The Sri Lankan relict ant (''Aneuretus simoni'') is a

species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...

ant Ants are Eusociality, eusocial insects of the Family (biology), family Formicidae and, along with the related wasps and bees, belong to the Taxonomy (biology), order Hymenoptera. Ants evolved from Vespoidea, vespoid wasp ancestors in the Cre ...

placed in a

tribe The term tribe is used in many different contexts to refer to a category of human social group. The predominant worldwide use of the term in English is in the discipline of anthropology. The definition is contested, in part due to conflict ...

of its own within the family Formicidae. The genus is

monotypic In biology, a monotypic taxon is a taxonomic group (taxon) that contains only one immediately subordinate taxon. A monotypic species is one that does not include subspecies or smaller, infraspecific taxa. In the case of genera, the term "unisp ...

, with the only species

endemic Endemism is the state of a species being found only in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also foun ...

Sri Lanka Sri Lanka, officially the Democratic Socialist Republic of Sri Lanka, also known historically as Ceylon, is an island country in South Asia. It lies in the Indian Ocean, southwest of the Bay of Bengal, separated from the Indian subcontinent, ...

, where it is known from just a few locations. It is one of the few ant species considered endangered.

Description

The species is the only

extant Extant or Least-concern species, least concern is the opposite of the word extinct. It may refer to: * Extant hereditary titles * Extant literature, surviving literature, such as ''Beowulf'', the oldest extant manuscript written in English * Exta ...

genus in the tribe Aneuretini (other members include the

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 ...

''Protaneuretus'', ''Paraneretus'', and ''Mianeuretus''). They are believed to be intermediate in their

phylogenetic In biology, phylogenetics () is the study of the evolutionary history of life using observable characteristics of organisms (or genes), which is known as phylogenetic inference. It infers the relationship among organisms based on empirical dat ...

position between the

Myrmeciinae Myrmeciinae is a subfamily of the Formicidae, ants once found worldwide but now restricted to Australia and New Caledonia. This subfamily is one of several ant subfamilies which possess gamergates, female worker ants which are able to mate an ...

Ponerinae Ponerinae, the ponerine ants, 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 replac ...

and the

Dolichoderinae Dolichoderinae is a subfamily of ants, which includes species such as the Argentine ant (''Linepithema humile''), the erratic ant, the odorous house ant, and the cone ant. The subfamily presents a great diversity of species throughout the wor ...

. The workers show very distinct dimorphism with "majors" being much larger than the "minors" and lacking few workers intermediate in size. The minor workers are found in the largest numbers within a

nest A nest is a structure built for certain animals to hold Egg (biology), eggs or young. Although nests are most closely associated with birds, members of all classes of vertebrates and some invertebrates construct nests. They may be composed of ...

and have small compound eyes having only about 30 ommatidia (units within the compound eye). The antennae have 12 segments, with the segments increasing gradually in size from the base to the tip. The clypeus is broad and flat, lacking any central ridge. The mouthparts show dolichoderine affinities. Outward-facing spines occur on the propodeum. The petiole node is separated from the anterior peduncle by swellings on the sides and tops. They have a well-developed sting that is similar in structure to that of the Dolichoderinae. Workers are yellow to orange in colour and the surface has striations running transversely. The queen is larger than the major and has reduced propodeal spines and a much broader head than the major worker. The pupae are characteristic in being enclosed in cocoons. They are predatory and forage mainly on the ground in leaf litter. Major workers are rare – at most two per colony. The social organization of the colony was found to be similar to that of the Dolichoderinae.

Distribution

They are known from only a few areas in central Sri Lanka. In Gilimale forest, E O Wilson and other researchers found colonies mainly at the edge of forest clearings. The nests are small and have only a small number of individuals, ranging from two to a hundred. The nests are most often made mainly within rotting and crumbly wood pieces or fallen logs. The few areas in which they live are often disturbed by humans. The species has not been recorded in many of the areas where it was formerly collected and it was recommended for conservation by Wilson. A study in 1985 recorded the species at just one location, Gilimale.

References

External links

* * {{Taxonbar, from=Q308872 Aneuretinae Monotypic ant genera Hymenoptera of Asia Endemic fauna of Sri Lanka Insects of Sri Lanka Critically endangered insects Insects described in 1893 Taxa named by Carlo Emery Taxonomy articles created by Polbot