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Julimar Shield-backed Trapdoor Spider (Idiosoma mcclementsorum)

The Julimar shield-backed trapdoor spider is a Western Australian species of shield-backed trapdoor spider, described in 2018 and recorded from the Avon Wheatbelt, Jarrah Forest and Swan Coastal Plain bioregions. Its habitat preferences, size and seasonal activity are not documented, so potential burrow habitat should be checked carefully before ground disturbance. It is listed as Priority 2 on the WA DBCA Priority Fauna List.

Conservation status

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

Seasonal information

Species-specific seasonal activity, breeding and movement periods have not been documented. The rows below provide precautionary planning guidance, not a description of known seasonal biology.

Breeding season: Not recorded.

Survey season: No species-specific survey season has been recorded.

No month-specific biological information for this species was found.

  • Survey and works planning: Planning window only: seasonal activity is unknown, so arrange surveys and precautions in time to inform works rather than assuming any month is low risk.
  • Potential ground disturbance: Planning window only: apply pre-disturbance checks and stop-work precautions year-round because species-specific seasonal risk is unknown.

Identification: Appearance and size

Described in 2018, this species has limited field-identification information. Refer uncertain records to a suitably experienced arachnologist.

It is a shield-backed trapdoor spider in the Idiosoma nigrum-group. Species in this group have enlarged, hardened third abdominal sigilla associated with phragmotic defence. No size data have been recorded for Idiosoma mcclementsorum.

Identification: Similar species

Idiosoma jarrah is identified as its sister species in the 2018 study. Field characters for separating these species are not documented, so do not identify this spider from locality alone.

Identification: Field signs

No distinctive entrance or burrow sign is documented for this species. As general trapdoor-spider search practice, inspect the soil surface for possible burrow openings and avoid treating an unverified opening as a confirmed record.

Distribution: Known range

The species is recorded in south-western Western Australia. Its full range is not established.

The species is reported from the Avon Wheatbelt, Jarrah Forest and Swan Coastal Plain bioregions. The type locality is Julimar Conservation Park, about 60 km north-east of Perth.

Distribution: WA regions and records

The DBCA Priority Fauna List flags the Wheatbelt and Swan regions. Atlas of Living Australia records show 15 Western Australian records at nine distinct 0.1-degree locations, between latitude -31.6 and -31 and longitude 116 and 116.5. Records outside Western Australia were excluded as likely errors.

Habitat: Documented setting

The species is known from several broad bioregions and a type locality, but its preferred vegetation, soils and site conditions are not documented.

Records are associated with the Avon Wheatbelt, Jarrah Forest and Swan Coastal Plain bioregions. Julimar Conservation Park is the named type locality.

Habitat: Limits of habitat information

Soil type, vegetation structure, slope, moisture conditions and use of disturbed land have not been documented for this species. Assess each site on its observed conditions rather than assuming the species is restricted to a particular vegetation type.

Foraging habitat: Diet and foraging

The species' diet and foraging habitat have not been documented.

No prey, foraging method or foraging period has been recorded for Idiosoma mcclementsorum.

Foraging habitat: Site checks

Do not infer prey availability or foraging habitat from records of other Idiosoma species. During site assessment, note the ground conditions and potential burrow locations without disturbing them.

Breeding habitat: Breeding information

Breeding habitat and timing have not been documented for this species.

Information on mating, egg laying, egg sacs, young and seasonal breeding is not documented for this species.

Breeding habitat: Precaution

Do not schedule works on the assumption that a particular season is free of breeding activity. Treat potential shelter sites cautiously throughout the year unless site-specific evidence supports another approach.

Sheltering habitat: Species information

This is a trapdoor spider, but its burrow structure and shelter-site requirements have not been documented.

Burrow dimensions, entrance features, depth and sheltering conditions have not been recorded for this species.

Sheltering habitat: General search precaution

As general practice for trapdoor spiders, check suitable ground carefully for possible burrow openings before disturbing soil. Do not excavate or probe suspected burrows merely to confirm their presence.

Threats: Conservation status

The species is listed as Priority 2 by DBCA. Specific threats to Idiosoma mcclementsorum have not been identified.

Priority 2 means the species is poorly known and known from few locations, with some locations on conservation lands, as stated in the DBCA listing. This is a DBCA priority category, not a listing under the Biodiversity Conservation Act 2016. No national listing is given.

Threats: Disturbance risks

Specific threats to this species have not been assessed. As a precaution for burrow-dwelling spiders, avoid unnecessary soil disturbance and compaction where potential burrow habitat is present.

Survey methodology: 1. Desktop assessment

Species-specific survey methods and detectability have not been documented. Use a cautious, non-destructive search and record the limits of each survey.

Check whether the site lies in the reported Avon Wheatbelt, Jarrah Forest or Swan Coastal Plain range, and review records and previous survey information. A regional match is not confirmation of presence.

Survey methodology: 2. Ground search

As general trapdoor-spider survey practice, slowly inspect the ground surface for possible burrow openings in areas that may be affected. Avoid trampling, scraping, probing or excavating suspected burrows.

Survey methodology: 3. Record and verify

Photograph and map potential signs without disturbing them, and record search effort, conditions and areas that could not be checked. Seek expert identification for specimens or signs that cannot be confidently assigned to species.

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. Review the footprint

Plan works on the basis that the species is poorly known and may be difficult to detect. A lack of observed spiders is not evidence that potential burrow habitat is unoccupied.

Check the development footprint against the known regional range and the named Julimar locality. Review records and survey limitations with the project ecologist.

Before habitat disturbance: 2. Survey and mark

Arrange a pre-disturbance ground search by a suitably experienced ecologist where potential habitat will be affected. Mark any suspected burrow areas for avoidance and communicate these locations to the clearing crew.

Before habitat disturbance: 3. Brief the crew

Explain the species' Priority 2 status, the limits of identification information, and the stop-work and escalation process for unexpected spider or burrow finds.

During habitat disturbance: 1. Maintain marked areas

Use avoidance and careful supervision where potential burrow habitat overlaps the works area. Do not handle or destroy suspected spiders or burrows.

Keep machinery, vehicles, stockpiles and foot traffic out of marked avoidance areas. Keep clearing within the approved footprint.

During habitat disturbance: 2. Stop and assess

If a suspected spider or burrow is found, stop work in the immediate area, prevent further disturbance and contact the project ecologist. Do not excavate, fill or move the animal.

During habitat disturbance: 3. Document the event

Record the location, photographs, circumstances and any work already undertaken. Resume only after the ecologist has assessed the find and advised on the appropriate response.

After habitat disturbance: 1. Check managed areas

After works, retain records of searches, finds and management actions to inform future site decisions.

Have the ecologist inspect affected and retained areas for signs of additional disturbance or unrecorded potential burrows, where this can be done without damaging them.

After habitat disturbance: 2. Report and retain records

Keep survey results, photographs, mapped locations, incident records and the actions taken in the project file. Follow applicable DBCA advice and project approval conditions.

Rehabilitation actions: 1. Restore the site carefully

Species-specific rehabilitation requirements have not been documented. Avoid additional ground disturbance and follow site-specific ecological advice.

Reinstate disturbed ground and vegetation using the approved site rehabilitation plan, while avoiding unnecessary compaction or grading in retained potential habitat.

Rehabilitation actions: 2. Monitor and adapt

Record rehabilitation methods and inspect outcomes as required by the project plan. Do not claim habitat suitability or successful recolonisation without supporting evidence.

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