Lizards of Tonga with Description of a New Tongan ...

Lizards of Tonga with Description of a New Tongan Treeskink (Squamata: Scincidae: Emoia samoensis Group) Author(s) :George R. Zug, Ivan Ineich, Gregory Pregill, and Alison M. Hamilton Source: Pacific Science, 66(2):225-237. 2012. Published By: University of Hawai'i Press DOI: http://dx.doi.org/10.2984/66.2.9 URL: http://www.bioone.org/doi/full/10.2984/66.2.9

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Lizards of Tonga with Description of a New Tongan Treeskink (Squamata: Scincidae: Emoia samoensis Group)1 George R. Zug,2,6 Ivan Ineich,3 Gregory Pregill,4 and Alison M. Hamilton5 Abstract: The present-day vertebrate fauna of Tonga contains 17 species of lizards from three families: Gekkonidae, Iguanidae, and Scincidae. Are any of these lizard species members of a fauna before humans arrived? This question is examined and partially resolved. Endemic taxa, such as Lepidodactylus euaensis, Emoia adspersa, and E. tongana, are likely inhabitants whose ancestors arrived, before the arrival of humans, via waif dispersal and subsequently differentiated in isolation. Recognition of these species is essential to interpret correctly the evolutionary history of the Tongan herpetofauna. The largest surviving Tongan skink previously has been identified incorrectly as a population of the Fijian Emoia trossula lineage. It is not and, herein, is differentiated from Emoia trossula and other central Pacific members of the Emoia samoensis species group and subgroup. Emoia mokolahi Zug, Ineich, Pregill & Hamilton, n. sp., differs from its sister taxa in the Emoia samoensis species subgroup by body size, dorsal and digital scalation, and coloration. The extant Tongan lizard fauna consists of eight geckos, eight skinks, and an iguana (Table 1). A large terrestrial, likely semifossorial, skink (Tachygyia microlepis) is presumably extinct (Ineich and Zug 1996). The first and only record of this Tongan lizard is from the early nineteenth-century report of the L’Astrolabe expedition (Dumont d’Urville 1832) when they were discovered. During the expedition’s around-the-world scientific exploration, it spent a month on Tongatapu in 1827 and brought two specimens back to Paris. This large, reduced-limbed lizard was

described subsequently as Eumeces microlepis by Duméril and Bibron (1839) and has never been seen again in the Islands, hence known only by the two syntypes. Other lizards occurred in the Tonga archipelago but disappeared shortly after the arrival of the Polynesians (Pregill and Dye 1989). An archeological excavation in the Hai‘apai group revealed the remains of an iguana, significantly larger than the iguana (Brachylophus fasciata) currently occurring in the Tongatapu group. This extinct iguana was subsequently described (Pregill and Steadman 2004) as Brachylophus gibbonsi.

1 Research supported by Smithsonian Visiting Scholars program and Action Transversal du MNHN (ATM) “Biodivesité actuelle et fossile” to I.I.; National Geographic Society 5032-93, University Professorship University of San Diego for G.P.; National Science Foundation (DEB 0408010, DEB 0445213, DBI 0400797) to Christopher C. Austin and A.M.H.; an EPSCoR Fellowship to A.M.H.; grants from Graduate Women in Science, American Society of Ichthyologists and Herpetologists, Society for the Study of Amphibians and Reptiles, Sigma Xi (LSU chapter), and Louisiana State University (Museum of Natural Science and BioGrads) to A.M.H.;

and the National Geographic Society, Smithsonian Scholarly Studies Program, and NMNH-Research Opportunities Fund to G.R.Z. Manuscript accepted 30 June 2011. 2 Department of Vertebrate Zoology, National Museum of Natural History, Smithsonian Institution, Washington, D.C. 20013. 3 Département Systématique & Evolution, Muséum national d’Histoire naturelle, UMR 7205 (OSEB), CP30, 25 rue Cuvier, 75005 Paris, France (e-mail: ineich@ mnhn.fr). 4 Department of Biology, University of San Diego, 5998 Alcala Park, San Diego, California 92110 (e-mail: [email protected]). 5 Department of Ecology and Evolutionary Biology, University of California, Los Angeles, California 90095 (e-mail: [email protected]). 6 Corresponding author (e-mail: [email protected]).

Pacific Science (2012), vol. 66, no. 2:225 – 237 doi:10.2984/66.2.9 © 2012 by University of Hawai‘i Press All rights reserved

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PACIFIC SCIENCE · April 2012 TABLE 1 Extant Terrestrial Reptiles of Tonga

Taxa Gekkonidae Gehyra insulensis Gehyra oceanica a Hemidactylus frenatus Hemidactylus garnotii Hemiphyllodactylus typus Lepidodactylus euaensis Lepidodactylus lugubris Nactus pelagicus Iguanidae Brachylophus fasciatus b Scincidae Cryptoblepharus poecilopleurus Emoia adspersa Emoia cyanura Emoia impar Emoia nigra Emoia mokolahi Emoia tongana Lipinia noctua

Island and Island Groups Niuafo‘ou — + — — — — + —

Niuatoputapu — + — — — — + —

Vava‘u — + — — + — + +

Ha‘apai + + + — — — + +

Tongatapu + + + + — — + +

‘Eua — + — — + + + +

—

—

+

—

+

—

+ + + + + — + +

— — + + + — + +

+ — + + — + + +

+ — + + — + + +

+ — + + +c + — +

+ — + + — + — +

Sources: Gill (1987, 1990), Gill and Rinke (1990), Gill et al. (1994), Zug and Gill (1997), Zug and Ineich field notes 1992 (Tongatapu, ‘Eua), 1993 ( Vava‘u, Ha‘apai, Tongatapu). Note: Symbols: —, no museum voucher specimens or reliable literature records; +, occurrence confirmed by museum voucher specimens or reliable literature records. a The presence of Gehyra vorax in Tonga was proposed tentatively by Beckon (1992:450): “Fiji and perhaps Tonga (Fig. 5).” He saw no Tongan G. vorax specimens, and no specimens with unquestionable Tongan locality data exist. A recent proposal for a Society Island occurrence was based on specimens with questionable locality data. b Pregill and Steadman (2004) argued for the Tongan B. fasciatus as a pre-European introduction from the Lau group. Their argument is strong owing to the absence of subfossil B. fasciatus in Tonga in contrast to its abundance as subfossils in the Lau group of islands (Steadman et al. 2002), and the molecular identity of the Tongan iguanas demonstrating their origin from Lau iguanas ( Keogh et al. 2008). c The Natural History Museum, London, collection ( BMNH) contains specimens of Emoia nigra and E. lawesi ( BMNH 90.11.14.4, 90.11.14.3, respectively) with Tongatapu locality datum. The occurrence vouchered by these specimens has been not confirmed by any recent (since the 1950s) herpetological fieldwork. Darevsky and Orlov (1994 [1993]) reported E. atrocostata and E. caeruleocauda from Niuafo‘ou; those records are considered erroneous because of other peculiarities associated with their species identifications from other Pacific island groups (Zug 1991:10); however, we accept their Niuafo‘ou records of E. cyanura, a sample of which included E. impar, because those vouchers were examined and identity confirmed (I.I.).

The extinction of these two large species and possibly also smaller lizard species generates several questions. What was the lizard fauna of the Tongan Islands before humans arrived? We examine this question subsequently in our Biogeographic Comments; however, we realize that our present-day faunal data set of extant lizards and those that arrived before humans is inadequate and will provide an incomplete answer. Closely associated with this primary question is how many components of the current lizard fauna are members of the fauna before human arrival? One hypothesis is that

species endemic or indigenous to the Tongan Islands represent natural dispersal events, whose populations had thousands or more years to differentiate and adapt before the arrival of the first human settlers. Another possibility is that one or more of the Tongan endemics occurred more broadly in the central Pacific but is now restricted to Tonga. A third hypothesis is that widespread Pacific species and species that are largely genetically uniform over wide reaches of Oceania are recent dispersants, arriving with or subsequent to the first human settlers. We will examine these propositions later.

Lizards of Tonga · Zug et al.

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Figure 1. A schematic cladogram showing relationships of Emoia mokolahi to its nearest sister-group relatives in the South-central Pacific. All listed populations are members of the Emoia samoensis species subgroup. This cladogram derives from a phylogeny constructed using Maximum Likelihood and Bayesian Inference on a mitochondrial and nuclear DNA data set (Hamilton et al. 2010: fig. 2).

Because our biogeographic questions require the resolution of the origins of Tongan lizards, we demonstrate the unique status of the largest surviving Tongan treeskink. This skink is currently recognized as a population of the putatively widespread central Pacific Emoia trossula. Our field observations revealed that the Tongan E. “trossula” differed in appearance from individuals of the various Fijian and Samoan populations. Subsequently, phylogenetic analysis of a mitochondrial and nuclear DNA data set (Hamilton et al. 2010: fig.

2) revealed that the Tongan “trossula” was a member of a large clade composed of Samoan and Fijian populations, yet was genetically quite distinct from other populations. The Tongan population represents a basal or early divergence within a Samoan-Fijian clade (Figure 1) and indicates an early arrival and subsequent in situ speciation within the Tongan archipelago. This Samoan-Fijian sister group contains several distinct genetic lineages. The taxonomy of these lineages will be addressed in subsequent reports.

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PACIFIC SCIENCE · April 2012

materials and methods The large Tongan skink has mistakenly been identified with Fijian Emoia trossula largely because of its large size and general coloration. Its affinities (Figure 1) are with members of the E. samoensis subgroup, and it is with those taxa that the Tongan skink is compared and differentiated (Appendix). Our character set contains 13 mensural and 20 scalation (meristic) characters, although not all characters are reported herein. Sex and maturity were determined by examination of gonads. Locality data for the examined specimens are in the Appendix. All mensural characters are straight-line measurements of body segments to the nearest 0.1 mm with dial calipers. Scalation features of head, body, and limbs were recorded from the right side on paired features. All statistical analyses were performed with SYSTAT 11. Sexual dimorphism among adults was tested by Student’s t tests (P < .05). The character set is an expansion of the set defined in a study of morphological variation of Emoia tongana (Zug and Gill 1997) and subsequently expanded and new characters defined in the description of Emoia tuitarere (Zug et al. 2011). The following lists provide character names and their abbreviations. Measurements: Eye – ear length (EyeEar); head height (HeadH); head length (HeadL); hindlimb length (HindlL); interorbital width (Interorb); jaw width ( JawW ); naris – eye length ( NarEye); snout – eye length (SnEye); snout width (SnW ); snout – forelimb length (SnForel); snout – vent length (SVL); tail length (TailL); trunk length (TrunkL). Scalation: Anterior loreal shape (AntLor); auricular lobes, number (AuricL); dorsal body scales, number (Dorsal); eyelid scales, number (Eyeld); frontoparietal scale (Frontpa); infralabial scales, number (Inflab); interparietal scale, present or absent (Interpa); keeling of body scales, number of keels (DorsKN, LatKN, VntlKN ); loreal scales, number (Lor); midbody scale rows, number (Midbody); nuchal scales, number of pairs ( Nuchal); precloacal scales size (Precl); prefrontal scales, in contact or not (Prefr); subdigital lamellae, number on fourth finger (4FingLm)

and on fourth toe (4ToeLm); supralabial scales, number (Suplab); supralabial scale below orbit (BlwEye); supraocular scales, number (Suproc); supraciliary scales, number (Suprcil). taxonomic results Emoia mokolahi Zug, Ineich, Pregill & Hamilton, n. sp. Figures 2, 3 type material. Holotype: USNM 333684, adult female from Kingdom of Tonga, Vava‘u group, Vava‘u (Island), approximately 1 km W of Neiafu (∼18° 39′ S, 173° 59′ W ), south side of Mt. Talau, collected by George R. Zug, 10 November 1993. Paratypes: All specimens from the Kingdom of Tonga. Vava‘u group: AIM LH1304, Vava‘u (Island) near Holonga, by B. J. Gill, 27 September 1989; AIM LH1312, Vava‘u (Island) near Sia Ko Kafoa, by B. J. Gill, 28 September 1989; CAS 158241, USNM 259331 – 259332, Vava‘u (Island), by J. R. H. Gibbons, January 1985. Ha‘apai group: AMNH 40567 – 40568, Tonomaia (Island) [=Tonumeai ∼20° 28′ S, 174° 46′ W], by Rollo H. Beck, 18 July 1925; USNM 333763, Lifuka (Island), 1.5 – 2.0 km ESE of Pangai, by G. R. Zug, 14 November 1993; USNM 333764, Lifuka (Island), Point Port au Prince, by G. R. Zug, 15 November 1993. Tongatapu group: AMS R116162, Tongatapu (Island), Euaiki Island, east of Tongatapu (21° 7′ S, 174° 58′ W ), H. G. Cogger, 10 November 1984; CAS 159999, Tongatapu (Island), Toloa forest, by M. Miller, 20 February 1986; USNM 333577, Tongatapu (Island), ca. 2 km W of Kolovai, by G. R. Zug, 19 November 1993. ‘Eua: AMS R96577 – R96578 ‘Eua Island, Tonga group (21° 23′ S, 174° 57′ W ), H. Ehmann, 10 May 1980; AMS R96584, ‘Eua Island, Tonga group (21° 23′ S, 174° 57′ W ), H. Ehmann, 10 May 1980; CAS 158245, ‘Eua (Island), by J. R. H. Gibbons, January 1985; CAS 159407 – 159408, ‘Eua (Island), by J. R. H. Gibbons, 19 – 20 October 1985; FMNH 191762, ‘Eua (Island), by N. L. H. Kraus, 24 February 1972; SDSNH 66147, ‘Eua (Island), 2 km E of Houma village, by G. K. Pregill, 21 November 1987; USNM 259333, ‘Eua (Island),


Figure 2. A paratype of Emoia mokolahi, n. sp., head; C, ventral view of right hind foot.

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USNM

322230, from ‘Eua. A, Dorsal view of head; B, lateral view of

by J. R. H. Gibbons, January 1985; USNM 322228, ‘Eua (Island), 0.5 – 2.0 km W of Pangai, by I. Ineich and G. R. Zug, 9 October 1992; USNM 322229, ‘Eua (Island), 2 – 6 km E and SE of Petani, by I. Ineich and G. R. Zug, 10 October 1992; USNM 322230, ‘Eua (Island), 0.5 – 2.5 km W of Pangai, by I. Ineich and G. R. Zug, 12 October 1992. Juvenile females: AMS R116262, FMNH 191762, USNM 259333; juvenile males: USNM 322228, 333763 – 333764; unsexed juvenile: USNM 322229; adult females: AIM LH1304, AMS R96577, R96584, CAS 158241, 158245, 159407; adult males: AIM LH1312, AMNH 40567 – 40568, AMS R96578, CAS 159408, 159999, SDSNH 66147, USNM 259331 – 259332, 322230, 333577. diagnosis. Emoia mokolahi is a member of the Emoia samoensis species group and the samoensis subgroup (Zug et al. 2011). Emoia

mokolahi differs from other subgroup members by a combination of traits. Emoia mokolahi females average (mean 96 mm, range 86 – 105 mm SVL) larger than E. tuitarere females (81 mm, 72 – 93 mm) (Table 2) and the E. trossula type-series females (90 mm, 87 – 101 mm), and smaller than Samoan E. samoensis females (97 mm, 86 – 109 mm) and Vanuatuan E. sanfordi females (103 mm, 97 – 109 mm). In female scalation, E. mokolahi averages more dorsal scales [Dorsal] (65, 62 – 69) than E. sanfordi (58, 56 – 61) and Samoan E. samoensis (63, 62 – 66); E. mokolahi has fewer 4th-finger lamellae [4FingLm] (34, 32 – 36) than E. sanfordi (47, 43 – 51) and E. tuitarere (37, 36 – 40) and fewer 4th-toe lamellae [4ToeLm] than E. sanfordi (66, 57 – 71) and E. tuitarere (49, 47 – 51). description of holotype. An adult female, 97.9 mm SVL (103.9 mm in life), 136 mm TailL (135 mm in life, two-thirds

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PACIFIC SCIENCE · April 2012 TABLE 2

Summary of Select Mensural Characters (Mean ± Standard Deviation and Range) in Central Pacific Samples of Adult Members of the Emoia samoensis Species Group Taxa

Taxon

SVL

Emoia mokolahi (Tonga) Females [8] 96.2 ± 6.50 86.0 – 105.2 Males [11] 96.9 ± 4.60 90.5 – 103.7 Emoia samoensis (Samoa) Females [13] 97.2 ± 5.55 84.3 – 108.8 Males [15] 100.0 ± 7.64 86.8 – 111.9 Emoia sanfordi ( Vanuatu) Females [11] 102.8 ± 4.49 96.9 – 110.5 Males [8] 102.0 ± 7.10 91.8 – 114.8 Emoia trossula (type seriesa) Females [11] 90.2 ± 7.48 87.0 – 101.2 Males [18] 90.9 ± 8.53 75.9 – 102.4 Emoia tuitarere (Cook Islands) Females [13] 80.8 ± 5.49 72.0 – 92.6 Males [9] 83.7 ± 7.06 67.5 – 93.0

HeadL

TrunkL/ SVL

HindlL/SVL

SnForel/ SVL

HeadL/SVL

20.2 ± 1.03* 18.8 – 21.5 21.9 ± 1.15* 19.5 – 23.3

0.50 ± 0.027 0.46 – 0.55 0.48 ± 0.024 0.44 – 0.51

0.47 ± 0.026 0.45 – 0.53 0.49 ± 0.026 0.43 – 0.52

0.35 ± 0.017 0.32 – 0.36 0.37 ± 0.024 0.34 – 0.40

0.21 ± 0.006* 0.20 – 0.22 0.23 ± 0.006* 0.21 – 0.24

21.2 ± 1.29* 19.9 – 24.7 23.1 ± 1.83* 20.0 – 25.7

0.49 ± 0.027* 0.44 – 0.53 0.48 ± 0.015* 0.46 – 0.51

0.47 ± 0.028* 0.43 – 0.54 0.48 ± 0.022* 0.45 – 0.52

0.37 ± 0.024 0.34 – 0.43 0.37 ± 0.021 0.34 – 0.41

0.22 ± 0.011* 0.21 – 0.25 0.23 ± 0.010* 0.22 – 0.25

22.4 ± 0.82* 21.3 – 23.9 24.7 ± 1.92* 22.5 – 26.9

0.49 ± 0.017 0.46 – 0.52 0.49 ± 0.032 0.42 – 0.54

0.43 ± 0.024* 0.41 – 0.48 0.47 ± 0.028* 0.43 – 0.51

0.35 ± 0.015* 0.33 – 0.38 0.37 ± 0.022* 0.34 – 0.40

0.22 ± 0.005* 0.21 – 0.22 0.24 ± 0.011* 0.23 – 0.26

20.2 ± 2.19 17.4 – 24.9 21.2 ± 2.16 17.0 – 24.2

0.48 ± 0.031 0.45 – 0.55 0.46 ± 0.02 0.42 – 0.50

0.48 ± 0.031 0.45 – 0.55 0.49 ± 0.034 0.40 – 0.55

0.38 ± 0.019 0.36 – 0.41 0.38 ± 0.020 0.35 – 0.43

0.22 ± 0.010* 0.21 – 0.25 0.23 ± 0.008* 0.22 – 0.25

17.5 ± 0.80* 16.3 – 19.3 19.6 ± 1.50* 16.1 – 21.3

0.49 ± 0.019* 0.46 – 0.52 47.0 ± 0.015* 0.45 – 0.49

0.47 ± 0.031* 0.42–0.53 0.50 ± 0.030* 0.45 – 0.53

0.36 ± 0.017* 0.33 – 0.38 0.38 ± 0.015* 0.36 – 0.40

0.22 ± 0.010* 0.20 – 0.24 0.23 ± 0.004* 0.23 – 0.24

Note: *, Denotes statistically significant sexual dimorphism (Student t, P ≤ .05). Sample size in brackets; SVL and HeadL in mm. a Excludes the Rotuma specimens; main Fiji Islands only.

regenerated), 48.1 mm TrunkL, 34.1 mm SnForel, 44.8 mm HindlL, 20.3 mm HeadL, 13.4 mm JawW, 9.8 mm HeadH, 8.6 mm SnEye, 6.8 mm NarEye, 7.9 mm EyeEar, 3.7 mm SnW, and 7.2 mm Interorb. Body proportions: 49% TrunkL/SVL, 46% HindlL/ SVL, 35% SnForel/SVL, 21% HeadL/SVL, and 9% SnEye/SVL. Scalation right side for bilateral traits: modest-sized semilunate rostral posteriorly contacting 1st supralabial, anterior nasal, elongate rectangular supranasal and medially large pentagonal frontonasal; large rectangular prefrontals with moderate contact medially, large elongate pentagonal frontal, large hexagonal frontoparietal, elongate triangular interparietal (with distinct parietal eye) separating paired large rectangular parietals except posteriorly, large paired nuchals; 4 Supoc 1st and 2nd sub-

equal in area and largest Supoc, 8 Supcil, 10 Eyeld, horizontal elliptical palpebral disk about one-third area of lower eyelid; large circular naris dividing nasal into equal-sized anterior and posterior halves, AntLor nearly square and posterior loreal longer than high, two loreals subequal in area, 2 preoculars and 1 subocular on anterior margin of orbit, double row of postoculars with dorsalmost one largest, 2 modest-sized primary temporals, lower twice size of upper, 2 large secondary temporals, upper twice size of lower; 8 Suplab, 6th BlwEye, 8 Inflab, moderate nearly circular ear opening with 4 blunt-triangular AuricN on anterior border; 66 smooth Dorsal, 33 Midbody, 35 smooth 4FingLm, 48 4ToeLm, and precloacal scale distinctly enlarged. Coloration in life: Dorsally head unicolor coppery brown merging into brown with


tarnished copper tint on neck, trunk, and tail, from midneck to base of tail a series of short longitudinal dark-edged streaks of cream and infrequent small dark brown spots; streaks arranged in about nine transverse series with five to six streaks per series and streaks become shorter and more irregularly arranged after midbody, streaks confined to dorsal surface; laterally three modest-sized dark brown spots, one on neck, another above shoulder, and final one on anterior trunk; dorsally limbs uniform brown of dorsum. Uniform brown of top of head extends ventrally on upper lips in front of eye; posteriorly and below eye diffuse cream with a dusky blotch at upper corner of jaw; eyelids’ edges coppery brown. Lateroventrally neck and trunk lighten and merge into cream-colored venter with orange highlights, chin to anterior chest immaculate, dark speckling begins behind axilla and continues on to base of tail. Undersides of limbs lighter colored than venter and underside of manus and pes bright yellow. Coloration in preservative: Coloration is modestly muted by preservation. Pattern of dark and light markings unchanged. Dorsal ground color retains coppery brown background, venter with light olive cast, limbs remain uniform cream. description. A large Emoia ranging in adult size from 86 to 105 mm SVL, females 86.0 – 105.2 mm (adult Ƃ, n = 8); males 90.5 – 103.7 mm (adult ƃ, n = 11) with HeadL 18.8 – 21.5 mm (Ƃ) 19.5 – 23.3 mm (ƃ), JawW 10.2 – 13.9 mm (Ƃ) 12.7 – 15.9 mm (ƃ), HeadH 8.7 – 9.9 mm (Ƃ) 9.3 – 11.5 mm (ƃ), SnEye 8.3 – 9.8 mm (Ƃ) 8.8 – 10.9 mm (ƃ), NarEye 5.9 – 7.0 mm (Ƃ) 6.3 – 8.1 mm (ƃ), EyeEar 6.4 – 12.3 mm (Ƃ) 6.9 – 12.2 mm (ƃ), SnW 3.3 – 3.7 mm (Ƃ) 2.8 – 3.8 mm (ƃ), Interorb 7.0 – 7.9 mm (Ƃ) 7.0 – 8.8 mm (ƃ), SnForel 32.9 – 34.4 mm (Ƃ) 31.7 – 40.4 mm (ƃ), TrunkL 42.1 – 55.6 mm (Ƃ) 40.9 – 52.5 mm (ƃ), and HindlL 42.4 – 47.7 mm (Ƃ) 41.1 – 54.1 mm (ƃ). Emoia mokolahi is sexually dimorphic in most mensural features of the head, with only EyeEar and SnW monomorphic between adult females and males. Males are larger than females in all other head metrics. In contrast, none of the body metrics is dimorphic. Males

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average slightly larger (96.9 mm SVL) than females (96.2 mm), although the means are not significantly different, similarly for TrunkL (48.1, 46.5 mm; means females [n = 8], males [11], respectively), HindlL (45.3, 47.7 mm), and SnForel (33.8, 36.2 mm). Only two proportions show significant dimorphism: HeadL/SVL (21, 23%) and SnEye/SVL (9.8, 10.0%). The nondimorphic metrics are TrunkL/SVL (50, 48%), HindlL/ SVL (47, 49%), HindlL/TrunkL (95, 103%), SnForel/SVL (35, 37%), JawW/HeadL (63, 65%), NarEye/SnEye (75, 75%), EyeEar/ SnEye (107, 89%), and SnW/HeadL (17, 16%). None of the scalation traits displays or suggests sexual dimorphism (Table 3). The interparietal is always present, frontoparietal always single, and prefrontals usually in contact; 4 Supoc, 8 (uncommonly 7 or 9) Supcil, 9 – 15 Eyeld, 8 (rarely 9) Suplab, 6th (rarely 7th) BlwEye, and 7 (uncommonly 8) Inflab on each side. Palpebral disk small, about onefourth to one-third area of lower eyelid area; moderate-sized, oblong vertical (occasionally oblique) ear opening with 0 – 5 (median 2) AuricN, usually blunt, on anterior margin. Trunk scales usually smooth, uncommonly weakly tricarinate or striated dorsally and laterally, with 58 – 72 Dorsal (median 64), single pair of Nuchal, 30 – 36 Midbody (34). Subdigital lamellae smooth, 29 – 38 4FingLm (34), 42 – 52 4ToeL (47). Variation is relatively low in most mensural and meristic traits, typically V ≤ 10 for mensural ones and