Carlia decora, Hoskin & Couper, 2012

Hoskin, Conrad J. & Couper, Patrick J., 2012, Description of two new Carlia species (Reptilia: Scincidae) from north-east Australia, elevation of Carlia pectoralis inconnexa Ingram & Covacevich 1989 to full species status, and redescription of Carlia pectoralis (de Vis 1884), Zootaxa 3546, pp. 1-28 : 3-7

Carlia decora sp. nov.

Elegant Rainbow Skink

( Figs 1A & B, 2A, 3A, 4A, 5A, 6A, 7A, 8A, 9A, 10A–C.)

Holotype. QMJ90875, female, Alligator Ck, Mt Elliot, Bowling Green Bay National Park (19°26'07"S, 146°56'48"E, 50 m), north-east Queensland, C. J. Hoskin, 6 October 2011.

Paratypes. J42498 -500 Townsville Common (19°16'S, 146°49'E) ; QMJ90878-79 Riverside Gardens, Townsville (19°19'14"S, 146°44'30"E) ; J48391 Townsville, James Cook University Campus (19°20'S, 146°46'E) ; QMJ90876-77 Alligator Ck, Mt Elliot (19°25'54"S, 146°56'37"E) ; J86515 Deadman's Creek , Proserpine (20°30' 14"S, 148°33'23"E) ; J86516 Deadman's Ck, Proserpine (20°30'15"S, 148°33'22"E) ; J86449 Deadman's Creek , Proserpine (20°30'6"S, 148°33' 21"E) ; J63912 Cathu SF, Horse Ck (20°48' 51"S, 148°34'11"E) ; J74809 Brampton Is (20°49'S, 149°17'E) ; J74805 Cape Hillsborough NP (20°54'30"S, 149°00'30"E) ; J74807 , J74812 Cape Hillsborough NP (20°55'30"S, 149°02' 30"E) ; J53395 Boulder Ck, campsite, via Mt Charlton (21°01'S, 148°43'E) ; J81405 East Point , Mackay (21°09'S, 149°13'E) .

Additional material. J79829 Curacoa Island (18°40'S, 146°33'E) ; J42502 , J42504 Bluewater, ca. 20 km N Townsville (19°11'30"S 146°33'30"E) ; J79565 Pallarenda (19°12'S, 146°46'E) ; J42497 Townsville (19°16'S, 146°49'E) ; J79270 , J79297 -98 , J79375 Townsville Common (19°16'S, 146°49'E) ; J48393 Townsville , James Cook University Campus (19°20'S, 146°46'E) ; J89137 Whitehaven Whitsunday Is (20°17'47"S, 149°3'13"E) ; J86754 Mount Macartney , Eungella (20°47'58.4"S 148°32'31.2"E) ; J79888 -89 Cape Hillsborough NP, Smalley's Beach (20°54'S, 149°00'E) ; J74806 , J74808 Cape Hillsborough NP (20°55'30"S, 149°02'30"E) ; J53396 Boulder Ck, campsite, via Mt Charlton (21°01'S, 148°43'E) ; J59968 Walkerston, 3 km W of the Peak Downs Hwy (21°13'S, 149°0'30"E) ; J60072 -73 Sarina Beach, 9 km E of Sarina (21°23' 10"S, 149°18'30"E) .

Diagnosis. A moderate-sized Carlia (max SVL 49 mm) that can be distinguished from all its congeners by a combined suite of characters. Interparietal scale free. Dorsal scales tricarinate and hexagonally-shaped. Palpebral disc large. Ear aperture vertically elliptic (usually angled back) with a single large, rounded lobule on the anterior margin ( Fig. 8A). Supraciliaries usually five. Prefrontals usually moderately separated ( Fig. 9A). Upper preocular usually well developed and contacting posterior edge of 2 nd loreal scale (if not contacting loreal, then broadly triangular in shape) ( Figs. 10A–C). Breeding male with a pale blue throat and distinct orange upper lateral stripe that extends from forelimb to hindlimb; sometimes a less distinct orange lower lateral stripe is also present; black speckling present on neck and jawline but usually no, or limited, black-edging to scales on throat ( Figs 1A, 2A, 4A, 5A). Adult female with a distinct, black-edged, white mid-lateral stripe that always extends to the groin ( Figs 1B, 6A, 7A). Both sexes with an immaculate white or cream ventral surface.

Etymology. From the Latin decora (feminine), meaning ‘beautiful'. In recognition of the beautiful form and colour pattern of this species. The species epithet is treated as a noun in apposition.

Description of holotype ( Fig. 7A). QMJ90875, female. Measurements (mm): SVL 38.2; tail 71.6; interlimb 19.2; HLL 18.9; TL 5.9; HW 6.0; HL 8.6. Scalation: Dorsal scale keels 3; midbody scale rows 30; paravertebrals 47; supralabials 7; infralabials 6; supraciliaries 5, subdigital lamellae (4 th toe) 24; subdigital lamellae (3 rd finger) 19. Upper preocular in contact with posterior edge of 2 nd loreal scale; palpebral disc large; ear smaller than palpebral disc, vertically elliptic with one large rounded lobule on anterior margin; postsupralabial divided; nasals widely spaced; prefrontals moderately spaced.

Colour pattern of holotype in preservative. Dorsum brown; top of head tawny brown. Indistinct, silvery dorso-lateral line, most prominent at the shoulders. Distinct, white mid-lateral line, bordered above and below by a thin black edging. Tawny brown upper flanks between mid-lateral and dorso-lateral lines. Lower flanks smudged greyish, merging to white belly. Ventral surfaces immaculate white. Tail brown with irregular fine black markings. Prominent white spot at posterior base of hindleg. Legs brown with dark mottling. Fine white line from nare, under eye, through tympanum, and continuous with mid-lateral line.

Description of type series. Body robust with keeled dorsal scales. Head barely distinct from neck. Snout rounded in profile. Limbs moderate; four fingers; five toes. Adult measurements and proportions: see Table 1. Scalation: Rostral in broad contact with frontonasal. Postsupralabial divided. Nasals widely spaced. Prefrontals large and usually in moderate separation (moderate separation 74%, narrow separation 26%) ( Fig. 9A). Supraoculars 4; 1 and 2 in contact with frontal; 2, 3 and 4 in contact with frontoparietal. Frontoparietals fused, forming a single shield. Interparietal distinct. Enlarged nuchal scales 2. Loreals 2. Preoculars 2. Presubocular single. Supraciliaries 5 (very rarely 6 or 7). Upper preocular well developed and contacting posterior edge of 2 nd loreal scale (66%) or, if not contacting loreal, then broadly triangular in shape (33%) ( Fig. 10A–C). Lower eyelid movable, with clear window; palpebral disc large, occupying more than half of lower eyelid. Ear aperture smaller than palpebral disc; usually vertically elliptical (68%) but sometimes rounded (32%); with 1 large rounded lobule on anterior margin ( Fig. 8A). Supralabials 7, with the fifth positioned below the eye. Infralabials 6. Three scales between the nasal scale and the presubocular. Midbody scale rows 26–30 (mean = 29); dorsal scales with tricarinate keels. Paravertebral scale rows 46–50 (mean = 47). Subdigital lamellae under 3 rd finger 17–22 (mean = 20). Subdigital lamellae under 4 th toe 22–31 (mean = 27).

Colour pattern in preservative. Males ( Figs 3A, 4A, 5A): Dorsal surfaces brown, with paired paravertebral dark markings (and occasionally white flecks) present on some individuals, particularly on the posterior half of the body and tail. Iridescent sheen to scales. Top of head generally lighter brown; often with fine black dots. Flank light brown with a thin orange upper lateral line from above forelimb to above hindlimb; sometimes a faint orange lower lateral line. Ventral surfaces immaculate white, cream or creamy yellow. Throat, neck and jawline blue or white. Throat generally unmarked but sometimes with grey or black flecking or fine edging to scales; occasionally grey or dark smudging. Neck and jawline generally marked with fine dark flecks or dark scale edging. Limbs brown on top, pale below. Prominent white spot at posterior base of hindleg. Females ( Figs 6A, 7A): Dorsal surfaces brown, with paired paravertebral dark markings and white flecks present on some individuals. Iridescent sheen to scales of some individuals. Top of head generally lighter brown; often with fine black dots. Bold, white mid-lateral line, edged with black, always extends full length of flank to groin. Sometimes also a faint, silvery dorso-lateral line, particularly evident at shoulders. Upper flanks coppery, bronze or tawny. Lower flanks coppery or brown and merging with pale underside. White line from nare, under eye, through tympanum, and continuous with white midlateral line. Ventral surfaces immaculate white, cream or grey. Limbs brown on top, pale below. Prominent white spot at posterior base of hindleg.

Colour pattern in life ( Figs 1A, 1B, 2A). Dorsum of both sexes brown with paravertebral row of black and pale dots, generally becoming more distinct posteriorly. Ventral surfaces immaculate white or cream. Breeding males with uniform pale blue or white throats and fine dark speckling along edge of jawline. A sharply defined orange or red upper lateral stripe encompasses two scale rows and extends from just in front of the forelimb to groin. At maximum breeding extent a ragged, orange lower lateral line is also present, the throat can be sky blue, and grey speckling on the neck and throat can be quite pronounced in some individuals. Occasionally, fine grey or black edging is present on scales of the throat. Adult females have a white mid-lateral stripe, with well-defined dark edges, extending from nostril or eye to groin. The upper flanks, above the white mid-lateral line, are usually tawny brown. In many females a narrow, coppery dorsolateral stripe is also discernable, particularly at the shoulders.

Comparison. Only likely to be confused with C. vivax de Vis 1884 , members of the C. pectoralis group ( C. pectoralis , C. rubigo sp. nov. and C. inconnexa ), and female C. jarnoldae Covacevich & Ingram 1975 . Carlia decora sp. nov. is most closely related to C. vivax (C. Hoskin, unpublished data) and females of the two species are superficially similar. The two species also share some key traits, such as an upper preocular that contacts the 2 nd loreal or is a broad triangular wedge, and a vertically elliptical ear opening with a single large, rounded lobule on the anterior margin. However, C. decora sp. nov. can be readily distinguished from C. vivax by tricarinate versus bicarinate mid-dorsal scales, respectively. Tricarinate mid-dorsal scales also separates C. decora sp. nov. from C. inconnexa (predominately bicarinate), and the latter is also a larger skink with higher midbody, paravertebral and subdigital lamellae scale counts ( Table 1). The male and female colour patterns also differ obviously between C. decora sp. nov. and C. inconnexa ( Table 1, Figs 1–7; see C. inconnexa Comparison section). Carlia decora sp. nov. differs from C. pectoralis and C. rubigo sp. nov. in a variety of ways. The upper preocular scale in C. decora sp. nov. is broadly triangular (and usually contacts the loreal) versus a narrow vertical sliver in C. pectoralis and C. rubigo sp. nov. ( Fig. 10). The prefrontals are generally moderately separated in C. decora sp. nov. versus narrowly separated or in point contact in C. pectoralis and C. rubigo sp. nov. ( Fig. 9). Carlia decora sp. nov. generally has one large, rounded anterior ear lobule whereas C. rubigo sp. nov. often has low, rounded lobules present on other margins and C. pectoralis generally has lobules present on all margins of the ear (and these lobules are often pointed) ( Fig. 8). Additionally, the ear opening of C. pectoralis is usually rounded, versus typically vertically elliptical in C. decora sp. nov. ( Fig. 8). Carlia decora sp. nov. is a more elongate (> interlimb/SVL) skink than C. pectoralis and C. rubigo sp. nov., and is larger (average and max SVL) than C. rubigo sp. nov. ( Table 1). Female C. decora sp. nov. have a bold white, dark-edged mid-lateral line that always extends to the groin, whereas this stripe rarely extends as a distinct white line onto the posterior half of the flank in C. pectoralis and C. rubigo sp. nov. ( Figs 1, 6). Additionally, in female C. decora sp. nov. the upper flanks are generally tawny brown and there is often some indication of a pale dorso-lateral line at the shoulders ( Figs 1, 6). The colour pattern of breeding males differs between Carlia decora sp. nov., C. pectoralis and C. rubigo sp. nov. ( Figs 1–5). Breeding male C. decora sp. nov. have a thin orange upper lateral line and occasionally also a less distinct, ragged orange lower lateral line. The throat is pale or light blue and grey or black flecking is generally restricted to the jawline and side of the neck and rarely extends obviously onto the throat. In male C. pectoralis , the lower lateral orange line is often more obvious and the orange regularly extends onto the chest, and the scales of the neck and throat are typically heavily edged with black (i.e. black scalloping). The flanks of male C. rubigo sp. nov. are diffusely washed with orange or copper colouration, rather than the orange being restricted to upper and lower lateral lines. The ventral surfaces of male and female C. decora sp. nov. are typically immaculate white or cream, versus tinged with grey in C. pectoralis and C. rubigo sp. nov. Female C. decora sp. nov. and C. jarnoldae are superficially similar in that both have a white mid-lateral line that always extends to the groin. This line is broader on C. jarnoldae and bordered above by a more obvious dark band. Additionally, C. decora sp. nov. is larger (mean SVL 44 mm vs. 38 mm), generally has 5 supraciliaries (vs. usually 7), has vertically elliptical ear opening (vs. horizontally elongate) and with a large, rounded lobule on anterior margin (vs. a small pointed lobule on anterior margin and smaller pointed lobules on other margins).

Genetics. Carlia decora sp. nov. is approximately 16% divergent (900 bp ND4 mtDNA) from C. rubigo sp. nov., C. inconnexa and C. pectoralis . Carlia decora sp. nov. is genetically most similar to Carlia vivax (approximately 13% divergence) (C. Hoskin, unpublished data). A representative ND4 mtDNA sequence for this species from the type locality is JX291972 (GenBank accession number).

Distribution. Carlia decora sp. nov. is found in high rainfall coastal areas of mid-east and north-east Queensland from approximately Sarina in the south to Mt Molloy in the north ( Fig. 11). The distribution is centred on two areas: the Sarina-Mackay-Proserpine region and the Townsville region (Mt Elliot, Townsville city area, Bluewater Range). There are no records from the drier forests that separate these two regions. Carlia decora sp. nov. is also known from some offshore islands in these regions (e.g. Brampton Is., Whitsunday Is., and Curacoa Is. in the Palm Islands).The most northerly record of C. decora sp. nov. (Mt Molloy, north-west of Cairns) is a considerable distance from the records in the Townsville region. The lack of records in the intervening area is interesting because wet forests are fairly continuous through this region, and generally well surveyed. This may represent a genuine disjunction in the distribution (perhaps due to competing species in the Wet Tropics wet forests) or C. decora sp. nov. may be distributed through this area patchily or at low density.

Habitat and habits. Carlia decora sp. nov. is found in riparian forest, vine thickets, rainforest margins, seasonally moist open forests and town gardens. It generally occurs in thicker vegetation amongst a matrix of open woodland and is particularly abundant in vine thickets and in the ecotone between riparian rainforest and grassy Eucalyptus woodland ( Fig. 12A). It occurs in areas with thick leaf litter and other ground cover (low vegetation, rocks, logs, etc.). It is a common garden skink in Townsville. Carlia decora sp. nov. is an active, ground-dwelling skink that retreats rapidly to thick leaf litter and dense vegetation when disturbed.