Formiciinae
Encyclopedia
Formiciinae is an extinct subfamily of ant
s known from Eocene
deposits in Europe
and North America
.
is Formicium
with the genus Titanomyrma
being described in 2011. Formicium includes the described species
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 of Bournemouth
, Dorset, England. The third species named, Formicium berryi was named by Frank M. Carpenter
in 1929 from the middle Eocene Claiborne Formation in Puryear, Tennessee
, USA, though he misidentified the formation as the Wilcox Formation. 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.
wet climate and had and average mean annual temperature of 20 °C (68 °F) or greater. This is similar to the restricted ranges found in 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 though to have been lower than the range needed for Formiciinae species, a series of hyperthemal events throughout the Eocene are suggested as aides in the crossing.
Ant
Ants are social insects of the family Formicidae and, along with the related wasps and bees, belong to the order Hymenoptera. Ants evolved from wasp-like ancestors in the mid-Cretaceous period between 110 and 130 million years ago and diversified after the rise of flowering plants. More than...
s known from Eocene
Eocene
The Eocene Epoch, lasting from about 56 to 34 million years ago , is a major division of the geologic timescale and the second epoch of the Paleogene Period in the Cenozoic Era. The Eocene spans the time from the end of the Palaeocene Epoch to the beginning of the Oligocene Epoch. The start of the...
deposits in Europe
Europe
Europe is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally 'divided' from Asia to its east by the watershed divides of the Ural and Caucasus Mountains, the Ural River, the Caspian and Black Seas, and the waterways connecting...
and North America
North America
North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...
.
Genera
The type genusGenus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
is Formicium
Formicium
Formicium is an extinct collective genus of giant ants in the Formicidae subfamily Formiciinae. The genus currently contains three species, Formicium berryi, Formicium brodiei, and Formicium mirabile...
with the genus Titanomyrma
Titanomyrma
Titanomyrma was a genus of giant ant. The latest species to be discovered, T. lubei, was described in 2011, when a fossilized winged queen ant, comparable in size to hummingbirds, was found in Wyoming. This fossil is the first body of a giant ant found in the Western Hemisphere...
being described in 2011. Formicium includes the described species
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
which are known from fossil wings only. Formicium is known from three species. Formicium mirabile, named by Theodore D. A. Cockerell
Theodore Dru Alison Cockerell
Theodore Dru Alison Cockerell was an American zoologist, born at Norwood, England, and brother of Sydney Cockerell. He was educated at the Middlesex Hospital Medical School, and then studied botany in the field in Colorado in 1887-90...
in 1920, and Formicium brodiei, named by John O. Westwood
John Obadiah Westwood
John Obadiah Westwood was an English entomologist and archaeologist also noted for his artistic talents.Born in Sheffield, he studied to be a lawyer but abandoned that for his scientific interests....
in 1854, are both known from fore wings found in the middle Eocene of Bournemouth
Bournemouth
Bournemouth is a large coastal resort town in the ceremonial county of Dorset, England. According to the 2001 Census the town has a population of 163,444, making it the largest settlement in Dorset. It is also the largest settlement between Southampton and Plymouth...
, Dorset, England. The third species named, Formicium berryi was named by Frank M. Carpenter
Frank M. Carpenter
Frank M. Carpenter received his PhD from Harvard University, and was curator of fossil insects at the Harvard Museum of Comparative Zoology for 60 years. He studied the Permian fossil insects of Elmo, Kansas, and compared the North American fossil insect fauna with Paleozoic taxa known from...
in 1929 from the middle Eocene Claiborne Formation in Puryear, Tennessee
Puryear, Tennessee
Puryear is a city in Henry County, Tennessee, United States. The population was 667 at the 2000 census.-Geography:Puryear is located at .According to the United States Census Bureau, the city has a total area of , all of it land....
, USA, though he misidentified the formation as the Wilcox Formation. 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 52 millimetres (2 in) as the smallest species of Titanomyrma, T. lubei. Formiciinae members were restricted in habitat to living in regions which had a mesicMesic
Mesic may refer to:* Mesic, North Carolina, a town in the United States* Mesic habitat, a type of habitat...
wet climate and had and average mean annual temperature of 20 °C (68 °F) or greater. This is similar to the restricted ranges found in 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 though to have been lower than the range needed for Formiciinae species, a series of hyperthemal events throughout the Eocene are suggested as aides in the crossing.