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Centralian Ranges Brood Frog (Pseudophryne robinsoni)

The Centralian Ranges Brood Frog is a small terrestrial myobatrachid frog known from spring-fed pools, rock holes and creek gorges in the Musgrave and Everard Ranges of north-west South Australia. It shelters in damp litter, sedge, bulrush stems, rock crevices and beneath loose rocks, so clearing, access tracks, groundwater change and damage to riparian areas can affect occupied habitat even where surface water is limited.

Conservation status

South Australia, National Parks and Wildlife Act 1972: Vulnerable.

Breeding season

Breeding is believed to occur from autumn to spring, with calling recorded mainly from March to October and a calling peak in May. Eggs and larval timing are poorly documented, so clearing, draining and dewatering near spring-fed pools, waterholes, damp margins and rock crevices should be managed as a year-round risk.

Reproductive mode: Not confirmed for this species. The genus generally lays non-aquatic eggs in concealed terrestrial nests, with hatching triggered when nests flood.

Clutch size: Not recorded.

Incubation or gestation: Not recorded for this species.

Size at hatching or birth: Not recorded.

Age at maturity: Not recorded.

Nest or egg sites: Species-specific egg sites have not been documented. Recorded habitat includes spring-fed pools, waterholes, damp margins, damp soil, litter and horizontal crevices immediately above the water line.

Breeding frequency: Not recorded. Breeding is reported as opportunistic from autumn to spring.

Confirm timing locally before works, especially after rainfall, because breeding and calling are linked to autumn to spring conditions and the available evidence indicates rainfall and moisture can trigger reproductive activity.

  • Calling: Calling is recorded as possible in March and April, definite in May, possible from June to October, and absent in November to February. May is the only documented peak month in the supplied monthly table.
  • Egg laying: Breeding is believed to occur in autumn and is also reported as opportunistic from autumn to spring, which corresponds broadly to March to November. Eggs have not been documented for this species; genus-level information indicates terrestrial eggs are laid in concealed nests near areas that can flood.
  • Eggs in nest: The species' egg stage and nest sites are unknown. As a genus-level pattern, eggs are held in terrestrial nests until flooding induces hatching, so autumn to spring breeding habitat should be retained and checked.
  • Active period: No species-specific activity season is documented. Adults have been recorded in March, May, June, September, October and November, and occupied shelters are associated with permanent or semi-permanent water features, so spotters should allow for activity and movement in all months, particularly after suitable rainfall.
  • Highest clearing risk: Use a year-round high-risk rating for occupied habitat. Breeding and young timing are incomplete, and adults may shelter at water features and damp margins in any month; clearing, rock movement, vegetation removal, draining and dewatering can therefore affect frogs or unknown life stages.

Identification

This is a small, compact Pseudophryne with a distinctive dark and white belly pattern. Identification should be confirmed from several characters because western Pseudophryne species can be similar in size and colour.

Adults are small, with a rounded, slightly prominent snout and short hind legs. The dorsal surface is tubercular and may show short longitudinal ridges. The crown is light brown and low contrast, while the back is khaki to light brown with irregular dark, nearly black lines or patches.

A narrow orange-brown stripe is usually present along the urostyle, typically about 10 percent of snout to vent length. Orange-brown colour may occur on the upper arm and along the upper thigh. The abdomen has large irregular white marks on a black background, with finer white spotting on the throat and groin.

Female snout to vent length: 27.0 ± 1.8 mm, range 25.2 to 29.4 mm in the measured sample.

Male snout to vent length: 25.3 ± 1.3 mm, range 23.8 to 27.3 mm in the measured sample.

Tympanum: Absent.

Interdigital webbing: Absent on the fingers and toes.

Identification: Distinguishing characters

The species has very small inner and outer metatarsal tubercles, usually unequal in size. Its underside has large white marks on a black background, unlike Pseudophryne guentheri, which has small black marks on white, and P. occidentalis, which has large black marks on white.

It lacks the post-femoral gland found in some eastern Pseudophryne and lacks the strong red, yellow or striped characters used to separate several eastern species. Compared with western Pseudophryne, the combination of very small metatarsal tubercles and the black and white ventral pattern is the most useful field distinction.

Identification: Field signs and sex

The male advertisement call is not known. No reliable species-specific information is supplied for tracks, scat, eyeshine, nests or sloughs. Do not record an absence of calling as evidence that the species is absent.

Males and females overlap in size. The measured females were generally larger than the measured males, but size alone is not a reliable field sexing character.

  • Search damp mud, litter, sedge bases, rock crevices and the margins of spring-fed pools for live animals rather than relying on calls.
  • Photograph the dorsal and ventral surfaces and the feet where handling is authorised, as the underside pattern and metatarsal tubercles assist confirmation.

Distribution: Confirmed range

The confirmed Australian range is restricted to central South Australia. Records outside the described range need careful checking because the status of some Central Ranges specimens remains unresolved.

Pseudophryne robinsoni is known from the Musgrave Ranges and a limited number of locations near Mount Illbillee in the Everard Ranges of north-west South Australia. The type locality is Alalka Creek gorge, 14.1 km north of Pukatja in the Musgrave Ranges.

The supplied sources do not assign the species to named IBRA bioregions. No confirmed population is documented from another Australian state.

Confirmed state: South Australia.

Known range areas: Musgrave Ranges and sites near Mount Illbillee in the Everard Ranges.

Type locality: Alalka Creek gorge, 14.1 km north of Pukatja, Musgrave Ranges.

Distribution: Subpopulations and status

The Musgrave Ranges population is represented by six specimens collected between 1973 and 2009. Everard Ranges specimens were collected over a 30 year period from 1970 to 2000, and the species was reported as common in rock holes in the Everard Ranges during surveys from 1991 to 2001.

The authors considered the species range to be poorly surveyed and recommended broader surveys. They described potential populations as highly fragmented and restricted, but no total population estimate or population trend was provided.

Population estimate: Not available.

Population trend: Not established.

Survey evidence: Reported common in Everard Ranges rock holes during 1991 to 2001 surveys.

  • Treat records from the Bell Rock and Tomkinson Ranges as requiring confirmation. Their taxonomic status was unresolved in the supplied study.
  • Do not extend the confirmed range into Western Australia solely from the Ninuku Spring photograph or Bell Rock specimens described in the study.

Habitat: Habitat types

The species is associated with rocky ranges containing permanent or semi-permanent water features, damp ground and dense plant material. The available records are from springs, pools, rock holes, creek gorges and waterhole margins.

In the Everard Ranges, animals were collected in water under loose rocks at the main waterhole in Victory Well Creek. In the eastern Musgrave Ranges, animals were found around spring-fed pools on damp soil below seepage areas and beside dense bulrush stands.

Other records came from horizontal crevices just above the water line and from a creek gorge. These observations indicate that habitat can include both saturated sites and damp refuges immediately above water level.

Habitat: Vegetation and structure

Recorded vegetation included collapsed Cyperus vaginatus sedge growing in rock crevices below spring seepage and dead Typha domingensis stems below dense bulrushes on pool margins. Loose rocks, rock crevices, damp mud, leaf or plant litter and stable water edges are important habitat features at known sites.

No elevation limits, rainfall limits, tree size thresholds or vegetation community mapping were provided in the supplied sources.

  • Retain spring seepage, creek gorges, waterholes, pool margins, loose rocks, sedge, bulrush and damp litter within and beside the work area.
  • Map drainage lines and groundwater-dependent sites before clearing, including habitat above the visible water line.

Foraging habitat: Known information gap

The supplied sources do not report the species' diet, prey, feeding technique or foraging range. For field assessment, damp ground and sheltered margins around known water features should be treated as potential feeding habitat until specialist survey shows otherwise.

No food items, prey plants, feeding observations or home range measurements are provided. The species was recorded in damp mud and litter, under sedge, beneath bulrush stems, in rock holes and under loose rocks, but the sources do not state whether those locations were used for feeding, breeding or shelter at the time of capture.

Diet: Not reported.

Foraging range: Not reported.

Feeding period: Not reported.

  • Do not infer that dry ground is unused habitat solely because frogs were not visible during a daytime inspection.
  • Record damp litter, mud, sedge bases, bulrush margins, rock holes and seepage zones as potential foraging habitat during habitat mapping.

Breeding habitat: Breeding biology

Breeding requirements are poorly known. The species has been recorded around spring-fed pools, waterholes and water margins, but the supplied study did not establish the breeding season, eggs, larvae or nesting site.

The male advertisement call is not known. The sources do not report mating observations, egg deposition, tadpoles, clutch size, incubation, age at maturity or lifespan.

Records from March, May, June, September, October and November show that adults or specimens have been present across several parts of the year, but collection dates cannot be used to define the breeding season.

Breeding season: Unknown.

Clutch size: Not reported.

Incubation or larval period: Not reported.

Age at maturity: Not reported.

Lifespan: Not reported.

Male advertisement call: Unknown.

Breeding habitat: Breeding habitat features

Known sites include spring-fed pools, a main waterhole, pool margins, damp soil below spring seepage and horizontal crevices immediately above the water line. Dense Typha domingensis and collapsed Cyperus vaginatus were present at recorded Musgrave Ranges sites.

Because breeding has not been observed, all water edges, seepage zones, damp crevices and adjacent litter should be retained and assessed before disturbance.

  • Avoid changing surface drainage into or away from spring-fed pools, rock holes and creek waterholes.
  • Inspect damp margins and crevices above the water line, not only open water, before excavation or vegetation removal.

Sheltering habitat: Recorded refuges

The frog uses small, ground-level refuges associated with water and damp substrates. Several shelter types and substrates have been recorded directly.

Animals were found in water beneath loose rocks at the main waterhole in Victory Well Creek. In the Musgrave Ranges they were found on damp soil beneath collapsed sedge, under dead bulrush stems, and in horizontal crevices just above the water line.

A specimen was captured in damp mud and litter beneath Cyperus vaginatus growing at the base of Melaleuca in a creek gorge. These observations show that shelter is not limited to open water.

Recorded shelter substrates: Loose rocks, damp mud, litter, collapsed Cyperus vaginatus, dead Typha domingensis stems and horizontal rock crevices.

Shelter dimensions: Not reported.

Known association with water: Shelters were in water, beside spring-fed pools or just above the water line.

  • Retain loose rocks, rock crevices, damp mud, litter, collapsed sedge and dead bulrush stems at and above occupied water features.
  • Before moving rocks or removing aquatic and riparian vegetation, inspect the underside of cover and damp crevices with an experienced amphibian handler.

Threats: Documented threats

The documented threats relate mainly to damage to riparian and spring habitats and changes to groundwater persistence. The species' restricted and fragmented range increases the importance of protecting each occupied site.

The study identifies damage to riparian habitat by introduced camels and donkeys as a potential threat. Groundwater drawdown associated with mining operations may reduce the persistence of springs and other water features used by the species.

The authors considered populations potentially highly fragmented and restricted, and noted that much of the north-western South Australian range country remained unsurveyed.

  • Prevent vehicle and machinery access to spring margins, creek gorges, waterholes and rock holes where practicable.
  • Keep camels, donkeys and other introduced stock away from sensitive riparian sites where the project can control access.
  • Assess whether groundwater abstraction, dewatering or altered drainage could reduce spring flow or waterhole persistence.

Threats: Other project risks

The supplied sources do not specifically document effects from roads, fire, clearing, fragmentation, predation, disease or construction noise. These risks should still be assessed as standard amphibian project risks because they can remove cover, damage damp refuges or alter water movement.

No disease records or predator studies are provided for this species. Do not describe these pressures as confirmed local threats without site evidence.

  • Schedule habitat searches before clearing and after rainfall or other suitable wet conditions identified by the project ecologist.
  • Keep spoil, sediment, fuel and concrete washout away from pools, seepage zones, creek gorges and drainage lines.
  • Treat isolated spring and waterhole habitat as potentially occupied even if no frog is detected during a single visit.

Survey methodology: 1. Habitat assessment and daytime searches

Survey this frog in rocky ranges, spring-fed pools, waterholes and damp shelter close to seepage. The supplied species account does not provide a prescribed survey effort, and the male advertisement call is not known, so use habitat searches and document the limitations of detection.

Map rocky ranges, gorges, creek pools, spring seepages, waterholes, rock crevices, dense sedge and bulrush margins before selecting survey sites.

Search beneath loose rocks, collapsed sedge, dead bulrush stems, damp litter and other cool, moist shelter at the margins of water.

The species has been recorded in the Musgrave Ranges and at a limited number of locations near Mount Illbillee in the Everard Ranges in north-west South Australia.

Known range: Musgrave Ranges and limited locations near Mount Illbillee in the Everard Ranges, South Australia

Recorded shelter: Loose rocks, damp soil, collapsed Cyperus vaginatus sedge, dead Typha domingensis stems and rock crevices above the water line

  • Search all suitable habitat within the disturbance footprint and retained areas that could receive relocated animals.
  • Record the location, habitat feature, date, time, weather, recent rainfall, search duration, observers and area searched for every search.
  • Replace rocks, sedge and other cover immediately after inspection and avoid damaging spring-fed pools, seepage areas and riparian vegetation.

Survey methodology: 2. Nocturnal searches and call surveys

Use nocturnal searches around pools, seepages, waterholes and rock crevices when conditions are damp and animals are likely to be active.

Use a torch and inspect the ground, rock margins, vegetation bases and crevices systematically, while avoiding trampling wet margins.

Do not rely on call playback or call detection as the sole method because the species male advertisement call is not known in the supplied account.

Recorded collection months: March, May, June, September, October and November

Known call information: Male advertisement call not known

  • Time searches to include the months in which specimens have been recorded: March, May, June, September, October and November.
  • Record temperature, rainfall or recent rainfall, wind, cloud, humidity if available, water condition and start and finish times for each night.
  • Repeat searches after suitable rain where project timing allows, and state the number of nights and hours completed even when no frogs are detected.

Survey methodology: 3. Aquatic margin, rock and shelter searches

Inspect the main waterholes, spring-fed pools and damp ground below seepage points, with particular attention to shelter directly beside or above the water line.

Search both sides of suitable drainage lines and inspect rock holes, gorge floors, sedge bases and bulrush stands without removing more cover than necessary.

Treat a lack of detections cautiously because the published surveys did not target all rocky ranges and much of the north-west South Australian and eastern central Western Australian range country remained unsurveyed.

Survey limitation reported by authors: Much of the north-west range country of South Australia and eastern central Western Australia remained unsurveyed for amphibians

Historical observation: The species was reported as common in rock holes in the Everard Ranges area during the 1991 to 2001 Anangu Pitjantjatjara lands biological survey

  • Use fixed transects or mapped search areas where practical, and record transect length, width, search time and the area covered.
  • Separate records from occupied habitat, potential habitat and locations searched without detection.
  • Obtain photographs and precise coordinates for each detection and for each habitat feature proposed for retention.

Survey methodology: Minimum effort and reporting

  • Complete a habitat assessment, daytime shelter search and nocturnal search for every suitable habitat unit in the disturbance footprint and any proposed relocation area.
  • Set and report project-specific effort before fieldwork, including the number of observers, searchers, nights, hours, transect lengths, areas searched and conditions, because the supplied species account does not prescribe a minimum effort.
  • Have a suitably experienced amphibian ecologist review the method where works affect spring-fed pools, rock holes, gorges or other habitat in the known South Australian range.
  • Submit confirmed records, including zero-result survey data where required, to the relevant South Australian wildlife database and any other relevant state or territory biodiversity database.
  • Report the species name as Pseudophryne robinsoni and retain photographs, voucher details where authorised, coordinates and habitat notes with the project record.

Before habitat disturbance: Avoid and minimise

Plan works around the small number of known habitat types and the species' restricted recorded distribution. Avoid changes to water persistence, shelter and access between rocky habitat and wet areas.

Retain spring-fed pools, waterholes, rock holes, gorge floors, seepage lines and damp shelter beneath rocks, sedge and bulrush.

Keep intact connections between pools, seepages, rock crevices and nearby damp ground rather than isolating individual water points.

Prevent damage to riparian habitat and avoid activities that could reduce spring water persistence.

  • Keep construction compounds, access tracks, spoil, sediment stockpiles and drainage changes out of suitable frog habitat wherever practicable.
  • Do not remove loose rocks, collapsed Cyperus vaginatus, dead Typha domingensis or damp litter unless the approved method specifically addresses their removal.
  • Treat camel and donkey access, groundwater drawdown and mining-related changes to spring persistence as relevant risks when they occur in the project area.

Before habitat disturbance: Approvals and work planning

Check the current national and state conservation listing before works begin, and confirm whether the project needs a referral, state authorisation, scientific permit or wildlife handling authority.

Use the species' South Australian range and the presence of suitable rocky wet habitat to inform the approval assessment, even where the proposed footprint has no previous record.

Schedule works to avoid the recorded activity and collection months where the risk assessment indicates that animals may be using shelter or breeding habitat.

Known South Australian areas: Musgrave Ranges and limited locations near Mount Illbillee in the Everard Ranges

Recorded months to consider in scheduling: March, May, June, September, October and November

  • Include the species in the project fauna management plan when suitable habitat is present or when survey results are unresolved.
  • Stage clearing so that retained wet habitat remains available before any adjacent shelter or access route is removed.
  • Nominate an ecologist, fauna spotter catcher and stop-work decision maker before mobilisation.

Before habitat disturbance: Pre-clearance preparation

Complete a pre-clearance search immediately before disturbance in all mapped pools, seepages, rock holes, rock crevices, damp litter, sedge and bulrush habitat.

Mark habitat to be retained and mark approved access routes, exclusion zones and any relocation area before machinery enters the site.

Use exclusion fencing only where it can be installed without damaging seepage, wet margins, rocks or shelter, and inspect it regularly.

  • Brief machine operators on the frog's likely shelter sites and the requirement to stop when directed by the fauna spotter catcher.
  • Provide clean containers, damp unbleached cloth or other approved temporary holding equipment, clean water where directed by the amphibian handler, gloves and a transport plan before clearing starts.
  • Confirm the receiving habitat is nearby, suitable, free of active machinery and approved for relocation before any animal is moved.

During habitat disturbance: Daily controls and machinery interface

Use an active stop-and-search system during clearing. The spotter catcher must control the interaction between machinery, shelter features and any frog found.

Inspect exclusion fencing, retained pools, seepages, rock holes and access routes at the start of each shift and after heavy rain or site changes.

Keep machinery outside marked habitat until the fauna spotter catcher has completed the required search and given clearance.

Use staged, slow removal of cover and give the spotter catcher a clear view of rocks, damp litter, sedge bases, bulrush stems and ground beside water.

  • Stop machinery immediately when the spotter catcher signals, when an animal is found, when a marked habitat feature is disturbed unexpectedly or when sediment, fuel or contaminated water reaches wet habitat.
  • Do not allow operators or workers to handle frogs unless they are authorised under the project plan and applicable permit.
  • Keep vehicles, pumps, fuels, concrete washout and spoil away from pools, seepages and drainage lines.

During habitat disturbance: Handling and relocation

Have the authorised fauna handler identify the animal before moving it and minimise handling time, heat exposure, drying and contact with contaminated surfaces.

Relocate a healthy animal only to nearby, suitable retained habitat with comparable damp shelter and access to water, and only where the project approval and fauna management plan allow it.

Do not release an animal into exposed ground, flowing water, a construction area or habitat separated from the retained wet and rocky features it needs.

  • Record the capture location, time, condition, identification, handler, temporary holding method, release location and release time for every animal.
  • Keep handling and transport methods consistent with the relevant state permit, animal ethics requirements and amphibian disease-control procedures.
  • Place an injured or unwell animal in approved temporary care and contact the nominated wildlife carer, veterinarian or wildlife authority without delay.
  • Do not collect specimens or retain animals beyond the approved period unless the relevant authority has authorised it.

During habitat disturbance: Habitat features and stop-work triggers

Treat loose rocks, rock crevices, spring margins, collapsed sedge, dead bulrush, damp litter and waterholes as potential shelter until checked and cleared.

Stop work if a frog is found, if an unsearched suitable habitat feature is exposed, if water persistence is threatened, or if sediment, chemicals or machinery damage affects a pool or seepage.

Stop and seek ecological advice if the animal cannot be confidently identified or if the proposed relocation area is unsuitable.

  • Reinstate inspected rocks, sedge, bulrush and litter where practicable after the animal has been removed or the area has been cleared.
  • Notify the project ecologist and environmental manager of every detection, injury, mortality, relocation and unplanned habitat impact on the day it occurs.
  • Escalate repeated detections or mortality to the approval holder and relevant wildlife authority as required by the project approvals.

After habitat disturbance: Post-clearance checks

Post-clearance work must confirm that retained wet and rocky habitat remains intact and that controls continue to protect animals from construction impacts.

Inspect the cleared area, retained pools, seepages, waterholes, rock holes, access routes and exclusion fencing after each clearing stage.

Check for stranded, injured or dead frogs in machinery work areas, stockpiles, drainage structures and along fencing before the next work stage.

Repeat targeted searches after suitable rain and during the recorded March to November activity period where the risk assessment requires ongoing surveillance.

  • Keep fauna controls in place until the ecologist confirms that construction no longer poses a risk to retained habitat.
  • Repair damaged fencing and remove spoil, sediment, rubbish and other materials that block wet habitat or shelter.
  • Record search effort, weather, habitat condition, detections, mortalities, incidents and corrective actions.

After habitat disturbance: Monitoring and reporting

Monitor waterholes, spring-fed pools and seepage areas for drying, sedimentation, altered drainage, vegetation loss and damage to rock shelter.

Compare post-work habitat condition with the pre-clearance photographs, maps and feature register.

Report survey results, captures, relocations, injuries, deaths, habitat damage and permit compliance to the approval holder and relevant wildlife authority.

  • Submit confirmed records and relevant monitoring data to the relevant state wildlife database.
  • Review monitoring results with the project ecologist and adjust exclusion zones, drainage controls, work staging or rehabilitation if impacts are detected.
  • Apply any approved offset or compensatory habitat requirement where residual impacts cannot be avoided or minimised.

Rehabilitation actions: Restore wet and rocky habitat

Rehabilitation should restore the combination of wet habitat, rocky shelter and damp ground used by this species. The supplied account does not provide a planting schedule, density, nest-box design or success threshold, so set these through the project ecologist and approval conditions.

Reinstate natural drainage to maintain spring-fed pools, seepage areas, waterholes and damp ground without creating polluted or unstable standing water.

Replace suitable local rocks and coarse shelter in stable positions, including around retained pools and seepage margins, where construction has removed them.

Re-establish local sedge and bulrush habitat, including Cyperus vaginatus and Typha domingensis where they are appropriate to the original site and approved by the land manager.

Plants recorded at habitat sites: Cyperus vaginatus sedge and Typha domingensis bulrush

Documented habitat features: Spring-fed pools, waterholes, rock crevices, loose rocks, damp soil and litter

  • Use locally appropriate provenance and avoid introducing non-local plants, weeds or material that could alter the frog's shelter or water conditions.
  • Do not use hollow-bearing trees, nest boxes or large timber as a substitute for the species' documented rocky and wet shelter unless other fauna requirements also apply.
  • Control weeds, sediment, feral animal access and other pressures that degrade wet margins and rocky shelter.

Rehabilitation actions: Fire, predators and site maintenance

Develop fire management that protects retained sedge, bulrush, litter, rock shelter and spring margins from unplanned high-intensity fire.

Manage introduced animals where they damage riparian habitat, disturb rocks or reduce water persistence, with camels and donkeys identified as potential threats in the species account.

Prevent construction lighting, access and drainage from concentrating predators or causing ongoing disturbance at retained wet habitat.

  • Inspect rehabilitation after rain, extreme heat, fire and maintenance activities.
  • Remove weeds and repair erosion before they change the moisture or shelter conditions at pools and seepages.
  • Use an amphibian disease-control procedure for footwear, vehicles, equipment and any material moved between water sites.

Rehabilitation actions: Monitoring and success measures

Monitor whether pools and seepages persist, whether damp shelter and native wet-margin vegetation return, and whether rocks and crevices remain stable and connected to retained habitat.

Use repeat searches with the same mapped areas, timing and effort as the baseline so that changes in occupancy and detection can be assessed.

Set measurable project-specific success criteria for water persistence, vegetation establishment, shelter retention, weed cover, erosion and frog detections before rehabilitation begins.

  • Continue monitoring until the ecologist and approval holder confirm that the rehabilitation area provides stable wet and rocky shelter through the agreed monitoring period.
  • Investigate any failure of water persistence, vegetation establishment or shelter retention and implement corrective works.
  • Report rehabilitation results and any species records to the relevant wildlife database and approval authority where required.

Sources