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Arafura snake-eyed skink (Cryptoblepharus gurrmul)

The Arafura snake-eyed skink is a very small, diurnal, carnivorous, rock-dwelling skink known from islands in Australia. It is listed as Endangered under the EPBC Act and in the Northern Territory, so clearing, access tracks, rock removal and disturbance on occupied islands require careful assessment and fauna handling.

Conservation status

Commonwealth, EPBC Act 1999: Endangered.

Northern Territory, Territory Parks and Wildlife Conservation Act 1976: Endangered.

Breeding season

Species-specific seasonal breeding data are limited. The genus is reported to breed year-round, and this skink is diurnal, so plan for eggs, hatchlings and sheltering animals in every month. Avoid rock and beach-debris clearing without local pre-clearance checks.

Reproductive mode: Oviparous.

Clutch size: Typically two eggs in the genus, but not confirmed for this species.

Incubation: Not recorded.

Size at hatching or birth: Not recorded.

Age at maturity: Both sexes mature at approximately 34 mm snout-vent length.

Nest or egg sites: Not recorded for this species. Related genus records include cavities, ant plants, brick walls, damp earth and sites beneath rock or coral litter.

Breeding frequency: Species-specific frequency is not recorded. The genus is reported to breed year-round.

Confirm timing locally before works, particularly after rainfall or temperature changes that may alter surface activity, shelter use and breeding activity.

  • Mating: No mating months are recorded for this species. Based on the genus-level report that Cryptoblepharus breeds year-round, mating may occur in any month.
  • Gravid females: No gravid females or carrying period are recorded for this species. Treat females carrying eggs as possible year-round because breeding in the genus is reported throughout the year.
  • Egg laying: The species is oviparous, but no egg-laying months or sites are recorded. Genus records show communal and secretive egg laying, including in cavities and beneath rock or coral litter, so eggs may be present in any month.
  • Incubation: Incubation length is not recorded for this species or genus. With year-round breeding reported for Cryptoblepharus, treat potential egg sites as occupied in every month rather than assigning a peak.
  • Hatchlings: Hatching months and juvenile emergence are not recorded for this species. Hatchlings may occur in any month as a precaution because the genus is reported to breed year-round.
  • Active period: The species is diurnal, but no seasonal activity limits are recorded. Treat adults as surface active during daylight in every month, subject to local weather conditions.
  • Highest clearing risk: No peak risk months are supported. Apply the same high-risk controls year-round because eggs, hatchlings, gravid females and animals sheltering in rock, beach debris or other cavities may be present in any month.

Identification

This is a very small, four-legged skink in the family Scincidae. Field identification should rely on a combination of species-level reference material, location and habitat because no diagnostic colour pattern or illustrated key is available.

Adults reach 44.3 mm snout to vent length. The recorded mean adult female length is 37.8 mm. A maximum body mass of 1.65 g has been calculated from body length, rather than measured directly.

The species is diurnal, non-venomous and has no fangs. It is described as saxicolous, meaning associated with rock surfaces or rocky shelter.

Maximum snout to vent length: 44.3 mm

Mean adult female snout to vent length: 37.8 mm

Maximum computed mass: 1.65 g

Identification: Distinguishing features

No reliable dorsal colour pattern, scale count, head shape, eye characters or other diagnostic feature has been published for separating this species from other Cryptoblepharus. Do not identify a small snake-eyed skink from size alone.

Confirm records with a qualified herpetologist or an approved identification reference. Record clear photographs, snout to vent length where practical, exact coordinates, substrate and the rock or vegetation setting.

  • Treat all small Cryptoblepharus found in suitable island habitat as requiring identification before release or removal.
  • Do not handle or retain specimens longer than required for identification and approved fauna procedures.
  • Check the current approved species name against project permits and the EPBC Act listing, because the species is gazetted as Cryptoblepharus gurrmul.

Identification: Field signs

Species-specific information on tracks, scats, calls, nests, sloughs and eyeshine is lacking. These signs should not be used alone to confirm presence.

Direct sightings are most likely to be useful during daylight, when the skink is active on or around rocky surfaces. Absence during a short search is not evidence that an occupied rock refuge is unused.

  • Search rock faces, ledges, crevices and rock piles during daylight and record the exact refuge location.
  • Photograph the animal in place where possible, rather than relying on a brief visual impression.
  • Use experienced reptile spotters and follow the project fauna interaction procedure before moving rocks or starting clearing.

Distribution

The species has a restricted island distribution in Australia. A mapped national range, named islands, bioregions and confirmed subpopulation boundaries have not been established.

The species occurs only on islands and has a stated range size of 44.4 km². It is listed as Endangered in the Northern Territory, but the occupied islands and bioregional range are not identified.

For project screening, an island occurrence in the Northern Territory should be treated as potentially important until current records and habitat mapping show otherwise.

State listing.: Northern Territory, Endangered

Island occurrence: Found only on islands

Reported range size: 44.4 km²

Named strongholds or subpopulations: Not documented.

Distribution: Population information

A population estimate, density, number of subpopulations and generation length have not been established. One dataset records the population trend as stable and the global assessment category as Data Deficient, while Australian government material confirms Endangered listing.

Population size: Not provided

Population density: Not provided

Trend in dataset: Stable

Global assessment: Data Deficient, assessed in 2017

Habitat

The Arafura snake-eyed skink is associated with rocky habitat in a tropical island setting. The available records are not detailed enough to define a vegetation association, elevation band or climatic limit.

The species is described as saxicolous and is associated with Tropical and Subtropical Grasslands, Savannas and Shrublands. A Queensland habitat dataset assigns the species to a marine habitat category, but does not provide a detailed site description.

The strongest habitat signal is the presence of exposed or partly sheltered rock on islands. Retain rocky surfaces, crevices, ledges and connected ground habitat during planning and construction.

Primary habitat association: Rock dwelling, or saxicolous

Broad biome: Tropical and Subtropical Grasslands, Savannas and Shrublands

Occurrence setting: Islands

Elevation limits: Not provided

Vegetation community: No species-specific community is provided

Habitat: Habitat features to retain

Rock dimensions, crevice widths, vegetation heights and ground-cover thresholds have not been published. In the absence of those measurements, habitat assessment should focus on the continuity and condition of rocky microhabitat rather than on a single vegetation type.

  • Map rock outcrops, boulder fields, exposed slabs, ledges, rock piles and crevice networks before clearing.
  • Retain connected rocky habitat and avoid isolating small rock patches with roads, pads, laydown areas or cleared corridors.
  • Keep construction materials, spoil and sediment out of crevices and rock piles that may provide shelter.
  • Record whether proposed works alter shade, surface temperature, drainage or access between adjacent rocky patches.

Foraging habitat

The species is a small, daytime predator that feeds in rocky habitat. Invertebrates make up its diet, but prey taxa, prey plants, hunting method and foraging distance are not well documented.

The Arafura snake-eyed skink is carnivorous and the available diet information specifies invertebrates. It is diurnal, so foraging activity and direct observations are most likely during daylight.

No project-relevant food plant, prey list, home range or foraging radius is available. Protecting the rock habitat and its surrounding ground layer is therefore the most defensible management approach.

Diet: Carnivorous, with invertebrates recorded as prey

Foraging period: Daytime

Foraging range: Not provided

Named prey taxa: Not provided

Foraging habitat: Project controls

Clearing that removes rocks, ground cover or connected habitat may reduce both shelter and access to invertebrate prey. Dust, sediment, chemical spills and broad-spectrum pesticide use may also alter the small invertebrate fauna available around rocky habitat.

  • Keep machinery, spoil, concrete washout, fuels and chemicals away from occupied or potentially occupied rock habitat.
  • Avoid unnecessary pesticide use near retained rocky habitat and follow project chemical management controls.
  • Inspect rock surfaces and adjacent ground before disturbance, because the species may be active in the open during daylight.
  • Retain undisturbed ground links between rocky patches where these links remain within the project area.

Breeding habitat: Breeding biology

The species is oviparous, meaning it lays eggs. Breeding months, clutch size, incubation, maturity, lifespan and the specific features used for nesting are not well documented.

The only species-specific breeding information is oviparity. Egg-laying sites and seasonal breeding activity cannot be located from the published information alone.

Reproduction: Oviparous

Breeding season: Not provided

Clutch size: Not provided

Incubation period: Not provided

Age at maturity: Not provided

Lifespan: Not provided

Breeding habitat: Breeding habitat and safeguards

Specific nesting substrates and egg-site dimensions are not documented. Until local survey information is available, treat sheltered rock crevices and stable rocky ground within occupied habitat as potential breeding habitat.

  • Do not lift, roll or break rocks in occupied habitat unless the action is covered by an approved fauna management procedure.
  • Plan pre-clearance searches to include rock crevices, ledges, rock piles and the ground immediately around them.
  • Use a qualified fauna spotter catcher for any capture, exclusion or relocation decision.
  • Record any eggs, hatchlings or adults found together and report the observation to the project environmental officer.

Sheltering habitat

The skink is rock dwelling, but a particular refuge type or refuge size has not been identified. Rocky crevices, ledges and stable rock piles should be treated as potential shelter until checked.

No species-specific information is available on burrows, hollows, dens, refuge depth, crevice width, ground-cover height or shelter dimensions. The species is nevertheless described as saxicolous, so rock surfaces and associated crevices are the most relevant shelter features identified.

A small-bodied skink may use narrow gaps that are difficult to inspect safely. Do not assume that a rock is unoccupied because no animal is visible on its surface.

Known shelter association: Rock habitat

Refuge dimensions: Not provided

Burrows, hollows or dens: No species-specific information provided

Sheltering habitat: Handling shelter habitat

Before clearing, map and inspect rock habitat from a safe position. If rocks must be moved, use the approved fauna procedure and ensure the person undertaking the work is authorised for the relevant species and activity.

  • Mark exclusion buffers around retained rock outcrops, crevices, ledges and rock piles where practicable.
  • Do not use rocks from occupied habitat as construction material or place spoil over crevice systems.
  • Search the underside and edges of movable rocks only under an approved spotter catcher procedure.
  • Retain natural rock cover rather than replacing it with artificial rubble unless a site-specific ecological assessment supports that action.

Threats: Clearing and construction

The species is listed as Endangered, but no formal species-specific threat list has been published. For development projects, the main foreseeable risks are loss and fragmentation of rocky island habitat, direct mortality during clearing and altered habitat condition.

Removal of rocky habitat, rock piles, crevices and surrounding ground cover can directly destroy shelter and potential breeding sites. Machinery movement can kill animals that are active on rock surfaces or sheltering beneath rocks.

Roads, pads, trenches, utility corridors and laydown areas can divide small habitat patches. The reported range size of 44.4 km² means that local losses may be significant where occupied habitat is concentrated.

  • Avoid clearing rocky habitat where practicable and establish no-go areas before mobilisation.
  • Complete pre-clearance searches during daylight, when the species is active.
  • Use a fauna spotter catcher for rock removal, vegetation clearing and any required relocation.
  • Stage clearing so that retained habitat remains connected and does not become an isolated rock patch.

Threats: Roads, fire and predators

Road mortality, fire response and predator impacts have not been quantified for this species. Roads and vehicle access remain direct mortality risks for a small, ground-associated reptile, particularly where they cross rocky habitat.

Fire can alter ground cover, rock temperatures and invertebrate prey. The appropriate fire response will depend on local island conditions, and no general response should be assumed.

  • Set low vehicle speeds and restrict driving to formed routes in occupied or potential habitat.
  • Do not create informal tracks across rocky areas.
  • Prevent domestic animals and unauthorised predators from entering work areas where project controls allow.
  • Use local fire ecology advice before burning, slashing or changing fuel loads around occupied habitat.

Threats: Hydrology, pollution and disease

No species-specific evidence has been published on hydrology change or disease. Drainage alteration, sediment movement and chemical contamination may still change the condition of rocky habitat and its invertebrate food resources.

Disease status, pathogens and treatment requirements are not provided. Avoid moving reptiles, rocks, soil or equipment between islands or project areas without following hygiene and biosecurity procedures.

  • Keep drainage, erosion and sediment controls away from rock crevices and retained habitat.
  • Prevent concrete, fuel, herbicide and other contaminants from entering rocky shelter areas.
  • Clean and disinfect relevant equipment between work areas under the project biosecurity procedure.
  • Do not translocate animals between islands or sites unless specifically authorised.

Survey methodology: 1. Desk assessment and habitat mapping

The Arafura snake-eyed skink is a small, diurnal, rock-dwelling skink. It is listed as endangered under the EPBC Act, and project surveys should focus on rocky habitat and associated crevices, ledges and refuges. No species-specific survey effort or seasonal survey window has been published.

Confirm whether the project area contains rocky habitat, exposed rock surfaces, rock piles, crevices or other hard refuges that could support this species.

Prioritise survey coverage on islands, because the available species account records the species as found only on islands.

Map all potential rocky habitat within the disturbance footprint and in retained areas before selecting survey locations.

Survey methodology: 2. Diurnal active searches

Survey during daylight because the species is recorded as diurnal.

Search systematically across exposed rocks, rock edges, ledges and crevices, checking both the disturbance footprint and nearby retained habitat.

Use quiet observation and careful visual searches because the species reaches only 44.3 mm snout to vent length and may be overlooked among small rock refuges.

Maximum recorded snout to vent length: 44.3 mm

Activity period: Diurnal

Recorded shelter association: Saxicolous, or rock dwelling

  • Record the search date, start and finish time, weather, observers, area searched, habitat features inspected and all detections.
  • Photograph the animal or its location where this can be done without causing unnecessary disturbance.

Survey methodology: 3. Targeted searches of disturbance features

Inspect each rock pile, slab, crevice and hard refuge that will be removed, buried or isolated by the works.

Search immediately before clearing and repeat the inspection if clearing is delayed or conditions change materially.

No prescribed number of survey days, transect length, search hours, trap nights or minimum area has been published, so the ecologist should document site-specific effort based on the amount and distribution of rocky habitat.

  • Do not use trapping or handling as a default method for this species when careful daylight searches can address the risk.
  • Use a suitably authorised fauna spotter catcher if capture is needed for animal safety or lawful relocation.

Survey methodology: Minimum effort and reporting

  • Define the search area and effort before fieldwork and justify any unsurveyed rocky habitat in the report.
  • Record negative results as well as positive detections, including the habitat searched and the conditions at the time.
  • Submit verified records to the relevant state wildlife database and provide the required records to the project approval authority.
  • Escalate any confirmed detection or likely occupied habitat to the project ecologist and environmental officer before disturbance proceeds.
  • Check the current EPBC Act listing and approval requirements because the species is listed as endangered nationally.

Vegetation associations: Shrubland

Source-checked associations and automatically indexed candidates are separated below. An association does not establish site presence, preference or dependence.

The species is described as saxicolous and is associated with Tropical and Subtropical Grasslands, Savannas and Shrublands.

Automatically indexed from existing profile text. Not a verified preference, mapped occurrence or habitat requirement. Check the original source and regional qualifiers before use.

Evidence: Unreviewed profile-derived candidate

Confidence: Not independently verified

Region: Scope as described in the quoted profile text; not independently verified. Profile states: NT.

Habitat use: general

Attribution gap: No sentence-level reference is attached to the original profile block. Review the profile bibliography; this candidate is not source-verified.

Vegetation associations: Tussock grassland

The species is described as saxicolous and is associated with Tropical and Subtropical Grasslands, Savannas and Shrublands.

Automatically indexed from existing profile text. Not a verified preference, mapped occurrence or habitat requirement. Check the original source and regional qualifiers before use.

Evidence: Unreviewed profile-derived candidate

Confidence: Not independently verified

Region: Scope as described in the quoted profile text; not independently verified. Profile states: NT.

Habitat use: general

Attribution gap: No sentence-level reference is attached to the original profile block. Review the profile bibliography; this candidate is not source-verified.

Ecosystem associations

Source-checked associations and automatically indexed candidates are separated below. An association does not establish site presence, preference or dependence.

No species-specific ecosystem association has been indexed or source-checked in this evidence library. This is an evidence gap, not evidence of no association.

Soil and substrate associations

Source-checked associations and automatically indexed candidates are separated below. An association does not establish site presence, preference or dependence.

No species-specific soil association has been indexed or source-checked in this evidence library. This is an evidence gap, not evidence of no association.

Water and wetland associations

Source-checked associations and automatically indexed candidates are separated below. An association does not establish site presence, preference or dependence.

No species-specific water association has been indexed or source-checked in this evidence library. This is an evidence gap, not evidence of no association.

Fauna records and mapped habitat: Not yet analysed

Record locations can be overlaid with mapping, but record frequency alone does not measure habitat preference. No species is excluded from desktop assessments by this analysis.

No quality-controlled record-to-map analysis has been completed for this species. The existing generalised distribution dots and indicative range polygons have not been treated as precise occurrence coordinates.

A defensible run needs dated, independently attributable records, coordinate uncertainty, duplicate and captive-record checks, layer versions and regional scope. Preference and absence require additional survey-effort and detection evidence.

Habitat limitations and contrary evidence: No supported exclusion recorded

Not recorded is not the same as cannot occur. Low suitability, resident habitat, breeding habitat and occasional movement are different conclusions.

This library has not established a vegetation, ecosystem or soil-type exclusion for this species. This does not mean all habitat is suitable; the evidence needed to justify an exclusion has not been assembled.

Habitat limitations and contrary evidence: Before using a negative association

  • Confirm the taxon, geographic region, life stage and habitat function covered by the evidence.
  • Check survey methods, season, repeated effort and detectability before interpreting non-detection.
  • Investigate credible contradictory records and microhabitats absent from broad mapping.
  • Do not convert a missing map class, low record count or failed data request into species absence.

Before habitat disturbance: Avoid and minimise

Avoid disturbance to rocky refuges first. The species is nationally endangered, small and rock dwelling, so project planning should prevent the removal or isolation of occupied or suitable rocky habitat wherever practicable.

Redesign the footprint to retain rocky outcrops, slabs, crevices, ledges and rock piles that may provide shelter.

Retain connected patches of rocky habitat rather than leaving isolated small remnants surrounded by cleared ground.

Keep disturbance away from retained rocky habitat and establish a project-specific no-go area after the habitat assessment.

Do not move rocks or stockpile them in retained habitat unless this is authorised through the fauna management plan.

Before habitat disturbance: Approvals and work planning

Check whether the proposed action requires an EPBC Act referral or approval because the species is listed as endangered.

Confirm all applicable state or territory permits, wildlife authorisations and clearing approvals before works begin.

Prepare a fauna management plan that identifies rocky habitat, survey methods, fauna spotter catcher responsibilities, stop-work triggers, relocation arrangements and reporting requirements.

Stage clearing so that retained habitat remains available while each work area is checked and cleared.

EPBC Act status: Endangered

NT status in the project brief: Endangered

Before habitat disturbance: Site preparation

Complete the pre-clearance inspection of all rocky habitat and proposed access areas before machinery enters.

Mark retained rocks, crevices, exclusion areas and fauna access routes clearly on the ground and in project plans.

Install exclusion fencing where it can prevent machinery, materials or people entering retained rocky habitat without creating a barrier that traps animals.

Brief all operators on the species identification, the no-go areas, the stop-work process and the requirement to follow the fauna spotter catcher's directions.

During habitat disturbance: Daily controls and spotter catcher duties

Clear only after the approved controls are in place and the fauna spotter catcher has inspected the work area. Stop work when a skink or potentially occupied rocky refuge is found and resolve the risk before machinery continues.

Inspect the active work area at the start of each day and after breaks, delays or changes to the clearing sequence.

Keep the fauna spotter catcher close enough to see the machinery interface and require operators to stop immediately on instruction.

Clear in small, controlled sections so rocky refuges can be inspected before they are disturbed.

Prevent spoil, equipment and traffic from blocking retained rocky habitat or creating new barriers between retained areas.

  • Maintain a daily record of the area cleared, habitat features removed, observers, weather, detections, relocations, injuries, incidents and stop-work events.
  • Use only personnel with the required authority and competency to capture, handle or relocate native fauna.

During habitat disturbance: Rock and refuge management

Inspect rocks, slabs, crevices and rock piles before removal, burial or crushing.

Where a rock feature must be removed, lift or dismantle it under fauna spotter catcher supervision rather than allowing uncontrolled crushing or grading.

Keep potentially occupied rocks undisturbed until the authorised fauna spotter catcher has completed the inspection and given clearance.

Do not assume that an empty crevice is unused without checking it carefully.

During habitat disturbance: Animal found, injury and stop-work response

Stop work immediately in the local work area when an Arafura snake-eyed skink is found or when machinery exposes a suspected occupied crevice.

Keep people, machinery and pets away from the animal and allow the authorised fauna spotter catcher to decide whether observation, capture or relocation is safest and lawful.

Relocate the animal only to nearby retained rocky habitat that is outside the disturbance area and approved in the fauna management plan.

Do not handle the animal unnecessarily, and do not permit untrained workers to catch or move it.

Take an injured animal to an appropriately qualified wildlife veterinarian or wildlife carer through the approved project procedure.

Resume work only after the fauna spotter catcher and environmental officer confirm that the animal and nearby rocky refuges are safe, or that the approval conditions have been met.

  • Treat a confirmed detection, an injured animal, an animal trapped by fencing and an uninspected rocky refuge as stop-work triggers.
  • Record the location, time, photographs where appropriate, action taken, relocation location and the names and authorisations of people involved.

After habitat disturbance: Post-clearance checks

Post-clearance checks should confirm that no animal has been left in the work area and that retained rocky habitat remains functional. Reporting should link each detection and incident to a mapped location and the relevant approval condition.

Inspect the cleared area and the edges of retained rocky habitat after each clearing stage.

Check for animals trapped against exclusion fencing, inside excavations, beneath stored materials or within isolated rock features.

Remove temporary barriers, waste and materials that could trap animals only when the area is confirmed safe and the fauna management plan allows it.

After habitat disturbance: Monitoring and controls

Monitor retained rocky habitat where it is exposed to vibration, dust, altered access or edge disturbance from the works.

Maintain exclusion fencing, no-go markers and access controls until the environmental officer confirms that they are no longer needed.

Use the species account's recorded rock-dwelling and diurnal traits to guide follow-up inspections during daylight.

  • Investigate any new detection, injured animal or repeated movement into the work area and revise controls before continuing the affected activity.
  • Include survey effort, detections, relocations, injuries, mortality, photographs, mapped habitat and corrective actions in the completion report.

After habitat disturbance: Compliance and offsets

Report the outcome to the approval authority and relevant wildlife agency when required by the approval or permit.

Submit confirmed records to the relevant state wildlife database.

Apply any approved offset, habitat protection or rehabilitation requirement specified by the EPBC Act decision or state approval; do not treat an offset as a substitute for retaining suitable rocky habitat on site.

Rehabilitation actions: Rocky habitat reinstatement

Rehabilitation should recreate secure rocky refuges and maintain connected retained habitat. No species-specific plant species, breeding substrates, fire intervals or predator controls have been published for this skink, so rehabilitation should be based on the pre-clearing habitat assessment and approval conditions.

Retain and reinstate stable rocks, slabs, ledges and crevice-forming features where they are part of the approved rehabilitation design.

Place reinstated rocks so they provide secure gaps and shaded crevices without creating unstable piles that could collapse or injure fauna.

Reconnect reinstated rocky patches with retained rocky habitat wherever practicable.

Do not place rocks in drainage paths or locations where erosion could remove the refuge.

  • Use locally sourced material where permitted and record the location and design of reinstated rocky features.
  • Do not introduce artificial hollows, nest boxes, wetlands or logs as substitutes for rocky refuges unless the habitat assessment shows that they are relevant to the wider site.

Rehabilitation actions: Vegetation, weeds and predators

Restore the surrounding native vegetation community identified during the pre-clearing assessment rather than selecting plant species without site evidence.

Control weeds where they reduce access to rocky crevices, increase erosion or alter the structure of retained habitat.

Manage introduced predators and domestic animal access where required by the approved rehabilitation plan and site risk assessment.

Apply fire management measures required for the local habitat and approval conditions, because no species-specific fire regime has been established.

Rehabilitation actions: Monitoring and success measures

Inspect rehabilitated rocky features after installation, after major rainfall and during follow-up daylight fauna checks.

Measure whether rocks remain stable, crevices remain available, connected habitat is protected and weed cover is controlled.

Use repeat daylight searches and verified records to check whether the species continues to use retained or rehabilitated rocky habitat.

Set corrective actions for failed rock structures, erosion, weed invasion, predator access or animal mortality, and document when each action is completed.

  • Define monitoring dates, observers, search areas and detection outcomes in the rehabilitation plan because no standard monitoring period or effort has been established.
  • Submit confirmed rehabilitation detections to the relevant state wildlife database and include them in the project completion report.

Sources