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Irvine's Bothriembryontid Land Snail (Cape Naturaliste) (Bothriembryon irvineanus)

Irvine's bothriembryontid land snail is a terrestrial snail known from a small number of records in the South West of Western Australia. Its appearance, habitat and life history are poorly documented, so works should use cautious search and handling practices. It is listed as DBCA Priority 2.

Conservation status

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

Seasonal planning

Species-specific activity, breeding and movement months are unknown. This is a general planning note, not a taxon-specific seasonal window.

Months are not specified for this species. The general planning row does not indicate known activity or breeding periods.

  • Survey and works planning: No species-specific seasonal information is known. Plan checks before disturbance throughout the year and seek ecological advice on conditions appropriate for local survey work.

Identification: Appearance and size

This is a terrestrial land snail, but diagnostic field characters have not been documented.

The live animal and shell have not been described, including their colour, shape and size. Do not identify this species from an assumed shell feature.

Identification: Similar species

Species-level differences from other land snails have not been documented. Record uncertain finds as land snails for expert review rather than assigning a species name in the field.

Identification: Field signs

Species-specific field signs have not been documented. As general land-snail search practice, look carefully for live snails and shells in ground-level material, and retain photographs and location details for identification.

Distribution: Known range

Known records place the species in the South West of Western Australia. No named survey sites are recorded beyond the place referenced in its common name.

Atlas of Living Australia records show 9 Western Australian records at 7 distinct 0.1-degree locations, spanning approximately latitude -34.3 to -33.5 and longitude 115.0 to 115.2. Records outside Western Australia were excluded as likely errors.

Distribution: WA region and status

DBCA flags the South West region. The taxon is Priority 2 on the DBCA Threatened and Priority Fauna List dated 1 July 2025, described as poorly known and known from few locations, with some on conservation lands. It has no national listing. DBCA Priority 2 is a priority-list category, not a listing under the Biodiversity Conservation Act 2016.

Habitat: Recorded habitat

The species' habitat, vegetation and landforms have not been documented.

Species-specific habitat information has not been recorded. Regional occurrence data do not establish which site features the species occupies.

Habitat: Site assessment

Do not infer that a site is unsuitable from broad vegetation or landform descriptions alone. Check for land snails and shells wherever works overlap the known regional range, and document the site conditions around any find.

Foraging habitat: Diet and feeding

The species' diet and feeding locations have not been documented.

Food items, feeding behaviour and foraging habitat are unknown.

Foraging habitat: Precaution

Avoid removing or disturbing ground material during searches unless authorised. If a snail or shell is found, record its position and the immediate site context without assuming what it was feeding on.

Breeding habitat: Breeding information

Breeding season, breeding sites and reproductive details have not been documented.

The timing and location of breeding, and details of eggs, clutch size and development, are unknown.

Breeding habitat: Works planning

Do not assume any time of year is free of breeding risk. If a snail is found before or during works, seek ecological advice on the appropriate response and avoid disturbing it unnecessarily.

Sheltering habitat: Shelter information

The species' sheltering sites and behaviour have not been documented.

It is unknown where the species shelters, whether it uses particular cover, or how it responds to dry or adverse conditions.

Sheltering habitat: Search approach

As general land-snail search practice, inspect accessible ground-level cover and accumulated material carefully, returning it to its original position where practical. Treat any shell or live snail as a potential record until identified.

Threats: Documented threats

Specific threats to this species have not been identified.

The Priority 2 category reflects that the species is poorly known and known from few locations, rather than a stated threat assessment.

Threats: Potential site pressures

Clearing, vehicle movements and handling of ground material may affect land snails generally. Treat these as precautionary worksite risks, not as confirmed species-specific threats.

Survey methodology: 1. Desktop assessment

No species-specific survey method or detectability information is available. Use a cautious, documented land-snail search approach and seek expert advice where needed.

Check the proposed works against the known Western Australian record envelope and the South West region flagged by DBCA. Review records and site information, but do not assume the species is absent because no records are mapped.

Survey methodology: 2. Field search

As general practice for land snails, search suitable ground-level material methodically and carefully, including accessible cover and accumulations of natural material. Avoid unnecessary disturbance and do not collect specimens unless authorised.

Survey methodology: 3. Record and verify

Photograph any live animal or shell in place, record coordinates and conditions at the find, and have the identification checked by a suitably experienced person. Taxon-specific detectability, a seasonal survey window and a survey protocol are not known.

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. Plan and brief

Plan works with the species' habitat and survey requirements in mind, noting that these are not known.

Make the crew aware of the species' DBCA Priority 2 status and the limits of current knowledge. Define areas to be cleared and arrange an ecological inspection where works are within the known regional range.

Before habitat disturbance: 2. Inspect and minimise

Before clearing, have a suitably experienced person check the work area for land snails and shells using a careful, low-disturbance search. Minimise the area disturbed and avoid moving ground material before the inspection is complete.

During habitat disturbance: 1. Pause nearby work

If a possible land snail or shell is encountered during works, stop and check before proceeding.

Stop work in the immediate area of a possible find, avoid crushing or handling it, and notify the fauna spotter catcher or project ecologist. Do not assume an unidentified snail is Irvine's bothriembryontid land snail.

During habitat disturbance: 2. Assess and proceed

Photograph and record the find in place, then seek identification and direction from the responsible ecologist. Resume work in the affected area only after the appropriate response has been agreed.

After habitat disturbance: 1. Report findings

After works, retain search and find records to preserve information about this poorly known species.

Document survey effort, locations checked, conditions, photographs and any live snails or shells found. Clearly distinguish confirmed identification from an unverified land-snail record.

After habitat disturbance: 2. Review outcomes

Pass relevant records and identification outcomes to the project ecologist for review and any required reporting. Do not infer absence from a survey where the method or detectability is uncertain.

Rehabilitation actions: 1. Reinstate disturbed areas

Species-specific rehabilitation requirements and habitat targets have not been documented.

Where consistent with the approved rehabilitation plan, reinstate disturbed ground and ground-level material carefully, avoiding unnecessary movement of material from elsewhere. These are general precautions, not a species-specific prescription.

Rehabilitation actions: 2. Check and document

Record rehabilitation actions and any subsequent land-snail observations. Describe an area as suitable for this species only if this has been established through appropriate ecological assessment.

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