Monomorium oodnadatta

Monomorium oodnadatta

Monomorium oodnadatta is a medium-sized ant species described in 2015,belonging to the Monomorium rothsteini species group. Workers measure 0.82-0.92mm in head width and 0.88-0.96mm in head length, making them a fairly small ant species ^[1]. They have a distinctive appearance with a dark brown body featuring a reddish-orange tinge, a glossy appearance, and a narrow petiole node. The species is named after its type locality, the Oodnadatta Track in northern South Australia, where it was collected from stony plains ^[1].

This is one of the newer additions to the ant-keeping hobby, having only been formally described in 2015. Very little is known about their biology in the wild, as they are known from only two localities in the stony plains region of northern South Australia ^[1]. As a member of the Solenopsidini tribe (which includes fire ants and other venomous species), they belong to the Myrmicinae subfamily.

Quick Summary

• Difficulty: Unknown
• Origin & Habitat: Endemic to the stony plains region of northern South Australia, Australia. Found only at two localities along the Oodnadatta Track, approximately 110-160km east of Marla ^[1]. This is an arid to semi-arid region with stony terrain.
• Colony Type: Colony structure is unconfirmed. Based on typical Monomorium patterns, likely single-queen (monogyne) colonies, but this has not been directly studied.
• Size & Growth:
  • Queen: Undescribed, queen measurements not available in scientific literature ^[1]. Estimated based on genus patterns at 5-7mm.
  • Worker: 0.82-0.92mm HW,0.88-0.96mm HL ^[1]. This is a small ant species.
  • Colony: Unknown, no colony size data available. Likely similar to related Monomorium species at 100-500 workers.
  • Growth: Unknown, no development data available. Estimated as moderate based on genus patterns.
  • Development: Unconfirmed, no direct development data exists. Based on similar Monomorium species, estimate 6-10 weeks at optimal temperature. (Development timeline is unconfirmed for this species. Estimates based on related species in the genus.)
• Antkeeping:
  • Temperature: Keep at room temperature, roughly 20-26°C. No specific thermal requirements documented. Australian desert species typically tolerate warmer conditions.
  • Humidity: Low to moderate humidity, arid region species. Allow substrate to dry between waterings. Provide a shallow water source for drinking.
  • Diapause: Unknown, no studies on overwintering requirements. The stony plains region experiences cool winters but not extreme cold. A cool period around 10-15°C during winter months may be beneficial.
  • Nesting: Natural nesting is unconfirmed. Based on habitat (stony plains), likely nests under stones or in shallow soil chambers. In captivity, a small test tube setup or acrylic nest with tight chambers works well for their small size.
• Behavior: Behavior is unstudied. Based on genus patterns, they are likely active foragers that search for small prey and sugary liquids. Their small size means escape prevention is important, they can squeeze through small gaps. Exercise caution, as Solenopsidini ants can deliver a painful sting.
• Common Issues: very limited scientific data means care requirements are largely inferred from genus patterns, escape prevention is critical due to their tiny size, use fine mesh and tight-fitting lids, no established feeding data exists, start with small live prey and sugar water, observe acceptance, no documented colony development timeline makes growth tracking difficult, wild-caught colonies may be difficult to locate as the species has a very restricted range

Species Discovery and Taxonomy

Monomorium oodnadatta was formally described in 2015 by Kathryn Sparks as part of her doctoral research on Australian Monomorium species ^[1]. The species is named after its type locality, the Oodnadatta Track (often spelled Oonadatta in the original description), which is a famous outback road in northern South Australia. It belongs to the Monomorium rothsteini species complex, a group of closely related ants that have historically caused taxonomic confusion due to their similar appearance ^[1].

The species was collected in June 2009 during fieldwork in the stony plains region. Only two populations are known, both along the Oodnadatta Track. This makes it one of the most restricted ant species in terms of known distribution ^[1]. The holotype and paratypes are housed in the South Australian Museum.

Identification and Appearance

Workers of Monomorium oodnadatta are medium-sized for the genus, measuring 0.82-0.92mm in head width. They have a distinctive dark brown coloration with a reddish-orange tinge, particularly on the head and mesosoma (the middle body section). The gaster (the rear body segment) is dark brown and completely smooth without any sculpture ^[1].

Key identification features include a narrow petiole node (2-2.5 times the eye width when viewed from above), a concave clypeus (the face shield above the mouth), and a small median projection on the anteroventral clypeal margin. The eyes are medium-sized with 13 ommatidia in the longest vertical axis. The overall appearance is glossy due to limited sculpture on most body parts ^[1].

Habitat and Distribution

This species is known only from the stony plains region of northern South Australia, specifically from two localities along the Oodnadatta Track, one approximately 110km east of Marla and another 160km east of Marla. The Oodnadatta Track passes through an arid to semi-arid landscape characterized by stony terrain, sparse vegetation, and extreme temperature variations ^[1].

The range overlaps with another species in the complex, Monomorium subapterum. This region experiences very hot summers and mild to cool winters. Rainfall is low and sporadic. The ants likely survive by nesting in protected microhabitats under stones or in shaded locations that buffer against temperature extremes.

Housing and Care

Since this is a newly described and rarely kept species, care recommendations are based on what we know about related Monomorium species and the species' natural habitat. Keep them in a small nest setup, a test tube or small acrylic formicarium works well given their tiny size. Use a tight-fitting lid and fine mesh on any ventilation holes to prevent escapes.

For substrate, use a dry to moderately moist mixture. Allow the nest area to dry partially between waterings. Room temperature (20-26°C) should be suitable. Provide a shallow water dish for drinking and offer small live prey like fruit flies or pinhead crickets. Sugar water or honey can be offered occasionally, but monitor acceptance.

Because so little is known about this species in captivity, observation of colony behavior is valuable. Watch for preferred temperatures, humidity levels, and food preferences, then adjust care accordingly.

Caution and Safety

Monomorium belongs to the tribe Solenopsidini, which includes fire ants (Solenopsis) and other species known for their painful stings. While M. oodnadatta has not been specifically studied for venom, exercise caution when handling them. They should be kept in secure enclosures with excellent escape prevention.

Do not handle these ants without proper protection, especially when the colony grows larger. If you need to move or inspect the colony, do so carefully and consider using tools rather than your hands. The small size of workers means they can easily escape through tiny gaps that would not concern larger ant species.

Frequently Asked Questions

References