Lophognathus gilberti

Melville, Jane, Ritchie, Euan G., Chapple, Stephanie N. J., Glor, Richard E. & Schulte, James A., 2018, Diversity in Australia’s tropical savannas: An integrative taxonomic revision of agamid lizards from the genera Amphibolurus and Lophognathus (Lacertilia: Agamidae), Memoirs of Museum Victoria (Mem. Mus. Vic.) 77, pp. 41-61 : 53-54

Lophognathus gilberti

(fig. 5)

Lophognathus gilberti Gray, J.E., 1842 . Description of some hitherto unrecorded species of Australian reptiles and batrachians. Pp. 51–57: in Gray, J.E. (ed.). The zoological miscellany. London: Treuttel, Würz & Co. [53].

Redtenbacheria fasciata Steindachner, F. 1867 . Reptilien. Pp. 1–98 in: Reise der Österreichischen Fregatte Novara um die Erde in den Jahren 1857, 1858, 1859 unter den Befehlen des Commodore B. von Wüllerstorff-Urbair. Zoologie 1(3). Vienna: State Printer. [1869 on title page] [31]. Type data. Holotype whereabouts unknown (not found), Australia.

Physignathus incognitus Ahl, E. 1926 . Neue Eidechsen und Amphibien. Zoologischer Anzeiger 67: 186-192 [190]. Type data. Holotype ZMB 30086 , Australia.

Synonymy that of: Melville, J., this work; Cogger, H.G. 1983, in Cogger, H.G., Cameron, E.E., and Cogger, H.M. Amphibia and Reptiles . Pp. 121–122 in: Walton, D.W. (ed.) Zoological catalogue of Australia. Vol. 1. Netley, South Australia: Griffin Press Ltd. vi 313 pp. [121].

Holotype. BMNH 1946.8 .28.69 from Port Essington , NT.

Diagnosis. As for genus. Lophognathus gilberti is distinguished from Lophognathus horneri sp. nov. by lacking a distinct white spot on the tympanum (fig. 7) that is surrounded by or adjacent to black pigmentation.

Description of Holotype. A large robust male dragon lizard with large robust limbs and tail. Large head in comparison with body size, prominent nuchal crest of 18 enlarged spinose scales, extending from anterior of ear to shoulders. Small nasal scale and nares, below canthal ridge. Supralabials 13; anterior point of lower jaw damaged. Head scales heterogeneous and strongly keeled; 3–5 enlarged white spinose scales protruding from rear of head, posterior to the jaw. Dorsal scales on body and tail strongly keeled and heterogeneous. Gulars smooth and ventrals weakly to strongly keeled. Scales on thighs heterogeneous and strongly keeled. Very broad white lip stripes, extending under jaw and up to anterior border of ear. Broad pale dorsolateral stripes, continuous from neck to hips, bordered and well defined by row of darker scales. Dorsolateral stripes discontinuous with lip stripes. Poorly defined and discontinuous pale stripe between eye and top of ear, bordered dorsally and ventrally by darker scales. No clearly defined white spot on a dark background on the tympanum, although there is a patch of pale pigment in the upper-back quadrant of the tympanum. Colour dorsally is light to dark brown and grey. Ventral surface of head, throat and upper chest darkly pigmented with the dark pigmentation extending to the lateral surfaces of the throat and up over the shoulders, bordering the white dorsolateral stripes. Femoral pores 6; preanal pores 4.

Variation. Some specimens of L. gilberti do have white areas on the tympanum but they are not a well-defined spot surrounded by the black pigmented area (fig. 7); instead, they are a diffuse white or off-white smear or patch of pale pigment without the associated black pigmentation. An example of this is specimen NMVD74026 collected from Mt Wells Road, near Grove Hill in the Northern Territory (13° 28' 47" S, 13° 132' 41" E), which has a smear of white pigmentation across the posterior half of the tympanum .

Distribution and ecology. Far northern Australia in woodlands and tropical savannahs. In the Northern Territory north of Katherine, in Arnhem Land, and across coastal areas into Western Australia and western Queensland. In Western Australia, occurs north of Kununurra and extending up into the eastern coastal Kimberley.

Remarks. Lophognathus gilberti shares similar body proportions and meristic characters with L. horneri sp. nov., with extensive distributional overlap (fig. 4) but is readily separated by the lack of a well-defined white spot on the tympanum. Lophognathus gilberti is also superficially similar to Amphibolurus centralis and potentially has distributional overlap, but it differs in mostly having a well-defined white or pale stripe extending the full length between the ear and the eye, and a broad white stripe running the extent of the upper lip being mostly present.