Varanus fyfei

Ecology. Based on the field observations of GSB at the Bullo River, the species is mostly saxicoline inhabiting and foraging on sheer rock faces in gorges. The species utilises horizontal crevices on rock faces that are fractionally wider than the lizards head depth and at least 2 m above ground level as night-time refugia. The species forages diurnally for small lizards and insects on vertical rock-faces.

(Figs 5 A – D, 6 A – D, 8)

Description. Size and proportions. Summary of the mensural and meristic data for V. fyfei sp. nov. are presented in Table 5. Only four male specimens were available, one voucher MAGNT R 24867 has a damaged head. A medium-sized species (adult SVL males: 186 ± 8.7, 175 – 195 mm with very long tail (TL / SVL 2.02 – 2.30). Body dorsoventrally compressed. Head elongate and dorsoventrally compressed; tail long and gradually tapers distally; proximally moderately dorsoventrally compressed, circular centrally, distally becoming triangular in crosssection. Limbs well developed, moderately slender. Claws darkly pigmented, relatively short, very thick, laterally compressed with sharp recurved tips. Snout is moderately long, rounded in dorsal and lateral view, nostrils large and visible from above, wider than high approximately equidistant between tip of snout and anterior edge of eye. Eye large with scaly upper and lower eyelids; closer to nostril than ear opening; supraocular brow present. Ear openings much higher than wide, oriented distally at 45 ° to the corner of the jaw. Scalation. 122 – 140 midbody scales rows; 89 – 95 ventral scale rows, and 23 – 25 lamellae under the 4 th toe (Table 5). Head scales small, smooth and unornamented; supraocular scales smaller than those on the rostrum, frontal and parietal regions; canthus rostralis weak; rostral scales at least twice as large as adjacent scales, almost rounded, slightly narrower anteriorly; mental scale higher than wide and almost hexagonal. Dorsal primary scales small, non-overlapping, relatively uniform and ovate, approximately twice as long as wide and with a small central keel; bordered by a row of small granules; ventral scales non overlapping and more rectangular, approximately 75 % longer and 150 % wider than dorsal scales, grading smaller on the throat and vent. Ventral surface of digits with enlarged paired circular lamellae, scales on manus and pes otherwise comprising conical tubercles. Proximal lateral caudal scales are weakly keeled and mucronate (Fig. 7), then more prominently keeled and mucronate to tip of tail, proximal scales smaller than distal scales. Males have lateroventral cloacal spinal cluster of 4 – 6 long narrow pointed scales that form a rosette. Colouration. Dorsal pattern varies from a less structured alternating pattern of 15 – 19 wide and narrow rows of ocelli separated by a dark row due to numerous dark scales randomly distributed across the entire dorsum, neck and first half of the tail, such that the margins of the “ ocelli ” are not discrete and are variably densely peppered (Fig. 6 B – D) to having alternating lighter and darker transverse rows without any internal structure (Fig. 6 A). The transverse minor bands of narrow ocelli on the dorsum can be white or lemon / lime compared with the bands with wider ocelli which are lemon / lime. Head spotted or mottled, neck dark with subdued transverse rows with contrast between light and dark rows less than on the dorsum. Neck bands extend laterally around the neck to the throat region where they appear as a line but do not connect under the throat on a cream to lemon background. Abdomen ventrally with narrow grey bands on a cream unmottled background. Head with black stripe starting between the snout and nostril, proceeding below the nostril through the eye to above the ear, bordered below by a light stripe from below the eye to the upper half of the ear, with a shorter black stripe on its lower border from the angle of the jaw to the ear. Hindlimbs black with irregularly shaped variably sized whitish spots that appear as broken bands around the leg and toes. Forelimbs with broken transverse bands of pale spots on a smoky-grey base colour (Fig. 5 A – D). Tail with alternating unbroken bands with boldly contrasting colours. On the proximal first third of tail, the pattern is a continuation of the dorsal banding but the larger and smaller ocelli are smaller than their dorsal counterparts. On the distal two thirds of the tail, highly contrasting alternating black and white to cream bands with black bands 0.9 to 1.3 times as wide as white bands. On the ventral surface the bands are less contrasting due to the darker scales being smokey to dark grey (Fig. 8 B). Holotype measurements and scale counts. (Figs 5 C, 6 C, 8). MAGNT R 36793 an adult male, SVL = 190 mm, with a long tail (TL / SVL = 2.2). 128 midbody scale rows, 94 ventral scale rows, and 24 lamellae under the 4 th toe (Supplementary Table S 2).

Diagnosis. A member of the subgenus Odatria distinguished from all others by the combination of long tail (202 – 230 % of SVL) strongly patterned with alternating black and whitish rings, and with dorsal and lateral scales not keeled and uniformly oval in shape and medium body size (SVL up to 195 mm). Varanus fyfei sp. nov. is further diagnosed from its sister species, V. glauerti, by tail bands in the middle section of the tail that are similar in width (black bands 0.9 to 1.3 times as wide as white bands), versus black bands 1.6 to 3.7 times wider than white bands. In comparison with V. glauerti, it has a less demarked alternating pattern of wide and narrow, light-coloured transverse bands separated by narrow dark transverse bands, with numerous small dark scales randomly distributed across the entire dorsum, neck and first half of the tail, such that the margins of the bands are not discrete and the dorsum has a variably densely peppered appearance. The wide and narrow light-coloured transverse bands are usually not the same colour (Fig. 6 A – D), contrasting with V. glauerti in which the narrow and wide rows of ocelli are both typically the same colour (Fig. 6 E – L). It is also diagnosed by small, low keeled, moderately mucronate lateral scales on the proximal tail versus small keeled but not mucronate lateral scales on the proximal tail in eastern V. glauerti (Fig. 7). Varanus fyfei sp. nov. is diagnosable from V. glauerti by apomorphic nucleotide states at 12 sites in a 667 bp alignment of the mitochondrial ND 4 gene (Table 4)

Distribution. On rocky ranges and isolated hills from the Keep River National Park on the NT / WA border, north-east along ranges between the Keep and Victoria Rivers then north across the Victoria River into the gorge country of the Bradshaw Military Training Area (Fig. 9). The species’ range is dissected by the Victoria and Keep Rivers, effectively dividing it into at least three discontinuous areas of rocky habitat, with locations a and b east of the Victoria River, locations c, d and e west of the Victoria River and east of the Keep River and location f on the west bank of the Keep River (Fig. 9). We estimated the Extent of Occurrence (EOO) for Varanus fyfei sp. nov., as calculated with the Atlas of Living Australia online tool, at around 8400 km 2. The extent of the distributions of Varanus fyfei sp. nov. and V. glauerti along the Northern Territory — Western Australian border is presently largely undetermined but adjacent records from the Keep River National Park were only separated by 6.5 km (Fig. 9).

Etymology. Varanus fyfei sp. nov. is named for Greg Fyfe, biologist and ecologist with a dedicated interest in central Australian reptiles for over 30 years. As curator of both the Arid Australian Reptile Display and vertebrates at the Alice Springs Desert Park, Greg mentored many talented biologists who have had successful herpetological careers.

Holotype. MAGNT R 36793. An adult male collected by Gavin Bedford in 2005 from a small gorge on Bullo River Station, Northern Territory (- 15.5044 °, 129.5756 °). Material examined. Supplementary Table S 2.

Victoria River Rock Goanna