Lerista karichigara, Zozaya & Vanderduys & Macor & Read & Amey, 2025

Zozaya, Stephen M., Vanderduys, Eric, Macor, Scott A., Read, Wesley J. & Amey, Andrew P., 2025, Lerista karichigara sp. nov. (Scincidae; Sphenomorphini), a new fossorial skink from Australia's underexplored Gulf Plains Bioregion, Zootaxa 5613 (2), pp. 262-278 : 267-273

Lerista karichigara sp. nov.

Tagalaka Slider urn:lsid:zoobank.org:act:F9F01B5C-5DA6-4C79-BE0E-7524A15761C3

( Figures 1 , 3–7a )

Holotype ( Figs 4 , 5a , 6 ). QM J97925 , immature female, New Water Station (19.400° S, 142.990° E). Collected 8 July 2023 by S.A. Macor, S.M. Zozaya, & W.J. Read.

Paratypes (N = 5). QM J97921 – J97924 , one adult and one immature female and two adult males, Strathpark Station (19.489° S, 143.078° E) ; QM J97926 , adult female, Agantra Station (19.190° S, 142.611° E). All collected 8 July 2023 by S.M. Zozaya, S.A. Macor, & W.J. Read .

Diagnosis. Distinguished from all other Lerista by the unique combination of the following characters: 18 midbody scale rows; eyelid moveable; forelimb entirely absent; hindlimb with two toes; two supraciliaries, separated from each other by the supraoculars ( Fig. 6 ).

Etymology. Karichigara is derived from 'Kari Chigara Changgala', meaning 'no-leg lizard' in the Tagalaka language, referring to the species' lack of forelimbs. The name is treated as an indeclinable word in apposition and was recommended by the Tagalaka Elders, with assistance from the Tagalaka Aboriginal Corporation. Three of the five known localities of L. karichigara sp. nov. — including all observations north of the Clara River—fall within Tagalaka Native Title. Considering this, we also recommend the common name 'Tagalaka Slider' for this species.

Description of holotype (QM J97925 ). Snout moderately angular; lower jaw strongly underslung; eyelid free; ear minute, somewhat below the line of the rictus; front limb absent, no trace of a depression; hindlimb with two clawed digits. Prefrontals absent; frontoparietals free; interparietal present; parietal eye placed centrally; nuchals contacting paired parietals two (combined sides); supraoculars two, first larger and contacts frontal; supraciliaries two, first much larger than second, widely separated from each other by the supraoculars; first supraciliary contacts preocular, loreal, frontonasal, frontal, and first supraocular; loreal single; preocular single, contacts single presubocular, second supralabial, loreal, and first supraciliary; postocular single, contacts single postsubocular, fourth supralabial, primary temporal, pretemporal, and second supraciliary; supralabials five, third below eye, last (fifth) about half size of the fourth; postsupralabial single; scales between last supralabial and ear four; pretemporal single; temporals three, upper secondary largest, lower secondary smallest and overlaps upper secondary; primary temporal does not contact parietal; enlarged chin shields in three pairs, anterior pair not in contact with each other; medial pair of preanals enlarged, right overlaps left. Mensural and meristic data are presented in Table 2 .

Variation. The preocular in J97921 contacts the third supralabial; in J97921 –2 it fails to contact the presubocular. The postocular in J97921 has point contact with the third supralabial, in J97922 it does not contact the second supraciliary, and in J97924 it does not contact the primary temporal. Scales between last supralabial and ear four, except in J97921 (three). Primary temporal in narrow or point contact with parietal in J97921 and J97924 . Infralabials contacting postmental two, except in J97922 and J97923 (one). Anterior pair of chin shields in contact with each other in J97921 –2 and J97926 . In J97922 left preanal overlaps right. Mensural and meristic data are presented in Table 2 .

Colouration in life ( Figs. 1 , 5 , 7a ). Dorsal surfaces of head, body and tail fawn to pale golden-brown, becoming increasingly grey on tail. Lower flanks pale grey to off-white. Each dorsal and lateral scale bears a dark brown to black central streak that align to form ragged, near-continuous stripes along body and tail. Mid-lateral stripes usually broader than those on dorsum; lower lateral stripes often narrower and more diffuse. Lateral stripes on posterior half of original tails often broken into dark flecks and blotches. Regenerated tail dark grey with obscure dark mottling. Head shields bear irregular, dark brown edging. A dark zone from secondary temporals, through eye, extending forward to ventral edge of nasal. Throat and ventral surface cream to off-white. Specimens J97922 and J97923 have several dark, longitudinal lines along ventral surface. Limbs mottled brown above and white below. Colour-pattern is bolder and more intense on young adults (e.g., Fig. 5d ) and juveniles.

Colouration in preservative ( Fig. 4 ). As in life but less lustrous, with fawn to pale golden-brown dorsum faded to grey.

Comparisons. While the extent of limb and digit reduction can vary within some Lerista species (e.g., Storr 1971, Amey & Worthington Wilmer 2014, Amey et al. 2018), examination of these characters is often useful for discriminating among species. Twenty-one species can share the character state of no front limbs and didactyl hindlimbs, and we compare these with L. karichigara sp. nov. They are: L. allanae ( Longman, 1937) , L. bipes ( Fischer, 1882) , L. connivens Storr, 1971 , L. gascoynensis Storr, 1986 , L. greeri Storr, 1982 , L. griffini Storr, 1982 , L. ips Storr, 1980 , L. kendricki Storr, 1991a , L. labialis Storr, 1971 , L. miopus ( Günther, 1867) , L. nichollsi ( Loveridge, 1933) , L. onsloviana Storr, 1984a , L. petersoni Storr, 1976 , L. praefrontalis Greer, 1986 , L. robusta Storr, 1990 , L. simillima Storr, 1984b , L. uniduo Storr, 1984 , L. varia Storr, 1986 , L. vermicularis Storr, 1982 , L. wilkinsi , and L. yuna Storr, 1991a . Of these, twelve are endemic to Western Australia ( L. connivens , L. gascoynensis , L. kendricki , L. nichollsi , L. onsloviana , L. petersoni , L. praefrontalis , L. simillima , L. uniduo , L. varia , L. robusta , and L. yuna ) and another four are also not known from Queensland ( L. greeri , L. griffini , L. ips , and L. vermicularis ). Only three of the twenty-one with no front limbs and didactyl hind limbs share the character of free frontoparietals and a free interparietal, namely L. allanae , L. petersoni , and L. wilkinsi . From L. allanae and L. petersoni , L. karichigara sp. nov. can be distinguished by prefrontal absent (vs. present), supraoculars two (vs. three), loreal single (vs. two), and third supralabial below eye (vs. fourth). Lerista karichigara sp. nov. would key to L. wilkinsi using Cogger (2014) or Wilson (2022). It can be distinguished from L. wilkinsi by having two supraciliaries, which are separated from each other by the supraoculars (vs. four, with the posteriormost separate from the first three), and a moderately angular snout and strongly under-slung lower jaw (vs. a blunt, snub-nosed profile; Fig. 6 ).

Three other Lerista species have been recorded in the region where L. karichigara sp. nov. is found: L. emmotti , L. vanderduysi , and L. zonulata ( Fig. 7 ). Among other differences L. karichigara sp. nov. is most easily differentiated from L. emmotti and L. zonulata in that it entirely lacks forelimbs (vs. present in both L. emmotti [ Fig. 7b ] and L. zonulata [ Fig. 7d ]), and from L. vanderduysi in having two digits on the hind limb (vs. one) and a lateral colour-pattern of thin, ragged, dark stripes (vs. a single broad, dark lateral stripe; Fig. 7c ).

Distribution and habitat. This species is known from five sites in the Gulf Plains Bioregion ( Fig. 2 ), with records originating from the Claraville Plains subregion and the western margin of the Gilberton Plateau subregion. The three sites where the type series were collected can each be described as Eucalyptus / Corymbia open woodland on reddish sand sheets with abundant leaf-litter and woody ground debris, sparse grass cover, and a lower tree or shrub layer dominated by Acacia spp. ( Fig. 8 ). These three sites are mapped as Regional Ecosystems (RE; Queensland Government 2017) 2.5.20, 2.5.18a and 2.5.28a. All individuals were found in friable soil in areas of abundant leaf-litter near the base of trees, particularly Eucalyptus miniata and Corymbia spp. ( Fig. 8 ). The first known (unvouchered) individual was from low Melaleuca viridiflora woodland with a strong component of Terminalia platyptera and occasional Corymbia , Eucalyptus , other Melaleuca species, and Petalostigma banksii . The ground layer was relatively open, dominated by Aristida species and annual grasses. The soil was a fine grey sandy podzol. The area is mapped predominantly as RE 2.5.14a and closely matches this description. The unvouchered individual from Glenora Station was found in loose, pale sandy soil within a lancewood ( Acacia shirleyi ) thicket near a sandstone outcrop (RE 2.10.51). Numerous Lerista tracks were observed nearby in loose sand beneath sandstone overhangs, although it cannot be confirmed that these were made by L. karichigara sp. nov.

Additional life-history notes. All voucher specimens were collected on the same day in July. Four individuals are female. Two of these had somewhat enlarged follicles (0.72–0.93 mm 3) with poorly developed oviducts, implying early-stage vitellogenesis, whereas the other two females had very small follicles (0.11–0.22 mm 3) and no development of the oviducts, implying they were not yet mature. These were the two smallest specimens (51.1–57.3 mm SVL). Both male specimens were mature and in the early stages of reproductive activity, with testis volume between 5.4–9.6 mm 3 but little development of the epididymides. With only two adults of each sex, no assessment of secondary sexual dimorphism could be made.

Suggested IUCN Red List status. Lerista karichigara sp. nov. has an estimated extent of occurrence (EOO) of 1,368 km 2 and area of occupancy (AOO) of 20 km 2. These meet the thresholds for listing as Endangered and Critically Endangered, respectively, under Criterion B of the IUCN Red List guidelines ( IUCN 2019), but this Criterion additionally requires a known or inferred threat. There is no evidence of historical, ongoing, or projected declines in this species and habitat across its distribution is largely intact. It is likely that the EOO and AOO are vastly underestimated given that this species is known from a remote and poorly surveyed region. Considering these points, we suggest L. karichigara sp. nov. currently be treated as Least Concern.

Figures

FIGURE 1. The first observed (but not vouchered) individual of Lerista karichigara sp. nov., from Dumas Station, Queensland. Photo: E. Vanderduys.

FIGURE 2. Occurrence records showing the known distribution of L. karichigara sp. nov. (orange stars) and six other Lerista species found in the surrounding area.The Australian state of Queensland is shown on the top-left, with the Gulf Plains Bioregion (GUP) shown in grey shading.

FIGURE 3. Mitochondrial DNA relationships among 37 samples representing 18 Lerista species, inferred using IQ-TREE. Lerista karichigara sp. nov. forms a deeply divergent, monophyletic lineage that is recovered as sister to a clade of nine species, here referred to as the “L. wilkinsi clade” (highlighted blue). Ultrafast bootstrap (UFB) support values are provided for major branches. Branch lengths represent the expected number of substitutions per site as estimated under the chosen substitution model. The tree was rooted with Ctenotus rungulla, which is excluded here for graphical clarity. The photo shows paratype QM J97923. Photo: W. Read.

FIGURE 4. Lerista karichigara sp. nov. holotype QM J97925 in preservative, showing: (a) the full body in dorsolateral view; (b) a close-up of the hindlimb displaying two toes; and (c) the left side of the head in lateral profile. Note that five infralabials are visible here, in contrast to the four reported for the right side of the head (see Table 2). The scale bar applies only to the full-body image (a). Photos: S. Zozaya.

FIGURE 5. Lerista karichigara sp. nov. in life: a) holotype QM J97925, slightly opaque prior to shedding; and paratypes b) QM J97921 with partially regenerated tail, c) QM J97922 with partially regenerated tail, d) QM J97923. Photos: S. Zozaya.

FIGURE 6. Lateral head scalation in Lerista karichigara sp. nov. compared with the otherwise morphologically similar L. wilkinsi. Note that L. karichigara sp. nov. possesses only two supraciliaries (orange) that are separated by the two supraoculars (blue), whereas L. wilkinsi has four supraciliaries, with the first three arranged in a continuous row.

FIGURE 7. a) Lerista karichigara sp. nov. QM J97924 compared to three geographically proximate Lerista species: b) L. emmotti QM J97915; c) L. vanderduysi QM J97927; and d) the sympatric L. zonulata QM J97912. Photos: a) S. Macor; b–d) S. Zozaya.

FIGURE 8. Photos of habitat at two capture locations: a) collection site of holotype QM J97925; b–d) collection site of paratypes QM J97921–J97924. Photos: a) S. Macor; b–d) S. Zozaya.