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Gutha Pintharuka Shield-backed Trapdoor Spider (Idiosoma gutharuka)

The Gutha Pintharuka Shield-backed Trapdoor Spider is a Western Australian species of Idiosoma in the nigrum-group. It is known from few locations around Gutha and Pintharuka, but its habitat and ecology are poorly documented, so development works in the area should use precautionary survey and clearing practices. It is listed as Priority 1 on the DBCA Threatened and Priority Fauna List.

Conservation status

Western Australia, WA Threatened and Priority Fauna List: Priority 1.

Seasonal planning

Species-specific seasonal activity and breeding information are not available. Use year-round precautionary planning rather than assuming a seasonal low-risk period.

Species timing: Not documented.

Planning approach: Plan surveys and precautionary work controls for any season.

Seasonal timing for this species is unknown.

  • Precautionary works planning: Planning window only. These markers do not represent known seasonal activity or breeding for this species.

Identification: Appearance and size

This poorly known Idiosoma species should be identified cautiously in the field and confirmed by a suitably qualified arachnologist.

The species belongs to the Idiosoma nigrum-group of shield-backed trapdoor spiders. The group is characterised by an enlarged, hardened third pair of abdominal sigilla associated with phragmotic defence.

No body size has been recorded for this species. The group-level feature alone is not sufficient to confirm a field identification.

Identification: Similar species

Other Idiosoma species occur in Western Australia, including members of the nigrum-group. Field characters that reliably distinguish this species from those relatives have not been documented.

Identification: Field signs

A species-specific description of its burrow entrance or other field signs has not been documented. As general practice for trapdoor spiders, look carefully for possible burrow entrances in suitable ground, but do not treat an unconfirmed entrance as evidence of this species.

Distribution: Known range

Records indicate a very restricted and incompletely known Western Australian range.

The species is recorded from Western Australia. Gutha, near Pintharuka, is identified as its type locality and is described as being in the northern Avon Wheatbelt.

Atlas of Living Australia records show seven Western Australian records at three distinct 0.1-degree locations, with coordinates spanning latitude -29.2 to -29 and longitude 115.9 to 117.2. These records identify no additional named places.

Distribution: WA listing region

The DBCA list flags the Midwest region. Records are few, and the species is known from few locations, none of which are on conservation lands.

Habitat: Recorded habitat

The species' preferred vegetation, soil and other habitat conditions have not been documented.

The type locality is Gutha near Pintharuka, but habitat conditions at the site and for the species have not been described.

Habitat: Site assessment

Do not assume that apparently unsuitable or modified ground is unoccupied. For site planning, use the known locality and any verified records as search prompts, and assess ground conditions across the proposed disturbance area.

Foraging habitat: Diet and foraging

Species-specific foraging habitat and diet have not been documented.

Prey items, foraging schedules and species-specific foraging behaviour have not been reported.

Foraging habitat: Practical consideration

Avoid disturbing potential shelter sites while searching for indirect signs. Do not infer species presence or absence from prey availability or the absence of visible foraging activity.

Breeding habitat: Available records

Breeding sites and timing have not been described for this species.

A 2026 paper reports the first female specimens of the species. It provides no information about mating, egg laying, offspring or breeding habitat.

Breeding habitat: Precaution

Do not schedule works on the assumption that the species breeds only in a particular season or habitat. Treat potential shelter sites as potentially important throughout the works period.

Sheltering habitat: Shelter information

The species is a shield-backed trapdoor spider, but its burrow construction and shelter-site preferences have not been described.

Burrow depth, entrance form, soil type and shelter placement have not been documented for this species. A general Idiosoma overview describes burrow-dwelling behaviour, but this does not establish this species' burrow details.

Sheltering habitat: Search implication

As general practice for trapdoor spiders, inspect the ground surface closely for possible burrow openings. Avoid probing, digging or pouring liquid into suspected burrows during initial searches.

Threats: Conservation status

Specific threats to this species and the effects of disturbance have not been identified or quantified.

The species is Priority 1 on the DBCA Threatened and Priority Fauna List, dated 1 July 2025. This is a DBCA priority category, not a listing under the Biodiversity Conservation Act 2016.

The species is poorly known, recorded from few locations, and has no records from conservation lands. No national listing is given.

Threats: Works risk

Because the known range is limited and records are sparse, disturbance in or near known locations warrants careful checking. This is a precaution for planning and does not indicate a documented species-specific response to disturbance.

Survey methodology: 1. Desktop assessment

Survey methods should account for sparse records and the possibility that a ground-dwelling trapdoor spider may not be visible during a brief inspection.

Check current DBCA information and available occurrence records, including the known Gutha and Pintharuka area and the Midwest region flagged on the WA list. Confirm whether records have been updated since the datasets were compiled.

Survey methodology: 2. Ground search

As general practice for trapdoor spiders, conduct a slow, close inspection of the ground surface for possible burrow entrances. Search across the proposed disturbance footprint and relevant adjacent areas, including areas where machinery access or laydown is proposed.

Record search effort, ground conditions, locations and any suspected signs. Photograph potential signs without disturbing them, and seek expert confirmation where identification is uncertain.

Survey methodology: 3. Detection limits

A validated survey method, seasonal detection window and detectability rate have not been reported for this species. A survey that finds no signs should not be presented as proof of absence.

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 records and footprint

Plan works around uncertainty in the species' distribution and ecology, especially near known records.

Review current occurrence information and map known records against the development footprint. Include access routes, temporary work areas and service corridors in the assessment.

Before habitat disturbance: 2. Survey and plan controls

Arrange a suitably experienced survey before clearing where the site is within or near the known range. Agree on a response process for suspected burrows or spiders before works begin, including who can pause work and who can confirm identification.

During habitat disturbance: 1. Work carefully

Use cautious, staged work practices and respond promptly to suspected animals or burrows.

Keep clearing within the approved footprint and avoid unnecessary vehicle movements over ground that has not been checked. Where practical, use staged clearing so newly exposed ground can be inspected before work proceeds.

During habitat disturbance: 2. Respond to finds

If a suspected spider or burrow is found, pause disturbance in the immediate area, prevent trampling or machinery entry, and contact the nominated fauna specialist. Do not excavate or handle the animal unless an appropriately authorised and competent person determines the safe response.

After habitat disturbance: 1. Record outcomes

Maintain records and check the outcome of any fauna response after disturbance has occurred.

Document the location, date, work activity, photographs, identification outcome and actions taken for any suspected or confirmed record. Share confirmed records through the relevant project and agency reporting processes.

After habitat disturbance: 2. Review controls

Review whether the survey and work controls were effective before continuing in similar areas. Keep any agreed avoidance or access controls in place until the responsible specialist or relevant authority advises otherwise.

Rehabilitation actions: 1. Protect retained ground

Rehabilitation should avoid creating further disturbance and should not be treated as a substitute for avoiding impacts to known or suspected shelter sites.

Keep machinery, stockpiles and rehabilitation traffic out of retained areas identified as potential habitat or containing suspected burrows. Avoid grading or compaction beyond what the approved rehabilitation design requires.

Rehabilitation actions: 2. Track recovery

Record rehabilitation actions and any later observations of possible burrows or spiders. Species-specific rehabilitation requirements and evidence that restored sites will be recolonised have not been documented.

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