page_title: Nothomyrmecia
section_title: Description
hierarchical_section_title: Nothomyrmecia / Description
caption_attribution_description: English: Stinger of N. macrops
context_page_description: Nothomyrmecia, also known as the dinosaur ant or dawn ant, is a 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. Workers are monomorphic, showing little morphological differentiation among one another. Mature colonies are very small, with only 50 to 100 individuals in each nest.
context_section_description: Nothomyrmecia is a medium-sized ant measuring 9.7–11 mm (0.38–0.43 in) in length. Workers are monomorphic, meaning that there is little morphological differentiation among one another. The mandibles, clypeus (one of the sclerites that make up the "face" of an arthropod or insect), antennae and legs are pale yellow. The hairs on the body are yellow, erect and long and abundant, but on the antennae and legs they are shorter and suberect (standing almost in an erect position). It shows similar characteristics to Myrmecia, and somewhat resembles Oecophylla, commonly known as weaver ants. Workers are strictly nocturnal (active mainly at night) but navigate by vision, relying on large compound eyes. The mandibles are shorter than the head. They have 10 to 15 intermeshing teeth and are less specialised than those of Myrmecia and Prionomyrmex, being elongate and triangular. The head is longer than it is wide and broader towards the back. The sides of the head are convex around the eyes. The long antennal scapes (the base of the antenna) extend beyond the occipital border, and the second segment of the funiculus (a series of segments between the base and club) is slightly longer than the first, third and fourth segment. The node, pronotum, epinotum and thorax are longer than broad, and the mesonotum is just as long as it is wide. The first segment of the gaster (the bulbous posterior portion of the metasoma) is broader than long by a third and broader at the back than the front with strongly convex sides.
  A long and retractable stinger is present at the rear of the abdomen. It has been described as "prominent and effective" and is capable of inflicting a painful sting to humans. A 'sting bulb gland' is also present in Nothomyrmecia; this is a small exocrine gland of unknown function, first discovered and named in 1990. It is situated in the basal part of the insect's sting, and is located between the two ducts of the venom gland and the Dufour's gland. Despite its many plesiomorphic features, the sting apparatus of Nothomyrmecia is considered less primitive than those found in other ants such as Stigmatomma pallipes. It is the only known species of ant that contains both a sting and a 'waist' (i.e. it has no postpetiole between the first and second gastral segments).
  Queens look similar to workers, but several morphological features distinguish the two castes from each other. The queen's body is usually larger. Ocelli are highly developed, but the eyes on the queen are not enlarged. The structure of the pterothorax (the wing-bearing area of the thorax) is consistent with other reproductive ants, but it does not occupy as much of its mesosomal bulk. The wings of the queens are rudimentary and stubby, barely overlapping the first gastral segment, and are brachypterous (non-functional). Males resemble those of Myrmecia, but Nothomyrmecia males bear a single waist node. The wings on the male ant are not stubby like a queen's; rather they are long and fully developed, exhibiting a primitive venational complement. They have a jugal anal lobe (a portion of the hindwing), a feature found in many primitive ants, and basal hamuli (hook-like projections that link the forewings and hindwings). Most male specimens collected have two tibial spurs (spines located on the distal end of the tibia); the first spur is a long calcar and the second spur is short and thick. Adults have a stridulatory organ on the ventral side of the abdomen – unlike all other hymenopterans in which such organs are located dorsally.
  In all castes, these ants have six maxillary palps (palps that serve as organs of touch and taste in feeding) and four labial palps (sensory structures on the labium), a highly primitive feature. The females have a 12-segmented antenna, whereas males have 13 segments. Other features include paired calcariae found on both the hind and middle tibiae, and the claws have a median tooth. The unspecialised nature of the cuticle (outer exoskeleton of the body) is similar to Pseudomyrmex, a member of the subfamily Pseudomyrmecinae. Many of the featu
caption: Stinger of N. macrops
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