Emoia tuitarere Zug, Hamilton & Austin, 2011, n. sp.
Creators: name: Zug, George R.
name: Hamilton, Alison M.
name: Austin, Christopher C.
Publisher: name: Zenodo
Year: 2011
Subjects: Biodiversity
Taxonomy
Animalia
Chordata
Reptilia
Squamata
Scincidae
Emoia
Emoia tuitarere

description: Emoia tuitarere n. sp. Zug, Hamilton and Austin
(Fig. 2)
Type material. Holotype. USNM 533712, adult male from Cook Islands, Rarotonga, ca. 7 km. [by road] WSW of Avarua [estim. 21°12’30”S 159°46’32”W], collected by George R. Zug and Patricia B. Zug, 19 March 1999.
Paratypes. All specimens from Cook Islands, Rarotonga. AIM LH 1896 Avana Valley by Brian Gill, 28 September 1995; CAS 183322-325 Tupapa stream by Ted J. Case, 15 September 1991; SDNHM 66114-117, Avana stream, 1 to 2 km W of mouth, by Gregory K. Pregill, 4 November 1987; SDNHM 66145-146, Avana stream, 1 to 2 km W of mouth, by Gregory K. Pregill, 13 November 1987; USNM 249663-664 Turangi stream, 1.5 mi W of Ngatangia, collected by David W. Steadman, 15 March 1984; USNM 249665-666, data as preceding record, 16 March 1984; USNM 252391, Avana stream, 2.0 km [upstream] of Ara Tapu, by David R. Steadman, 29 May 1985; USNM 539181-182, Takitumu Conservation Area [21°15’05”S 159°46’00”W], collected by James R. Stewart and Rebecca A. Pyles, 11 January 2000; USNM 539184-186, 539188, data as preceding, 13 January 2000; USNM 539183, Marae Arai-Te Tonga parking lot [21°12’00”S 159°45’00”W, NE end of Rarotonga, by James R. Stewart and Rebecca A. Pyles, 12 January 2000; USNM 539189-190, Te Rua-Manga track [21°13’00”S 159°47’00”W], N end of Rarotonga, by James R. Stewart and Rebecca A. Pyles, 16 January 2000. Juvenile females SDNHM 66146, USNM 249665, 539186, 539190; juvenile males SDNHM 66144-145; adult females SDNHM 66115, USNM 249663, 252391, 539181-182, 539184-185, 539189; adult males SDNHM 66116-117, USNM 249664, 533712, 539183, 539188; sex not confirmed AIM LH 1896, USNM 249666.
Diagnosis. Emoia tuitarere is a member of the Emoia samoensis species group and differs from other group members by a combination of traits. E. tuitarere averages (mean 82 mm, range 72–93 mm SVL) smaller than the E. trossula type-series (90 mm, 87–101 mm; Table 2), E. ‘ trossula ’ Tonga (94 mm, 82–101 mm), E. samoensis (98 mm, 92–109 mm), E. sanfordi (103 mm, 97–109 mm), E. erronan (85 mm, 69–101 mm), and E. nigra (~ 100 mm, 85–114 mm), and larger than E. concolor (~ 72 mm, 57–86 mm), E. flavigularis (67 mm, 59–73 mm), E. loyaltiensis (~ 68 mm, 66–68 mm), E. mokosariniveikau (~ 55 mm), E. nigromarginata (63 mm, 55–68 mm), E. parkeri (47 mm, 40–52 mm), and E. tongana (62 mm, 56–75 mm). E. tuitarere has fewer dorsal scales [Dorsal] (65, 62–69) than E. aneityumensis (78, 74–80) and E. ‘trossula’ Rotuma (71, 65–77), and more than E. nigromarginata (58, 57–61), E. parkeri (56, 52–60), and E. sanfordi (58, 56–61). E. tuitarere has fewer 4th toe lamellae [4ToeLm] (49, 47–51) than E. sanfordi (66, 67–71) and more 4ToeLm than E. aneityumensis (35, 33–38), E. nigromarginata (37, 35–42), and E. parkeri (35, 33–40).
Description of holotype. An adult male, 84.7 mm SVL (88.6 mm in life), 170 mm tail length (~ 20 mm regenerated tip), 38.5 mm TrunkL, 32.8 mm SnForel, 42.2 mm HindlL, 20.0 mm HeadL, 11.6 mm JawW, 9.4 mm HeadH, 8.9 mm SnEye, 6.3 mm NarEye, 6.3 mm EyeEar, 3.1 mm SnW, and 6.4 mm Interorb. Scalation right side for bilateral traits: modest-sized semilunate rostral posteriorly contacting 1st supralabial, anterior nasal, elongate triangular supranasal and medially large pentagonal frontonasal; large rectangular prefrontals broadly in contact medially, large elongate pentagonal frontal, large hexagonal frontoparietal, moderate elongate interparietal separating paired oblong parietals except posteriorly, large paired nuchals; 4 Supoc 1st and 2nd subequal and largest, 9 Supcil, 10 Eyeld, oblong palpebral disc about third area of lower eyelid; large circular naris dividing nasal into anterior and posterior halves, AntLor and posterior loreal longer than high and subequal, 2 preoculars and 1 subocular on anterior margin of orbit, double row of postoculars with dorsalmost one largest, 2 modest-sized primary temporals, upper twice size of lower, 2 large secondary temporals, upper twice size of lower; 8 Suplab, 6th BlwEye, 7 Inflab, moderate nearly circular ear-opening with 1 blunt-triangular AuricN on lower anterior border; 62 smooth Dorsal, 32 Midbody, 37 smooth 4FingLm, 49 4ToeLm, and precloacal scale distinctly enlarged.
Coloration in life: boldly colored lizard; dorsally head unicolor coppery brown merging into brown with tarnished copper tint on neck, trunk, and tail with miscellaneously shaped blotches and stripes of dark brown to nearly black; dorsally on nape fragmented dark transverse bar, followed midneck and anterior axilla by complete transverse bars, bars remaining relatively thick but fragmented into middorsal bar and dorsolateral bar on each side, dorsum accentuated by numerous small longitudinally elongate lime-green spots arranged in irregular transverse rows; laterally loreal area with dark smudge and broad dark stripe between eye and axilla, dorsolateral dark bars well defined anteriorly becoming smaller and irregular posteriorly on trunk, lateroventrally neck and trunk lighten and merge into lime-green venter from posterior throat onto base of tail, chin golden yellow and chin to anterior chest immaculate, dark speckling begins behind axilla increasing in number posteriorly although not darkening the bright venter, dark speckling on tail coalesces into midventral stripe.
Coloration in preservative: Still boldly colored although muted by preservation. Pattern of dark and light markings unchanged. Dorsal ground color muted olive brown, ventrally tannish white and elongate dorsal and lateral spots also tannish white. Fore- and hindlimbs lighter brown ground color than trunk and with numerous small irregularly shaped dark blotches and smaller light flecks, ventrally limbs as venter and both with dark spotting.
Description. A moderately large Emoia ranging in adult size from 67 to 93 mm SVL, females 72.0– 92.6 mm (adult Ƥ, n = 13); males 67.5–93.0 mm (ad. 3, n = 9) with HeadL 16.3–19.3 mm (Ƥ) 16.1–21.3 mm (3), JawW 8.3–12.3 mm (Ƥ) 11.2–14.9 mm (3), HeadH 6.5–8.0 mm (Ƥ) 6.3–10.1 mm (3), SnEye 7.0– 8.7 mm (Ƥ) 6.3–9.2 mm (3), NarEye 5.0– 6.7 mm (Ƥ) 5.1–6.7 mm (3), EyeEar 4.9–6.8 mm (Ƥ) 5.4–7.0 mm (3), SnW 2.4–2.9 mm (Ƥ) 2.5–3.2 mm (3), Interorb 5.6–7.2 mm (Ƥ) 6.3–8.1 mm (3), SnForel 26.3–31.7 mm (Ƥ) 27.3–33.6 mm (3), TrunkL 35.0– 47.3 mm (Ƥ) 30.6–43.7 mm (3), and HindlL 34.6–46.0 mm (Ƥ) 35.9–45.5 mm (3).
Taxon SVL HeadL TrunkL/SVL HindlL/TrunkL SnForel/SVL HeadL/SVL
SAMOENSIS SUBGROUP
Emoia tuitarere
females [13] 80.8±5.49 17.5±0.80* 0.49±0.019* 0.96±0.077* 0.36±0.017* 0.22±0.010* 72.0–92.6 16.3–19.3 0.46–0.52 0.83–1.10 0.33–0.38 0.20–0.24
males [9] 83.7±7.06 19.6±1.50* 0.47±0.015* 1.06±0.077* 0.38±0.015* 0.23±0.004* 67.5–93.0 16.1–21.3 0.45–0.49 0.97–1.19 0.36–0.40 0.23–0.24
Emoia trossula (type-series)
females [11] 90.2±7.48 20.2±2.19 0.48±0.031 1.01±0.098 0.38±0.019 0.22±0.010* 87.0–101.2 17.4–24.9 0.45–0.55 0.88–1.23 0.36–0.41 0.21–0.25
males [18] 90.9±8.53 21.2±2.16 0.46±0.02 1.07±0.10 0.38±0.020 0.23±0.008* 75.9–102.4 17.0–24.2 0.42–0.50 0.82–1.25 0.35–0.43 0.22–0.25
Emoia trossula (northern Fiji)
females [7] 94.4±6.55 20.9±2.96 0.48±0.012 0.95±0.056 0.38±0.011 0.22±0.014 81.5–101.2 17.9–24.9 0.47–0.50 0.88–1.04 0.37–0.39 0.20–0.25
Emoia? trossula (Rotuma)
females [17] 81.6±2.87 17.9±0.67* 0.48±0.019 0.94±0.053* 0.36±0.015 0.22±0.004* 75.4–85.3 16.9–19.2 0.45–0.52 0.86–1.02 0.34–0.39 0.21–0.23
Emoia? trossula (Tonga)
females [11] 95.5±6.70 20.7±1.64* 0.49±0.033 0.99±0.110 0.37±0.035 0.22±0.014* 84.3–105.2 18.8–24.7 0.44–0.55 0.0.84–1.25 0.32–0.43 0.20–0.25
Emoia samoensis (Samoa)
females [10] 98.2±4.54 21.0±0.78 0.50±0.018* 0.92±0.041* 0.36±0.013 0.21±0.003* 92.4–108.8 19.9–22.7 0.46–0.53 0.87–1.02 0.34–0.38 0.21–0.22
Emoia sanfordi
females [11] 102.8±4.49 22.4±0.82* 0.49±0.017 0.89±0.062* 0.35±0.015* 0.22±0.005* 96.9–110.5 21.3–23.9 0.46–0.52 0.80–1.01 0.33–0.38 0.21–0.23
CONCOLOR SUBGROUP
Emoia aneityumensis (Anatom, Vanuatu)
adults [4] 84.8±8.47 17.4±1.13 0.50±0.027 0.91±0.084. 0.22±0.004 76.0–92.9 16.6–18.2 0.48–0.53 0.82–1.03. 0.21–0.22
Emoia nigromarginata (Efate & Malakula, Vanuatu)
females [8] 63.0±3.99 14.6±0.819* 0.49±0.025* 0.93±0.062* 0.38±0.018 0.23±0.010* 55.4–66.7 13.3–15.5 0.46–0.53 0.87–1.02 0.35–0.41 0.22–0.25
Emoia parkeri (Fiji)
females [10] 46.8±4.28 10.5±0.629 0.47±0.018* 0.95±0.079 0.39±0.030 0.22±0.015 40.0–52.0 9.8–11.6 0.45–0.50 0.88–1.10 0.36–0.45 0.20– 0.25 E. tuitarere is sexually dimorphic in most mensural features and nearly half the proportions. Males average larger (83.7 mm SVL) than females (80.7 mm), although the means are not significantly different. In contrast, all measurements, except TrunkL (39.8, 39.3 mm; means females [n = 13], males [9], respectively), and SnW (2.7, 2.8 mm), are dimorphic (statistically significant) in adults: HindlL (38.2, 41.6 mm), SnForel (30.0, 31.3 mm), HeadL (17.5, 19.6 mm), JawW (10.6, 12.5 mm), HeadH (7.2, 8.5 mm), SnEye (7.7, 8.4 mm), NarEye (5.7, 6.3 mm), and EyeEar (5.6, 6.4 mm). Body proportions showing significant dimorphism in adults are: HeadL/SVL (22, 23%), TrunkL/SVL (49, 47%), HindlL/TrunkL (96, 106%) and SnForel/SVL (36, 38%); the statistically non-dimorphic ones are: JawW/HeadL (60, 62%), SnEye/SVL (9.5, 10.1%), NarEye/SnEye (74, 75%), EyeEar/SnEye (74, 78%) and SnW/HeadL (15, 15%).
Of the scalation traits, only Eyelid (10, 11) shows sexually dimorphism. The interparietal is rarely absent, frontoparietal almost always single, and prefrontal usually in contact; 4 Supoc, 8 (uncommonly 7 or 9) Supcil, 9–12 Eyeld, 8 (rarely 9) Suplab, 6th (rarely 7th) BlwEye, and 7 (uncommonly 8) Inflab on each side. Palpebral disc small, about one-quarter area of lower eyelid area; moderate-sized, oblong vertical (occas. oblique) ear opening with 2–5 (commonly 3) AuricN, usually blunt, on anterior margin. Trunk scales usually smooth, uncommonly weakly tricarinate dorsally and laterally, with 60–69 Dorsal (median 64), single (uncommonly 2 or 3) pair of Nuchal, 32–35 Midbody (33). Subdigital lamellae smooth, 34–42 4FingLm (37), 46–53 4ToeL (49).
taxon Dorsal Midbody 4FingLm 4ToeLm DorsKN
SAMOENSIS SUBGROUP
Emoia tuitarere
females [10] 65±2.3 32±1.0 37±1.4 49±1.0 0±0 62–68 32–34 36–39 47–51 0–0
males [8] 64±1.1 33±0.9 36±2.6 50±2.3 0±0 62–65 32–34 34–42 46–53 0–0
Emoia trossula (type-series)
females [11] 65±2.7 34±1.4 33±2.2 47±3.7 0±1.1 62–71 31–36 30–37 42–55 0–3
males [18] 65±3..0 33±1.5 33.5±2.5 46.5±3.4 0±0 59–70 31–36 30–38 41–55 0–0
Emoia trossula (northern Fiji)
females [7] 63±1.4 34±1.9 36±2.9 51±5.2 0±1.2 62–66 31–36 30–39 42–47 0–3
Emoia? trossula (Rotuma)
females [17] 71±3.1* 35±1.6 39±1.7 56±2.4 0±0 65–77 33–38 34–40 50–59 0–0
Emoia? trossula (Tonga)
females [11] 65±1.9 33±1.2 34±1.1 47±2.2 0±0 62–69 30–34 32–36 44–51 0–0
Emoia samoensis (Samoa)
females [10] 63.5±1.6 31±1.0 33±1.0 46±2.4 0±0 62–66 30–33 31–34 44–51 0–0
Emoia sanfordi
females [11] 58±1.8 31±0.9 47±2.7 66±4.0 3±1.6* 56–61 30–32 43–51 57–71 0–4
CONCOLOR SUBGROUP
Emoia aneityumensis (Anatom, Vanuatu)
adults [4] 78±3.1 40.5±1.0 26±2.2 35.5±2.9 0±0 74–80 39–41 23–28 33–38 0–0
Emoia nigromarginata (Efate & Malakula, Vanuatu)
females [8] 58.5±1.2 30±0.7 28±1.5 37±2.4 0±1.4 57–61 30–32 26–31 35–42 0–3
Emoia parkeri (Fiji)
females [10] 56±2.2 30±2.2 25.5±2.4 35±2.7 0±0.9 52–60 26–33 22–30 33–40 0–3 Variation is relatively low in most mensural and meristic traits. Using a repeated data-gathering protocol, GZ examined one specimen multiple times (n = 11) on different days to estimate intra-observational variation (see discussion in Hayek and Heyer (2010) and Schmaltz and Zug (2002)). This repeats protocol establishes a measure of an observer’s variation in data-gathering and serves as a guide, either using standard deviations (s) or coefficients of variation (V), to the minimum level of variation within a data set that derived from data collection and that is not a component of trait variation within a population of a species. The level of variation seen in the E. tuitarere sample, or for that matter any other sample, is a composite of actual (natural) populational variation and data-gathering variation. Overall, morphological variation in E. tuitarere is low, and that may be a reflection of their high genetic homogeneity (Hamilton et al., 2010).
For the mensural traits, the repeats protocol gives a range of V from 0.7% (SVL) to 5.8% (HeadL) with a median of 3.45% and mode of 3.5% for the twelve traits. Comparison of V s for adult females and males shows female measurements range from 4.7 to 8.6% (median 8.3%) and for males 7.0 to 15.0% (9.5%). These ranges are typically V s for animal populations (Simpson et al., 1960). The difference (Table 2) between males and females is the broader range of body size in adult males, suggesting that males mature at a smaller size and then grow longer (time) than females. JawW variation has the highest V value (10.9%) in female measurements and is nearly the same in males (10.7%). HeadH has the highest V in males (15%) and much lower in females (5.9%), further emphasizing the dimorphism in head size and shape between females and males (HeadL/SVL 22% vs. 24%, see Table 2).
Observer variation (repeats protocol) is less among the scalation traits. Within the repeats, twelve scalation traits had no variation among successive counts. Variable counts occurred for Eyeld (V = 5%), Dorsal (1%), and 4FingLm (1.6%). More traits showed variation within the adult samples. Females and males share subequal variation in Supcil, Eyeld, Inflab, Dorsal, Midbody, 4FingLm, and 4ToeLm, ranging 1.7–6.5% and 1.8–9.2%, respectively. Five other traits (Interpa, Frontpa, Suprcil, AuricL, Nuchal) had V s ranging 22.3–40.4%) because one or two individuals in the sample had a different state, such as Interpa absent when this scale is present in the majority.
Color variation in alcohol. Dorsal ground color is dark to light brown with a coppery sheen, particularly on head and anterior neck. The darker brown occurs in the older preserved specimens, although a set of specimens preserved in mid-2000 range from dark to light, two of which (USNM 539185, 539190) are nearly olive. Ventrolaterally, ground color lightens as it grades into dull yellow venters, greenish overtones in some and dusky beige in longer preserved specimens. Dorsally head and neck are immaculate and similarly unicolor in loreal area. All individuals have moderately broad, black postorbital stripe on each side extending from posterior edge of orbit rearward above ear-opening to axilla. This stripe is continuous only in two individuals; in most, stripe is a series of irregular, black blotches narrowly separated by brown interspaces. In the lightest two individuals, a black postorbital spot is widely separate from dark stripe above ear to axilla. All individuals have yellow eyelid scale borders, highlighted with a dark border on upper eyelid. Dark marking occurs dorsally and dorsolaterally on trunk from mid neck onto base of tail; size and density of dark marks vary from a few black spots (occupying one to two scales) to broad transverse crossbars. These crossbars are best developed on posterior neck and over shoulders, becoming smaller and fragmented on trunk. In a few individuals, the postorbital stripe continues posteriorly on trunk as fragmented stripe. Narrow, longitudinal greenish flecks occur on dorsum from posterior neck to posterior trunk in slightly less than half the sample and flecks are numerous in about half of these individuals. Venters of most individuals (~80%) are immaculate from chin to vent; scattered, tiny black flecks occur from chest posteriorly in a few other individuals. Ventrally, tails have larger (although still small) black flecks, and in some, fleck forms a midventral series.
Distribution. Presently known only from Rarotonga, Cook Islands. The other Cook Islands are visited regularly by naturalists, but no one has reported seeing this skink on any of them (G. McCormack, in litt. 11 Nov. 2009).
Etymology. The specific name derives from the Cook Island Maori tuitarere for wanderer, pilgrim, stranger, alien, and is proposed in reference to the putative recent arrival of this species on Rarotonga. It is proposed as a noun in apposition.
Comparison to other taxa. In a review (Brown and Gibbons, 1986) of central Pacific arboreal Emoia populations, Brown proposed the samoensis species group [= complex]. Neither in this review nor in his subsequent monograph (Brown, 1991) did he provide a definition of the samoensis group or its subgroups, the concolor and the samoensis subgroups, proposed therein. The group can be defined by extracting couplets from his key to Emoia species groups (1991: 4): 11 premaxillary teeth; nasal bone paired (not fused); parietal eye present; anterior loreal elongate, its length equal or nearly so that of posterior loreal; less than 88 Dorsal; less than 44 Midbody; subdigital lamellae smooth rectangular to moderately narrowed (not blade-like). His samoensis subgroup is less easily characterized, and at the present, there is no unique character or character set differentiating concolor and samoensis subgroup members. Three samoensis subgroup members (E. samoensis, E. sanfordi, E. trossula) are large Emoia (> 66 mm minimum adult SVL), but several concolor subgroup members also do not mature (females) at SVLs less than 65 mm (e.g., Emoia nigra). In spite of this difficulty, we tentatively accept Brown’s two subgroups, although recognizing that our molecular data do not advocate his species assignments [our molecular data set lacks representation from many islands, hence it is too soon to re-partition membership in Brown’s two subgroups]. Because of its gross similarity to other member of the samoensis subgroup, we treat E. tuitarere as a member of that subgroup.
The following comparison focuses on the members of that subgroup and select members (E. aneityumensis, E. nigromarginata, E. parkeri) of the concolor subgroup identified as sister-group taxa in our molecular analysis (Hamilton et al., 2010: Fig. 1).
Conceptually for Brown (1991), Emoia samoensis was the large, ‘green’ skink of Samoa; we similarly accept the Samoan populations as E. samoensis. For Brown, E. trossula was the large, greenish brown and usually dark cross-barred skinks of Fiji, Rotuma, Tonga, and Rarotonga. Although we initially accepted the skinks from Fiji, Rotuma, and Rarotonga as E. trossula, our molecular analysis (Hamilton et al., 2010) revealed the uniqueness of populations of ‘ trossula ’, hence requiring a conceptual adjustment; thus, we compare E. tuitarere with ‘ trossula ’ from separate island groups. A sample from Brown’s and Gibbon’s type series (Table 2, 3) immediately reveals differences; however, use of these data is inappropriate because the type series encompasses a broad geographic area including Rotuma and all Fijian island groups and probably represents multiple genetic entities (see Fig. 1). The northern Fijian E. trossula sample includes individuals from the type-locality, Ovalau, and other islands (e.g., Viti Levu, Vanua Levu) that were parts of single landmasses or separated by narrow marine straits during the last glacial period (Zug, 1991:fig. 17B).
The E. trossula population of Kadavu has insufficient specimens for valid morphological comparison even though it is genetically distinct from other trossula populations. The Rotuman trossula sample is large, but we lacked genetic samples for inclusion in our molecular analysis. With these caveats, we compare E. tuitarere to five samoensis subgroup populations/samples: E. samoensis (Samoa); E. trossula (northern Fiji, including the typelocality); E. trossula (Rotuma); E. trossula (Tonga); E. sanfordi (Vanuatu); and to its three sister-group taxa (E. aneityumensis, E. nigromarginata, E. parkeri).
Size Scale Characters Genetic Data Taxa SVL Dorsal Midbody 4FingLm 4ToeLm Divergence Among the samoensis subgroup, E. tuitarere and E. trossula -Rotuma are the smallest members (Table 2, 4). Although males tend to average slightly larger in all members of the samoensis subgroup, mean SVLs of females and males are not statistically different in any subgroup taxon. Indeed, sexual dimorphism does not occur in most mensural traits, although dimorphism is strongly present in the head and body proportional differences for some samples. Emoia tuitarere share smaller headed females (than males, mensurally) with trossula -Rotuma, trossula - Tonga, and E. sanfordi; the preceding samples and E. samoensis and trossula -type-series share dimorphism of HeadL/SVL. The trossula -type-series displays no dimorphism of mensural traits. The proportional differences in size and shape are not greatly different between females and males in any subgroup member, yet statistically significant in all members, for example, E. samoensis HeadL/SVL 21% female vs. 23% male. The most striking dimorphism is the relative differences in TrunkL and HindlL; samoensis subgroup females have longer trunks and shorter hindlimbs than their conspecifics males. These differences are significantly only in E. samoensis, E. sanfordi, E. trossula -Rotuma, and E. tuitarere. Among the sister taxa, E. nigromarginata displays a relatively smaller head in females, but E. parkeri is not dimorphic; E. aneityumensis sample is too small for statistical testing. E. nigromarginata also has proportionately larger trunk and shorter hindlimbs in females.
In most scalation features, E. tuitarere is similar to other samoensis subgroup members. It matches E. trossula - type-series, E. trossula - Tonga, and E. samoensis in Dorsal, and those three taxa as well as E. samoensis and E. sanfordi in Midbody. In digit lamellae, E. trossula type-series, E. trossula - Tonga, and E. samoensis average slightly fewer lamellae than E. tuitarere (Table 3). In contrast, E. trossula -Rotuma and E. sanfordi have distinctly more lamellae, especially so for E. sanfordi. The sister taxa have distinctly fewer digital lamellae than E. tuitarere. E. nigromarginata and E. parkeri also have fewer Dorsal and Midbody than E. tuitarere; in contrast, E. aneityumensis has the highest number of Dorsal and Midbody of all the samples compared (Table 3,4).
Coloration in the samoensis subgroup has two general patterns: a dorsal black barred (transverse) pattern on a brown to olive background, or a bright green background with black smudges dorsally. The latter pattern occurs only in E. sanfordi. The top of the head of E. sanfordi almost always has a black blotch, usually covering the posterior third of the head, occasionally the posterior two-thirds of the head. The black smudging on the dorsum of the neck and trunk is variable, ranging from absent to extensive, i.e., covering ½ to 2/3 of dorsal surface. The barred pattern occurs in E. samoensis, E. trossula, and E. tuitarere, with the amount of barring variable within and among these taxa. In E. samoensis (from Samoa), the bars are numerous, narrow, and fragmented, commonly of four parts, two dorsolateral and a lateral one on each side. This latter pattern also occurs in E. trossula -northern Fiji; although generally with fewer bars and those bars concentrated on the neck and anterior half of the trunk. E. trossula - Rotuma has narrower dorsal bars that are continuous across the midline on most individuals, but separated in some and absent in a few individuals. The lateral barring forms a nearly continuous, broad black lateral stripe from posterior edge of eye to axilla in most individuals. Almost all Rotuman E. trossula have numerous bright, ‘yellow’ longitudinal flecks on dorsal, dorsolateral, and lateral surface of the trunk. E. trossula - Tonga has a few small black dorsal and dorsolateral bars, mainly on the posterior half of neck and anterior half of trunk. Of the samoensis subgroup members, the Rotuma and Rarotongan populations are the most similar in appearance.
None of the concolor subgroup taxa have the transverse barred and bright flecking pattern of E. tuitarere. E. concolor, as name implies, is nearly unicolor, ranging from green to greenish brown., E. aneityumensis, E. nigromarginata, and E. parkeri are most closely related to E. tuitarere yet they have dissimilar patterns to one another and to E. tuitarere. E. aneityumensis has a brownish olive background, either unicolor or with vague dark brown blotches dorsally and dorsolaterally on the trunk. E. nigromarginata has a silvery to coppery gray ground color with a series of small, black spots on trunk and a scattering of small black blotch dorsally. E. parkeri is a brightly striped lizard, with a coppery brown middorsal stripe bordered parasagittally by black, irregularly edged stripe, dorsolateral light stripe, and laterally another black, irregularly edged stripe. The lateral stripe extends from snout onto tail.
Natural history. Emoia tuitarere is an arboreal lizard, but not strictly so. Individuals are most frequently seen on the sides of trees, often in head-down position, perhaps to scan the forest floor or lower shrubby vegetation for prey. They also forage amidst the tangle of branch in secondary forest and ecotonal zone between gardens and forest.
The abundance or at least visibility of this species appears to be affected by weather. Few individuals were observed during a rainy period following a tropical cyclone in March 1999. The single male (holotype) captured at this time was also reproductive quiescent. During March of other years, E. tuitarere was abundant.
Biogeographic comments. The E. samoensis group is a south-central and south-west Pacific clade of largely arboreal lizards. The two subgroups (concolor and samoensis) overlap broadly throughout this area of Oceania, and in most areas, a concolor and a samoensis subgroup member are sympatric. Also in most areas, Emoia nigra, one of the two primarily terrestrial species in this clade, has a broad distribution and co-occurs with arboreal congeners through much of the Southwest Pacific. Our present knowledge of phylogenetic relationships supports the monophyly of the samoensis group and suggests paraphyly of the two subgroups (Hamilton et al., 2010). Furthermore, our morphological and molecular data indicate that diversity is considerably greater than our present taxonomy displays. Until this diversity is described, biogeographic hypotheses are premature.
description: Published as part of Zug, George R., Hamilton, Alison M. & Austin, Christopher C., 2011, A new Emoia samoensis group lizard (Squamata: Scincidae) from the Cook Islands, South-central Pacific, pp. 47-57 in Zootaxa 2765 on pages 49-55, DOI: 10.5281/zenodo.276845