''Formicodiplogaster'' is an

extinct Extinction is the termination of an organism by the death of its Endling, last member. A taxon may become Functional extinction, functionally extinct before the death of its last member if it loses the capacity to Reproduction, reproduce and ...

form genus Form classification is the classification of organisms based on their morphology, which does not necessarily reflect their biological relationships. Form classification, generally restricted to palaeontology, reflects uncertainty; the goal of sc ...

nematode The nematodes ( or ; ; ), roundworms or eelworms constitute the phylum Nematoda. Species in the phylum inhabit a broad range of environments. Most species are free-living, feeding on microorganisms, but many are parasitic. Parasitic worms (h ...

s in the family

Diplogasteridae Diplogastridae, formerly Diplogasteridae, are a family of nematodes (roundworms) known from a wide range of habitats, often in commensal or parasitic associations with insects. Description Diplogastrid nematodes are characterized by a distinc ...

which currently includes a

single Single may refer to: Arts, entertainment, and media * Single (music), a song release Songs * "Single" (Natasha Bedingfield song), 2004 * "Single" (New Kids on the Block and Ne-Yo song), 2008 * "Single" (William Wei song), 2016 * "Single", by ...

described species ''Formicodiplogaster myrmenema''. The species is known from

early Miocene The Early Miocene (also known as Lower Miocene) is a sub-epoch of the Miocene epoch (geology), Epoch made up of two faunal stage, stages: the Aquitanian age, Aquitanian and Burdigalian stages. The sub-epoch lasted from 23.03 ± 0.05 annum, Ma to ...

fossils found on

Hispaniola Hispaniola (, also ) is an island between Geography of Cuba, Cuba and Geography of Puerto Rico, Puerto Rico in the Greater Antilles of the Caribbean. Hispaniola is the most populous island in the West Indies, and the second-largest by List of C ...

. ''F. myrmenema'' has been preserved in association with '' Azteca alpha'', one of only two known fossil species in the ant genus '' Azteca''.

History and classification

When described ''Formicodiplogaster myrmenema'' was described from approximately seven fossil nematodes which were group inclusions with ants in transparent chunks of

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 in ...

. The amber was produced by the extinct '' Hymenaea protera'', which formerly grew on

, across northern South America and up to southern Mexico. The specimens were collected from a number of 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 is a country located on the island of Hispaniola in the Greater Antilles of the Caribbean Sea in the Atlantic Ocean, North Atlantic Ocean. It shares a Maritime boundary, maritime border with Puerto Rico to the east and ...

. 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 unicellular organism, single-celled organisms, members of a phylum or class (biology), class of Rhizarian protists characterized by streaming granular Ectoplasm (cell bio ...

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 the youngest that it might be. At the time of description, the

holotype A holotype (Latin: ''holotypus'') is a single physical example (or illustration) of an organism used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of s ...

dauer stage larva, in addition to the

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 (biology), isotype ...

larvae, adults and juveniles, were preserved in the Poinar amber collection at

Oregon State University Oregon State University (OSU) is a Public university, public Land-grant university, land-grant research university in Corvallis, Oregon, United States. OSU offers more than 200 undergraduate degree programs and a variety of graduate and doctor ...

. The fossils were first studied by paleontologist

George Poinar Jr. George O. Poinar Jr. (born April 25, 1936) is an American entomologist and writer. He is known for popularizing the idea of extracting DNA from insects fossilized in amber, an idea which received widespread attention when adapted by Michael Crich ...

of Oregon State University, with his 2011

type description A species description is a formal scientific description of a newly encountered species, typically articulated through a scientific publication. Its purpose is to provide a clear description of a new species of organism and explain how it differ ...

of the new genus and species being published in the journal ''Nematology monographs and perspectives pages''. The

generic epithet Genus (; : genera ) is a taxonomic rank above species and below family as used in the biological classification of living and fossil organisms as well as viruses. In binomial nomenclature, the genus name forms the first part of the binomial spec ...

''Formicodiplogaster'' is derived from the

Latin Latin ( or ) is a classical language belonging to the Italic languages, Italic branch of the Indo-European languages. Latin was originally spoken by the Latins (Italic tribe), Latins in Latium (now known as Lazio), the lower Tiber area aroun ...

''formica'', meaning "ant", and the nematode genus ''

Diplogaster ''Diplogaster'' is a genus of nematodes belonging to the family Diplogastridae Diplogastridae, formerly Diplogasteridae, are a family of nematodes (roundworms) known from a wide range of habitats, often in commensal or parasitic associations w ...

'', while the specific epithet is a derivation of the

Greek Greek may refer to: Anything of, from, or related to Greece, a country in Southern Europe: *Greeks, an ethnic group *Greek language, a branch of the Indo-European language family **Proto-Greek language, the assumed last common ancestor of all kno ...

''myrmex'', meaning ant, and ''nema'', meaning "thread". Portions of ant nests have been fossilized and identified and show an association of the extinct ant '' Azteca alpha'' colonies and ''Formicodiplogaster myrmenema''. The nests show active ant colonies in which adult and juvenile ''F myrmenema'' are present. Examples of

phoretic Phoresis or phoresy is a temporary Commensalism, commensalistic relationship when an organism (a phoront or phoretic) attaches itself to a host organism solely for travel. It has been seen in tick, ticks and mite, mites since the 18th century, ...

''F myrmenema'' are preserved as individuals in a dauer stage that was possibly carried in the abdominal intersegment membranes. The transition and transport of the dauer stage ''F myrmenema'' may have been a result of deteriorating conditions in the host colony. No direct evidence has been found for ''F. myrmenema'' living in the postpharyngeal glands or head glands of ''A. alpha''.

Description

Adult ''F myrmenema'' are long with rounded heads and tails that come to a point and the lips of the mouth are not offset. Similarly the dauer stage juveniles are the same general shape, with rounded heads and tapered tails, ranging from long.

References

{{Taxonbar, from=Q18355887 †Formicodiplogaster Monotypic prehistoric nematode genera Miocene animals of North America Burdigalian life Neogene Dominican Republic Fauna of Hispaniola Fossils of the Dominican Republic Dominican amber Fossil taxa described in 2011