''Acropyga glaesaria'' is an

extinct Extinction is the termination of a kind of organism or of a group of kinds (taxon), usually a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and ...

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

ant Ants are eusocial insects of the family Formicidae and, along with the related wasps and bees, belong to the order Hymenoptera. Ants evolved from vespoid wasp ancestors in the Cretaceous period. More than 13,800 of an estimated total of 22 ...

in the subfamily

Formicinae The Formicinae are a subfamily within the Formicidae containing ants of moderate evolutionary development. Formicines retain some primitive features, such as the presence of cocoons around pupae, the presence of ocelli in workers, and little ...

known from a group of possibly

Miocene The Miocene ( ) is the first geological epoch of the Neogene Period and extends from about (Ma). The Miocene was named by Scottish geologist Charles Lyell; the name comes from the Greek words (', "less") and (', "new") and means "less recen ...

fossils found on

Hispaniola Hispaniola (, also ; es, La Española; Latin and french: Hispaniola; ht, Ispayola; tnq, Ayiti or Quisqueya) is an island in the Caribbean that is part of the Greater Antilles. Hispaniola is the most populous island in the West Indies, and th ...

. ''A. glaesaria'' is the first species of the ant genus '' Acropyga'' to have been described from fossils found in

Dominican amber Dominican amber is amber from the Dominican Republic derived from resin of the extinct tree ''Hymenaea protera''. Dominican amber differentiates itself from Baltic amber by being nearly always transparent, and it has a higher number of fossil incl ...

and is the one of several species of ''Acropyga'' found in the West Indies. As with other members of the genus, ''A. glaesaria'' was most likely

trophobiotic Trophobiosis is a symbiotic association between organisms where food is obtained or provided. The provider of food in the association is referred to as a trophobiont. The name is derived from the Ancient Greek τροφή (''trophē''), meaning "n ...

History and classification

''Acropyga glaesaria'' is known from six fossil insects which are inclusions in transparent chunks of

. The amber was produced by the extinct ''

Hymenaea protera ''Hymenaea protera'' is an extinct prehistoric leguminous tree, the probable ancestor of present-day ''Hymenaea'' species. Most neotropical ambers come from its fossilized resin, including the famous Dominican amber. ''H. protera'' once grew in ...

'', which formerly grew on

, across northern South America and up to southern Mexico. The specimens were collected from undetermined amber mines in fossil bearing rocks of the

Cordillera Septentrional The Cordillera Septentrional is a mountain range that runs parallel to the north coast of the Dominican Republic, with extensions to the northwest as Tortuga island in Haiti, and to the southeast through lowlands to where it rises as the Sierra d ...

mountains, northern

Dominican Republic The Dominican Republic ( ; es, República Dominicana, ) is a country located on the island of Hispaniola in the Greater Antilles archipelago of the Caribbean region. It occupies the eastern five-eighths of the island, which it shares wit ...

. The amber dates from at least the

Burdigalian The Burdigalian is, in the geologic timescale, an age (geology), age or stage (stratigraphy), stage in the early Miocene. It spans the time between 20.43 ± 0.05 annum, Ma and 15.97 ± 0.05 Ma (million years ago). Preceded by the Aquitanian (sta ...

stage of the Miocene, based on studying the associated fossil

foraminifera Foraminifera (; Latin for "hole bearers"; informally called "forams") are single-celled organisms, members of a phylum or class of amoeboid protists characterized by streaming granular Ectoplasm (cell biology), ectoplasm for catching food and ot ...

and may be as old as the Middle Eocene, based on the associated fossil

coccoliths Coccoliths are individual plates or scales of calcium carbonate formed by coccolithophores (single-celled phytoplankton such as ''Emiliania huxleyi'') and cover the cell surface arranged in the form of a spherical shell, called a ''coccosphere''. ...

. This age range is due to the host rock being secondary deposits for the amber, and the Miocene the age range is only the youngest that it might be. Acropyga glaesaria SMFBE457B1 01

The

holotype A holotype is a single physical example (or illustration) of an organism, known to have been used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of several ...

amber specimen, number DR-16-603, entombs an

alate Alate (Latin ''ālātus'', from ''āla'' (“wing”)) is an adjective and noun used in entomology and botany to refer to something that has wings or winglike structures. In entomology In entomology, "alate" usually refers to the winged form o ...

queen associated with the only known '' Electromyrmococcus inclusus'', and one

paratype In zoology and botany, a paratype is a specimen of an organism that helps define what the scientific name of a species and other taxon actually represents, but it is not the holotype (and in botany is also neither an isotype nor a syntype). Of ...

queen, in a separate amber specimen with the '' E. reginae'' holotype, are currently preserved in the

American Museum of Natural History The American Museum of Natural History (abbreviated as AMNH) is a natural history museum on the Upper West Side of Manhattan in New York City. In Theodore Roosevelt Park, across the street from Central Park, the museum complex comprises 26 inter ...

in New York. A single specimen in the collections at the

Naturmuseum Senckenberg The Naturmuseum Senckenberg is a museum of natural history, located in Frankfurt am Main. It is the second-largest of its type in Germany. The museum contains a large and diverse collection of birds with 90,000 bird skins, 5,050 egg sets, 17,0 ...

Frankfurt Frankfurt, officially Frankfurt am Main (; Hessian: , "Frank ford on the Main"), is the most populous city in the German state of Hesse. Its 791,000 inhabitants as of 2022 make it the fifth-most populous city in Germany. Located on its na ...

, Germany preserves two more paratype queens and the two known paratype males, all in association with the holotype of '' E. abductus''. The fossils were first studied by entomologist John LaPolla of the

Smithsonian Institution The Smithsonian Institution ( ), or simply the Smithsonian, is a group of museums and education and research centers, the largest such complex in the world, created by the U.S. government "for the increase and diffusion of knowledge". Founded ...

. LaPolla's 2005

type description A species description is a formal description of a newly discovered species, usually in the form of a scientific paper. Its purpose is to give a clear description of a new species of organism and explain how it differs from species that have be ...

of the new species was published in the journal '' Transactions of the American Entomological Society''. The

specific epithet In taxonomy, binomial nomenclature ("two-term naming system"), also called nomenclature ("two-name naming system") or binary nomenclature, is a formal system of naming species of living things by giving each a name composed of two parts, bot ...

''glaesaria'' is derived from the

Latin Latin (, or , ) is a classical language belonging to the Italic branch of the Indo-European languages. Latin was originally a dialect spoken in the lower Tiber area (then known as Latium) around present-day Rome, but through the power of the ...

for "of amber" in reference to the preservation of the fossils. Prior to the species formal description in 2005 the fossils had been attributed to the genus ''

Brachymyrmex ''Brachymyrmex'' is a genus in the ants subfamily Formicinae. The genus can be recognized by the combination of having nine antennal segments (fewer than most ants) and the petiole concealed by the gaster in dorsal view. They are sometimes called ...

'' and in the 2001 description of ''Electromyrmococcus'' specimens of ''A. glaesaria'' were suggested to represent several different ''Acropyga'' species. The generic placement was stabilized with a review and clarification of the scope of ''Acropyga'' by LaPolla in 2004, while the suggestion of multiple species based on morphology was shown to be an artifact of distortion and preservation in the amber. The association of ''A. glaesaria'' and the ''Electromyrmococcus'' species is one of the oldest examples of

trophobiosis Trophobiosis is a symbiotic association between organisms where food is obtained or provided. The provider of food in the association is referred to as a trophobiont. The name is derived from the Ancient Greek τροφή (''trophē''), meaning "n ...

. Modern ''Acropyga'' are thought to be fully reliant on mealy bug species as their source of food and reproductive only emerge from the nest during the mating flight, each carrying a seed bug in their mandibles.

Description

The ''Acropyga glaesaria'' specimens are well preserved, though the specimens show some distortion from the amber moving after entombment. The specimens of queens have estimated body lengths between ,while the measured male shows a length of about . The overall coloration of the ''A. glaesaria'' queens is a light yellow tone, typical for members of the genus and the males are a slightly darker dusky yellow which is also typical. The antennae are thickened with nine total segments, the apical of which is a little longer than the next three segments combined. The mandibles have eight teeth overall, with the fourth and seventh from the mandible apex being the longest overall.

References

External links

* {{Taxonbar, from=Q16748031 Miocene insects of North America Fossil taxa described in 2005 Fauna of Hispaniola Insects of the Dominican Republic Extinct animals of the Dominican Republic Fossils of the Dominican Republic Dominican amber Formicinae Fossil ant taxa Prehistoric insects of the Caribbean