# Atomic Dwarf Tarantula (Aphonopelma atomicum) **URL:** https://reptilecommunity.com/t/atomic-dwarf-tarantula-aphonopelma-atomicum/880 **Category:** Invertebrates **Created:** [October 11, 2026, 1:58pm UTC](https://reptilecommunity.com/t/atomic-dwarf-tarantula-aphonopelma-atomicum/880 "2026-10-11T13:58:33Z") **Posts on this page:** 2 **Page:** 1
### Author: ![ReptileCommunity](https://reptilecommunity.com/user_avatar/reptilecommunity.com/reptilecommunity/32/3_2.png) [@ReptileCommunity](https://reptilecommunity.com/u/ReptileCommunity) #### Post date: [October 11, 2026, 1:58pm UTC](https://reptilecommunity.com/t/atomic-dwarf-tarantula-aphonopelma-atomicum/880/1 "2026-10-11T13:58:34Z")
# Atomic Dwarf Tarantula (_Aphonopelma atomicum_) **Comprehensive Species Care Guide — The Vivarium Vault** ## Quick Facts | Category | Information | | --- | --- | | Scientific name | _Aphonopelma atomicum_ | | Scientific authority | Hamilton, 2016 | | Common name | Atomic Dwarf Tarantula (descriptive name) | | Family | Theraphosidae | | Species group | Paloma species group | | Native distribution | Southern Nevada and eastern California, USA | | Known region | Amargosa Desert, Amargosa Range and surrounding foothills | | Ecoregion | Mojave Basin and Range | | Recorded elevation | Approximately 850–1,220 m | | Adult size | Miniaturised; among the smallest US tarantulas | | Lifestyle | Terrestrial, burrowing | | Characteristic burrow | Entrance often surrounded by a soil-and-silk turret | | Likely breeding season | October–November | | Diet | Small terrestrial invertebrates | | Urticating hairs | Present | | Venom | Present | | Cohabitation | Solitary | | Experience level | Advanced | | Captive availability | Uncommon; verify provenance | | Principal care priorities | Secure housing, stable burrowing substrate, moisture gradient and appropriately sized prey | **Evidence distinction:** The taxonomy, recorded distribution, elevation, turreted burrows and probable mating season are documented in the original species description. Captive temperature ranges, enclosure dimensions, feeding schedules and longevity are not supported by controlled species-specific husbandry studies. * * * ## 1. Species Overview The Atomic Dwarf Tarantula (_Aphonopelma atomicum_) is a remarkably small terrestrial tarantula native to the Mojave Desert region of the south-western United States. It was formally described by Chris A. Hamilton in 2016 during a major revision of the North American genus _Aphonopelma_. The species is particularly interesting because of its small adult size, restricted documented distribution and distinctive burrow entrances. Unlike the much larger tarantulas commonly associated with desert habitats, _A. atomicum_ is a miniaturised species. Its name refers to the former Nevada Test Site, where specimens were collected, and the atomic-testing history of the region. The original description also notes the irony of the name, given that the species is among the smallest tarantulas known from the United States. Although it inhabits desert country, this does not mean that it should be exposed to intense heat or maintained on completely dry substrate. Its underground retreat provides a protected microhabitat that can differ substantially from exposed surface conditions. In captivity, the principal aim is to provide an appropriately scaled, escape-proof enclosure with sufficient substrate to permit burrowing, reliable access to water and a moderate thermal environment. Because very little species-specific captive husbandry information is available, this guide uses conservative recommendations and identifies important areas of uncertainty. ## 2. Taxonomy and Scientific Identification ### Classification - Kingdom: Animalia - Phylum: Arthropoda - Class: Arachnida - Order: Araneae - Infraorder: Mygalomorphae - Family: Theraphosidae - Genus: _Aphonopelma_ - Species: _Aphonopelma atomicum_ ### Original description _Aphonopelma atomicum_ was described by Hamilton in 2016. The description appeared in the comprehensive revision of United States _Aphonopelma_ by Hamilton, Hendrixson and Bond. ### Species group It belongs to the Paloma species group. ### Closely related species Molecular analyses place it close to several other small-bodied _Aphonopelma_, including: - _Aphonopelma mojave_ - _Aphonopelma icenoglei_ - _Aphonopelma prenticei_ - _Aphonopelma joshua_ ### Similarity to other species Small-bodied _Aphonopelma_ can be difficult to distinguish by appearance alone. ### Identification methods The original taxonomic treatment uses a combination of: - Morphological characteristics. - Molecular evidence. - Geographical distribution. - Comparison with related species. ### Colouration Colour should not be considered diagnostic by itself. ### Provenance Accurate provenance is important, particularly because the species may occur near other closely related tarantulas. ### Sex determination Sex determination can be attempted using suitable moults, but the small size makes examination difficult. ### Breeding precaution Do not breed individuals of uncertain identity or combine unrelated locality records without appropriate documentation. ## 3. Natural Distribution and Ecology ### Geographic distribution _Aphonopelma atomicum_ is known from a relatively small number of specimens collected around the Amargosa Desert. Its documented distribution includes: - Southern Nye County, Nevada. - South-eastern Inyo County, California. - The Amargosa Range. - The Nevada Test Site region. ### Ecoregion The species inhabits the Mojave Basin and Range ecoregion. ### Elevation Published specimen records occur between approximately 850 and 1,220 metres above sea level. ### Habitat characteristics The region contains arid valleys, rocky foothills, desert slopes and sparse vegetation. However, precise microhabitat preferences should not be assumed from regional climate alone. ### Natural burrows One of the most distinctive documented features is the burrow entrance. The original species description reports that entrances are commonly surrounded by a small turret formed from excavated soil and silk. This structure may help define and protect the entrance, although its precise function has not been experimentally established for this species. ### Importance of substrate This natural behaviour supports providing a substrate that can hold its shape. ### Associated species _A. atomicum_ may occur in the same general areas as the much larger _Aphonopelma iodius_. It may also occur near populations of _A. prenticei_. ### Seasonal reproductive activity The original description suggests that mating most likely occurs during daylight hours in October and November. This is a field-based interpretation rather than a validated captive breeding schedule. ### Environmental implications Captive housing should support burrowing and protected microclimates rather than simply copying exposed desert surface temperatures. ## 4. Adult Size, Growth and Lifespan ### Adult size _Aphonopelma atomicum_ is one of the smallest tarantulas documented in the United States. ### Measurements The original scientific treatment includes measurements of diagnostic specimens. Because adult dimensions vary, enclosure selection should be based on the individual spider rather than an unsupported universal leg-span figure. ### Growth rate Reliable species-specific captive growth data are unavailable. ### Female lifespan A verified maximum female lifespan has not been established. ### Male lifespan As with many tarantulas, mature males generally have shorter remaining lifespans than females. ### Growth monitoring Record: - Moulting dates. - Feeding responses. - Abdominal condition. - Behavioural changes. - Development of mature male structures. ### Avoid assumptions Do not apply lifespan or growth-rate figures from large _Aphonopelma_ species without evidence. * * * ## 5. Housing and Enclosure Requirements Housing should reflect the spider’s miniaturised size and documented burrowing behaviour. ### Adult enclosure dimensions For a small adult, a practical starting enclosure is: **6 × 6 × 8 inches (15 × 15 × 20 cm)** An alternative providing additional floor space is: **8 × 8 × 8 inches (20 × 20 × 20 cm)** These dimensions are practical recommendations rather than scientifically validated minimum requirements. ### Floor space Provide enough horizontal room for movement, retreat construction, feeding and access to water. ### Substrate depth A practical starting depth is: **4–5 inches (10–13 cm)** This allows meaningful excavation while maintaining a relatively low fall height above the substrate. ### Burrow construction Provide a small starter excavation beneath cork bark or another stable shelter. ### Soil-and-silk turrets If the spider constructs a turret around its entrance, leave it undisturbed. Do not remove it merely for cosmetic reasons. ### Enclosure security Very small tarantulas can escape through narrow gaps. Check: - Lid fittings. - Ventilation holes. - Door gaps. - Cable openings. - Sliding-door tracks. - Feeding access points. ### Ventilation Provide secure, suitably fine ventilation openings. ### Fall prevention Keep the unobstructed height above the substrate low. ### Enclosure materials Suitable plastic, acrylic or glass containers may be used. ### Furnishing stability Secure heavier decorations against collapse during excavation. ### Spiderling housing Spiderlings require appropriately scaled secure containers. Provide: - Compactable substrate. - A small retreat. - Fine ventilation openings. - Carefully managed moisture. - Tiny suitable prey. ### Juvenile housing Increase enclosure size gradually. ### Subadult housing Provide sufficient floor space and substrate depth for normal excavation. ### Individual housing Keep all specimens separately. ## 6. Substrate and Burrowing Substrate design is especially important for this species. ### Natural evidence Wild burrow entrances may have turrets constructed from excavated soil and silk. ### Suitable substrate materials - Reptile-safe topsoil. - Soil-based terrestrial tarantula substrate. - Topsoil blended with coco coir. - Other clean, compactable mixtures. ### Structure Lightly compact the substrate during setup. ### Depth Approximately 4–5 inches is a practical adult starting point. ### Moisture Maintain a modest moisture gradient. ### Surface conditions Allow substantial surface areas to remain relatively dry. ### Lower substrate A small portion may remain slightly moist. ### Starter burrow Create a shallow excavation beneath a stable hide. ### Avoid collapse Do not use excessively loose substrate that repeatedly collapses. ### Avoid contamination Do not use fertilised compost, pesticide-treated soil or strongly scented wood products. ### Burrow preservation Avoid unnecessary excavation of established retreats. ## 7. Furnishings and Environmental Enrichment The enclosure should support natural behaviour without introducing hazards. ### Suitable furnishings - Small cork bark hides. - Ground-level shelters. - Fine leaf litter. - Stable low stones. - A shallow drinking-water dish. ### Retreat construction Allow the spider to modify its shelter. ### Turret preservation Do not destroy soil-and-silk structures during routine maintenance. ### Environmental choice Provide more than one sheltered location where space permits. ### Stability Secure heavier furnishings. ### Avoid climbing hazards Tall branches and elevated platforms are unnecessary. ## 8. Temperature and Heating The Mojave Desert experiences extreme environmental variation. However, the temperatures inside underground retreats may differ considerably from exposed surface conditions. ### Provisional captive starting temperatures | Condition | Suggested temperature | | --- | --- | | General daytime | 21–25°C | | Slightly warmer area | Up to approximately 26°C | | Cooler retreat | Approximately 20–22°C | | Night-time | Approximately 18–21°C | These figures are cautious husbandry recommendations, not experimentally established species-specific preferences. ### Avoid extreme heat Do not expose the enclosure to the extreme surface temperatures recorded in desert habitats. ### Heating in Ireland Supplementary heating may be needed during colder months. ### Preferred approach Stable ambient room heating is generally easier to control than concentrated localised heat. ### Thermostatic control Use appropriate control equipment with supplementary heating. ### Under-enclosure heating Avoid heating directly beneath deep substrate. ### Temperature monitoring Measure actual enclosure temperatures. ### Seasonal variation Modest seasonal variation may occur naturally in a suitable room. Do not impose severe winter cooling without species-specific evidence. ## 9. Lighting and UVB Specialist UVB lighting is not routinely required. ### Day-night cycle Provide a normal light-dark rhythm. ### Ambient lighting Indirect room lighting is generally sufficient. ### Display lighting Low-output LEDs may be used if they do not cause overheating. ### Night-time Provide darkness. ### Avoid Do not use intense basking lamps. ## 10. Humidity, Ventilation and Hydration A scientifically validated relative humidity target is unavailable. ### Drinking water Provide a small, stable drinking-water dish. ### Moisture gradient Maintain slightly moist substrate in one lower area. ### Surface Allow substantial surface areas to remain relatively dry. ### Ventilation Provide effective airflow. ### Spiderlings Small containers can dry rapidly and require careful moisture monitoring. ### Misting Routine heavy misting is unnecessary. ### Warning signs Persistent condensation, mould or waterlogged substrate indicate unsuitable conditions. ### Observation Monitor burrow use, feeding, activity and moulting. ## 11. Feeding and Nutrition The Atomic Dwarf Tarantula is a carnivorous predator. ### Suitable prey - Small crickets. - Small feeder cockroaches. - Appropriately sized mealworms. - Other suitable captive-bred insects. ### Spiderlings Offer tiny prey or suitable portions of freshly killed feeder insects. ### Juveniles Approximately weekly feeding is a practical starting point. ### Adults Offer appropriately sized prey approximately every 7–14 days initially. ### Prey size Avoid prey that is excessively large relative to the spider. ### Adjustments Modify feeding according to body condition, appetite and moulting. ### Burrow feeding Offer prey near the retreat entrance without repeatedly disturbing the spider. ### Uneaten prey Remove uneaten insects promptly. ### Wild insects Avoid wild-caught feeders because of pesticide and parasite risks. ### Vertebrate prey Vertebrate feeding is unnecessary. ## 12. Calcium and Vitamin Supplementation Routine reptile calcium and vitamin dusting is not recommended. Tarantulas consume whole prey. Maintain feeder insects under appropriate conditions. No validated supplementation schedule exists for _A. atomicum_. ## 13. Moulting and Growth Moulting allows the spider to grow and renew its exoskeleton. ### Premoult signs - Reduced appetite. - Increased concealment. - Retreat closure. - Reduced activity. - Changes in abdominal appearance. ### During moulting Do not disturb the spider. A tarantula lying on its back may be moulting normally. Do not turn it over. ### After moulting Allow the exoskeleton and fangs to harden before feeding. ### Small specimens Because the spider is small, assessing fang hardening may be difficult. Do not rush feeding. ### Complications Do not forcibly remove retained exoskeleton. Seek specialist advice where necessary. ## 14. Urticating Hairs and Defensive Behaviour _Aphonopelma_ tarantulas possess defensive urticating hairs. ### Defensive responses A disturbed spider may retreat, release hairs, adopt a defensive posture or bite. ### Possible effects Urticating hairs may cause: - Itching. - Skin irritation. - Eye irritation. - Respiratory irritation. ### Eye exposure Do not rub the eye. Seek prompt medical assessment. ### Individual variation Defensive behaviour varies. ### Prevention Avoid unnecessary handling. ## 15. Venom and Bite Safety The species possesses venom-bearing fangs. ### Possible effects - Puncture wounds. - Local pain. - Swelling. - Redness. - Individual reactions. Detailed species-specific clinical evidence is limited. ### First aid Wash a bite wound with clean running water. Seek medical advice where appropriate. Severe allergic symptoms or breathing difficulties require urgent medical attention. ## 16. Handling and Safe Rehousing Routine handling is not recommended. ### Main risks - Escape. - Falls. - Bites. - Urticating-hair exposure. - Unnecessary disturbance. ### Rehousing equipment Use a suitably sized catch cup, soft brush and secure receiving enclosure. ### Preparation Prepare the receiving enclosure before moving the spider. ### Transfer Gently guide the spider into a transfer container. ### Burrowed individuals Avoid forcibly excavating the spider unless necessary. ### Escape prevention Work in a controlled area without accessible gaps or drains. ### After transfer Check all enclosure openings before leaving the spider unattended. ## 17. Cohabitation House Atomic Dwarf Tarantulas individually. ### Risks - Cannibalism. - Injury. - Competition for retreats. - Feeding interference. - Stress. Temporary supervised breeding introductions do not justify permanent cohabitation. ## 18. Cleaning and Routine Maintenance ### Daily Check water, temperature and enclosure security. ### After feeding Remove uneaten prey. ### Weekly Clean the water dish, remove visible waste and inspect for mould. ### Periodically Review substrate condition, ventilation and equipment. ### Substrate replacement Replace contaminated substrate when necessary. Avoid unnecessary complete enclosure disruption. ### Burrow preservation Avoid destroying established soil-and-silk structures. ## 19. Common Health Concerns ### Dehydration Ensure access to drinking water and appropriate substrate moisture. ### Moulting complications Incomplete moults can cause serious injury. ### Falls Abdominal injuries may be fatal. ### Mites Not all small organisms in substrate are parasites. Persistent mites concentrated on the spider require investigation. ### Mould Persistent mould may indicate excessive moisture or inadequate ventilation. ### Feeding refusal Consider premoult, body condition and environmental conditions. ### Abnormal posture Severe leg curling, weakness or unresponsiveness warrants urgent specialist assessment. ### Veterinary support Seek advice from a suitably experienced exotic or invertebrate veterinarian. ## 20. Quarantine Maintain new acquisitions separately from established collections. A precautionary observation period of approximately **60–90 days** may be used. This is not a scientifically validated disease-free interval. ### Monitor - Feeding. - Moulting. - Body condition. - Visible mites. - Abnormal behaviour. - Enclosure hygiene. ### Equipment Use separate maintenance equipment where practical. ### Provenance Retain identification and acquisition records. ## 21. Breeding Breeding _Aphonopelma atomicum_ requires reliable identification and experience with small terrestrial tarantulas. ### Identification Confirm the identity and provenance of both animals. ### Sex determination Examine a suitable moult where possible. ### Mature males Males develop specialised reproductive structures. ### Seasonal activity The original description suggests mating most likely occurs during daylight hours in October–November. ### Pairing Supervise introductions. ### Cannibalism Females may attack or consume males. ### Egg sacs Successful mating may result in egg-sac production. ### Incubation A validated species-specific captive incubation protocol is unavailable. ### Spiderlings Provide secure accommodation, suitable substrate, carefully managed moisture and appropriately sized prey. ### Records Maintain accurate parentage, pairing and offspring records. ## 22. Conservation and Responsible Captive Breeding _Aphonopelma atomicum_ has a restricted documented distribution around the Amargosa Desert and Death Valley region. ### Conservation considerations Its geographical restriction makes accurate identification and provenance important. ### Original assessment The 2016 species description suggested that the species was likely secure. This is not equivalent to a current formal IUCN assessment. ### Habitat pressures Potential pressures include habitat disturbance and inappropriate collection. ### Captive-bred acquisition Prioritise legally sourced captive-bred individuals with credible provenance. ### Wild collection Do not assume collection is permitted. ### Breeding responsibility Maintain accurate identification and parentage records. ### Conservation value Responsible captive breeding may reduce demand for wild-collected specimens. However, captive breeding does not replace habitat conservation. ### Release Never release captive tarantulas into the environment. ## 23. Legal and CITES Information Current CITES status should be checked against the official CITES Checklist before international trade. ### United States Collection, possession and export requirements may vary by jurisdiction and protected-area status. ### European Union Check applicable wildlife trade, customs and import requirements. ### Ireland Consult the National Parks and Wildlife Service where clarification is required. ### Documentation Retain: - Scientific identification. - Supplier details. - Acquisition date. - Evidence of lawful origin. - Captive-bred records where available. - Relevant permits. - Breeding records. ### Important distinction Absence from CITES does not necessarily mean that collection or international trade is unrestricted. ## 24. Common Husbandry Mistakes - Confusing Mojave Desert species with Sonoran Desert species. - Using an enclosure intended for a much larger tarantula. - Leaving escape-sized ventilation openings. - Providing excessive enclosure height. - Providing insufficient substrate. - Using substrate that collapses around burrows. - Destroying soil-and-silk turrets during maintenance. - Maintaining permanently wet conditions. - Providing no accessible drinking water. - Overheating a small enclosure. - Heating directly beneath deep substrate. - Offering excessively large prey. - Leaving live prey during moulting. - Disturbing established retreats. - Routine handling. - Communal housing. - Breeding animals of uncertain identity. ## 25. Husbandry Summary | Requirement | Practical recommendation | | --- | --- | | Scientific name | _Aphonopelma atomicum_ | | Common name | Atomic Dwarf Tarantula | | Native range | Southern Nevada and eastern California | | Ecoregion | Mojave Basin and Range | | Recorded elevation | Approximately 850–1,220 m | | Adult size | Miniaturised | | Lifestyle | Terrestrial and burrowing | | Natural burrow | Soil-and-silk entrance turret | | Adult enclosure | Approximately 6 × 6 × 8 inches | | Larger enclosure | Approximately 8 × 8 × 8 inches | | Substrate depth | Approximately 4–5 inches | | Daytime temperature | Approximately 21–25°C | | Night-time temperature | Approximately 18–21°C | | Moisture | Modest gradient, relatively dry surface | | Ventilation | Effective, escape-proof airflow | | Water | Small accessible drinking-water dish | | Lighting | Normal day-night cycle | | UVB | Not routinely required | | Diet | Small captive-bred feeder insects | | Likely breeding season | October–November | | Urticating hairs | Present | | Venom | Present | | Handling | Not recommended | | Cohabitation | Solitary | | Experience | Advanced | | CITES | Verify current status | ## 26. References and Further Reading 1. Hamilton, C. A., Hendrixson, B. E. & Bond, J. E. (2016). Taxonomic revision of the tarantula genus _Aphonopelma_ within the United States. _ZooKeys_, 560, 1–340. [Taxonomic revision of the tarantula genus Aphonopelma Pocock, 1901 (Araneae, Mygalomorphae, Theraphosidae) within the United States](https://doi.org/10.3897/zookeys.560.6264) 2. World Spider Catalog. _Aphonopelma atomicum_ Hamilton, 2016. Natural History Museum Bern. [World Spider Catalog](https://wsc.nmbe.ch/spec-data/61154/Aphonopelma_atomicum) 3. Integrated Taxonomic Information System. _Aphonopelma atomicum_, Taxonomic Serial Number 1088709. [https://www.itis.gov](https://www.itis.gov) 4. Foelix, R. F. _Biology of Spiders_. General reference for spider anatomy and behaviour. 5. CITES. Checklist of CITES Species. [https://checklist.cites.org](https://checklist.cites.org) 6. National Parks and Wildlife Service, Ireland. [https://www.npws.ie](https://www.npws.ie) ### Evidence Note The accepted taxonomy, scientific description, Mojave Desert distribution, recorded elevation, small adult body size, soil-and-silk burrow turrets and probable autumn mating activity are supported by the 2016 taxonomic revision. The enclosure dimensions, temperature ranges, feeding intervals and moisture-management recommendations are provisional captive husbandry guidance. Detailed species-specific captive longevity, preferred thermal conditions and breeding protocols remain insufficiently documented. * * * ## IMPORTANT INFORMATION This care sheet provides general husbandry guidance and does not replace species-specific research or veterinary advice. Individual requirements may vary. Always check current legislation governing the acquisition, collection, import, transport, keeping, breeding or sale of reptiles and invertebrates in your jurisdiction. If you have concerns about an animal’s health or care, consult a suitably experienced exotic or invertebrate veterinarian. Information correct at the date of publication, subject to subsequent changes in scientific knowledge and legislation. **[ReptileCommunity.com](http://ReptileCommunity.com) | Revised: October 2026** ---
### Author: ![ReptileCommunity](https://reptilecommunity.com/user_avatar/reptilecommunity.com/reptilecommunity/32/3_2.png) [@ReptileCommunity](https://reptilecommunity.com/u/ReptileCommunity) #### Post date: [October 11, 2026, 1:58pm UTC](https://reptilecommunity.com/t/atomic-dwarf-tarantula-aphonopelma-atomicum/880/2 "2026-10-11T13:58:42Z")