Lophognathus horneri, Melville & Ritchie & Chapple & Glor & Schulte, 2018

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 : 54-56

Lophognathus horneri sp. nov.

ZooBank LSID: urn:lsid:zoobank.org:act: 4E027CDD-F9B2-

451B-B08E-26D6A0B8A8ED.

( Figs. 8 & 9 )

Grammatophora temporalis (part.) Günther, A., 1867. Additions to the knowledge of Australian reptiles and fishes. Annals and Magazine of Natural History 20(3): 45–68 [52].

Synonymy that of: Melville, J., this work.

Holotype. NTM R16472 Sambo Bore, Wave Hill Station , Northern Territory (18º 52' 48" S, 130º 40' 12" E).

Paratypes. NMV D72658 Wave Hill Homestead, Northern Territory (17º 23' 08" S, 131º 06'44" E) ; NMV D73846 King Edward River Camp, Mitchell Plateau, Kimberley , Western Australia (14º 52' 57" S, 126º 12'10" E) ; NMV D74687 road to Davenport Ranges National Park , Northern Territory (20º 37' 34" S, 134º 47' 14" E) ; WAM R131990 Kununurra, Kimberley, NE Western Australia (15° 48' 0.00" S, 128° 43' 0.12" E) ; WAM R108806 Mabel Downs Station , Calico Springs, NE Western Australia (17° 16' 59.88" S, 128° 10' 59.88" E) ; WAM R132850 Kununurra, NE Western Australia (5° 47' 37.68" S, 128° 43' 10.92" E) ; BMNH 1946.8 .12.73 Nickol Bay , Western Australia [paralectotype Grammatophora temporalis (part.) Günther, 1867] .

Diagnosis. A member of the Australian genus Lophognathus Gray, 1842 , characterised by broad white stripe on the upper and lower lips, extending along the full extent of the jaw, a pale stripe from behind the eye to the top of the ear, which is cream, white, grey or yellow in life. This pale stripe is well defined ventrally and dorsally by a row of darkly pigmented scales (fig. 6). It is a large robust dragon with long head and well-built moderately long limbs. It has heterogenous scales on the back, both at the midline and dorsolaterally, associated with a weak to prominent row of enlarged strongly keeled scales. Lophognathus horneri is distinguished from Lophognathus gilberti by the presence of a distinct white spot on the tympanum (fig. 7). This well-defined white spot is wholly surrounded or bordered dorsally and to the anterior by an area of black pigmentation that is positioned on the upper posterior quarter of the tympanum. This area of black pigmentation also runs along a raised ridge that extends from the outer dorsoposterior edge of the tympanum towards its centre (fig. 9).

Description of holotype. A large robust male dragon lizard (snout–vent length: 102 mm; head length: 36.1 mm; head width at widest point: 23.2 mm; head depth: 14.4 mm; hindlimb length: 102 mm). Head moderately long and wide, slightly rounded profile of snout and slightly dorsolaterally compressed. Nuchal crest low, extending from anterior of ear to shoulders and composed of enlarged strongly keeled scales. Gulars smooth and ventrals weakly to strongly keeled. Dorsal scales strongly keeled and heterogeneous in size. Broad pale dorsolateral stripes, continuous from neck to the hips, bordered and well-defined by row of darker scales. Dorsolateral stripes discontinuous with lip stripes. Well-defined pale stripe between eye and top of ear, bordered dorsally and ventrally by row of darker scales. Well-defined white spot on the tympanum, which is adjacent to an area of black pigmentation that runs along a raised ridge that extends from the outer dorsoposterior edge of the tympanum towards its centre. Femoral pores 2L/3R; preanal pores 4.

Variation. The white stripe on the lower lip and the white spot on the tympanum are always present. The white stripe between the eye and the ear is almost always present. The broad white stripe on the upper lip can be pale and not prominent in a few individuals. The pale dorsolateral stripes are not continuous with the white lip stripes. Dorsolateral stripes are often absent between the ear and neck or are intersected by wedges of darker scales along the back. Three specimens collected from 80 Mile Beach (fig. 8), Western Australia (NMV D74362– D74364), lacked a distinct stripe between the eye and the ear – superficially similar to Amphibolurus centralis – but they still had the white spot on the tympanum. A range of specimens were examined from large adult males, females, juveniles and hatchlings. All these specimens had a white stripe on the lower lip and the white spot on the tympanum.

Coloration in alcohol. Specimens retain key diagnostic characters in preservative. For example, the paralectotype Grammatophora temporalis (part.) BMNH1946.8.12.73 from Nickol Bay, Western Australia, which has also been designated as a paratype for L. horneri sp. nov., was collected before 1867. This specimen, which has been in preservative for over 150 years, still retains diagnostic characters: broad white stripe on upper and lower lips, white spot on the tympanum and a pale stripe between eye and ear, which is bordered ventrally and dorsally by a row of darkly pigmented scales.

Distribution and ecology. Arid and semi-arid eucalypt woodlands and tropical savannahs of the central and western portions of northern Australia. Specimens were collected in 2009 as far south as the Davenport Ranges in the Northern Territory, which are south-east of Tennant Creek. This species extends north of Threeways but south of Katherine, west through Timber Creek and Wave Hill and into Western Australia. They have been collected in the Kununurra area, along the Gibb River Rd and in the Mitchell Plateau area. In Western Australia they extend south of Halls Creek and down to the northern Pilbara coast, southwest to Coral Bay and offshore islands.

Comparison with other species. Lophognathus horneri shares similar body proportions and meristic characters with L. gilberti with extensive overlap ( Tables 2 and 3; fig. 4). It is readily separated from this species by the presence of a well-defined white spot on the tympanum (fig. 7), which is wholly surrounded or bordered by an area of black pigmentation. Lophognathus horneri is also superficially similar to Amphibolurus centralis , but it differs in having proportionally shorter tail, hindlimbs and head. Additionally, L. horneri has a well-defined white spot on the tympanum and a well-defined stripe between the eye and the ear (figs 6 and 7), which are lacking in A. centralis . Some specimens of L. gilberti and A. centralis do have white areas on the tympanum but they are not a well-defined spot surrounded or adjoining the black pigmented area; instead, they are a diffuse white or off-white smear or a patch of pale pigment without the associated black pigmentation. Lophognathus horneri can be distinguished from Tropicagama temporalis gen. nov. by having a well-defined stripe between the eye and the ear and heterogeneous dorsolateral scales along the back. In addition, Lophognathus has> 2 preanal pores, whereas Tropicagama temporalis gen. nov. has only two. Gowidon longirostris differs from L. horneri by having very long limbs and tail, being dorsoventrally compressed, having 1–3 white spots on a black background behind the ear and having> 10 femoral pores.

Etymology. This species is named in honour of Paul Horner, the Curator of Terrestrial Vertebrates at the Museum and Art Gallery of the Northern Territory, in recognition of his contributions to the knowledge of the tropical lizard fauna of Australia and his instrumental role in the taxonomic review of agamid lizards from this region.

Figures

Figure 8. Photos in life of species under revision: a, Lophognathus horneri sp. nov., adult male with breeding colouration, 80 mile beach, Western Australia (photo: R. Glor); b, Lophognathus gilberti, Katherine, Northern Territory (photo: R. Glor); c, Amphibolurus centralis, adult male with breeding colouration, West MacDonnell Ranges, Northern Territory (photo: J. Melville); d, Amphibolurus burnsi, adult male with breeding colouration, Westmar, Queensland (photo: S. Wilson); e, Tropicagama temporalis, Jabiru, Northern Territory (photo: S. Wilson); f, Gowidon longirostris, adult male with breeding colouration, Ormiston Gorge, Northern Territory (photo: R. Glor).

Figure 9. Holotype of Lophognathus horneri sp. nov. (NTM R16472).