Sri Lankan relict ant
Encyclopedia
The Sri Lankan relict ant (Aneuretus simoni) is a species
of evolutionarily ancient ant
that is placed in a separate tribe
of its own within the Formicidae family. The genus is monotypic
, with the only species endemic to Sri Lanka
where it is known from just a few locations. It is one of the few ant species that are considered endangered.
The species is the only extant genus in the tribe Aneuretini (other members include the extinct Protaneuretus, Paraneretus and Mianeuretus). They are believed to be intermediate in their phylogenetic position between the Myrmeciinae
-Ponerinae
and the Dolichoderinae
. 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
and have a small compound eye 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. There are outward facing spines 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 coloured 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 and there are at the most two per colony. The social organization of the colony was found to be similar to that of the Dolichoderinae.
They are known from only a few areas in central Sri Lanka. In Gilimale forest, E O Wilson and other researchers found that the colonies were 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 logs fallen on the ground. 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 E O Wilson. A study in 1985 recorded the species at just one location, Gilimale.
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...
of evolutionarily ancient ant
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...
that is placed in a separate tribe
Tribe (biology)
In biology, a tribe is a taxonomic rank between family and genus. It is sometimes subdivided into subtribes.Some examples include the tribes: Canini, Acalypheae, Hominini, Bombini, and Antidesmeae.-See also:* Biological classification* Rank...
of its own within the Formicidae family. The genus is monotypic
Monotypic
In biology, a monotypic taxon is a taxonomic group with only one biological type. The term's usage differs slightly between botany and zoology. The term monotypic has a separate use in conservation biology, monotypic habitat, regarding species habitat conversion eliminating biodiversity and...
, with the only species endemic to Sri Lanka
Sri Lanka
Sri Lanka, officially the Democratic Socialist Republic of Sri Lanka is a country off the southern coast of the Indian subcontinent. Known until 1972 as Ceylon , Sri Lanka is an island surrounded by the Indian Ocean, the Gulf of Mannar and the Palk Strait, and lies in the vicinity of India and the...
where it is known from just a few locations. It is one of the few ant species that are considered endangered.
The species is the only extant genus in the tribe Aneuretini (other members include the extinct Protaneuretus, Paraneretus and Mianeuretus). They are believed to be intermediate in their phylogenetic position between the Myrmeciinae
Myrmeciinae
The Myrmeciinae is a subfamily of the Formicidae that was once found worldwide but is 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 and reproduce, thus sustaining the colony after...
-Ponerinae
Ponerinae
Ponerinae is a subfamily of ants in the Poneromorph subfamilies group, with about 1,600 species in 28 extant genera, including Dinoponera gigantea - one of the world's largest species of ant....
and the Dolichoderinae
Dolichoderinae
Dolichoderinae is a subfamily of ants, which includes species such as the Argentine ant , the erratic ant, the odorous house ant, and the cone ant. This subfamily is distinguished by having a single petiole and a slit-like orifice, rather than the round acidopore encircled by hairs that typifies...
. 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
Nest
A nest is a place of refuge to hold an animal's eggs or provide a place to live or raise offspring. They are usually made of some organic material such as twigs, grass, and leaves; or may simply be a depression in the ground, or a hole in a tree, rock or building...
and have a small compound eye having only about 30 ommatidia
Ommatidium
The compound eyes of insects, mantis shrimp and millipedes are composed of units called ommatidia . An ommatidium contains a cluster of photoreceptor cells surrounded by support cells and pigment cells. The outer part of the ommatidium is overlaid with a transparent cornea...
(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
Clypeus
The clypeus is one of the sclerites that makes up the "face" of an arthropod.In insects, the clypeus delimits the lower margin of the face, with the labrum articulated along the ventral margin of the clypeus. The mandibles bracket the labrum, but do not touch the clypeus. The dorsal margin of the...
is broad and flat, lacking any central ridge. The mouthparts show Dolichoderine affinities. There are outward facing spines on the propodeum
Propodeum
The propodeum is the first abdominal segment in Apocrita Hymenoptera . It is fused with the thorax to form the mesosoma. It is a single large sclerite, not subdivided, and bears a pair of spiracles. It is strongly constricted posteriorly to form the articulation of the petiole, and gives apocritans...
. 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 coloured 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 and there are at the most two per colony. The social organization of the colony was found to be similar to that of the Dolichoderinae.
They are known from only a few areas in central Sri Lanka. In Gilimale forest, E O Wilson and other researchers found that the colonies were 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 logs fallen on the ground. 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 E O Wilson. A study in 1985 recorded the species at just one location, Gilimale.