Description of type series. Measurements and scale counts. Measurements and scale counts for the holotype and paratypes are presented in Table 1. SVL = average 40.9 mm (34.9–45.7). Proportions (average, followed by range in brackets): AG/SVL = 0.51 (0.49–0.53), FL/SVL = 0.11 (0.10–0.12), LHL/SVL = 0.12 (0.11–0.13), L1/SVL = 0.27 (0.24–0.29), L2/SVL = 0.37 (0.34–0.39), HL/SVL = 0.20 (0.19–0.21), HW/SVL = 0.15 (0.15–0.17), HD/SVL = 0.10 (0.09–0.11), TL/SVL (original) = 1.36 (1.22–1.43), TL/SVL (regrown) = 1.04 (1.02–1.07). Scale counts (average, followed by range in brackets): midbody scale rows = 28 (28–29), paravertebrals = 51 (49–54), supralabials = 7 (7–7), infralabials = 6 (6–6), supraciliaries = 7 (7–7), subdigital lamellae under 4th toe = 24 (22–26). General morphology. Robust. Head and body continuous, with almost no narrowing at neck. Snout rounded in profile. Limbs well-developed, pentadactyl, overlapping when adpressed. Scalation. Dorsal scales smooth (or with three faint striations), with a broadly curved posterior edge; nasals widely spaced; rostral and frontonasal in broad contact; prefrontals widely separated; frontal contacting frontonasal, prefrontals, first two supraoculars and frontoparietal; supraoculars four, second largest; supraciliaries seven, first generally largest; lower eyelid movable with small palpebral disc about half the size of lower eyelid; ear opening round, similar in size to palpebral disc; frontoparietals fused, interparietal free; primary temporal single, secondary temporals two (upper largest and overlapping lower); loreals two, similar in size, first taller, second broader; preoculars two, lower larger or similar in size; presuboculars two, upper largest; supralabials seven, with fifth below eye and last overlapping lower secondary temporal and postsupralabials; postsupralabial divided; infralabials six, two in contact with postmental; fourth toe longest, with enlarged subdigital lamellae, and a single row of scales on the dorsal surface; evenly-sized, rounded scales on plantar surface; outer preanal scales overlap inner preanals; three pairs of enlarged chin shields, first pair in contact, second pair separated by a single scale row, third pair separated by three scale rows. Colour pattern in spirit. Adult males (QM J98076, QM J98077, QM J98078). Body: Dorsal ground colour light brown, generally unmarked except for occasional darker flecks (most prominent on QM J98077). A narrow, pale dorsolateral stripe is faint (QM J98078) to moderately distinct (QM J98076, QM J98077), extending from above ear to mid body. This is bordered below by a dark brown upper lateral zone, with a reasonably sharp transition to paler lower flanks. Faint orange behind armpits on QM J98078, and QM J98077 has an appearance of pale spotting in the groin area of the posterior flanks. Head: As for dorsum, even brown and generally unmarked. Ventral surfaces: Evenly pale cream or grey, with fine black edging to most scales, giving a finely speckled appearance; chins white. Limbs: Light brown, generally unmarked, but scattered dark and pale spots/smudges on hindlimbs of QM J98076 and QM J98077. Tail: Dorsal surface light brown with little pattern; some dark flecking on sides and ventral surfaces, particularly for original tails on which more pronounced dark flecking on a whiter background colour can give a flecked appearance. Subadult males (QM J98080, QM J98081). As described above but dorsal surfaces darker brown and not marked with fine black flecks; white dorsolateral line particularly prominent on QM J98080; darker upper lateral area grades more evenly to paler lower flank on both; lower flanks flecked with white spots; white flecks and spots on limbs (particularly hindlimbs on QM J98081); ventral surfaces paler and less marked. Adult female (QM J98079). More evenly coloured on dorsal and lateral surfaces than males, to the point of being almost patternless (no dark striations on dorsal scales, or fine dark markings on head, and very faint dorsolateral line above shoulders). Upper lateral zone mahogany brown, with more of a gradation to pale lower flanks than for adult males. Paler ventrally than males, but still with fine black flecks. Also paler on underside of original tail, with more obvious black flecking, and scattered white spots down sides of tail. Colour pattern of in life. Males (e.g., Figs 3A, 4A–E, 5A). Light brown to copper or straw coloured on dorsal surface of head, body and tail; essentially unmarked except for black or pale flecks on some individuals. Faint yellowish or gold dorsolateral stripe from posterior ear to mid body or hindlimbs; conspicuous on some individuals, almost absent on others. Thin, dark brown line along lower edge of rostral scale, with dark markings extending through nasal and loreal scales to eye and then continuing posterior to eye along upper temporal region to above ear. Typically, a black spot in the middle of the interparietal scale, and often black flecks on supraoculars and other head scales. Lateral surfaces, from forelimbs to hindlimbs, bright orange to reddish, evenly bright along entire lower flank in some individuals, or concentrated from forelimb to mid body in others; upper lateral zone darker, faintly to heavily marked with diffuse dark markings to give a two-tone appearance of dark upper flank and orange lower flank; transition between darker upper and orange lower flanks fairly abrupt in most individuals, but more of a transition in others; pale spotting on the flanks of some individuals. Sides of neck brownish orange in most individuals, or bright orange in some. Sides of tail brown with pale spots, with an orange flush on some individuals. Upper surfaces of limbs brown, with sparse to heavy dark and light flecking or spotting. Ventral surfaces consist of white chin and throat, with sparse dark flecks or smudges, and faint bluish wash on chin of some individuals; belly cream with black and orange flecks; underside of tail white and mottled with black, brown and orange markings; underside of feet black; underside of limbs white/cream with heavy black spotting. Females (e.g., Fig. 4F). As described for males but lacking all orange markings; flanks are more evenly dark brown.

Etymology. The species name isla is Spanish for ‘island’, referring to the restriction of this species to an island. The name is used as a noun in apposition.

Proposed common name: Scawfell Island Sunskink.

Comparison with congeners. Most similar in general appearance to L. adonis, which occurs in rainforest areas of the adjacent mainland (Fig. 1). Readily distinguished from L. adonis by free interparietal scale (vs. fused with frontoparietals in L. adonis to form one scale), and by bright orange flanks of males (vs. more reddish and generally more heavily marked dark in L. adonis; e.g., Fig. 5B). In addition to the type series, about 30 individuals of L. isla sp. nov. were assessed in the field and all had a free interparietal scale, compared to a fused interparietal for all 45 specimens of L. adonis examined by myself (Appendix) and the very large series examined by Ingram (1991).

Lampropholis isla sp. nov. is distinguished from all other congeners by orange colouration on the flanks of breeding males. Further distinguished from L. couperi by shorter body (AG/SVL 0.49–0.53 vs. 0.52–0.60 in L. couperi), longer forelimbs (FL/SVL 0.10–0.12 vs. 0.08–0.10 in L. couperi), and snout marking of a black band around lower rostral scale (vs. black ‘ball point pen’ mark on tip of rostral in L. couperi). Further distinguished from members of the L. coggeri group (L. coggeri, L. similis, L. elliotensis) of the Wet Tropics by dorsal and lateral surfaces generally not marked with pale or dark flecks or spots (vs. typically flecked with black dashes and paler spots in L. coggeri group). Further distinguished from L. robertsi, L. bellendenkerensis, L. delicata, L. colossus Ingram, 1991 and L. guichenoti (Duméril & Bibron, 1839) by lack of sharp demarcation between dark upper and lighter lower flanks (often involving mid-lateral pale line or dashes in those species, especially for females). Further distinguished from L. mirabilis Ingram & Rawlinson, 1981 by general lack of pattern on body (vs. dark and white spots and flecks in L. mirabilis) and relatively short limbs (vs. long in L. mirabilis). Further distinguished from L. amicula Ingram & Rawlinson, 1981 by having 7 supraciliaries (vs. 5 in L. amicula) and by larger size (SVL max. 46 mm vs. max. 35 mm in L. amicula). Further distinguished from L. caligula Ingram & Rawlinson, 1981 and L. elongata Greer, 1997 by having 4 supraoculars (vs. 3 in those species) and moderate body length (vs. obviously elongate body form in those species).

Distribution. Appears to be restricted to Scawfell Island, approximately 50 km north-east of Mackay, in mid-eastern Queensland (Fig. 1). Targeted surveys of other islands in the region have not found the species (Fig. 1), including surveys of South Cumberland islands by myself: Carlisle Island (13/11/2021–16/11/2021), Keswick Island (14/11/2023–15/11/2023), St Bees Island (15/11/2023–17/11/2023). Known from five of the larger gully catchments surveyed on Scawfell Island, on both the north and south sides of the island. Observed from near sea level to approximately 250 m elevation.

Habitat and habits. Occurs in leaf-litter in gullies in rainforest and associated moist sclerophyll communities. Habitat at all sites includes granite rocks. The species is particularly common where leaf-litter has accumulated on and among rocks, under a closed forest canopy (Fig. 6). Diurnal — seen basking in sun gaps on the forest floor and actively foraging among leaf-litter. Occurrence is patchy, with high density in closed forest gullies and absence in open forest communities. The only other skink species observed in micro-sympatry with L. isla sp. nov. in rainforest gullies was Concinnia brachysoma (Lönnberg & Andersson, 1915), which primarily uses rock surfaces rather than the leaf-litter.

Conservation. A minimum convex polygon around known sites (i.e., an estimate of extent of occurrence, EOO) totals approximately 5.5 km2. However, assessing habitat on the island from satellite imagery would suggest an EOO more in the order of 10 km2. Lampropholis isla sp. nov. is restricted to closed canopy areas, so the area of occupancy (AOO) would be much smaller than this. However, abundance is generally high within occupied areas and there are likely to be many such areas across the island. Additionally, no threats have been identified that are currently likely driving decline or could drive decline in the foreseeable future. The only potential threat to consider is fire, if the frequency or severity increased to the point of reducing the area of fire-sensitive closed canopy forest on the island. Fire is not currently deemed a threat because many sites are known across the island and most of these have significant rock substrate, which excludes fire or limits its impact. Therefore, despite a small distribution and restriction to a single ‘locality’ (Scawfell Island), L. isla sp. nov. does not currently fit any criteria for threatened species listing under IUCN Red List or EPBC Act guidelines due to a lack of identified threat.