Nothomyrmecia

Nothomyrmecia
Conservation status
Critically Endangered  (IUCN 2.3) [1]
Scientific classification
Kingdom:	Animalia
Phylum:	Arthropoda
Class:	Insecta
Order:	Hymenoptera
Family:	Formicidae
Subfamily:	Myrmeciinae
Tribe:	Prionomyrmecini
Genus:	Nothomyrmecia
Species:	N. macrops
Binomial name
Nothomyrmecia macrops Clark, 1951

Nothomyrmecia macrops, sometimes called the dinosaur ant or dawn ant,^[2] is the only extant species of its genus. Its morphological similarity with the Baltic Eocene fossil ant genus Prionomyrmex has resulted in the species often being considered a living fossil and stimulated several studies on its morphology, behavior, ecology, and chromosomes.

Habitat

It is found in the cool regions of the mallee of southern South Australia and Western Australia in old-growth areas populated with various Eucalyptus species.^[3] These ants were of special interest to entomologists since their similarity with the Eocene Baltic fossil Prionomyrmex was thought to offer a chance to observe and study "primitive" ant social organization. However, N. macrops is known to possess some behavioural habits of more advanced ant species, and morphological^[4] and molecular^[5] phylogenies of the ants indicate that other ant lineages such as Ponerinae are more properly considered "primitive" within the family.

Discovery

Nothomyrmecia was originally discovered in 1931 near Balladonia in Western Australia. At the time it was thought to be living proof that ants had evolved from wasps. However the amateur naturalists who discovered the species had failed to record collection sites, so no other specimens could be found in the area. In 1977 a solitary worker ant from the species was found by Dr. Bob Taylor and his party of entomologists from Canberra at Poochera, 1300 km (800 mi) from the site of the 1931 discovery. A further colony was found at Penong, 180 km (110 mi) to the west of Poochera, but the fate of the colony discovered in 1931 is not known.^[6]

Relationships

Nothomyrmecia was described in 1934 by Clark ^[7] as a new genus of Myrmeciinae, though with some hesitation due to its apparent similarity with the Eocene Baltic amber fossil Prionomyrmex unknown to him and of which remained only literature descriptions and figures. In 1951 Clark ^[8] proposed a new ant subfamily for his Nothomyrmecia, based on morphological differences with the other Myrmeciinae. Clark’s placement of Nothomyrmecia in isolated position within the ants was confirmed by Taylor’s rediscovery of this species in 1977 ^[9] and was universally accepted by the scientific community until 2003. In 1998, Baroni Urbani described a new Baltic fossil Prionomyrmex species. After examining specimens of N. macrops, Baroni Urbani stated that his new species and N. macrops belonged to the same genus, in which case the name Prionomyrmex would replace the name Nothomyrmecia and the subfamily Nothomyrmeciinae must be called Prionomyrmeciinae.^[10] Dlussky & Perfilieva in 2003 ^[11] separated again Nothomyrmecia from Prionomyrmex on the base of the fusion of an abdominal segment. In the same year Ward & Brady,^[12] using a different, broader set of characters, reached the same conclusion as Dlussky and Perfileeva ^[11] and, in addition, transferred both Nothomyrmecia and Prionomyrmex as distinct genera in the older subfamily Myrmeciinae. Later on, Dlussky ^[13] also refers only to Ward & Brady’s classification.^[12] However, Baroni Urbani (2005, 2008),^[14][15] suggested additional evidence in favor of his former interpretation and pretended the fallacy of Ward and Brady’s^[12] arguments. His views are not addressed in relevant papers, which continue to favor the classification of Ward and Brady.^[5][16][17]

References

External links

• Media related to Nothomyrmecia macrops at Wikimedia Commons