily. The genus contains a single described species Cananeuretus occidentalis and is known from one Late Cretaceous fossil which has been found in North America.

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

Gerontoformica is an extinct genus of stem-group ants. The genus contains thirteen described species known from Late Cretaceous fossils found in Asia and Europe. The species were described between 2004 and 2016, with a number of the species formerly being placed into the junior synonym genus Sphecomyrmodes.

<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.

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

Ceratomyrmex is an extinct genus of ant in the Formicidae subfamily Haidomyrmecinae. The genus contains a single described species Ceratomyrmex ellenbergeri and is known from several Late Cretaceous fossils which have been found in Asia.

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

Linguamyrmex 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 three described species, Linguamyrmex brevicornis, Linguamyrmex rhinocerus, and the type species Linguamyrmex vladi all known from Late Cretaceous fossils found in Asia.

References

  1. 1 2 3 4 5 6 7 8 Engel, M.S.; Grimaldi, D.A. (2005). "Primitive New Ants in Cretaceous Amber from Myanmar, New Jersey, and Canada (Hymenoptera: Formicidae)". American Museum Novitates (3485): 1–24. doi:10.1206/0003-0082(2005)485[0001:PNAICA]2.0.CO;2. S2CID   84043939.
  2. ↑ Shi, G.; Grimaldi, D.A.; Harlow, G.E.; Wang, Ji.; Wang, Ju.; Yang, M.; Lei, W.; Li, Q.; Li, X. (2012). "Age constraint on Burmese amber based on U-Pb dating of zircons". Cretaceous Research. 37: 155–163. doi:10.1016/j.cretres.2012.03.014.
  3. 1 2 Barden, P.; Grimaldi, D. (2013). "A New Genus of Highly Specialized Ants in Cretaceous Burmese Amber (Hymenoptera: Formicidae)" (PDF). Zootaxa. 3681 (4): 405–412. doi:10.11646/zootaxa.3681.4.5. PMID   25232618.
  4. ↑ 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 .
  5. ↑ Ward, P.S (2007), "Phylogeny, classification, and species-level taxonomy of ants (Hymenoptera: Formicidae).", Zootaxa, 1668: 549–563, doi:10.11646/zootaxa.1668.1.26
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