Nothomyrmecia

Nothomyrmecia
N. macrops workers
Conservation status
Critically Endangered  (IUCN 2.3)[1]
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Arthropoda
Class:	Insecta
Order:	Hymenoptera
Family:	Formicidae
Subfamily:	Myrmeciinae
Genus:	Nothomyrmecia Clark, 1934
Species:	N. macrops
Binomial name
Nothomyrmecia macrops Clark, 1934

Nothomyrmecia, also known as the dinosaur ant or dawn ant, is an extremely rare genus of ants consisting of a single species, Nothomyrmecia macrops. These ants live in South Australia, nesting in old-growth mallee woodland and Eucalyptus woodland. The full distribution of Nothomyrmecia has never been assessed, and it is unknown how widespread the species truly is; its potential range may be wider if it does favour old-growth mallee woodland. Possible threats to its survival include habitat destruction and climate change. Nothomyrmecia is most active when it is cold because workers encounter fewer competitors and predators such as Camponotus and Iridomyrmex, and it also increases hunting success. Thus, the increase of temperature may prevent them from foraging and very few areas would be suitable for the ant to live in. As a result, the IUCN lists the ant as Critically Endangered.

As a medium-sized ant, Nothomyrmecia measures 9.7–11 mm (0.38–0.43 in). Workers are monomorphic, showing little morphological differentiation among one another. Mature colonies are very small, with only 50 to 100 individuals in each nest. Workers are strictly nocturnal and are solitary foragers, collecting arthropod prey and sweet substances such as honeydew from scale insects and other Hemiptera. They rely on their vision to navigate and there is no evidence to suggest that the species use chemicals to communicate when foraging, but they do use chemical alarm signals. A queen ant will mate with one or more males and, during colony foundation, she will hunt for food until the brood have fully developed. Queens are univoltine (they produce just one generation of ants each year). Two queens may establish a colony together, but only one will remain once the first generation of workers has been reared.

Nothomyrmecia was first described by Australian entomologist John S. Clark in 1934 from two specimens of worker ants. These were reportedly collected in 1931 near the Russell Range, inland from Israelite Bay in Western Australia. After its initial discovery, the ant was not seen again for four decades until a group of entomologists rediscovered it in 1977, 1,300 km (810 mi) away from the original reported site. Dubbed as the 'Holy Grail' of myrmecology, the ant was subject to great scientific interest after its rediscovery, attracting scientists from around the world.^[2][3] In Poochera (the rediscovery site), pictures of the ant are stencilled on the streets, and it is perhaps the only town in the world that thrives off ant-based tourism. Some entomologists have suggested a relationship to the Baltic Eocene fossil ant genus Prionomyrmex based on morphological similarities, but this interpretation is not widely accepted by the entomological community. Owing to its body structure, Nothomyrmecia is regarded to be the most plesiomorphic ant alive and a 'living fossil', stimulating studies on its morphology, behaviour, ecology, and chromosomes.^[2]