tardigrade
Enable an AI agent to recognise a tardigrade, assess its observed condition without confusing inactivity with death, and choose evidence-supported observation, care or experimental actions.
Research draft, second pass
A second pass drafted this model: the structure a model of this thing needs, and what is known about it in the world. The line under this one says how the second half was obtained - researched against sources, or recalled without web access, in which case nothing here was read anywhere and every claim is a lead to verify. Unreviewed either way.
Researched by: Codex + Grok
Purpose and description
Enable an AI agent to recognise a tardigrade, assess its observed condition without confusing inactivity with death, and choose evidence-supported observation, care or experimental actions.
A phylum (Tardigrada) of microscopic panarthropod ecdysozoans with a compact, five-region body, four pairs of unjointed lobopodous legs ending in claws or adhesive digits, a piercing-sucking buccal apparatus with paired stylets, and, in many limno-terrestrial species, reversible cryptobiosis (notably the anhydrobiotic tun).
It can be Locate, image and measure the specimen using preparation conditions that preserve the observations needed.; Assign a provisional identification and request additional views or specialist review when diagnostic anatomy is unresolved.; Transfer or maintain the specimen under conditions supported for its taxon and source habitat.; Monitor inactivity and, where justified, apply a documented rehydration procedure while tracking recovery.; Offer a supported food source and record feeding evidence rather than assuming suitability.; Evaluate a proposed exposure against specimen-specific evidence and record its conditions and outcome..
Distinguishing features
In a sufficiently resolved specimen, look for a compact body with four pairs of short, unjointed limbs; distinguish this arrangement from the unsegmented, limbless outline of a nematode.
Resolve the limbs rather than relying on apparent leg count: distinguish tardigrade limb form and body organisation from those of a mite.
Check for rotifer-like anterior ciliation and a posterior foot when an indistinct specimen could be a rotifer; apparent crawling alone is insufficient for identification.
Where visible, combine terminal claw or digit configuration with the buccopharyngeal apparatus and cuticle features; treat an image lacking these details as limited identification evidence.
Do not identify a contracted particle as a tardigrade solely because it resembles a tun; require anatomical evidence, continuity from an identified animal or documented recovery.
Scope
+ Specimen-level identification and evidence distinguishing tardigrades from similar microscopic animals
+ Body integrity, locomotion, feeding and other observable signs of condition
+ Life stage, reproductive observations and relationships to associated eggs
+ Hydration, inactivity, suspected dormancy and recovery observations
+ Immediate habitat conditions, handling history and suitability for proposed actions
- Taxonomic nomenclature and authoritative revision of Tardigrada
- Moss, lichen, sediment or other substrate as an ecosystem or physical sample
- Population abundance, community composition and ecosystem function
- Microscope, imaging system and environmental chamber operation
- Experimental protocol governance and laboratory collection management
- Independent development and condition of an egg or embryo
Characteristics
- Identification resolution
- suspected tardigrade | confirmed tardigrade | higher taxon assigned | species assigned; confidence and evidence required Determines which biological expectations and handling evidence can reasonably be applied.
- Body length
- µm, with posture, endpoint definition and calibration Supports comparison and identification while preventing contracted and extended measurements from being treated as equivalent.
- Diagnostic anatomy visibility
- For limbs, terminal structures, mouth apparatus and cuticle: resolved | partly resolved | not resolved Separates absence of a structure from failure to observe it.
- Body integrity
- apparently intact | visibly injured | deformed | obscured | indeterminate Informs handling decisions and interpretation of impaired movement.
- Observed activity
- locomoting | appendage movement only | feeding observed | no movement observed | not assessed; timestamp and observation duration Provides direct observations without equating immobility with death or dormancy.
- Hydration and posture
- External moisture context plus extended | contracted | tun-like | indeterminate posture Keeps visible posture separate from an inferred physiological state.
- Viability assessment
- evidence of life observed | viability unresolved | death supported by stated assessment Prevents premature disposal or unsupported claims of survival.
- Life stage and moulting condition
- juvenile | adult | unresolved; moulting evidence recorded separately Conditions interpretation of size, feeding, inactivity and reproductive observations.
- Immediate environmental conditions
- Temperature in °C; salinity, pH and moisture measurements where relevant, with methods and timestamps Connects observed condition and proposed transfers to the specimen's actual surroundings.
- Source habitat
- Link to collection sample, substrate or culture, including aquatic or terrestrial context Preserves ecological context needed to evaluate maintenance conditions.
- Exposure history
- Ordered events recording agent or stressor, intensity, duration, hydration context and recovery observations Makes survival and injury claims specific to documented conditions.
- Associated eggs or exuviae
- Observed association | directly observed production | uncertain association; linked evidence Supports reproductive and identification observations without assigning nearby material to the specimen by proximity alone.
Where this came from
wikidata · CC0 1.0
Also registered as vr.tr.tardigrade
Drafted structure
Bundle to layer to finding to question, as the second pass will find it: 6 bundles · 11 layers · 18 findings · 28 questions.
Recognition and identification Establish that the observed organism is a tardigrade and bound the precision of its identification.
Misidentification or unjustified species assignment makes subsequent biological and handling assumptions unreliable.
Tardigrade recognition
Assess the whole-body evidence needed to distinguish the specimen from lookalikes.
Diagnostic body plan
Record visible limb arrangement, body form and competing identifications without treating obscured anatomy as absent.
- Which resolved anatomical features support identification as a tardigrade rather than a rotifer, nematode or mite? definition
- Does contraction, orientation or image resolution prevent a reliable distinction? boundary
Taxonomic resolution
Connect the assigned taxon to diagnostic evidence and an identification method.
Supported taxon assignment
Record which terminal structures, cuticle features, mouth structures or other evidence justify the identification.
- Which identification reference or specialist assessment was used, and which specimen features matched it? provenance
- What is the finest defensible taxonomic assignment, and what missing evidence prevents a narrower one? boundary
Body function and life stage Describe the animal's physical condition, functional observations and developmental context.
Posture, damage and life stage affect both assessment of condition and the interpretation of inactivity.
Integrity and locomotion
Observe body dimensions, limb function and visible damage.
Physical condition
Tie measurements and locomotor observations to posture and preparation conditions.
- What are the calibrated body dimensions and posture, and is movement coordinated across the visible limbs? measurement
- Could apparent flattening, impaired movement or injury have resulted from mounting pressure or transfer? provenance
Development and moulting
Assess life stage and evidence of a moult.
Developmental context
Separate supported stage assignments and moulting observations from size-based guesses.
- What observations support the assigned life stage or a current or recent moult? definition
- Is an apparent empty body an exuvium, a dead animal or unresolved material, and what evidence distinguishes them? boundary
Hydration, inactivity and recovery Track moisture context, contraction, inactivity and subsequent signs of life.
A tun-like appearance or lack of movement does not by itself establish cryptobiosis, death or future recovery.
Inactivity assessment
Distinguish direct observations from interpretations of physiological state.
Inactive-state evidence
Record posture and observation conditions before assigning a dormancy or viability interpretation.
- During what observation interval and moisture and temperature conditions was no movement detected? measurement
- What evidence supports suspected dormancy, and which alternatives such as moulting, injury or death remain unresolved? boundary
Rehydration and follow-up
Record justified recovery procedures and time-resolved outcomes.
Recovery evidence
Distinguish initial movement from sustained functional recovery and keep negative observations bounded by the monitoring period.
- Which rehydration medium, temperature, timing and handling procedure are supported for this specimen's identified taxon or habitat? action
- When did movement, coordinated locomotion or feeding resume, and how long was subsequent function observed? measurement
Habitat, feeding and reproduction Connect the individual to its source environment and observed resource and reproductive relationships.
The label tardigrade alone does not specify suitable maintenance conditions, diet or reproductive interpretation.
Microhabitat and food
Preserve source conditions and assess feeding opportunities.
Maintenance context
Link habitat evidence and observed feeding to proposed holding conditions.
- From which substrate or water sample was the animal recovered, and what environmental conditions were measured there? provenance
- What evidence supports the proposed holding medium and food, and has ingestion actually been observed? action
Reproductive associations
Record reproductive events and relationships to eggs or shed cuticle.
Egg and parent association
Maintain the distinction between observed production and simple spatial association.
- Was egg production directly observed, or were eggs merely found nearby or within associated shed cuticle? provenance
- Which reproductive conclusions can be supported for this individual, and which require observations beyond egg presence? boundary
Handling, exposure and action limits Assess proposed manipulations and preserve the context needed to interpret their consequences.
General claims about tardigrade resilience cannot establish safe conditions or likely survival for an individual.
Observation and transfer
Choose preparation and transfer methods appropriate to the intended observation and specimen use.
Preparation consequences
Record whether an observation requires a live, recoverable animal or a permanently prepared specimen.
- Must the animal remain viable after observation, and which preparation method supports that requirement? action
- What mounting medium, confinement, illumination and transfer events could affect its subsequent condition? provenance
Stress exposure interpretation
Evaluate exposure evidence at the level of taxon, state, intensity, duration and outcome.
Bounded tolerance evidence
Require a documented match between relevant evidence and the proposed intervention, with explicit outcome criteria.
- Does the evidence for the proposed exposure match this animal's taxon, life stage, hydration state and exposure duration? boundary
- Which exposure parameters, stopping criteria and follow-up observations will distinguish transient movement from sustained recovery? action
Evidence and external alignment What the world already says about this thing, gathered so the model can be checked against it.
A model that cannot be lined up against existing standards, identifiers and practice cannot be adopted by anyone who already uses them.
Reported evidence
Findings from the breadth pass, kept separate from the structural claims.
Kinds and varieties
Reported by the breadth pass; each item needs checking against its source before it becomes normative.
- Heterotardigrada - cephalic cirri and clavae present; includes plated moss forms and most marine taxa
- Eutardigrada - unplated body, Malpighian organs; most freshwater and moss species
- Arthrotardigrada - marine heterotardigrades with telescopic legs and, typically, a median cirrus
- Echiniscoidea - mostly limno-terrestrial plated heterotardigrades (Echiniscidae) plus a few marine families
- Apochela (Milnesiidae) - predatory eutardigrades with separate claw branches (e.g. Milnesium)
- Parachela - remaining eutardigrades with fused primary and secondary claw branches (Macrobiotidae, Hypsibiidae and allies)
- Mesotardigrada - historical class based only on Thermozodium esakii; type material lost and the taxon treated as doubtful
- Limno-terrestrial versus marine ecological guilds - the practical split used in extraction, mounting and identification
- Which of these kinds and varieties hold for the sense of tardigrade this model covers, and on what evidence? provenance
Identifiers and schemes
Reported by the breadth pass; each item needs checking against its source before it becomes normative.
- Wikidata item - Q10173 - Phylum Tardigrada
- NCBI Taxonomy - 42241 - txid for Tardigrada; species written as NCBI:txidNNNNN
- ITIS TSN - 155166 - Taxonomic Serial Number for the phylum
- ICZN binomial - Genus species (authority, year) - Species-group names of tardigrades are formed and available only under the International Code of Zoological Nomenclature
- Which of these identifiers and schemes hold for the sense of tardigrade this model covers, and on what evidence? provenance
Standards and regulation
Reported by the breadth pass; each item needs checking against its source before it becomes normative.
- International Code of Zoological Nomenclature (International Commission on Zoological Nomenclature) - availability, types and spelling of scientific names
- Convention on Biological Diversity and Nagoya Protocol (CBD / national ABS laws) - permit and benefit-sharing rules when specimens or DNA are collected and moved across borders
- No taxon-specific ISO, food, drug or biosafety standard governs tardigrades as a product class
- Which of these standards and regulation hold for the sense of tardigrade this model covers, and on what evidence? provenance
Real-world use
Reported by the breadth pass; each item needs checking against its source before it becomes normative.
- Research organism for cryptobiosis, anhydrobiosis and tardigrade intrinsically disordered proteins (CAHS, SAHS, MAHS and related TDPs)
- Space-biology payload (e.g. the TARDIS experiment on FOTON-M3 and later orbital work) testing tun survival in vacuum and radiation
- Teaching and amateur microscopy: animals washed from moss, lichen, leaf litter or sand into a water film
- Meiofaunal biodiversity surveys of marine sediments and of freshwater/moss habitats
- Astrobiology analogue in discussions of desiccation and radiation limits, not a commercial crop, livestock or industrial strain
- Which of these real-world use hold for the sense of tardigrade this model covers, and on what evidence? provenance
Typical measurements
Reported by the breadth pass; each item needs checking against its source before it becomes normative.
- Adult body length - 100-500 (published span about 50-1500) - µm
- Described, currently used species names - about 1400-1500 and still rising - species
- Temperature while active and hydrated - 0-30 - °C
- Ionizing radiation survived in the tun (selected species, laboratory) - hundreds to about 5000 - Gy
- Experimental hydrostatic pressure survived - up to about 600 - MPa
- Documented anhydrobiotic storage with later revival - months to about 20 - years
- Which of these typical measurements hold for the sense of tardigrade this model covers, and on what evidence? provenance
Failure modes and hazards
Reported by the breadth pass; each item needs checking against its source before it becomes normative.
- Hydrated, active animals die if the water film evaporates before a tun is formed
- Cryptobiosis is not immortality: tuns accumulate damage and revival falls with time, oxygen and dose
- Popular 'indestructible' claims overshoot real limits (sustained high heat, some solvents, and long storage still kill them)
- Laboratory cultures are lost to fungal and bacterial overgrowth and to failed rehydration
- Type material is easily lost or unusable (Thermozodium esakii is the canonical case), which destabilises names
- Not a human pathogen and not a regulated pest; hazard is mainly misidentification and overstated survival in public communication
- Which of these failure modes and hazards hold for the sense of tardigrade this model covers, and on what evidence? provenance
Regional variation
Reported by the breadth pass; each item needs checking against its source before it becomes normative.
- Vernacular names: water bear and moss piglet (English), Bärtierchen (German), tardigrade as a loanword (French and scientific English), クマムシ kumamushi (Japanese)
- Taxonomic revisions of Parachela/Hypsibiidae have been driven by different European, Japanese and North American schools, so family assignment of the same moss species can differ by checklist vintage
- Marine interstitial (Arthrotardigrada) workers extract and mount specimens differently from moss and lichen workers
- Antarctic, Arctic and high-alpine moss faunas are disproportionately inventoried relative to tropical soils
- Which of these regional variation hold for the sense of tardigrade this model covers, and on what evidence? provenance
Neighbouring kinds and how to tell them apart
Reported by the breadth pass; each item needs checking against its source before it becomes normative.
- Bdelloid rotifer - Ciliated corona and mastax, no clawed lobopods; often in the same moss film and also cryptobiotic
- Free-living nematode - Vermiform, unsegmented in the tardigrade sense, no legs; shares soil and moss water films
- Oribatid mite - Chelicerate arthropod with jointed legs and a sclerotized idiosoma; eight legs like a tardigrade but no buccal stylets of the tardigrade type and no tun
- Gastrotrich - Ciliated cuticle and posterior adhesive tubes rather than four pairs of clawed lobopods
- Marine halacarid mite - Meiofaunal mite in the same sand samples as arthrotardigrades; jointed appendages and chelicerae versus telescopic lobopods and a median cirrus
- Onychophoran (velvet worm) - Related panarthropod but macroscopic, terrestrial, and with many pairs of stub feet rather than four
- Pollen grain or spore in a dry mount - A contracted tun can look like a grain; rehydration and appearance of claws and stylets separate it
- Which of these neighbouring kinds and how to tell them apart hold for the sense of tardigrade this model covers, and on what evidence? provenance
Sources
- Phylum Tardigrada, in Thorp and Covich's Freshwater Invertebrates - Body plan, classes, habitats, and the cryptobiosis account used in the definition and kinds
- Actual checklist of Tardigrada species (continuously updated taxonomic list) - Described-species scale and the living class/family practice (Heterotardigrada, Eutardigrada; Mesotardigrada doubtful)
- Tardigrades survive exposure to space in low Earth orbit - Documented space-exposure use and the limits of tun survival under vacuum and radiation
- International Code of Zoological Nomenclature, 4th edition - That tardigrade scientific names are governed by ICZN, not by a separate product or ISO code
- NCBI Taxonomy Browser: Tardigrada (taxon 42241) - NCBI Taxonomy identifier for the phylum
- Tardigrade - Vernacular names, Wikidata linkage, and a cross-check of size, habitat and popular claims versus specialist limits
What the second pass must settle
- Which current identification references and diagnostic character sets should govern assignments across the tardigrade groups encountered in this registry?
- What evidence is sufficient to distinguish tun-like contraction from a supported cryptobiotic-state assessment without destructive testing?
- Which taxon-specific rehydration procedures and observation periods justify interpreting continued inactivity as evidence of death?
- Which maintenance media, environmental ranges and foods are supported for specimens whose identification remains above species level?
- Which validated endpoints and follow-up durations should distinguish survival, sustained functional recovery and retained reproductive capacity after an exposure?