''Afropone'' 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 ...

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 formicid subfamily

Ponerinae Ponerinae is a subfamily of ants in the Poneromorph subfamilies group, with about 1,600 species in 47 extant genera, including ''Dinoponera gigantea'' - one of the world's largest species of ant. Mated workers have replaced the queen as the fun ...

, and is currently unplaced in any of the tribes of that subfamily. The genus contains two described species, ''Afropone oculata'' and ''Afropone (?) orapa''. ''Afropone'' is known from a group of

Upper Cretaceous The Late Cretaceous (100.5–66 Ma) is the younger of two epochs into which the Cretaceous Period is divided in the geologic time scale. Rock strata from this epoch form the Upper Cretaceous Series. The Cretaceous is named after ''creta'', the ...

fossils, which were found at

Orapa Orapa is a town located in the Central District of Botswana. It is the site of the Orapa diamond mine, the largest diamond-producing mine in the world, and is considered to be the diamond capital of the country. Nearby is another kimberlite min ...

in the Central District of

Botswana Botswana (, ), officially the Republic of Botswana ( tn, Lefatshe la Botswana, label=Setswana, ), is a landlocked country in Southern Africa. Botswana is topographically flat, with approximately 70 percent of its territory being the Kalahar ...

History and classification

''Afropone oculata'' was described from two fossils, 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 ...

specimen number BP/2/28072a/2, identified as a female, and an additional poorly preserved fossil, number BP/2/26631-17. ''Afropone (?) orapa'' was based on a single holotype male, specimen BP/2/26628/1, and tentatively placed into the genus based on overall morphology. The specimens are mostly complete with variation in the quantity of detail, and are preserved as compression fossils in shale. The shales and mudstones of the Orapa site were rapidly deposited in a

crater lake Crater Lake (Klamath language, Klamath: ''Giiwas'') is a volcanic crater lake in south-central Oregon in the western United States. It is the main feature of Crater Lake National Park and is famous for its deep blue color and water clarity. The ...

formed as the result of a large volcanic eruption in the Cretaceous. The sediment originated as an epiclastic

kimberlite Kimberlite is an igneous rock and a rare variant of peridotite. It is most commonly known to be the main host matrix for diamonds. It is named after the town of Kimberley in South Africa, where the discovery of an diamond called the Star of ...

and derives from rapid weathering and decomposition of the sides of the kimberlite crater. Of the four major sedimentation types that have been observe at Orapa, fossils are found in only two, the granular mass flows and the fine-grained sediments: woody debris fossils are found in the granular mass flows, but well-preserved fossils are only recovered in the fine-grained sediments. The fossil-bearing stratum was uncovered during mining of the underlying diamond-bearing rocks at the site.

Radiometric dating Radiometric dating, radioactive dating or radioisotope dating is a technique which is used to date materials such as rocks or carbon, in which trace radioactive impurities were selectively incorporated when they were formed. The method compares t ...

of the kimberlite pipe reported in 1977 gave an age in the general range of . Further dating utilizing zircon crystals reported on in 2004 gave more defined age of approximately placing the date in the Turonian age of the late Cretaceous. The fossils were first studied by Russian paleontologists Gennady M. Dlussky and

Alexandr Rasnitsyn Alexandr Pavlovich Rasnitsyn (Russian: Александр Павлович Расницын) is a Russian entomologist, expert in palaeoentomology, and Honored Scientist of the Russian Federation (2001). His scientific interests are centered on ...

with South African paleontologist Denis Brothers. Their 2004

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 were published in the journal '' Insect Systematics and Evolution''. The genus name ''Afropone'' is a combination of Africa, where the fossil was found, and ''

Ponera ''Ponera'' is a genus of ponerine ants. The name is the Latinized form (') of the Ancient Greek ' (, 'wicked, wretched'). Description Workers are very small to small in size (1–4 mm); queen are similar to workers but winged. This genus ...

'', the type species of the subfamily Ponerinae. 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 ...

''oculata'', a derivation of 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 ...

word ''oculus'' meaning ''eye'' is a reference to the large eyes of the species. The specific epithet ''orapa'' is derived from the fossil locality name.

Description

The eyes of ''Afropone'' species are large and well developed placed in the front portion of the head capsule in ''A. oculata'' females, and in the rear portion of the head capsule in ''A. (?) orapa'' males. Based on the preserved areas of known fossils, the mandibles of both species are short and rounded, without a distinct

masticatory Chewing or mastication is the process by which food is crushed and ground by teeth. It is the first step of digestion, and it increases the surface area of foods to allow a more efficient break down by enzymes. During the mastication process, th ...

margin. Females of ''A. oculata'' are elongate being approximately long and have eyes which are 2.5 times as long as they are wide. The fore wings are narrow and 4.5 times longer than their width. As with other portions of the body both the mesosoma and petiole regions are narrowed. ''A. (?) orapa'' is smaller than ''A. oculata'' with a total body length of approximately . Overall the antennae are filiform and are composed of flagellomeres that are twice as long as wide. The scape at the base of each is generally short.

References

{{Taxonbar, from=Q15621678 Late Cretaceous insects Fossil taxa described in 2004 Prehistoric insects of Africa Ponerinae Fossil ant genera