Brownimecia

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Brownimecia
Temporal range: 94–90  Ma
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Brownimecia clavata AMNH-NJ667 holotype 01.jpg
Brownimecia clavata holotype
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily:† Brownimeciinae
Bolton, 2003
Tribe:† Brownimeciini
Bolton, 2003
Genus:† Brownimecia
Grimaldi, Agosti & Carpenter, 1997
Type species
Brownimecia clavata
Grimaldi et al., 1997
Species
  • Brownimecia inconspicua

Brownimecia is an extinct genus of ants, the only genus in the tribe Brownimeciini and subfamily Brownimeciinae of the Formicidae. Fossils of the identified species, Brownimecia clavata and Brownimecia inconspicua, are known from the Late Cretaceous of North America. The genus is one of several ants described from Late 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. B. clavata 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.

Contents

History and classification

Brownimecia clavata is known from three adult fossils: the holotype—specimen number AMNH NJ-667—collected by Yale Goldman; the paratype; and a third described in 2005. [1] At the time of the genus description, the type specimens were residing in the American Museum of Natural History, in New York City. [2] All the described specimens are worker caste adult females which have been preserved as inclusions in transparent chunks of New Jersey amber. The amber specimens were recovered from deposits of the South Amboy Fire Clay, part of the Raritan Formation. New Jersey amber has been dated to approximately 90 to 94 mya, placing it in the Turonian of the Late Cretaceous. Analysis of the amber composition indicates it originated as cupressaceous resins which were deposited in lagoons and salt water marshes along the Cretaceous eastern seaboard. [2] Brownimecia clavata is one of several ant species described from New Jersey amber, the others being Sphecomyrma freyi , Sphecomyrma mesaki , Baikuris casei , and Kyromyrma neffi . [1]

The type fossils were first studied by paleoentomologists David Grimaldi, Donat Agusti, and James Carpenter of the American Museum. The team's 1997 type description of the new genus and species was published in the journal American Museum Novitates . [2] The genus name was coined by them as a patronym honoring the ant systematist William L. Brown, Jr. who co-described the first Cretaceous ant genus and species Sphecomyrma freyi. The specific epithet clavata was chosen as a reference to the distinctive clubbed antennae seen in the workers. Grimaldi, Agusti, and Carpenter placed the new genus into the extant ant subfamily Ponerinae, without tribal assignment, based on a slight constriction of the gaster. They also noted several features that are shared with ants of the amblyoponine group, then a part of Ponerinae. The workers have genal spurs on the lower edge area under the small compound eyes. Workers also have narrow long mandibles, as do some amblyoponine genera. Placement in Ponerinae was unchanged until a revision of the subfamily was published in 2003 by myrmecologist Barry Bolton. In that paper the subfamily was shown to be a paraphyletic grouping and many of the included genera were moved to separate subfamilies, including the amblyoponines and Brownimecia. Due to the unique combination of morphological features found in Brownimecia, Bolton erected the new subfamily Brownimeciinae for the genus. Bolton notes that its sickle-like mandibles which lack teeth are not usual for ants and are often associated with dulotic, or slave-making, behavior in extant genera. In contrast to stem group ants such as the sphecomyrmines, the scapes of Brownimecia workers are more elongated like those of crown group ants. [1] [3] In his 2007 phylogenetic examination of Formicidae, entomologist Philip Ward notes the possibility that Brownimecia is a crown group genus and placed the subfamily into the informal "poneroid" grouping in his phylogony. [4]

Description

B. clavata holotype, dorsal view Brownimecia clavata AMNH-NJ667 holotype 02.jpg
B. clavata holotype, dorsal view

Both the Brownimecia holotype worker and the 2005 worker are complete and fully preserved in curled positions and have their stings extended. [2] [1] The paratype worker is very incomplete; the amber in which it is encased is highly likely to have been at least partly tumble polished in a rock causing the ant to be exposed and portions of the head, left antenna, mid legs, hind legs, and all of the right antennae and forelegs are gone. The exposure allowed the interior cavity of the fossil to be examined under scanning electron microscope after being coated in a layer of gold. [2]

The holotype has an overall body length of approximately 3.43 millimetres (0.135 in) with finely scattered setae on all parts except the notum and propodeum. The head is large with small rounded compound eyes composed of about one hundred ommatidia. The holotype does not clearly show whether the ocelli are present or absent, but they are clearly absent in the 2005 specimen. The mandibles are scimitar-shaped with no teeth present on the interior sides and almost the length of the head. The mandibles cross each other near their mid-length and the oral surfaces bear approximately thirty short needle-like setae. [2] The clypeus is short but wide, crossing almost the whole width of the head. [2] Perpendicular crenelations run along the upper margin of the clypeus on the 2005 specimen. [1] The gena have a distinct tooth-like structure on the lower sides. The eleven segmented antennae are distinct in having a definite clubbed tip, a feature not seen in any other described Cretaceous ants. The apical flagellomere segment is nearly twice the width of the other segments, while the third to the sixth segments are the shortest and the second flagellomere is slightly swollen. [2]

The metathoracic spiracles are raised on small cones projecting from the alitrunk, while the metapleural gland orifices are not notably raised, having a ridge leading to them. All of the alitrunk gland and spiracle orifices are to some degree obscured on the holotype by froths of bubbles that escaped them soon after the worker was entombed in the sap. [2] The petiole top forms a pointed apex instead of a more rounded dome. There is a covering of fine microtrichia hairs on the petiole and a pair of small setae are situated near the apex. At the front of the petiole there is a narrow attachment area to the propodeum, while the rear is flared into a large attachment to the gaster. The helcium, a small exoskeleton plate between the petiole and gaster, is developed and shows crenelations on the rear edge. There is a small but distinct constriction between the first and second segments of the gaster. Both the holotype and 2005 specimens have a fully preserved gaster tip showing the extended sting, while the paratype is missing the tip area. [2] [1]

Due to the unusual morphology of the mandibles, scientists have suggested that Brownimecia may have had a high level of feeding specialization. [5]

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>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.

<span class="mw-page-title-main">Sphecomyrminae</span> Extinct subfamily of ants

Sphecomyrminae is an extinct subfamily of ants in family Formicidae known from a series of Cretaceous fossils found in North America, Europe, and Asia. Sphecomyrminae contains eight genera, divided into two tribes Sphecomyrmini and Zigrasimeciini. The tribe Sphecomyrmini contains the six genera Armania, Cretomyrma, Gerontoformica, Orapia, Pseudarmania and Sphecomyrma; while Zigrasimeciini contains Boltonimecia and Zigrasimecia. A number of taxa have been removed from the subfamily and placed either in other subfamilies or are now treated as incertae sedis in Formicidae.

<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 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.

Armaniinae is subfamily of extinct ant-like hymenopterans known from a series of Cretaceous fossils found in Asia and Africa. It is usually treated as one of the stem-group subfamilies in family Formicidae, although some myrmecologists treat it as a distinct family. A 2007 study analysing petiole and antenna morphology led to the proposal that at least some of the armaniid genera be placed in Sphecomyrminae, although others are unconvinced by the arguments and retain Armaniinae. The subfamily contains seven genera with fourteen described species.

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

Baikuris is an extinct genus of ant in the Formicidae subfamily Sphecomyrminae, and is currently placed in the tribe Sphecomyrmini. The genus contains four described species: the type species Baikuris mandibularis, along with Baikuris casei, Baikuris maximus, Baikuris mirabilis, B. ocellantis.

<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>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>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.

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

Odontomachus spinifer is an extinct species of ant in the subfamily Ponerinae known from one possibly Miocene fossil found on Hispaniola. O. spinifer 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>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 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. 1 2 3 4 5 6 7 8 9 10 Grimaldi, D.; Agosti, D.; Carpenter, J. M. (1997). "New and rediscovered primitive ants (Hymenoptera, Formicidae) in Cretaceous amber from New Jersey, and their phylogenetic relationships". American Museum Novitates (3208): 1–43.
  3. ↑ Bolton, B. (2003). "Synopsis and classification of Formicidae" (PDF). Memoirs of the American Entomological Institute. 71: 1–370.
  4. ↑ Ward, P. S. (2007). "Phylogeny, classification, and species-level taxonomy of ants (Hymenoptera: Formicidae)" (PDF). Zootaxa . 1668: 549–563. doi:10.11646/zootaxa.1668.1.26. Open Access logo PLoS transparent.svg
  5. ↑ Rasnitsyn, A.P.; Quicke, D.L. (2002). History of Insects . Dordrecht: Kluwer Academic. p.  373. ISBN   978-0-306-47577-1.
  6. ↑ Sosiak, C.; Cockx, P.; Aragonés Suarez, P.; McKellar, R.; Barden, P. (2024). "Prolonged faunal turnover in earliest ants revealed by North American Cretaceous amber". Current Biology. doi:10.1016/j.cub.2024.02.058. PMID   38521061.

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