Formiciinae is an extinct subfamily of

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 ...

s known from

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'', " ...

deposits in

Europe Europe is a large peninsula conventionally considered a continent in its own right because of its great physical size and the weight of its history and traditions. Europe is also considered a subcontinent of Eurasia and it is located entirel ...

and North America.

Genera

*Formiciinae Lutz, 1986 **Formiciini Lutz, 1986 ***''

Titanomyrma ''Titanomyrma'' is a genus of prehistoric giant ant. The latest species to be discovered, ''T. lubei'', was described in 2011, when a 49.5-million-year-old fossilized winged queen ant, comparable in size to hummingbirds, was found in Wyoming, Uni ...

'' Archibald, ''et al.'', 2011 ****''Titanomyrma gigantea'' (Lutz, 1986) ****''Titanomyrma lubei'' Archibald, ''et al.'', 2011 ****''Titanomyrma simillima'' (Lutz, 1986) ***'' Formicium'' Westwood, 1854 (collective group genus) ****''Formicium berryi'' (Carpenter, 1929) ****''Formicium brodiei'' Westwood, 1854 ****''Formicium mirabile'' (Cockerell, 1920) The type

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nom ...

is '' Formicium'' with the genus ''

'' being described in 2011. ''Formicium'' includes the described

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 ...

which are known from fossil wings only. ''Formicium'' is known from three species. ''Formicium mirabile'', named by Theodore D. A. Cockerell in 1920, and ''Formicium brodiei'', named by John O. Westwood in 1854, are both known from fore wings found in the

middle 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'', "da ...

of Bournemouth,

Dorset, England Dorset ( ; archaically: Dorsetshire , ) is a county in South West England on the English Channel coast. The ceremonial county comprises the unitary authority areas of Bournemouth, Christchurch and Poole and Dorset. Covering an area of , D ...

. The third species named, ''Formicium berryi'' was named by Frank M. Carpenter in 1929 from the middle Eocene

Claiborne Formation The Claiborne Formation or Claiborne Group is a geologic formation in Arkansas, Illinois, Kentucky, and Texas. It preserves fossils dating back to the Paleogene period . See also * List of fossiliferous stratigraphic units in Kentucky Thi ...

Puryear, Tennessee Puryear is a city in Henry County, Tennessee, United States. The population was 671 at the 2010 census. Geography Puryear is located in northern Henry County at (36.444853, -88.333770). U.S. Route 641 passes through the east side of the city, le ...

, USA, though he misidentified the formation as the

Wilcox Formation The Wilcox Formation is a geologic formation in Tennessee. It preserves fossils dating back to the Paleogene period. The first hydrocarbon discover in the formation occurred in 1928, onshore Texas. Subsequent field discoveries included the S ...

. ''F. berryi'' was the first described occurrence of the genus and, until 2011, the subfamily, in North America. With the description of ''Titanomyrma'', the two species already described from complete body specimens, ''Formicium giganteum'' and ''F. simillimum'', were transferred to the new genus as ''Titanomyrma giganteum'' and ''T. simillimum'' respectively. ''Titanomyrma'' also contains a third species, ''T. lubei'' described in the same paper as the genus and which is the second member of the subfamily known from North America.

Size

While workers belonging to the subfamily have not been found, queens and males for ''T. giganteum'' and ''T. simillimum'' are known and ''T. lubei'' is known from a single queen. The average size for the queens and males in ''Titanomyrma'' is equal to that of some of the largest modern ants known. Only the queens of '' Dorylus wilverthi'' currently reach similar lengths, up to as the smallest species of ''Titanomyrma'', ''T. lubei''. Formiciinae members were restricted in habitat to living in regions which had a mesic wet climate and an average mean annual temperature of or higher. This is similar to the restricted ranges of the largest species of modern ants. The spread of the subfamily from Europe to North America is postulated to have been across the North Atlantic landbridges which were present in the Eocene. While the average temperatures for this route are thought to have been lower than the range needed for Formiciinae species, a series of warmer events throughout the Eocene are suggested as aides in the crossing.

References

External links

* * {{Taxonbar, from=Q1932313 †Formiciinae Eocene insects Fossil ant taxa Eocene first appearances Eocene extinctions