Carlia sexdentata ( Macleay, 1877 )

Donnellan, S. C., Couper, P. J., Saint, K. M. & Wheaton, L., 2009, Systematics of the Carlia ‘ fusca’ complex (Reptilia: Scincidae) from northern Australia, Zootaxa 2227 (1), pp. 1-31 : 18-24

Carlia sexdentata ( Macleay, 1877)

Figs 9 , 10 , & 11: Tables 3, 4 & 5

1877 Heteropus sexdentatus Macleay. Proc. Linn. Soc. N.S.W. 2: 67. Cape Grenville , north-eastern Queensland. Lectotype AMS R 31879.

1877 Heteropus variegatus Macleay, 1877 Proc. Linn. Soc. N.S.W. 2: 66. Darnley Island , N Queensland. Lectotype AMS R 31868.

1885 Heteropus maculatus de Vis. Proc. Roy. Soc. Qld 1: 169. Cape York , north-eastern Queensland. Type material missing, see Covacevich (1971) .

1885 Heteropus rubricatus de Vis. Ibid. 1: 170. Cape York , north-eastern Queensland. Type material missing, see Covacevich (1971) .

Material examined: Lectotype: AMS R 31879. Cape Grenville , north-eastern Queensland (11°58'S, 143°14'E).

Other material: Queensland. Torres strait - (Vouchers with associated genetic samples): QM J86364 , Saibai Island (9°24'S, 142°41'E) ; QM J86350 , Dauan Island (9°25'S, 142°32'E) ; QM J86353 , QM J86363 , Masig, Yorke Island (9°45'S, 143°24'E) ; QM J86360 -2 , Yam Island (9°54'S, 142°46'E) . Cape York Peninsula - QM J68594 , Cape York, Somerset (10°44'3”S, 142°35'3”E) ; QM J45598 , QM J45601 -2 , QM J45599 , near Telegraph crossing, north bank of Jardine River , (11°08'S, 142°22'E) ; QM J26200 , Heathlands, site 5 (11°39'S, 142°50'E) ; QM J26216 , QM J26220 , QM J26224 Cape York, Heathlands (11°39'S, 142°50'E) ; QM J39745 7.8km N mouth of Janie Creek (11°57'S, 141°52'E) ; QM J46366 , near Harmer Creek, 19km E Nixon’s Homestead, Shelburne Station (11°58'S, 142°55' E) ; QM J46341 , 21.8km from Nixon’s Homestead , on road to Double Point (11°58'S, 142°05'E) ; QM J46333 , Harmer Creek, 18km E Nixon Homestead, Shelburne Station (11°59'S, 142°53'E) ; QM J67615 , Haggerstone Island (12°03'S, 143°18'E) ; QM J80416 , Pennyfather River , 70km N Weipa (12°15'39”S, 141°42'40”E) ; QM J74714 , Thong Tree south of Pennyfather River (12°19'23"S, 141°41'26"E) ; QM J32017 , Kungathan (12°22' S, 143°12'E) ; QM J86997 -8 , Glennie Tableland (12°27'43"S, 142°55'26E) ; QM J62356 , Weipa area (12°28'41"S, 141°50'37”E) ; QMJ62357, Weipa area (12°28'01"S, 141°50'34”E) ; QM J70190 , Weipa area (12°28'37"S, 141°50'03”E) ; QM J86984 -7 Pascoe River mouth (12°29'09"S, 143°16'28"E) ; QM J62354 , Weipa Area (12°30'28"S, 141°47'52"E) ; QM J34394 -5 Portland Roads turnoff, Iron Range (12°38'S, 143°23'E) ; QM J70340 , Weipa area (12°43'22"S, 141°56'48"E) ; QM J34389 , W Claudie campsite, Iron Range, (12°46'S, 143°17'E) ; QM J39716 , QM J39748 , 6 km SW Boyd Point, Pera Head (12°57'S, 141°36'E) ; QM J34478 , Buthen Buthen, Nesbit River, E Coen (13°21'S, 143°27'E) ; QM J41927 -9 , Thanmala, via Aurukun (13°23'S, 141°42'E) ; QM J34502 , QM J34505 /7, Steen’s Hut, approx. 30km NE Coen (13°34'S, 143°13'E) ; QM J86893 -4 , Kulla NP, McIlwraith Range (13°42'36”S, 143°18'36”E) ; QM J37487 , 12 km NW Coen (13°51'17"S, 143°9'1"E) ; QM J46240 -1 , QM J46245 -6 , McIlwraith Range (13°50'S, 143°17'E) ; QM J78269 , 5 km N Coen (13°54'08”S, 143°10'56”E) ; QM J78264 , adjacent to ranger station Coen Creek, Coen (13°56'2”S, 143°11'59"E) ; QM J78341 approx. 3km S Coen (13°57'44”S, 143°11'24”E) ; QM J78266 S Coen , (14°08'S, 143°13'31”E) ; QM J60337 , Stanley Island , Flinders Group NP (14°8'58"S, 144°15'15”E) ; QM J72702 , Lilyvale Station (14°25'5"S, 143°45'42"E) . Northern Territory - (all specimens from NTM unless otherwise stated): R 19025, Cape Wessel Island (11°S, 136°46'E) ; R 26299, R 26310, Jensen’s Bay, Marchinbar Island (11°10'S, 136°41'E) ; R 08950, S Nip Point Marchinbar Island (11°21'S, 136°33'E) ; R28607-8 , Rimbija Island, Wessel Islands (11°34'S, 136°45'E) ; R 22757, R 22761/5, Astell Island, English Company Isles (11°52'S, 136°25'E) ; QM J84006 Maningrida (12°02'52”S, 134°13'20”E) ; QM J86281 -2 , Maningrida (12°02'55”S, 134°13'33”E) ; QM J86284 -5 , QM J86287 , Maningrida CEC (12°03'08”S, 134°13'20”E) ; R 23948, Ramingining area, Arafura Swamp (12°10'08”S, 134°58'04”E) ; R 23945, Ramingining area, Arafura Swamp (12°12'S, 134°59'E) ; R 16156/8 , R16161-2 , Blyth River crossing, Arnhem Land (12°21'S, 134°41'E) ; R 23902, Djapididjapin Creek, near Ramingining, Arafura Swamp (12°21'50”S, 134°54'19”E) ; R 23959, Ramingining Area, Arafura Swamp (12° 12°30S, 134°58’56”E) ; R 23995, Ramingining Aarea, Arafura Swamp (12°12'25”S, 134°59'11”E) ; R 28280, Groote Eylandt , Gulf of Carpentaria (13°56'S, 136°36'E) ; R 03357, Angurugu, Groote Eylandt (13°58'S, 136°26'E) ; R 07566, Angurugu, Groote Eylandt (13°59'S, 136°28'E) .

Distribution: North-eastern Northern Territory and north-eastern Queensland. Northern Territory – northeastern Arnhem Land, Crocodile Island, The Wessel Islands, the English Company’s Islands and Groote Eylandt. Queensland - Torres Strait Islands and Cape York Peninsula from the head of Princess Charlotte Bay (14°30'S) north.

Diagnosis: Carlia sexdentata most closely resembles C. longipes from which it is separated herein. The two species are distinguished most readily by the colour pattern of adult males and the nature of the ear lobules. In C. sexdentata the dark midlateral zone between ear and shoulder does not contrast sharply with the lower neck colour vs contrasting sharply with lower neck colour; in C. sexdentata the ear aperture usually has a well-developed series of lobules on the anterior margin often producing a distinctive comb- like effect, lobules poorly to moderately developed on other surfaces of ear ( Fig. 10a, b ) vs ear aperture completely surrounded by sharply pointed lobules ( Fig. 7 ). Carlia sexdentata lacks the dorsal and lateral pattern seen in C. quinquecarinata (large, longitudinally aligned, dark-edged, pale dashes on the dorsum and a broken midlateral line [ Fig. 12c ]). Carlia sexdentata need only be distinguished from other species of Carlia with a smoothly rounded posterior edge to the midbody scales. It is distinguished from C. munda and C. tetradactyla by the nature of its ear lobules (sharply pointed vs small and rounded); from C. rimula by its greater midbody scale count and larger size (31–38 vs ≤ 30; max SVL = 63.5mm vs 39mm); from C. rhomboidalis and C. rubrigularis by the state of the interparietal scale (free vs fused); from C. rostralis by its ear lobules and male breeding colours (ear aperture usually has a series of well-developed lobules on the anterior margin often producing a distinctive comb-like effect, lobules poorly to moderately developed on other surfaces of ear vs ear aperture generally with only one or two large pointed lobules on anterior edge; males with pale throat vs black throat). Of the above listed species, its broad distribution only overlaps with C. munda and C. rimula . Whether it overlaps with C. longipes remains unclear. The two species may be mutually exclusive but, if so, the southern limit for C. sexdentata is in close proximity to the northern limit for C. longipes .

Description: SVL (mm) 21.00–63.51, n = 83. Proportions as %SVL(mean ± standard deviation): TL 170.23–198.18 (185.37 ± 7.53, n = 20); AG 41.58–54.58 (48.19 ± 2.70, n = 82); L1 28.81–42.03 (34.69 ± 2.41, n = 82); L2 42.11–58.51 (50.84 ± 3.88, n = 82); HL 20.14–25.42 (22.75 ± 1.08, n = 81) Eye-ear 6.86–9.10 (8.01± 0.47, n = 81); Snout 7.86–10.74 (9.16± 0.53, n = 81). Body robust. Head barely distinct from neck. HW 59.15-79.30% HL (68.28 ± 3.44, n = 81). Limbs moderate. L1 59.42–80.42% L2 (68.40± 4.11, n = 82).

Scalation: Rostral in broad contact with frontonasal. Prefrontals large, narrowly (42% of specimens), moderately (51% of specimens) or widely (6% of specimens) separated; contacting in QM J86281 . Supraoculars 4; 1 and 2 in contact with frontal, 2, 3 and 4 in contact with frontoparietal. Frontoparietals fused, forming a single shield. Interparietal free. Enlarged nuchal scales 2–3 (mode = 2, n = 862). Snout rounded in profile. Loreals 2 (1 in QM J86284 ). Preoculars 2. Presubocular single. Supraciliaries 6–8 (7.05±0.31, mode = 7, n = 82). Lower eyelid moveable with clear window; palpebral disc small, occupying half or less of lower eyelid. Ear aperture subequal or larger than palpebral disc; usually vertically aligned (68% of specimens) but sometimes round (32% of specimens), with an enlarged, comb-like series of sharp lobules on anterior margin, usually some elongated sharp lobules projecting down from the posterior edge of the dorsal margin (66% of specimens) and sometimes a series of smaller lobules along the posterior margin (30% of specimens). Supralabials 6–8 (7.01±0.19, mode = 7, n = 82), with fourth to sixth below centre of eye (5.01±0.19, mode 5, n = 82). Infralabials 5–8 (mode = 6, n = 83). Dorsal scalation smooth to weakly tricarinate; posterior edge smoothly curved. Midbody scale rows 31–38 (mean = 34.64, mode = 34, SD = 1.62 n = 81). Paravertebral scale rows 44–50 (mean = 47.09 mode = 47, SD = 1.67, n = 79). Lamellae beneath 3 rd finger 17–25 (21.11±1.55, mode = 21, n = 82). Lamellae beneath 4 th toe 24-37 (30.61±2.44, mode = 32, n = 82).

The scale counts and body proportions of the Queensland and Northern Territory C. sexdentata populations are broadly overlapping (see Table 5).

Colour pattern in spirit: Dark olive brown dorsally; uniform, or with dark streaks aligned longitudinally on scale edges. Tail usually with a longitudinal series of dark-edged pale flecks. Venter off-white.

Colour pattern in life: adult males in breeding colours ( Fig. 9a, d & f ): usually with some indication of a poorly defined, white dorsolateral stripe (commencing behind supraciliaries, running through upper secondary temporals and terminating just behind forelimb). This is bordered below by a dark upper lateral zone (a grey to blackish smudge, encompassing 2–3 scales rows and extending from eye to just behind forelimb) which does not contrast sharply with the scales of the lower neck which, though paler, are often dark-edged. Dark upper lateral zone terminates just behind the forelimb and is continuous with the metallic pink flank colouration (rich orange in life). Limbs and sides of tail orange- brown. Females ( Fig. 9b, c ): with a narrow, pale facial stripe that begins beneath the eye and terminates near the dorsal margin of the ear aperture. The dark upper lateral is enclosed between narrow, white dorsolateral and midlateral stripes which are most prominent anterior to the forelimb (the former commencing behind the eye, the latter behind the ear). This pattern extends varying distances along the flanks (sometimes approaching the hindlimb insertion). The upper lateral zone is broken by one or more, obscure vertical, white bars in front of the forelimb and has irregular white dashes along its full length. Dorsum often with white flecking and sometimes a dark vertebral streak ( Fig. 9b ). Juveniles: similar to females but with more prominent pale flecking on dorsum and flanks. NT populations ( Fig. 9e ): general pattern similar to Queensland material, but less prominent. Dark upper lateral zone usually vague and sometimes broken into a series of narrow, longitudinal stripes.

Measurements and scale counts of Macleay Heteropus sexdentatus types: AMS R31879-81: SVL 38.43–53.59mm, n = 3; Proportions as %SVL (mean ± standard deviation): TL 200.03 (n = 1); AG 45.49– 51.83 (48.80 ± 3.18, n = 3); L1 34.63–38.10 (36.52 ± 1.74, n = 3); L2 54.0–58.05 (55.53 ± 2.20, n = 3); HL 23.31–23.80 (23.61 ± 0.27, n = 3); Eye – ear 8.12–8.60 (8.35 ± 0.24, n = 3); Snout 9.60–10.67(10.19 ± 0.55, n = 3) Body robust. Head barely distinct from neck. HW 60.87–71.58% HL (65.08 ± 5.71, n = 3). Limbs moderate. L1 64.18–67.52% L2 (65.76 ± 1.68, n = 3).

Raw measurements and scale counts of lectotype ( Fig. 11a ): AMS R31879. SVL 53.59 mm; AG 26.25 mm; L1 18.56 mm; L2 28.92 mm; HL 12.49 mm; HW 8.94 mm; Eye – ear 4.61; Snout 5.14: midbody scale rows 36; paravertebral scale rows 48; supraciliaries 7; supralabials 7; fifth supralabial below eye; infralabials 6; subdigital lamellae beneath 3 rd finger 23; subdigital lamellae beneath 4 th toe 34; enlarged nuchals 2; preoculars 2; presuboculars 1; postsupralabial divided; temporals – 1 primary, 2 secondary; ear vertical with sharp lobules at front and top – those along dorsal margin small and deeply recessed ( Fig. 11b ); palpebral disc smaller than ear opening.

The scales of the dorsal and lateral surfaces are weakly tricarinate.

Pattern of lectotype: AMS R 31879 is badly faded and has lost all traces of patterning, as has AMS R 31881. The paralectotype, AMS R 31880, still shows traces of the typical female colour pattern, i.e. a dark upper lateral zone bordered by a pale dorsolateral and midlateral stripe; broken by obscure, vertical, white bars in front of forelimb .

Comments: The diagnostic characters provided herein, separating C. longipes from C. sexdentata hold well for mainland C. sexdentata populations. However, the ear lobule state (ear aperture is completely surrounded by sharply pointed lobules in C. longipes vs usually a series of well-developed lobules on anterior margin often producing a distinctive comb-like effect, lobules poorly to moderately developed on other surfaces of ear for C. sexdentata ) is more variable in Torres Strait with island C. sexdentata specimens commonly approaching the`completely surrounded’ C. longipes condition. In Torres Strait, where the condition of the ear lobules may prove ambiguous, the diagnostic pattern differences hold well for adult males.

Two specimens listed in material examined were not included in the statistical analysis (QM J67615 , Haggerstone Island, and QM J72702 , Lilyvale Station) as they represent outliers to the main distribution and have pattern and ear lobule characteristics that, although generally consistent with C. sexdentata , are unusual. Both specimens have a single large lobule on the anterior margin of the ear (vs a ‘comb’ of enlarged lobules) and, although being females, exhibit a male-like colour pattern (anterior midlateral zone reduced to a dark smudge between ear and forelimb). Despite these inconsistencies, both specimens can be readily separated from C. longipes .

An issue arises concerning the names C. sexdentata and C. variegata and which of these is the senior synonym. Wells and Wellington (1985) resurrected C. variegata ( Macleay 1877) from the synonymy of C. longipes as the appropriate name for the Torres Strait island ‘ C. fusca ’, yet provided no explanation for doing so and made no mention of H. sexdentatus Macleay 1877 , which Macleay had published in the same paper. The action of Wells and Wellington (1985) potentially gives C. variegata priority over C. sexdentata . However, while the lectotypes of H. sexdentatus and H. variegatus are faded both retain the key diagnostic pattern elements, but the lectotype of H. sexdentatus has the majority ear lobule condition ( Fig.11b ) while the lectotype of H. variegatus has the minority condition for this trait ( Fig. 11d ). Therefore we can associate more strongly the lectotype of H. sexdentatus with our taxon C. sexdentata . Furthermore, as this is the first time in which these species alone have been considered as competing synonyms rather than as junior synonyms of a third species, C. longipes , we invoke the principle of the first reviser (ICZN, Article 24.2) and consider H. sexdentatus as the more appropriately applied name, with H. variegatus relegated to the synonymy of C. sexdentata .

The provenance and affiliations of two other types, Heteropus maculatus de Vis 1885 and H. rubricatus de Vis 1885 need to be considered to complete our analysis of the synonymy of the ‘ C. fusca ’ group in northern Australia. The descriptions of Heteropus maculatus and H. rubricatus are based on material collected on ‘Cape York’ by Kendall Broadbent some time prior to November 1884; the date that de Vis presented his ‘…conspect of the genus Heteropus ’ at a meeting of the Royal Society of Queensland (de Vis, 1885). Based on locality, colour pattern and scalation characters, these taxa clearly belong to the ‘ Carlia fusca ’ group and accordingly were assigned to the synonymy of C. longipes by Ingram and Covacevich (1989). With our resurrection of C. sexdentata (new combination) from the synonymy of C. longipes , it is necessary to revisit de Vis’ descriptions of H. maculatus and H. rubricatus to assess their taxonomic status. In the absence of specimens (types missing, see Covacevich, 1971), the only clues to their identities lie in: 1) information on the whereabouts of the collector in the period preceding publication. Importantly, where on Cape York Kendell Broadbent did collect in the period leading up to de Vis’ Heteropus descriptions? If he was north of Princess Charlotte Bay then these specimens are likely to belong to C. sexdentata , if he was south, C. longipes is the most likely identification; and 2) de Vis’ scant type descriptions.

1) The report of the Board of Trustees for the Queensland Museum for the year 1884 states that at the start of the year Broadbent was ‘…dispatched to Somerset, Cape York, and succeeded in making a large collection chiefly of fish, but including novelties in each department of vertebrate life.’ (Anon, 1885). Broadbent then proceeded to the Kimberley region of Western Australia where he met with limited collecting success and subsequently revisited Somerset on his return trip home. Here he supplemented his previous collections and was back in Brisbane in September, 1884. A summary of his Cape York (= Somerset) collections ( Anon, 1985, Appendix iv) shows that 54 reptile specimens representing 23 species were collected on the first visit with additional specimens obtained on the return visit (numbers not specified in report). This information is further corroborated by collection data contained in the Queensland Museum’s vertebrate registers. 2) Both descriptions refer to ‘free scales’ along the fore-edge (5-6 in H. maculatus , 3 in H. rubricatus ) of the ear aperture with no mention of lobules on the other edges of the ear, the typical C. sexdentata state. Further, the description of H. maculatus provides colour details that are consistent with male C. sexdentata but not C. longipes (i.e. H. maculatus has a broad lateral stripe, but no mention is made of this being bordered above by a distinct, pale dorsolateral). The lateral stripe of H. rubricatus is less informative, being ‘…edged above and below with white…’ (de Vis, 1885). This pattern could apply to either C. sexdentata or C. longipes , but would suggest the specimen examined by de Vis was likely to have been a female. The other descriptive details, i.e. measurements and midbody scale counts, fall within the range of both species.

On balance, the evidence points to the missing de Vis types being referable to C. sexdentata . It is likely that these specimens were collected at Somerset on northern Cape York Peninsula (10°45'S) in 1884. The ear lobule descriptions for both de Vis taxa point to an identification of C. sexdentata as does the colour pattern description of H. maculatus . It is likely that both H. maculatus and H. rubricatus are conspecific with C. sexdentata , the former description depicting a male, the latter a female. Heteropus maculatus and H. rubricatus are, herein, formally assigned to the synonymy of C. sexdentata .

Figures

FIGURE 7. Variation in the ear lobules of C. longipes. (a) QM J41349 Ellis Beach; (b) QM J20509 Melville Range; (c) QM J25163 Home Rule; (d) QM J53107 Cape Flattery. (All images G. Thompson).

FIGURE 9. Images of Carlia sexdentata in life. (a) ♂ from tip of Cape York Peninsula (image: S. Wilson). (b) ♀ from Somerset, Cape York Peninsula (image: H. Cogger). (c) ♀ Red Beach, Mapoon (image: S. Donnellan). (d) ♂ from Iron Range (image: S. Wilson). (e) QM J86281, non-reproductive ♂ from Maningrida, NT (image: A. Amey). (f) ♂ from Saibai Island, Torres Strait (image: S. Wilson).

FIGURE 10. Variation in ear lobules in C. sexdentata. (a) QM J45598 Jardine River; (b) QM J46341 road to Double Point; (c) QM J72702 Lilyvale Station; (d) QM J67615 Haggerstone Island. (all images: G. Thompson).

FIGURE 11. (a) AMS R31879, Lectotype of H. sexdentatus Macleay 1877 Cape Grenville, north-eastern Queensland (image: J. Wright). (b) Ear lobules, left side of AMS R31879. Note that the lobules on the dorsal margin are small and deeply recessed, hence not clearly discernible. (image: G. Thompson). (c) AMS R31868, Lectotype of H. variegatus Macleay 1877 Darnley Island, north-eastern Torres Strait (image: J. Wright). (d) Ear lobules, left side of AMS R31868. Note that the lobules on the dorsal margin are small and deeply recessed, hence not clearly discernible. (image: G. Thompson).

FIGURE 12. (a) AMS R31873, Lectotype of H. quinquecarinatus Macleay 1877 Darnley Island, north-eastern Torres Strait (image: J. Wright). (b) Ear lobules, left side of AMS R31873. Note that the lobules on the posterior margin are small and deeply recessed, hence not clearly discernible. (image: G. Thompson). (c) QM J86354 from Darnley Island, see Comments in C. quinquecarinata species account (image: J. Wright).