Lerista alia Amey & Couper & Wilmer 2019, sp. nov.

Lerista alia sp. nov.

Bulleringa Fine-lined Slider

(Figs. 3, 4, 7 & 8, also p 351 in Wilson & Swan 2017)

ZooBank ID No. 981253C1-AA4F-46DB-A835-AD62586EC6D9

Holotype. QM J94337, Van Lee Station, NWQ (17°51'19"S, 143°50'17"E), 20 September, 2015.

Paratypes. QM J74236, Donkey Spring, Bulleringa National Park, NWQ (17°37'18"S, 143°48'35"E), 30 October, 2000; QM J94306, Van Lee Station, NWQ (17°51'21"S, 143°50'15"E), 20 September, 2015; QM J94308, Van Lee Station, NWQ (17°51'19"S, 143°50'15"E), 20 September, 2015; QM J94309, Van Lee Station, NWQ (17°51'20"S, 143°50'13"E), 20 September, 2015; QM J94312, Van Lee Station, NWQ (17°51'23"S, 143°50'16"E), 20 September, 2015; QM J95798, Talaroo Rd, NWQ (18°02'04"S, 143°48'15"E), 8 May, 2017.

Diagnosis. Distinguished from all other Lerista by the complete absence of a forelimb, hindlimb styliform or with a reduced digit,>2.5% SVL, interparietal distinct from the frontoparietals, prefrontals absent, four supraciliaries and anterior chin shields with an intervening scale.

Comparisons. Lerista alia sp. nov. is very close morphologically to L. storri and would key to that species following Cogger (2014). It can usually be distinguished by its longer hindlimb, often with a distinct digit, but there is overlap in this character (range: 2.33–4.49% SVL vs. 1.70–2.46% SVL). Lerista alia sp. nov. always has discrete dark flecks forming more or less distinct longitudinal dark lines running along the body, strongest anteriorly, whereas, in L. storri, these are represented only by vague longitudinal bands of pigment. The two species are separated geographically by about 60 km, with L. alia sp. nov. centred on Bulleringa National Park and L. storri known only from Springfield Station (see Fig. 1). For comparisons with other species, see L. storri description above.

Description of holotype. Adult male, SVL = 66 mm; HL = 5.0 mm, 7.5% SVL; HW = 3.6 mm, 73% HL; SE = 1.7 mm, 34% HL; eyelid free (not fused into a spectacle); EE = 2.8 mm, 57% HL; RL = 0.97 mm, 19% HL; NL = 1.2 mm, 25% HL; IN = 1.3 mm, 26% HL; EN = 1.6 mm, 33% HL; RF = 1.5 mm, 31% HL; E = 0.83 mm, 17% HL; ear minute, smaller than the surrounding scales; MW = 3.5 mm, 5.3% SVL; forelimb absent; L2 = 1.6 mm, 2.4% SVL; TL = 66 mm (tip regrown). Hindlimb styliform, no recognisable digit or claw.

Midbody scale rows 20; NC = 32%; NaL = 21%; FN = 46%; FW = 110%; IW = 94%; PL = 59%; MV = 85%; two supraoculars; four supraciliaries, first enlarged, first three in contact, fourth separate at posterior edge of eye below last supraocular; first supraciliary contacts preocular, loreal, frontonasal, frontal, first supraocular and second supraciliary; frontal contacts interparietal, frontoparietal, first supraocular, first supraciliary and frontonasal; interparietal free (not fused to frontoparietals); single loreal; prefrontal absent; single preocular; single presubocular; five palpebrals; single postocular; single postsubocular; five supralabials; third supralabial bordering eye; single postsupralabial; five infralabials, single infralabial contacting postmental; five scales between last infralabial and ear; single pretemporal; temporal contacts fourth and fifth supralabials, postocular, pretemporal, second temporal and lower temporal; three rows of enlarged chin shields; primary chin shields separated by intervening scale; secondary chin shields separated by one scale; tertiary chin shields separated by three scales; three enlarged nuchal scales; 106 paravertebrals; two enlarged preanals; L2B = 5.

Variation. Sample size is six unless otherwise noted: SVL = 43–73 mm (58 + 11 mm); HL = 7.4–9.5% SVL (8.4 + 0.8%); HW = 50–68% HL (64 + 7%); SE = 22–31% HL (26 + 4%); EE = 48–57% HL (52 + 3%); RL = 16– 19 % HL (18 + 1%); NL = 18–22% HL (20 + 1%); IN = 20–24% HL (22 + 1%); EN = 31–36% HL (33 + 2%); RF = 25–31 % HL (28 + 2%); E = 13–18% HL (15 + 1%); MW = 5–7% SVL (6 + 1%); L2 = 2.3–4.5% SVL (3.1 + 0.8%); TL = 90% SVL (single original tail, QMJ94309, all others regrown). Hindlimb styliform, sometimes digit evident (N = 2), sometimes with a minute claw (N = 1).

NC = 39–58% (48 + 7%); NaL = 14–20% (17 + 2%); FN = 43–105% (59 + 23%); FW = 84–111% (97 + 10%); IW = 72–101% (90 + 11%); PL = 49–63% (56 + 5%); MV = 68–87% (80 + 7%); four supraciliaries, first enlarged, first three in contact, fourth separate at posterior edge of eye below last supraocular, sometimes third separate from first two (N = 2, both sides) and sometimes second supraciliary absent (N = 1); 2–5 palpebrals (mode = 4); 4–5 scales between last infralabial and ear (mode = 4); temporal contacts fourth and fifth supralabials, postocular, pretemporal, second temporal and lower temporal (sometimes point contact with parietal, N = 4); 3–6 enlarged nuchal scales (mode = 4), 105–111 paravertebrals (mode = 105); L2B = 3–7 (mode = 4); 97 subcaudals (N = 1).

Colouration in preservative (see Figs. 3 & 4). The dorsal surfaces of the head, body and tail are pale beige to silvery grey. Body with a series of chocolate brown streaks that form broken, longitudinal lines (scale rows one to three), the intensity and extent of which are variable. In QM J94308 these are barely discernible but in other specimens they are most visible on the anterior dorsum. The pattern is strongest in QM J95798, a juvenile, and extends the full length of the back. The lateral surfaces are usually marked by rows of dark streaks which may be obscure to well-defined. In specimen QM J94337, they appear as continuous, diffuse lines on scale rows four to seven. The lower flanks and ventral surface of the body are usually cream with a diffuse brown wash but on QM J95798 they are relatively dark. The head shields bear obscure mottling with some dark-edged scales. A dark zone is present beneath the eye, incorporating the dorsal edge of the supralabials and extending forward to the ventral edge of the nasal. This may also be continuous with a dark blotch on the secondary temporal scale. Broken, longitudinal rows of dark streaks are present on the dorsal and lateral surfaces of the tail. Ventrally, the tail is cream and strongly flecked with brown.

Colouration in life (as different from colouration in preservative, Fig. 8). As for spirit specimens but the ground colour is more lustrous. The photograph in Wilson & Swan (2017, p 351) for L. storri is of the holotype of L. alia sp. nov. The photograph of L. storri in Wilson (2015, p 162) is probably also this species, given its stated locality, but the specimen was not vouchered and consequently could not be examined for this study.

Etymology. The species epithet alia is Latin for different or changed, chosen to illustrate its relationship to its close relative, L. storri s.s.

Distribution and habitat (Figs. 1 and 9). Known only from the area of Bulleringa National Park and Talaroo, between Mount Surprise and Georgetown, NEQ. The EOO is approximately 235 km 2. Area of Occurrence (AOO, as defined by IUCN 2012) will be considerably less than this as areas of suitable habitat are small and patchily distributed within the EOO. There are only three known populations, one of which is in a protected reserve (Bulleringa National Park). The record from Bulleringa National Park falls within the Staaten River drainage in the Gulf Plains Bioregion of Queensland, while the other records are in the Einasleigh River drainage of the Einasleigh Uplands Bioregion. The Regional Ecosystems (Queensland Government Environment and Science 2018) are as follows:

2.7.2 x2 f: Mixed low open woodland to woodland, including combinations of the species Eucalyptus microneura, Corymbia pocillum, E. megasepala, C. gilbertensis, Melaleuca citrolens. Eucalyptus provecta, Terminalia platyptera and Adenanthera abrosperma may also occur in the canopy. A dense secondary tree or shrub layer of Petalostigma banksii and/or Acacia gonoclada commonly occurs. The ground layer is commonly tussock grasses, including Schizachyrium fragile, Heteropogon triticeus, Aristida spp. and Triodia sp. May occasionally form a Petalostigma banksii shrubland with emergent eucalypts. Occurs on low rises, breakaways and stripped surfaces on lateritised Cretaceous mudstones. Rock outcrop and skeletal soils.

2.7.2 x4: Eucalyptus provecta (predominantly) and/or E. tardecidens and/or E. chlorophylla low woodland to woodland. Eucalyptus microneura, Melaleuca foliolosa, Acacia shirleyi and Erythrophleum chlorostachys may occur in the canopy. A sparse shrub layer commonly occurs, including canopy species, Gardenia vilhelmii and Carissa lanceolata. The ground layer is tussock grasses, including Chrysopogon fallax, Aristida spp. and Schizachyrium fragile. Occurs on footslopes, flats and low rises of lateritised Cretaceous mudstone.

2.5.17 a: Melaleuca stenostachya and/or M. citrolens low woodland to woodland, occasionally with Eucalyptus microneura, E. provecta, Acacia leptostachya and Terminalia platyptera. A shrub layer of Petalostigma banksii may occur. The ground layer is variable, commonly tussock grasses. Occurs on undulating outwash deposits and erosional Tertiary sand sheets in the north of the bioregion. Brown sandy and texture contrast soils.

9.5.16: Woodland to open woodland of Eucalyptus tetrodonta frequently with Erythrophleum chlorostachys +/ - Corymbia clarksoniana +/- C. erythrophloia +/- Eucalyptus cullenii +/- E. chartaboma. The mixed shrub layer is open to absent and can include Gardenia vilhelmii, Grevillea spp., Melaleuca spp. The grassy ground cover is usually dominated by Heteropogon contortus but can include Sarga plumosum and Arundinella setosa. Occurs on Tertiary remnant sandsheets. Small areas of laterisation may be present.

9.11.22: Low woodland to low open woodland of Eucalyptus melanophloia +/- Corymbia erythrophloia +/- Terminalia platyptera +/- E. microneura and/or C. erythrophloia emergents. Eucalyptus microneura may dominate at the base of hills. A sparse to mid-dense shrub layer of Petalostigma banksii +/- Acacia spp., +/- Alphitonia spp. +/- Gardenia vilhelmii is present. The grassy ground layer is dominated by Heteropogon contortus, Schizachyrium spp. and Aristida spp. Occurs on rolling hills.

General ecology. Specimens were found in loose soil under logs and other debris. As far as is known, it feeds on small arthropods.

Comments. A single specimen (QM J95798) was vouchered from approximately 16 km south of the other specimens and exhibits some variation to the rest of the type series. It has the longest hindlimb, is the only specimen with an observable, though very small, claw and is considerably darker than the others. There was some genetic distinctiveness between this specimen and the other samples of L. alia sp. nov. but it is well within the range of intraspecific diversity normally seen in Lerista (Fig. 2). We therefore assign this specimen to L. alia sp. nov. and assume it exhibits some of the morphological diversity found within this taxon, pending the vouchering of further specimens.

Conservation status. Only three populations are known but more survey work may uncover new populations. It seems likely populations are naturally fragmented as the species is restricted to areas of suitable (sandy) soils and is probably unable to cross areas of unsuitable habitat. While one population is within a national park, the other two are subject to cattle grazing with its attendant soil impaction and ecological degradation. All populations are likely to suffer from invasive plant species altering soil structure. As the species, on current knowledge, has a known extent of occurrence well below 5,000 km 2, consisting of only three small populations, at least two of which are subjected to the direct threats of cattle grazing and weeds, from which declines in the area of occupancy, habitat quality and number of individuals can be inferred, we believe the species qualifies as Endangered under IUCN guidelines B1a, b (ii, iii, v) (IUCN 2012).