Ankylomyrma coronacantha

Ankylomyrma coronacantha

Ankylomyrma coronacantha workers measure about 4.6mm and look like tiny armored tanks covered in spines ^[1]. They live in the rainforest canopies of West Africa, including Ghana, Cameroon, Gabon, and the Central African Republic ^[1][2].

These ants defend themselves by curling into a ball. Their abdomen (gaster) consists almost entirely of a massively enlarged first segment that forms a sphere, allowing them to roll up and protect their vulnerable parts ^[3]. A crown of spines on the head gives them their name 'coronacantha' meaning 'crown-thorn' ^[3]. Scientists have only ever found workers, no queens have been collected despite decades of searching ^[1][2].

Quick Summary

• Difficulty: Expert (currently impossible to establish)
• Origin & Habitat: West African primary rainforest (Ghana, Cameroon, Gabon, Central African Republic) ^[1][2]
• Colony Type: Unknown, only the worker caste has ever been documented ^[1]
• Size & Growth:
  • Queen: Unknown, no queens have ever been collected ^[1]
  • Worker: 4.6 mm ^[1]
  • Colony: Unknown ^[1]
  • Growth: Unknown
  • Development: Unknown (No developmental data exists for this species.)
• Antkeeping:
  • Temperature: Unknown, based on their West African rainforest habitat, they likely need warm stable temperatures roughly in the mid-20s°C, but this is unconfirmed ^[1]
  • Humidity: Unknown, likely requires high humidity and damp conditions consistent with rainforest canopy habitats ^[1]
  • Diapause: No, this is a tropical species ^[1]
  • Nesting: Arboreal, likely nests in vegetation or tree cavities, but the specific nesting site remains unknown ^[1][3]
• Behavior: Workers curl into a defensive ball when threatened ^[3]. They are arboreal, living in rainforest canopies ^[2]. Escape risk is unknown, but workers are small enough to require secure barriers ^[1].
• Common Issues: no queens have ever been collected, making colony founding impossible., extreme rarity means specimens are unavailable to hobbyists and exist only in scientific collections., dietary requirements are completely unknown., arboreal nesting habits are poorly understood, making captive housing speculative.

The Mystery of the Missing Queens

Scientists have never collected a queen of Ankylomyrma coronacantha. Every specimen in museum collections is a worker ^[1][2]. This means we know nothing about how colonies reproduce or how they start. The species might have normal queens that are simply extremely rare or cryptic (well-hidden). Alternatively, they might reproduce through gamergates, workers that can lay eggs and take over queen duties, though this has never been observed ^[1]. Without a queen or established colony, you cannot start a captive colony. This makes the species effectively impossible to keep using current antkeeping methods.

Morphology and Ball-Rolling Defense

These ants possess one of the most unusual body plans in the ant world. The gaster (the rear body section) consists almost entirely of an enormously enlarged first segment that forms a subspherical ball ^[3]. The remaining abdominal segments telescope inside this ball, and the first sternite (the underside plate) is reduced to just a narrow rim ^[3]. When threatened, the worker can curl up completely, presenting only spines and armor to any predator ^[3]. The head carries a crown of spines along the back margin (the occipital lamella), and the body bears spines on the pronotum, mesonotum, and propodeum ^[3]. They also possess a well-developed sting that points forward rather than backward ^[3].

Collection History and Habitat

The first specimen came from Mount Atewa in Ghana in 1969,collected by fogging a tree canopy with insecticide ^[1]. Since then, only a few additional workers have turned up from Cameroon, Gabon, and the Central African Republic, mostly through canopy fogging or vegetation beating ^[1][2]. All collections come from primary (undisturbed) rainforest ^[1]. This arboreal lifestyle means they live entirely in the trees, not on the forest floor ^[3][2]. The specific nest site, whether they build in twig forks, under bark, or within plant cavities, remains unknown ^[1].

Phylogenetic Context

Ankylomyrma coronacantha belongs to the subfamily Agroecomyrmecinae, one of the rarest ant subfamilies ^[4]. It is the only living species in its genus and is sister to Tatuidris (the armadillo ants of Central and South America) ^[4][5]. Together, these two genera represent a relict lineage that split from other ants approximately 45 million years ago ^[6]. This ancient lineage explains their unusual morphology and potentially cryptic biology.

Frequently Asked Questions

References