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Yampi Ctenotus (Ctenotus decaneurus yampiensis)

The Yampi Ctenotus is a small skink known from Yampi Sound in the West Kimberley, although information on its habitat and ecology is limited. It is listed as Priority 2 on the WA DBCA Priority Fauna List, a priority-list category rather than a statutory threatened-species listing under the Biodiversity Conservation Act 2016.

Conservation status

Western Australia, WA Threatened and Priority Fauna List: Priority 2.

Seasonal planning

Activity and breeding months are not known for the Yampi Ctenotus. Use year-round precautions rather than assuming a taxon-specific seasonal window.

No species-specific seasonal timing is available.

  • Survey and works precautions: Planning window only. No seasonal activity or breeding months are recorded for this taxon; maintain appropriate survey and fauna safeguards throughout the year.

Identification: Appearance and size

Identification information is limited. Some descriptions apply to Ctenotus decaneurus more broadly rather than specifically to the Yampi form.

A taxonomic study examined four C. decaneurus yampiensis specimens. They had 29 to 32 midbody scale rows and measured 48.8 to 53.1 mm snout-to-vent length.

The broader C. decaneurus diagnosis describes a prominent pale mid-lateral stripe and usually ten pale body stripes on a dark ground colour. How consistently these features occur in the Yampi form is not known.

Identification: Similar forms

The reported midbody scale-row range for the Yampi form is 29 to 32, compared with 24 to 28 for C. decaneurus decaneurus. The Reptile Database identifies this as the character that reliably distinguishes the forms.

The names Ctenotus decaneurus yampiensis and Ctenotus yampiensis are both used. Where records or specimens are uncertain, consult a suitably qualified reptile specialist about identification and current nomenclature.

Identification: Field signs

No distinctive tracks, burrows, scats or other field signs are described for this taxon. A sighting or a captured specimen confirmed by an experienced identifier is preferable to an unverified sign.

Distribution: Known range

The Yampi Ctenotus is known from the West Kimberley, but records are few.

The Reptile Database gives the distribution of C. decaneurus yampiensis as Yampi Sound in the West Kimberley, Western Australia. Wotjulum Mission Station is the stated type locality.

Atlas of Living Australia records show six WA records at four distinct 0.1-degree locations, between latitude -16.2 and -15.6 and longitude 123.6 and 125.3. These figures summarise record locations, not individually named sites.

Distribution: WA region and status

The DBCA Priority Fauna List identifies the Kimberley region and assigns the taxon Priority 2, described as poorly known and known from few locations, some on conservation lands.

No national listing is identified.

Habitat: Recorded habitat

The Yampi Ctenotus's specific habitat has not been documented.

The form is known from Yampi Sound and the West Kimberley, but its vegetation type, soil, landform and elevation are not recorded.

Habitat: Site assessment

Do not assume that a proposed site is unsuitable because a particular habitat feature is absent. Record the vegetation, substrate, landform and ground cover present, and assess potential habitat using site observations and current specialist advice.

Foraging habitat: Diet and foraging

The Yampi form's foraging habitat and diet have not been documented.

What the Yampi Ctenotus eats, how it searches for food and which microhabitats it uses while foraging are not known.

Foraging habitat: Precaution at sites

During site inspections, record ground cover and other potential foraging features rather than treating any one feature as confirmed habitat. Avoid unnecessary removal or disturbance of ground cover before fauna checks.

Breeding habitat: Reproduction

Ctenotus decaneurus is recorded as oviparous, but breeding-site details for the Yampi form are not known.

The Yampi form's breeding months, egg numbers, incubation information and nesting-site locations and characteristics have not been documented.

Breeding habitat: Works planning

Do not assign a breeding season or presume a site is free of eggs or young based on calendar dates. Use fauna checks and staged works precautions where suitable habitat or animals are encountered.

Sheltering habitat: Known information

Shelter sites and refuge behaviour have not been documented for the Yampi Ctenotus.

Burrows, rock refuges, vegetation cover, sheltering behaviour and daily refuge use are not described for this taxon.

Sheltering habitat: Precautionary searches

As general skink survey practice, check ground-level cover and potential refuges carefully where present, and replace any cover objects after inspection. Do not infer that a particular refuge type is used by this taxon without evidence.

Threats: Known pressures

Specific threats to the Yampi Ctenotus have not been identified.

No taxon-specific threat assessment or documented response to clearing, fire, introduced predators or other pressures is available.

Threats: Site risk

Treat the limited known distribution and poor knowledge as reasons for cautious site assessment, not as evidence of a particular threat or population trend. Record potential impacts and refer significant findings to the project ecologist.

Survey methodology: 1. Desktop assessment

Survey detectability and effective survey conditions are not known for this taxon. Use methods appropriate for skinks and the habitat present.

Check current DBCA information, available fauna records and the project's ecological assessments. Note that Atlas of Living Australia records show few WA records and that taxonomic names may differ between sources.

Survey methodology: 2. Field searches

As general skink survey practice, use careful visual searches of ground-level habitat and potential refuges. Conduct searches across representative parts of the site and record effort, conditions, habitat and any animals observed.

Consider trapping only where appropriate to the assessment, with required approvals, suitable equipment, frequent checking and trained personnel.

Survey methodology: 3. Identification and records

Photograph animals where this can be done safely and without undue handling. Record location, date, identification basis and habitat observations; seek expert confirmation for uncertain records, especially where scale counts or names are in question.

Vegetation associations

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

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

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: 1. Confirm the assessment area

Plan surveys and clearing controls with the limited distribution information and lack of documented habitat or seasonal requirements in mind.

Review the clearing footprint, access routes and staging areas. Check current records and consult the project ecologist about whether targeted survey or further advice is warranted.

Before habitat disturbance: 2. Brief crews

Explain how to pause work and report a suspected skink, and identify the fauna spotter catcher responsible for decisions. Mark approved work areas and no-go areas clearly.

Before habitat disturbance: 3. Prepare controls

Where required by approvals or the project ecologist, arrange a pre-clearance inspection and staged clearing. Keep equipment, materials and vehicle movements within approved areas.

During habitat disturbance: 1. Supervise clearing

Use active supervision and a stop-work response for suspected Yampi Ctenotus or other fauna.

Have the fauna spotter catcher inspect the work area as required by the approved clearing procedure. Proceed in stages where specified, allowing inspections to keep pace with clearing.

During habitat disturbance: 2. Respond to an animal

Pause work around an animal or suspected refuge, protect it from vehicles and machinery, and notify the fauna spotter catcher. Capture, handling or relocation should be undertaken only by appropriately authorised and competent personnel in accordance with project requirements.

During habitat disturbance: 3. Record and escalate

Record the location, circumstances, photographs where appropriate, identification confidence and action taken. Escalate an uncertain identification, injury or mortality through the project's fauna incident procedure.

After habitat disturbance: 1. Check the work area

After clearing, document outcomes and check that disturbance stayed within the approved footprint.

Inspect the cleared area and adjoining work boundary for fauna, injured animals or unexpected refuge disturbance where required by the project procedure. Stop and report any new finding.

After habitat disturbance: 2. Close out records

Submit survey and fauna handling records, including negative search results, effort, locations and any uncertainty in identification. Provide confirmed records to the project ecologist for appropriate reporting.

Rehabilitation actions: 1. Reinstate disturbed areas

Rehabilitation requirements specific to the Yampi Ctenotus are not known.

Rehabilitate temporarily disturbed areas in line with project commitments and the locally appropriate restoration plan. Use site-derived reference information rather than assuming a particular habitat type for this taxon.

Rehabilitation actions: 2. Monitor and adapt

Record rehabilitation actions and outcomes, and report any later fauna observations to the project ecologist. Do not claim that rehabilitation provides habitat for the Yampi Ctenotus without supporting site evidence.

Sources