Amalosia rhombifer, Gray, 1845

Hoskin, Ad. J. & Couper, Patrick J., 2023, Revision of zigzag geckos (Diplodactylidae: Amalosia) in eastern Australia, with description of five new species, Zootaxa 5343 (4), pp. 301-337 : 332-334

A. cf. rhombifer (north-west Queensland populations)

( Figure 27 )

Material examined. QM J83990 , Kolorbidahdah (12° 39’ 02” S, 134° 17’ 53” E) NT; J92250, Pungalina (16° 28’ 59” S, 137° 33’ 33” E) NT; J74928, Hells Gate , Turnoff Lagoon Stn (17° 28’ S, 138° 22’ E) NW QLD; J83894, Leichardt Falls (18° 13’ 10” S, 139° 52’ 38” E) NW QLD; J43050, J43051, Repeater Stn , on Mt Isa to Camooweal Rd (20°06’ S, 138° 51’ E) NW QLD; J64474, Mt Isa (20° 42’ 34” S, 139° 26’ 56” E) NW QLD; J14852, J15874, J30422, Mt Isa (20° 44’ S, 139° 29’ E) NW QLD; J47514, Stony Range, 39 km E Mt Isa (20° 45’ S, 139° 56’ E) NW QLD .

Diagnosis. A small (max. SVL ~ 53 mm), elongate (AG/SVL 0.43–0.52), long-tailed (oTL/SVL 0.94–1.00) member of the A. rhombifer group with a pale, zigzag dorsal pattern that is even and continuous (i.e., typically not broken by any narrow, transverse lines from the nape to the hips). Pale dorsal pattern thinly marked with a dark zigzag edge or relatively straight with poorly defined edge. Webbing between third and fourth toes minimal to moderate. Males with 1 or 2 pointed or rounded postcloacal spurs (smaller and rounded in females) and 10–24 precloacal pores, with a 3–4 scale break in the series. The first supralabial is usually taller than the second, and wider or of equal width to the second.

Description of material examined. Measurements ( Table 2). SVL (mm): 41.6–52.8 (n = 11, mean = 47.0). Proportions as % SVL: oTL = 94–100 (n = 4, mean = 98); HL = 21–23 (n = 11, mean = 22); HW = 15–17 (n = 11, mean = 16); HD = 8.9–10.7 (n = 11, mean = 9.8); S = 7.9–9.7 (n = 11, mean = 9.0); AG = 43–52 (n = 11, mean = 48); L1 = 24–33 (n = 11, mean = 29); L2 = 29–38 (n = 11, mean = 36; FL = 10–12 (n = 11, mean = 11); LHL = 12–15 (n = 11, mean = 14); BW = 14–20 (n = 11, mean = 17). Head. Narrow, elongate, distinct from neck; head width 69–78 % head length (n = 11, mean = 73); head depth 54–69% head width (n = 11, mean = 61); snout length 37%–43% head length (n = 11, mean = 41); covered in small granules with slightly larger granules on the dorsal and lateral surfaces of the snout; rostral approximately twice as wide as deep, partially divided vertically by a medial groove extending 40–70% rostral height; 2–4 scales contacting dorsal margin of the rostral, lying between the nostrils (n = 11, mode = 3, mean = 2.9); 5–6 scales bordering nasal opening (n = 11, mode = 5, mean = 5.2); supralabials 10–11 (n = 11, mode = 10, mean = 10.2), 1 st supralabial widest or subequal to 2 nd supralabial; 1 st supralabial taller than 2 nd supralabial; infralabials 10–11 (n = 11, mode = 10, mean = 10.2); 3–6 scales contacting posterior margin of mental shield, between 1 st infralabials (n = 11, mode = 5, mean = 5). Neck. Broad. Body. Slender, slightly depressed, covered in small granules; granules on ventral surface noticeably larger than those on dorsum; a row of enlarged postcloacal spurs (1–2, n = 11, mode = 2, mean = 1.7) behind the lower posterior margin of the thigh in both sexes (larger in males and usually with a rounded margin). 10–24 (n = 7, mode = 16, mean = 16.9) precloacal pores present in mature males, extending to underside of thigh, and divided medially by 3–4 granular scales without pores (n = 7, mode = 4, mean = 3.6). Limbs. Moderate length; digits dorsoventrally compressed and expanded distally; an enlarged pair of apical lamellae followed by a transverse series, divided distally, single proximally; forelimb with 5–8 enlarged lamellae on 4 th finger (n = 11, mode = 7, mean = 7.0), 3–4 split or deeply grooved (n = 11, mode = 3, mean = 3.4); hindlimb with 6–8 enlarged lamellae on 4 th toe (n = 11, mode = 7, mean = 7.3), 3–4 split or deeply grooved; webbing present between 3 rd and 4 th toes variable (absent, minimal, moderate or pronounced). Original tail. Moderately long (94–100% SVL), narrow (oTW/oTL = 7–11%), tapered, and rounded to slightly flattened (oTW/oTD = 96–120%) ( Table 2); scales arranged in concentric rings, larger on ventral surface. Pattern in spirit. Dorsal view. Head and body grey to mid-brown with a pale vertebral zone and a darker, dorsolateral pattern. A diffuse dark patch may be present on the crown but usually absent, with a blotch or streak present on nape. There is some indication of a dark, central streak on dorsal surface of the snout and a dark facial stripe, beginning on snout and continuing behind eye, joins the darker dorsolateral zone. No dark bar is present across the nape. The dorsolateral zone is variable. In some specimens a distinct zigzag pattern consists of dark points extending into the pale vertebral zone (approx. nine from shoulders to hips), however, the dorsolateral/vertebral margin pattern is often weakly defined. The vertebral zone is variable and can be relatively straight edged (i.e., lacking pronounced zigzags) and it may contain a few dark blotches or be finely mottled. In one specimen, an obscure netted pattern is present. Flanks. Dark but usually diffusely patterned. Original Tail. Pattern as for dorsum. Limbs. Variegated. Ventral surface. Pale, unpatterned, off-white. Colour pattern in life ( Fig. 27 ). As described above but paler markings light grey or white (vs cream coloured in preservative) and darker markings shades of grey (vs often more brownish in preservative). White flecks on the lateral surfaces more obvious in life. Iris dark copper coloured or brown.

Comparisons. Separated from all other Amalosia in eastern Australia by having one or two postcloacal spurs (vs a mean of 3 or more in all other species; with 2 being a very rare state). It is one of the smaller (max. SVL ~ 53 mm), more elongate (mean AG/SVL 0.48) members of the eastern A. rhombifer group and hence is only likely to be confused with A. queenslandia sp. nov. and A. capensis sp. nov. For detailed comparisons with these two species, and with A. hinesi sp. nov., A. saxicola sp. nov. and A. nebula sp. nov., see Comparison section for each species above. Amalosia cf. rhombifer also has a relatively deeper head than A. queenslandia sp. nov. and A. capensis sp. nov. (see HD/SVL in Table 2), resulting in a more ‘boxy’ head shape (i.e., HD/HW) compared to these two species ( Table 2) and compared to other Amalosia ( Tables 1 , 2).

Genetics. Two ND4 sequences deposited on GenBank: OQ542971 (specimen: ANWCR10330; genetic sample code: CCM5113; Bang Bang Jump Up) and OQ542972 (specimen: SAMAR55290; genetic sample code: ABTC82447; The Monument, west side of Mt Bruce).

Distribution. In Queensland, known from the north-west—below the southern Gulf of Carpentaria, south through the Mt Isa/Cloncurry area, to near Boulia ( Fig. 3 ).

Natural history. Known from woodlands and shrublands in monsoonal and arid areas. Found at night on shrubs, tree trunks, and sticks. A nocturnal, arthropod feeder. Not known to occur with any other Amalosia but the area between A. cf. rhombifer and A. queenslandia sp. nov. records ( Fig. 3 ) is poorly surveyed.

Figures

FIGURE 3. Map of occurrence records of Amalosia species in Queensland and north-east New South Wales. For each species, individuals included in the ND4 sequencing (Fig. 2) are shown as triangles whereas specimen and sighting records are shown as circles. Records of A. robusta are not shown because the copious records obscure presentation of the focal species.

FIGURE 27. Amalosia cf. rhombifer in life: (A, B) Cloncurry area. Photos: Anders Zimny.