Diplodactylus tjoritjarinya, McDonald & Fenner & Torkkola & Oliver, 2024

McDonald, Peter J., Fenner, Aaron L., Torkkola, Janne & Oliver, Paul M., 2024, Vicars in the desert: Substrate specialisation and paleo-erosion underpin cryptic speciation in an Australian arid-zone lizard lineage (Diplodactylidae: Diplodactylus), Vertebrate Zoology 74, pp. 577-594 : 577-594

Diplodactylus tjoritjarinya sp. nov.

Figures 5 E, F, S 2

Tjoritja gecko

Holotype.

NTM R 20862 , a male collected in Alice Springs (23.7 ° S, 133.87 ° E) by P. Horner on 16 th October 1990.

Paratypes.

NTM R 20865 , male, Alice Springs (23.7 ° S, 133.87 ° E) ; SAMA R 38848 , female, junction of Larapinta and Namatjira Drives (23.77 ° S, 133.15 ° E) ; SAMA R 38861 , male, Junction Waterhole 10 km north of Alice Springs (23.62 ° S, 133.88 ° E) ; SAMA R 40591 , male, Upper Stokes Creek , Watarrka National Park (– 24.28 ° S, 131.68 ° E) .

Referred material.

NTM R 15378 , 6 km SSW of Claraville Homestead , NT (– 23.417 ° S, 134.726 ° E) ; NTM R 15795 , 4 km SSE of Southern Cross Bore , Garden Station, NT (– 23.417 ° S, 134.726 ° E) ; NTM R 32488 , Palm Valley Well No. , NT (– 24 ° S, 132.65 ° E) ; NTM R 32489 , Alice Springs , NT (– 23.7 ° S, 133.883 ° E) ; NTM R 32492–4 , Alice Springs , NT (– 23.7 ° S, 133.867 ° E) .

Diagnosis from other species in the D. galeatus complex.

Diplodactylus tjoritjarinya sp. nov. may be distinguished from D. galeatus and D. fyfei sp. nov. by the smaller ear opening (usually ≤ 5 % of head width or ≤ 0.6 mm in diameter in adults versus usually> 6 % of head width or ≥ 0.6 mm in diameter in adult D. galeatus and D. tjoritjarinya sp. nov.), the presence of dorsal blotches descending <1 / 4 and typically ~ 1 / 8 distance down torso when animal is viewed in lateral profile (versus typically descending ≥ 1 / 4 down torso in D. galeatus and D. fyfei sp. nov.), the absence of large white spots (> 3 scales in diameter) in the dorso-lateral region, and by the pinkish red or red-brown background colouration (versus dark red).

Description.

A medium-sized Diplodactylus (to 56.2 mm) with robust build; head moderately wide (HeadW / HeadL – mean = 0.66, range = 0.5–0.81) and deep (HeadD / HeadL – mean = 0.47, range = 0.4–0.54); eyes large (OrbL – mean = 3.5, range = 2.7–4.3); external ear opening relatively small (mean HeadW / ear = 0.05, range = 0.02–0.07). Supralabials much larger than bordering loreals, 8–10, wider than high and decreasing in height posteriorly, first supralabial slightly taller or equal in height to second; 10–12 infralabials; nostril surrounded by rostral scale, 2 supranasals and 3–5 postnasals; relatively low rostral scale (Ros / SVL – mean = 0.021, range = 0.015 –0.032), rostral crease usually present and descending one quarter to two thirds down from top of scale; mental scale lanceolate in shape and usually longer than wide.

Scales on dorsum enlarged, up to twice diameter of those on lateral and ventral surfaces; dorsal head scales larger relative to neighbouring sides of head; scales on throat small and granular. Subdigital lamellae in single row of enlarged rounded scales; large apical pads, much wider than proximal width of digit. Males have 3–10 cloacal spurs (median 5); females have rounded scales where the male spurs occur. Original tail short (mean Tail / SVL – mean = 0.52, range = 0.44–0.57) and thick, cylindrical, covered dorsally with regular annuli of slightly enlarged tubercles.

Top of head pale yellowish-brown and bordered posteriorly by a rounded dark line, dorsum of body pinkish red to red-brown with 3–8 (median = 5) dark-edged pale yellowish-brown blotches that descend <1 / 4 distance down torso when animal is viewed in lateral profile, lateral region of torso with numerous irregular white dots 1–3 scales wide, dorsal colouration and pattern continue onto original tail (with 2–5 blotches), and ventral surface white.

Particulars of the holotype.

An adult male (Fig. S 2). SVL = 44.2, TrunkL = 24.7, TailL = 24.0, TailW = 4.4, ArmL = 7.1, LegL = 8.7, HeadL = 12.4, HeadW = 8.8, HeadD = 6.6, IO = 7.4, NarEye = 3.4, Internar = 1.5, Ros = 0.9, RosCre = 0.6, MentalL = 1.5, MentalW = 1.2, SupNas = 2, SupLab = 13, InfLab = 11, CSpurs = 5, 4 Flam = 7; 4 TLam = 9, No. SC = 52. Six pale dorsal blotches present on body and extending <1 / 8 down torso when viewed in lateral profile. Irregular pattern of small white dots (<3 scales wide) on dorso-lateral region.

Etymology.

Tjoritja is a Western and Central Aranda name for the MacDonnell Ranges. Aranda people sometimes refer to themselves as Tjoritja - rinya (pronounced ‘ choor-it-ja-rin-ya’) – meaning belonging to Tjoritja. This name respects that Tjoritja is a living cultural landscape to which this gecko belongs and was suggested as a name for this gecko by the Traditional Owners of Tjoritja National Park. Used as a noun in apposition.

Distribution and ecology.

Endemic to the Northern Territory and restricted to the MacDonnell Ranges IBRA region ( Thackway and Cresswell 1995). The distribution includes the James and Krichauff Ranges in the south, as far southwest as the George Gill Range, east to the Hale River about 40 km southeast of Ruby Gap Nature Park, northeast to the Harts Range area, and north west to at least Ormiston Gorge in Tjoritja National Park. Recorded at elevations ranging from 416–1102 m a. s. l.

Nocturnally active on the ground on rocky substrates and geology types that include sandstone, limestone, gneiss, quartzite, and conglomerate. Landforms include low rolling hills, stony flats and rugged mountain ranges, with hummock or tussock grassland vegetation, usually with a sparse Acacia or mallee Eucalyptus shrub layer.

Individuals have been observed emerging from small invertebrate burrows at dusk and have also been found sheltering underneath small rocks during the day in cool weather (P. McDonald pers. obs). Frequently observed perched atop small loose or partially embedded rocks rather than actively foraging, suggesting an ambush predation foraging mode. Absent from exposed rock faces and escarpments. Recorded in syntopy with Crenadactylus horni , Diplodactlyus conspicillatus , Gehyra versicolor , Heteronotia binoei , Nephrurus amyae , and Rhynchoedura ornata (P. McDonald pers. obs.). Appears to be absent from large boulders, rock faces and escarpments inhabited by the saxicoline Central Ranges endemic geckos Gehyra moritzi , Heteronotia fasciolatus , Oedura cincta , and O. luritja .

Suggested IUCN Red List status.

Diplodactylus tjoritjarinya sp. nov. has a moderate range size (estimated EOO 9365 km 2) spanning areas that are not subject to widespread habitat destruction or disturbance and including several protected areas (e. g., Tjoritja National Park; terrestrial protected areas comprise 14.2 % of the MacDonnell Ranges IBRA). Recent attempts to locate D. tjoritjarinya sp. nov. in areas with dense Buffel grass ( Cenchrus ciliaris ) near Alice Springs have failed, suggesting this invasive species impacts habitat suitability for the species (P. McDonald pers. obs.). However, Buffel grass is a minor floristic component across most suitable habitats for D. tjoritjarinya sp. nov. (including both ESU’s). Based on these data we suggest that it be considered Least Concern, but the potential impact of Buffel grass on habitat suitability may warrant further investigation.

Figures

Figure 5. Colour-pattern variation in the Diplodactylus galeatus species complex: A, B Diplodactylus galeatus from Coober Pedy, SA (P. McDonald, A. Fenner), C, D Diplodactylus fyfei sp. nov. from foothills of Mt Beddome on New Crown Station, NT (P. McDonald, A. Fenner); E, F D. tjoritjarinya sp. nov. from Tjoritja National Park, Northern Territory (P. McDonald).