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Eastern Massif Assassin Spider (Zephyrarchaea robinsi)

Eastern Massif Assassin Spider (Zephyrarchaea robinsi) is an assassin spider (family Archaeidae), a tiny spider that hunts other spiders, listed for the South Coast region of Western Australia. It is Vulnerable under the Biodiversity Conservation Act 2016 (WA), Fauna Order 2025(2) in operation from 1 August 2026, and not listed under the EPBC Act. Rix and Harvey (2012) describe Zephyrarchaea as relictual assassin spiders of southern Australia, found in elevated leaf litter and low vegetation in mesic habitats.

Conservation status

Western Australia, Biodiversity Conservation Act 2016: Vulnerable.

Seasonal planning

No species-specific activity or breeding months are recorded. Use the following as a works-planning prompt, not as a statement of seasonal biology.

Seasonal knowledge: Unknown for this species.

The month values are a general planning prompt only and do not represent known activity or breeding months for Zephyrarchaea robinsi.

  • Plan checks before disturbance: General planning window only. Check the work area before disturbance whenever works are scheduled; no species-specific seasonal window is known.

Identification: Appearance

Eastern Massif Assassin Spider is an assassin spider (family Archaeidae), a tiny spider that hunts other spiders. Reliable identification needs a specialist.

A species-specific field description is not summarised here. Use the original description and museum specimens for identification.

Identification: Similar species

Related species in the same genus or group can look alike and may occur nearby. Confirm identity with a taxonomist before relying on a record.

Distribution: Known records

Listed for the South Coast region.

The Atlas of Living Australia holds 7 records at 2 distinct 0.1-degree locations, around latitude -34.4, longitude 118.3 to 118.4. Coordinates are often generalised for listed species, so treat this as an indicative area, not a boundary.

Distribution: Group pattern

Rix and Harvey (2012) describe Zephyrarchaea as relictual assassin spiders of southern Australia, found in elevated leaf litter and low vegetation in mesic habitats. Most south-western species are known from one mountain or a small coastal area.

Distribution: WA listing

DBCA lists the species for the South Coast region.

Habitat: Habitat

Moist, sheltered vegetation and suspended leaf litter on the slopes or summits of its known locality.

Moist, sheltered vegetation and suspended leaf litter on the slopes or summits of its known locality.

Species-specific habitat preferences have not been published in detail; this is based on the group and the listed locality.

Habitat: Site interpretation

Treat matching habitat in or near the listed locality as potentially occupied until a qualified survey shows otherwise.

Foraging habitat: Diet

Assassin spiders prey on other spiders. Feeding has not been studied in this species.

Assassin spiders prey on other spiders. Feeding has not been studied in this species.

Breeding habitat: Breeding

Not documented.

Not documented.

Sheltering habitat: Shelter

Dense, moist understorey and litter that hold humidity through summer.

Dense, moist understorey and litter that hold humidity through summer.

Threats: Threats

Rix and Harvey link their distributions to cool, wet refuges, so fire, drying climate and dieback that open up these refuges are the main threats.

Rix and Harvey link their distributions to cool, wet refuges, so fire, drying climate and dieback that open up these refuges are the main threats.

Threats: Works risk

Clearing of understorey, fire and dieback spread at the known locality.

Survey methodology: 1. Desktop review and design

Follow the EPA Western Australia technical guidance and engage specialists with the right licences.

Use the EPA Western Australia guidance on short range endemic invertebrates: desktop review of museum and survey records, targeted habitat searches, and collection or photography under the right licence.

Survey methodology: 2. Field survey

Search the habitat named in this profile by hand (litter, logs, rocks, burrows or host plants), and repeat after rain or in the cooler months when many short range invertebrates are active.

Survey methodology: 3. Identification and limits

Identification often needs a specialist taxonomist and voucher specimens. A non-detection is not 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 disturbance: 1. Pre-start review

Confirm whether the project could affect the species before any works begin.

Check the project footprint against the listed locality, DBCA records and any survey results. Map habitat that matches this profile.

Before disturbance: 2. Approvals

Taking or disturbing listed threatened fauna in WA needs authorisation under the Biodiversity Conservation Act 2016. Seek DBCA advice early.

Before disturbance: 3. Crew briefing

Brief crews on the habitat to avoid, the exclusion areas and who to call if the species or its habitat is found.

During disturbance: 1. Protect habitat

Keep works inside the approved footprint.

Clearing of understorey, fire and dieback spread at the known locality. Fence or flag known habitat and keep vehicles, stockpiles and spoil out of it.

During disturbance: 2. Stop and report

If the species or suspected habitat is found outside the approved area, stop work at that spot and contact the project ecologist and DBCA.

After disturbance: 1. Record outcomes

Record what was done.

Record any sightings, specimens, habitat lost or retained and any incidents, and submit records to DBCA as required by the authorisation.

Rehabilitation: 1. Restore

Restore disturbed areas where possible.

Return surface materials, logs, rocks and litter, restore drainage and revegetate with local species. Use hygiene controls for dieback in the south-west.

Sources