Linguamyrmex

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Linguamyrmex
Temporal range: Early Cenomanian
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Linguamyrmex vladi AMNH-BUPH01 profile.jpg
Linguamyrmex vladi Holotype worker
Scientific classification Red Pencil Icon.png
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily:† Haidomyrmecinae
Genus:† Linguamyrmex
Barden & Grimaldi, 2017
Species
  • L. brevicornisPerrichot et al. 2020
  • L. rhinocerusMiao & Wang, 2019
  • L. vladiBarden & Grimaldi, 2017

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.

Contents

History and classification

Linguamyrmex is known from a total of four adult fossils. The holotype is specimen number "AMNH BuPH-01" from the American Museum of Natural History; the other three specimens described are also in the same collection, but were not placed as members of L. vladi. The described specimens are of worker caste adults which have been preserved as inclusions in transparent chunks of Burmese amber. [1] The amber specimens were recovered from deposits in Kachin State, 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 Albian  – Cenomanian boundary, in the earliest Cenomanian. [2] [3] [4] [5]

The fossils were first studied by paleoentomologists Phillip Barden and David Grimaldi with their 2017 type description of the new genus and species being published in the journal Systematic Entomology. [1] The genus name Linguamyrmex was formed as a combination of the Greek "myrmex" which means ant, and the Latin "lingua", which means tongue, as a reference to the shape and appearance of the clypeal projection. The specific epithet vladi is a patronym honoring Vlad III, known as Vlad the Impaler, who was the ruler of Wallachia. It was coined as a reference to both Vlad's preferred execution style and for his inspiration of Bram Stoker's Count Dracula, who drank blood. [1]

The three remaining workers studied, BuPH-02, BuPH-03, and BuPH-04 were assigned to Linguamyrmex due to several factors. Each of the specimens is incomplete, all missing portions of the antennae, making comparison of the scape length to the other segments impossible, and all specimens are missing the terminal segments of the gaster. Based on the worker size and on paddle composition Barden and Grimaldi suggest the three workers may belong to undescribed species. [1]

Linguamyrmex is one of several ant genera described from Burmese amber, the others being Burmomyrma , Camelomecia , Ceratomyrmex , Gerontoformica , Haidomyrmex , Myanmyrma , and Zigrasimecia . [2] [4] [5] [1] Linguamyrmex is one of five genera in Haidomyrmecini, the other four being Ceratomyrmex , Haidomyrmex, Haidomyrmodes and Haidoterminus . The genus is distinguished from them by the well developed gasteral constriction on the abdomen, a feature only seen, to a lesser degree, in Haidomyrmodes mammuthus. Additionally Linguamyrmex has an enlarged and paddle shaped clypeus, similar to the extremely modified clypeus of Ceratomyrmex, but which is smooth along the stalk instead of sporting setae, and with trigger hairs placed at the base of the setae pad on the paddle instead of at the base of the paddle stalk. [1]

Behavior and ecology

Ceratomyrmex ellenbergeri head Ceratomyrmex ellenbergeri FANTWEB00005 head.jpg
Ceratomyrmex ellenbergeri head

As with all haidomyrmecine members, the head structure of Linguamyrmex is interpreted to facilitate trap-jaw behavior, as is seen in modern specialized genera of Formicinae, Myrmicinae and Ponerinae. In haidomyrmecines the clypeus is modified to span from near the oral opening up past the mandibles to near the vertex of the head, the only ant group with such a modification. Along with the clypeal structuring a pair of long setae are positioned in the path of the mandibles. In modern trap-jaw ants such setae are used as triggers that initiate the rapid closure of the mandibles, often to capture prey or sometimes in a defensive action. The upper areas of the clypeus are always coated in a brush of stout setae in the region where the mandibles came to rest when triggered to close. Based on the modification of the clypeus, it is probable that Linguamyrmex would have captured prey from the front, other strategies being made improbable due to the upward motion of the mandibles. In haidomyrmecines with highly modified cleypeal areas, such as Linguamyrmex and Ceratomyrmex the horn probably served as a pinning or trapping point for the mandibles with captured prey. [1]

This hypothesis for the purpose of the clypeus in Linguamyrmex is further supported by data obtained from X-ray micro-computed tomography scans of specimen "BuPH-03". Scanning of the specimen shows density variation in the paddle, with the outer edges less dense than the central core area on the paddles underside. This indicates the paddle was strengthened with thickened cuticle or with metals sequestering in the cuticle, the latter being more likely from the distinct contrast shown in the x-ray. [1] The location of the highest density is near the center of the paddle at the point of impact for the mandibles when they closed, likely to help brace the paddle against misfires of the mandibles, or impact through soft bodied prey, such as beetle larvae. Metals such as calcium, iron, manganese, and zinc are used by insects in both mandibles and ovipositors to reduce wear and increase durability. [1]

Description

Head of the holotype worker Linguamyrmex vladi AMNH-BUPH01 head profile.jpg
Head of the holotype worker

The head of the Linguamyrmex holotype measures 1.86 mm (0.07 in) from the front edge of the clypeus to the rear of the head at the occipital foramen, which is placed high on the back side, near the vertex. There are three ocelli placed just to the front of the vertex, and the bulging ovoid compound eyes are positioned high on the head capsule. The antennae are not fully preserved, with only three full segments, the scape, pedicel, and flagellomere I. The antennae insertion is just in front of and below the eyes, positioned in depressions on each side of the frontal triangle. The frontal triangle extends down from the vertex and merges with the base of the clypeal horn, which is reinforced with clear membrane-like cuticle. The clypeus is enlarged and modified into a paddle shaped horn that has a pad of setae on the underside. The stalk of the horn is smooth, with no setae, and the trigger hairs seen in haidomyrmecines sprout from near the base of the setae pad on the paddle. The pad is composed of long fine setae around the edges changing to shorter thicker setae in the center. The mandibles scythe shaped in general outline, curving out and upwards from the head towards the clypeal horn. There are expansions near the base of each mandible which angle in towards each other, and which have upper surfaces that are concave and covered with setae pointing towards the mouth. [1]

Linguamyrmex brevicornis Dorsal Linguamyrmex brevicornis FANTWEB00025 dorsal.jpg
Linguamyrmex brevicornis Dorsal

The mesosoma has a small propleuron that is hidden except where the mesosoma touches the head capsule, while the pronotum is broad and has a coating of fine setae. To the rear of the mesosoma, the propodeum is gently rounded upper front face that curves to become a shear rear face. Both the propodeal spiracle and metapleural gland are visible on the sides of the mesosoma, with the spiracle elongated into a slit shape, while metapleural gland is a horizontal opening placed rear of a well-developed bulla. The petiole has a gradually sloping front face and rounded upper surface. The rear is broadly attached to gasteral segment I and the distinctly showing helcium is striated. An incomplete fusion line runs along the side of the petiole and gaster, with a thin membranous section present below, while a constriction between segments I and II that rings the full gaster. There is a forward projecting horn on the underside of sternite III that also has distinct striations. The cuticle of the gaster is translucent, which shows that the apodemes of gastral sternites IV and V are expanded and heavily sclerotized. [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.

Haidomyrmecinae Extinct subfamily of ants

Haidomyrmecinae, occasionally called Hell ants, are an extinct subfamily of ants (Formicidae) known from Cretaceous fossils found in ambers of North America, Europe, and Asia, spanning the late Albian to Campanian, around 100 to 79 million years ago. The subfamily was first proposed in 2003, but had been subsequently treated as the tribe Haidomyrmecini and placed in the extinct ant subfamily Sphecomyrminae. Reevaluation of Haidomyrmecini in 2020 lead to the elevation of the group back to subfamily. The family contains the nine genera and thirteen species.

<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>Haidoterminus</i> Extinct genus of ants

Haidoterminus is an extinct genus of ant in the Formicidae subfamily Haidomyrmecinae, and is one of only nine genera placed in this subfamily. The genus contains a single described species Haidoterminus cippus and is known from one Late Cretaceous fossil which has been found in North America.

<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 ant-mimic wasp in the extinct family Falsiformicidae. The genus contains a single described species, Burmomyrma rossi. Burmomyrma is known from a single Middle Cretaceous fossil which was found in Asia.

Pristomyrmex tsujii is a species of ant in the genus Pristomyrmex. Known from Fiji, where they are widely distributed but rarely encountered. The species has a discrete ergatoid queen caste that is intermediate between a worker and an alate queen.

<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.

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.

<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.

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>Protopone</i> Extinct genus of ants

Protopone is an extinct genus of ants in the formicid subfamily Ponerinae described from fossils found in Europe and Asia. There are seven described species placed into the genus, Protopone? dubia, Protopone germanica, Protopone magna, Protopone oculata, Protopone primigena, Protopone sepulta, and Protopone vetula. Protopone is one several Lutetian Ponerinae genera.

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

Ceratomyrmex is an extinct genus of ant in the Formicidae subfamily Haidomyrmecinae, and is one of only nine genera placed in the 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>Boltonimecia</i> Extinct genus of ants

Boltonimecia is an extinct genus of ant in the formicid subfamily Zigrasimeciinae. The genus contains a single described species, Boltonimecia canadensis, and is known from a single Late Cretaceous fossil which was found in Canada. The type species was originally described as a species of the extinct genus Sphecomyrma under the combination Sphecomyrma canadensis.

References

  1. 1 2 3 4 5 6 7 8 9 10 11 Barden, P; Herhold, H. W.; Grimaldi, D. A. (2017). "A new genus of hell ants from the Cretaceous (Hymenoptera: Formicidae: Haidomyrmecini) with a novel head structure". Systematic Entomology. 42 (4): 837–846. doi: 10.1111/syen.12253 .
  2. 1 2 Perrichot, V.; Wang, B.; Engel, M. S. (2016). "Extreme Morphogenesis and Ecological Specialization among Cretaceous Basal Ants". Current Biology. 26 (11): 1468–1472. doi: 10.1016/j.cub.2016.03.075 . PMID   27238278.
  3. ↑ 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.
  4. 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.
  5. 1 2 Barden, P.; Grimaldi, D.A. (2016). "Adaptive radiation in socially advanced stem-group ants from the Cretaceous". Current Biology. 26 (4): 515–521. doi: 10.1016/j.cub.2015.12.060 . PMID   26877084.
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