Liopholis parva, Aplin & Maryan & Armstrong & Pavey & Donnellan, 2024

Aplin, Ken P., Maryan, Brad, Armstrong, Kyle N., Pavey, Chris R. & Donnellan, Stephen C., 2024, Molecular and morphological assessment of the Liopholis inornata (Rosén, 1905) species group (Reptilia: Squamata: Scincidae), with descriptions of two new species from northern Western Australia, Zootaxa 5551 (2), pp. 299-332 : 316-322

Liopholis parva sp. nov.

North-West Cape Skink

( Figs 6 , 7 , 8 )

Holotype. WAM R156452 , male, Learmonth Air Weapons Range, North-West Cape (-22.45, 113.83), Western Australia, Australia, collected by M. Bamford, 17 March 2005. Fixed in 10% formalin, stored in 70% ethanol, liver tissue stored at SAMA as ABTC 101420 .

Paratypes. Two from Western Australia. WAM R153831 , female, Bullara Station (-22.89, 113.92); WAM R156453 , male, Learmonth Air Weapons Range, North-West Cape (-22.45, 113.83) .

Referred specimen. WAM R 8601, male, Merlinleigh Outstation, Kennedy Range (-24.32, 115.18), Western Australia, Australia. This specimen has no specific collection date but was accessioned during 1943.

Diagnosis. A moderately robust, small-sized member of the L. inornata species group (maximum SVL 66 mm), with round pupil, smooth dorsal and caudal scales, a proportionally short neck and head, proportionally short forelimbs, a relatively short tail, up to 34 midbody scale rows, ≤ 24 fourth toe lamellae and a plain orange-brown colour with obscure pattern.

Comparisons with other species. Liopholis parva sp. nov. differs from nominate L. inornata from southern semiarid to arid Western Australia, all known populations of L. s. slateri , and L. s. virgata in its smaller adult size (SVL to 66 mm versus to 84 mm, 93 mm and 94 mm, respectively). Liopholis parva sp. nov. further differs from L. inornata and L. s. slateri by having a shorter head, modally lower midbody and paravertebral scale counts and subdigital lamellae counts ( Table 5 ). Liopholis parva sp. nov. further differs from L. s. virgata by lacking a black vertebral stripe ( Fig. 6 ). Liopholis striata attains a much larger size (SVL to 112 mm), has higher midbody and paravertebral scale counts, and has a vertically ovate rather than rounded pupil. Liopholis multiscutata attains a much larger size (SVL to 96 mm) and has a predominately greyish or brownish colour (often with dorsal stripes) and bicarinate subdigital lamellae. Liopholis parva sp. nov. differs from L. purnululu sp. nov. by having a smaller size (SVL to 66 mm versus to 77 mm) and orange-brown (versus brownish) colour ( Fig. 6 ).

Details of Holotype. ( Fig. 7A ). SVL 57.9; TL 71; HD 7.9; HL 13.1; HW 10.5; HNL 19.5; FLL 16.6; HLL 23.8; AGL 28.7; MBS 34; PV 50; SDL 23; nasals widely separated; prefrontals in broad contact; supraciliaries 8/8; nuchals 1/1; upper palpebrals 10/10; primary temporal single; enlarged upper secondary temporals 1/1, each with one adjacent smaller temporal bordering the parietal; supralabials 7/7; ear lobules 3/4, uppermost lobule largest in series.

Description. See Table 5 for summary statistics of mensural and meristic data and Supplementary Table S1 for measurements and counts of individual specimens. Fig. 6 shows the holotype WAM R156452 compared to a selection of other Liopholis species. Fig. 7B shows an adult and Fig. 7C a juvenile born in captivity, both photographed in life. Head and details of scalation are illustrated in Fig. 8 .

Head moderately deep, barely distinct from neck; external ear opening prominent, narrow and much higher than wide; snout very short, rounded in profile and slightly angular in lateral view; body moderately robust, round in cross-section with flat venter and well-developed, thickset pentadactyl limbs; digits moderately long and slender; claws strong with long sharp tip; tail round in cross-section gradually tapering to pointed tip.

Nasals widely separated; groove representing nasal-postnasal suture absent; two loreals, first slightly higher than wide and second mostly wider than high; two presuboculars, first much higher than second; prefrontals in broad or point contact (e.g. WAM R153831); frontal much wider anteriorly, tapering gradually to a rounded point, equal or only slightly wider than interparietal; frontoparietals paired; parietals bordered posteriorly by an enlarged nuchal scale and laterally by two temporal scales; 3‒4 ear lobules, small and obtusely rounded, uppermost lobule largest and with slight decrease in size downwards; 7‒8 supraciliaries, first and third largest; five supraoculars, second much larger and fifth smallest with anterior two in contact with frontal; 9‒10 upper palpebrals; one nuchal on each side; 6‒7 supralabials, the fifth and sixth or fourth and fifth largest and subocular, subocular supralabials separated from granular eyelid scales by a row of small scales; first pair of chin shields in broad contact, second pair separated medially by one scale; third pair widely separated medially by three scales; 34 midbody scale rows; 49‒50 paravertebral scales; 23‒24 lamellae under fourth toe, with moderately strong calli, outer edges denticulate, palmar and plantar scales small and ovate.

Colour in life. Colour in life is based on illustrated figures and field observations of live individuals. Dorsal surface pale orange-brown, grading to greyish on head above eyes. Dorsal scales immaculate (e.g. WAM R153831) or spotted on posterior edge with cream (e.g. WAM R156452‒3), the spots tending to be transversely elongate and forming very indistinct longitudinal lines that continue to dorsolateral surface of tail. Lateral surface with creamy white base colour. Some upper lateral scales bearing pale brown edges, forming an irregular reticulum that commences behind the ear aperture and terminates on proximal part of tail. Tail concolorous with dorsal surface, except for presence of brownish smudges, most prominent dorsolaterally and aggregated on the dorsal surface to form narrow transverse bands. Scales in interspaces between bands on tail with cream posterior edges, forming a central series of narrow pale bars. Upper surface of limbs pale brown, with no discernible markings. Posterior supralabials and temporals with diffuse brown smudges. Ventral surface creamy white. Claws with dark culmen on upper surface.

Juveniles are a rich bright orange with yellowish faces, dark crowns and prominent bands on the tail ( Fig. 7C ).

The referred specimen WAM R8601 has been in preservative for about 80 years and the ground colour has faded to a creamy white, with no discernible spots on the dorsum and only faint bands on the tail.

Etymology. From the Latin parvus, small, little, minute, in specific reference to the distinctive small size of this species. Used as a noun in apposition.

Distribution. Known from two disjunct populations in Western Australia, one in the dune systems on the North-West Cape, the other in similar habitat on the Kennedy Range ( Fig. 1C ). On the North-West Cape, it is known from four separate locations associated with two main dune systems: Cape Range National Park, Learmonth Air Weapons Range, Bullara Station and immediately north of Exmouth. Merlinleigh Outstation on the Kennedy Range has not been intensively surveyed and the status of L. parva sp. nov. at this location is not known. Herpetofaunal assessments on the North-West Cape, the Kennedy Range National Park and adjacent regions have not detected any populations of L. parva sp. nov. or any other Liopholis species (e.g. Storr & Hanlon 1980; Storr & Harold 1984, 1985; Kendrick 1993; McKenzie et al. 2000; Beranek et al. 2021). However, recent biological surveys have recorded this species for the first time in Cape Range National Park (L. Clausen, pers. comm.).

Based on collection records ( Atlas of Living Australia 2024), Liopholis parva sp. nov. is widely allopatric to any other Liopholis species. The geographically nearest congeners consist of single records of L. inornata recorded approximately 200 km to the southwest on the Peron Peninsula and Hamelin Station Reserve at Shark Bay ( Shea & Wells 1985; Maryan et al. 2024) and a disjunct population of L. multiscutata on Bernier Island, offshore from Carnarvon ( Storr et al. 1999).

Habitat, ecology and conservation. The holotype and WAM R156453 were pit or funnel-trapped on a sandplain. The vegetation comprised a low, mixed shrubland of Acacia Miller with emergent Corymbia Hill & Johnson over a mosaic groundcover of low shrubs and Triodia Brown hummocks, with patches of exposed limestone ( Metcalf & Bamford 2005; HLA‒Envirosciences, Ecoscape Australia 2005, Fig. 9A ). Nearby were stands of low, open woodland of Eucalyptus L’Héritier and Brachychiton Schott & Endlicher. The associated dune habitat supported predominately Triodia with scattered Banksia ashbyi Baker. Field observations of other individuals were pit-trapped on red dunes (L. Clausen, pers. comm., Fig. 9B ). One specimen (WAM R153831) was excavated from a burrow on a thinly vegetated crest of a red dune ( Fig. 9C ). The vegetation of the two main dune systems on the North-West Cape, the northern and southern red sand dunes, have been mapped by Beard (1975). The referred specimen from Merlinleigh Outstation on the Kennedy Range (WAM R8601) has no habitat details but this area is predominantly dunefield/sandplain habitat.

The ecology of this species is largely unknown. The limited field observations of L. parva sp. nov. suggest that it is numerous at two localities on the North-West Cape based on captures in traps, appearing to favour the lower slopes of dunes where sand is more compacted (M. Bamford & R. Browne-Cooper, pers. obs.). Typical of other burrow-digging members of Liopholis , their presence can often be indicated by excavated multi-entranced burrows ( Fig. 9C ). Bamford & Bamford (2012) provide details of behavioural observations and captive breeding for L. parva sp. nov. listed as Liopholis “Cape Range”. Their information also included the SVL measurements (in mm) of 62 in one adult male and 56 and 57 in two adult females that displayed no growth after six years in captivity.

The current land use of the locations where L. parva sp. nov. are known from comprise a mixture of protected gazetted conservation, Commonwealth Defence and non-protected areas. Currently, within the protected areas, L. parva sp. nov. has been recorded from single localities in both the Cape Range National Park (476 km 2) and Learmonth Air Weapons Range (189 km 2). Commonwealth Defence land is not routinely considered conservation estate, but it does fall under heritage management objectives that includes natural heritage in compliance with the Australian Government’s Environment Protection and Biodiversity Act (EPBC Act). The non-protected areas include both an active pastoral station and unallocated Crown Land (e.g. Meissner 2011). This mosaic of different land tenures is noted by Doughty et al. (2008), whereby only the Cape Range is currently protected within the Cape Range National Park, excluding much of the North-West Cape from the same statutory protection. The single record of L. parva sp. nov. from Merlinleigh Outstation on the Kennedy Range is protected within the Kennedy Range National Park (1, 416 km 2).

Similarly to other relatively small Liopholis species with restricted distributions ( Chapple et al. 2019), L. parva sp. nov. faces potential threats that warrant conservation attention. As highlighted for L. s. slateri populations in central Australia ( Pavey 2004, 2007; Pavey et al. 2010), the species is potentially impacted by the degradation of existing habitat caused by the invasion of the introduced pasture plant buffel grass Cenchrus ciliaris Linnaeus on the North-West Cape ( Keighery & Gibson 1993; Meissner 2011). The success of buffel grass as an invasive weed not only impacts on the vegetation communities but also on the fauna that use them for habitat and refuge ( Dixon et al. 2001). For example, it has been further hypothesised that the foraging behaviour of L. s. slateri , which rely on high visibility outside their burrow entrance to ambush prey, makes them particularly sensitive to the impacts of buffel grass ( McKinney et al. 2014). The trampling by feral herbivores and cattle in addition to altered fire regimes may also impact the long-term survival of the habitat occupied by L. parva sp. nov. Another significant consideration is the predation by cats and foxes that are both known to take small lizard prey; thus, juveniles are likely to be particularly vulnerable.

Available knowledge indicates this species occurs in fragmented populations on the North-West Cape associated with two main dune systems, the northern sand dunes that occur within unallocated Crown Land, and the southern sand dunes that are partially protected within the Cape Range National Park ( Meissner 2011). Based on existing collection records, including the Kennedy Range National Park (N = 4, Atlas of Living Australia 2024) and limited field observations, we calculated the extent of occurrence(EOO; minimum convex hull) and area of occupancy(AOO; 2 x 2 km grid cells) of L. parva sp. nov. in GeoCat (https;//geocat.kew.org; Bachman et al. 2011). The species’ EOO is 10, 076 km 2 and the AOO is considerably smaller at 24 km 2. Targeted biological surveys on the North-West Cape and Kennedy Range in suitable habitat for this species would improve the issue. Current distributional knowledge of L. parva sp. nov. allows for an IUCN listing assessment under criteria B2 of geographic range (AOO <500 km 2), B(a) number of locations (equal to 5) and possibly B(biii) reduction in quality of habitat due to buffel grass invasion and altered fire regimes, that qualifies this species for Endangered, under IUCN guidelines and criteria ( IUCN 2022). Further consideration is that without any detailed knowledge of the species’ ecology, life history, distribution and threats to effectively assess the species, it may also be considered as Data Deficient.

Remarks. One specimen (WAM R8601) from Merlinleigh Outstation on the Kennedy Range dunefield was included in L. inornata by Storr (1968: 59) and mapped as this taxon by Storr et al. (1981: 89). However, in a later revision Storr et al. (1999: 112) omitted this record from the species map, presumably due to emerging doubt over its true affinity. Despite the faded condition of the specimen which was accessioned over 80 years ago, the morphological evidence supports its inclusion within L. parva sp. nov. Further material from the Kennedy Range is required to clarify the genetic affinities of this significant outlier population.

Shea & Wells (1985) referred a Liopholis specimen (AMS R.105730) from Peron Peninsula at Shark Bay to L. inornata and this record was included on the updated map of Storr et al. (1999). We agree with this assessment based on its colour pattern and the following characteristics and measurements (in mm): SVL 71.7; tail broken; HD 8.9; HL 16.4; HW 13.5; HNL 28.1; FLL 13.6; HLL 18.2; AGL 37.2; MBS 38; PV 50; SDL 22; nasals widely separated; prefrontals in broad contact; supraciliaries 8/8; nuchals 1/1; upper palpebrals 10/10; primary temporal single; enlarged upper secondary temporals 1/1, each with one adjacent smaller temporal bordering the parietal; supralabials 7/7; ear lobules 3/4, first from top lobule largest in series.

The fact that only a few specimens of Liopholis have been collected in each of the Kennedy Range and Shark Bay regions, despite combined biological survey effort and numerous visits by field herpetologists in both areas ( Storr & Harold 1978, 1990; Shea & Wells 1985; McKenzie et al. 2000; Maryan et al. 2024), highlights the serendipity in locating populations of this genus in arid sandy habitats. For example, during a series of biological surveys by GHD Pty Ltd. in the Zuytdorp coast and hinterland, a total of 1,386 trap nights from 28 sites using buckets, Elliott and funnel traps captured only one L. inornata (G. Gaikhorst, pers. comm.).

Liopholis parva sp. nov. is the only reptile (or vertebrate) species that is known exclusively from disjunct populations on the North-West Cape and the Kennedy Range. Six reptile species are endemic to North-West Cape: the geckos Crenadactylus tuberculatus Doughty, Ellis & Oliver , Diplodactylus capensis Doughty, Oliver & Adams and Gehyra capensis Kealley, Doughty, Pepper, Keogh, Hillyer & Huey , the legless lizard Delma tealei Maryan, Aplin & Adams , the skink Lerista allochira Kendrick and the blind snake Anilios splendidus (Aplin) , with further endemics awaiting description. The only known endemic species on the Kennedy Range is the skink Lerista kennedyensis Kendrick , though Smith & Adams (2007: 323) mention another morphologically and allozymically distinctive population with similarities to Lerista clara Smith & Adams.

Figures

FIGURE 1. A) Map of Australia showing distribution and sample locations of the Liopholis inornata species group used in the molecular genetic analysis. Purple star L. parva sp. nov., pink triangle L. purnululu sp. nov., green circles L. inornata, blue crosses L. s. slateri. B) showing sample locations in central Australia. C) locations for L. parva sp. nov. a—Merlinleigh Outstation, Kennedy Range, b—Bullara Station, c—Learmonth Air Weapons Range, d—20 km W of Learmonth, e—8 km N of Exmouth. The location numbering scheme is used to identify individuals in plots and terminals on the trees in Figs 2–3. Locality details are provided in Table 1. Voucher collection records are based on the Atlas of Living Australia (2024).

FIGURE 6. Selection of Liopholis inornata species group specimens illustrating variation in colour and pattern. A) L. inornata WAM R166716, Tropicana Mine, Western Australia, B) L. inornata WAM R163368, Neale Junction Nature Reserve, Western Australia, C) L. inornata WAM R78798, 19 km ENE of Toomey Hills, Western Australia, D) L. inornata WAM R65835, 3 km NE of Comet Vale, Western Australia, E) L. parva sp. nov. holotype WAM R156452, Learmonth Air Weapons Range, Western Australia, F) L. purnululu sp. nov. paratype WAM R156716, Purnululu National Park, Western Australia, G) L. s. slateri holotype WAM R29130, Alice Springs, Northern Territory, and H) L. s. virgata SAM R48873, Neales Camp No. 1, South Australia (photos A‒G: B. Maryan, H: C. Kovach).

FIGURE 7. Liopholis parva sp. nov. A) Preserved holotype WAM R156452 in dorsal, ventral and lateral views, B) adult from the Learmonth Air Weapons Range, North-West Cape, Western Australia, and C) juvenile born in captivity, photographed in life (photos B. Maryan).

FIGURE 8. Lateral and dorsal views of head scalation of A‒B) L. parva sp. nov. holotype WAM R156452, and C‒D) L. purnululu sp. nov. holotype WAM R103112.

FIGURE 9. A) The habitat of L. parva sp. nov., dense Triodia sandplain in swale with sand dunes vegetated with low Acacia and emergent Corymbia on red sand, 8 km N of Exmouth, North-West Cape, Western Australia, B) aerial view of dunefield habitat on North-West Cape, and C) active burrow on crest of a red dune (photos A: B. Maryan, B: L. Clausen, C: S. Wilson).