''Archiponera'' 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 ...

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

of ant in the formicid subfamily Ponerinae. The genus contains a single described species, ''Archiponera wheeleri'' known from several

Late Eocene The Eocene ( ) Epoch is a geological epoch that lasted from about 56 to 33.9 million years ago (mya). It is the second epoch of the Paleogene Period in the modern Cenozoic Era. The name ''Eocene'' comes from the Ancient Greek (''ēṓs'', "daw ...

fossils which were found in North America.

History and classification

When described the genus ''Archiponera'' was known from a single pair of fossils preserved as an impression in fine

shale Shale is a fine-grained, clastic sedimentary rock formed from mud that is a mix of flakes of clay minerals (hydrous aluminium phyllosilicates, e.g. kaolin, Al2 Si2 O5( OH)4) and tiny fragments (silt-sized particles) of other minerals, especial ...

of the Florissant formation in Colorado. No further specimens have been reported since that time. The formation is composed of successive lake deposits which have preserved a diverse assemblage of insects. The insects and plants suggest a climate similar to modern Southeastern North America, with a number of taxa represented that are now found in the subtropics to tropics and confined to the old world. When ''Archiponera'' was described, the Florissant formation was considered to be

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 ...

in age, based on the flora and fauna preserved. Successive research and fossil descriptions moved the age older and by 1985 the formation had been reassigned to an

Oligocene The Oligocene ( ) is a geologic epoch of the Paleogene Period and extends from about 33.9 million to 23 million years before the present ( to ). As with other older geologic periods, the rock beds that define the epoch are well identified but the ...

age. Further refinement of the formation's age using radiometric dating of sanidine crystals has resulted in an age of 34 million years old. This places the formation in the Eocene Priabonian stage. At the time of description 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 ...

worker and allotype male of ''A. wheeleri'' were deposited in the Museum of Comparative Zoology paleontology collections at

Harvard University Harvard University is a private Ivy League research university in Cambridge, Massachusetts. Founded in 1636 as Harvard College and named for its first benefactor, the Puritan clergyman John Harvard, it is the oldest institution of higher le ...

. The fossils were first studied by paleoentomologist

Frank M. Carpenter Frank Morton Carpenter (September 6, 1902 – January 18, 1994) was an American entomologist and paleontologist. He received his PhD from Harvard University, and was curator of fossil insects at the Harvard Museum of Comparative Zoology for 60 y ...

of the Museum of Comparative Zoology. His 1930

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 genus and species was published in the ''Bulletin of the Museum of Comparative Zoology''. When described, Carpenter noted perceived similarities between ''Archiponera'' and the modern genera '' Streblognathus'' and ''

Dinoponera ''Dinoponera'' is a strictly South American genus of ant in the subfamily Ponerinae, commonly called tocandiras or giant Amazonian ants. These ants are generally less well known than ''Paraponera clavata'', the bullet ant, yet ''Dinoponera'' fe ...

'', suggesting that the two modern genera were the closest relatives of ''Archiponera''. Wheeler suggested that ''Streblognathus'' and ''Dinoponera'', at that time each known from a single described species, were members of a close generic grouping, or "super genus", which prior to the Pleistocene

ice age An ice age is a long period of reduction in the temperature of Earth's surface and atmosphere, resulting in the presence or expansion of continental and polar ice sheets and alpine glaciers. Earth's climate alternates between ice ages and gree ...

, was a tropicopolitan, with ''Archiponera'' being a northern member of the group. However molecular data analysis has shown that while ''Streblognathus'' and ''Dinoponera'' show general morphological similarities, they are not closely related as suggested by Wheeler, and the relationship status of ''Archiponera'' is not known. ''Archiponera'' is one of eleven extinct Ponerinae genera described as of 2012.

Description

In general ''Archiponera'' specimens have large heads with rounded sides and small, uncurved mandibles. The clypeus is large in proportion to the head, with a forward margin that has a cleft in the middle and a rearward margin with a large lobe present. The eyes are similar in placement and size to that seen in ''Streblognathus'' and ''Dinoponera'', being smaller and positioned high on the head capsule. The twelve segmented antennae are long, with a scape that extends past the rear of the head capsule. The gaster is notably rounded and small at long, being nearly the same size as the long head. The workers have an overall length of with a thorax of about . The male is overall smaller than the known worker, with an estimated length of , a condition that is seen in ''Dinoponera'' species. The wings of the male are long and bearing two cubital cells.

References

{{Taxonbar, from=Q11686630 Monotypic fossil ant genera Priabonian insects Fossil taxa described in 1930 Prehistoric insects of North America Ponerinae Florissant Formation