Lerista microtis ( Gray, 1845 )

Farquhar, Jules E., Prates, Ivan, Doughty, Paul, Rabosky, Daniel L. & Chapple, David G., 2024, Morphological and genetic data challenge species and subspecies in the Lerista microtis group (Squamata: Scincidae), Zootaxa 5437 (3), pp. 336-362 : 353-355

Lerista microtis ( Gray, 1845)

South-coast five-toed slider

Synonymy

Mocoa microtis Gray 1845

Lygosoma (Rhodona) microtis (Boulenger 1887: 223) Rhodona microtis (Loveridge 1934: 258) .

Nodohra microta (Mittleman 1952: 27)

Lygosoma (Rhodona) microtis (Glauert 1960: 94) Lerista microtis ( Greer 1967)

Lerista microtis arenicola ( Storr 1971)

Lerista microtis (Cogger et al. 1983)

Nodorha microtis (Wells & Wellington 1985)

Lerista microtis microtis (Storr 1991)

Lerista microtis intermedia (Storr 1991)

Lerista microtis schwaneri (Storr 1991)

Lerista arenicola (Storr 1991)

Figure 9 .

Holotype of Macoa microtis : BMNH 1946.8 .18.64, Swan River , Western Australia, obtained from Mr. J. Gilbert’s collection. As Storr (1971) notes, the type locality of ‘Swan River’ is likely incorrect, given the species does not occur near Perth; it was likely collected from Albany.

Diagnosis: A species of Lerista with five digits on each limb and a movable eyelid. Distinguished from the other two pentadactyl Lerista as follows: from L. viduata by its white midlateral stripe (absent in L. viduata ) and from L. bougainvillii by its four supraoculars (not three) and six supraciliaries (not five).

Description: Mensural characters. Sample size is 45 unless otherwise noted. Snout-vent length = 31.5–71.5 mm (average = 49.7 mm), head length = 5.3–9.6 (average = 7.5), head width = 3.3–6.2 (average = 4.9), axillagroin distance = 19.7–51.5 (average = 31.2), forelimb length = 5.8–11.9 (average = 9), hindlimb length = 8.8–20.9 (average = 15.3); original tail length (N = 19) = 36–79.7 (average = 57.4). There is geographic variation in body size, with size approximately increasing from west to east. For instance, the mean SVL of adults from the west (specimens previously assigned to L. m. microtis and L. m. intermedia) is 45.7, whereas mean SVL from eastern specimens (previously assigned to L. arenicola and L. m. schwaneri) is 55.3.

Scalation. Nasal scales widely separated (N = 4), narrowly separated (N = 12), just touching (N = 5), in short contact (N = 9) or in broad contact (N = 15). There is geographic variation in the degree of separation/ contact of the nasal scales, with western populations (previously assigned to L. m. microtis and L. m. intermedia) possessing either wide to narrowly separated nasals, or just touching nasals, whereas those from the east (populations previously assigned to L. arenicola and L. m. schwaneri) are in short to broad contact. Prefrontals widely separated. Frontoparietals divided, in broad contact and about as large as interparietal. Four supraoculars (first two in contact with frontal). Six supraciliaries (first largest). One postnasal, one loreal, two presuboculars. Nuchals 1 (N = 1), 2 (N = 7), 3 (N = 26) or 4 (N = 11) on each side. Mid-body scale rows 19 (N = 1), 20 (N = 19), 21 (N = 7) or 22 (N = 18). Subdigital lamellae under 4 th toe = 15–24 (average = 20).

Colour pattern in life. Variable in colour and pattern; dorsal ground colour may be pale whitish grey to dark greyish brown. Tail colour is typically a continuation of dorsal body colour, but in some specimens the tail is dull to bright orange, sometimes only beneath tail. Dorsal patterning variable; a vertebral stripe and/or paravertebral stripes may be either absent, form faint broken stripes, or continuous stripes with either bold or indistinct edges. If present, these stripes extend from nape to the tail base, becoming broken lines and dots on tail. Pale dorsolateral stripe is usually either absent or faint and narrow (occasionally bold and broad). Black upper lateral stripe is bold and wide, bordered below by a narrower white midlateral stripe. Conversely, mainland specimens from the east of the species’ range (specimens previously assigned to L. arenicola ), have a narrow and indistinctly edged black upper lateral stripe, with wide white midlateral stripe. Black lower lateral stripe usually present and narrower than upper lateral stripe, being very narrow and diffuse in mainland specimens from the east of the species’ range. SA island populations possess bolder patterning (those previously assigned to L. m. schwaneri). Lower flanks greyish white. Ventral surface greyish white with sparse to heavy stippling, sometimes with dark scale margins. Underside of tail and legs orange to pinkish white.

Colour pattern in preservative. Same as for live specimens, but with more faded and less vibrant colouration overall.

Distribution and habitat. Distributed over a long (2,200 km) but relatively narrow stretch of Australia’s southern coastline ( Figure 1 ), from Dwellingup State Forest (WA) east to Wedge Island (SA). Recorded from several islands, including Saint Alouarn (WA), Wickham (WA), Goat (SA), St Peter (SA) Franklin Islands (SA), Williams (SA), and Wedge (SA). Occurs in woodland, coastal heath, sandplains, and coastal dunes where it shelters within or on loose soil beneath surface cover such as leaf litter, clumps of dead vegetation, logs, and rocks. Occasionally found in abandoned stick-ant ( Iridomyrmex conifer ) nests (in south-west of range; Peterson & Metcalfe 2005) and under clumps of dry seaweed on beaches (on Eyre Peninsula).

Conservation. There are no known major threats to the species ( Chapple et al. 2019). We calculated extent of occurrence (EOO) and area of occupancy (AOO) in GeoCat (http://geocat.kew.org; Bachman et al. 2011). The species occurs in multiple protected areas and has a large EOO of 651,840 km 2 (measured as the minimum convex hull around all records, including ocean areas, as per IUCN guidelines). It has a relatively small AOO (2 x 2 km grid cells) of 516 km 2, which meets the IUCN threshold of Vulnerable under Criterion B2 (AOO <2,000 km 2; IUCN 2022). However, it is unlikely to qualify for listing given it does not meet other conditions of Criterion 2; it occurs at ≥ 10 locations, is not severely fragmented, and there is no evidence of continuing decline or extreme fluctuations in its distribution or populations. Further sampling across the species’ range is required to further clarify the AOO, which is likely to be higher than current records suggest.

Figures

FIGURE 1. Distribution of currently recognized Lerista microtis subspecies and Lerista arenicola. Taxon assignment reflects that of the original museum records and the purported distribution as described in the literature (e.g., Storr 1991a; Wilson & Swan 2021). Note that all confirmed records of L. m. schwaneri are confined to islands near the SA mainland. Photographs of live specimens as follows: L. m. microtis (green)—Anders Zimny; L. m. intermedia (blue)—Jordan Vos; Lerista arenicola (red)— Brad Maryan; L. m. schwaneri (yellow)—Trevor Peters. Record colours are made slightly transparent to show overlapping records better, with more saturated colours indicating greater density of records.

FIGURE 9. Select Lerista microtis specimens showing variability in size and colour pattern. (A) Specimen WAM_R113419 from Margaret River area (south-west WA) with dark grey-brown dorsal colour, orange tail and no dorsal pattering (formerly L. m. microtis); (B) specimen WAM_R129702 from Quagi Beach (south-west WA) with continuous paravertebral stripes and olive brown dorsal colour (formerly L. m. intermedia); (C) pale specimen WAM_R137656 from the Nullarbor coast in SA (formerly L. arenicola); (D) specimen SAMA_R45924 from Wedge Island (SA) showing continuous paravertebral stripes and vertebral stripe (formerly L. m. schwaneri); (E) the holotype of Lerista microtis.