Ctenotus ora, Kay, Geoffrey M. & Keogh, Scott, 2012

Kay, Geoffrey M. & Keogh, Scott, 2012, Molecular phylogeny and morphological revision of the Ctenotus labillardieri (Reptilia: Squamata: Scincidae) species group and a new species of immediate conservation concern in the southwestern Australian biodiversity hotspot, Zootaxa 3390, pp. 1-18 : 10-13

Ctenotus ora sp. nov.

Coastal Plains Skink ( Figures 5 j, 6, 7)

Holotype. WAM R131983. Type locality: Cape Naturaliste at 33°32`21"S, 115°01`13"E. Collected by M. D. Shapiro on 4th November 1997.

Paratypes. R73591 – Yalgorup National Park, 32°50`00"S, 115°39`00"E; R81601 – Eaton, 33°21`00"S, 115°42`00"E; R119059 – Lake Mealup (15km WSW Pinjarra), 32°40`00"S, 115°43`00"E; R 141244 – Yallingup Brook, 33°38`39"S, 115°02`15"E.

Diagnosis. Ctenotus ora is distinguished from sister taxon C. lancelini by its smaller size, generally darker colouration and lack of vertebral stripes (see Ford 1969). It is distinguishable from C. gemmula , C. delli and C. catenifer by a continuous white dorsolateral line, and from C. youngsoni by its smaller size and sharper dorsal patterning ( Figure 5 ). C. ora can be distinguished from C. labillardieri by its smooth copper-brown dorsum and absence of white specks above the dorsolateral line.

Description. A small to medium-sized (maximum SVL 60mm) member of the Ctenotus labillardieri species group. Measurements for 19 morphological characters are summarized in Table 6. In addition to these: external ear opening prominent, small and ovate, about half the diameter of eye; snout triangular in profile with nose rounded; body slender, pentadactyl limbs; forelegs extend beyond the eye when adpressed; hindlimbs long, reaching beyond two-thirds of the axilla-groin length when adpressed; digits moderately long and slender; finger length: 4>3>2>5>1; toe length: 4>3>5>2>1; tail round in cross-section with very gradual taper to its pointed tip; head scales smooth; nasals separated; prefrontals separated; supraoculars four, with first two in contact with frontal; ear lobules three, occasionally four, with either the 1st or 2nd the largest.

Colouration. Dorsal surface bronze-brown, without any black pigmentation within the bronze-brown ground colour, creating a smooth appearance; white dorsolateral, midlateral and ventrolateral stripes, the latter much less sharp and defined than the former two; below each white stripe is a dark brown-black band, the most ventral of which is narrowest and least defined ( Figure 5 ); some fine white flecks between the dorsolateral and upper lateral stripes; chin and throat uniform whitish-grey in preserved specimens; digital lamellae with slightly darker pigmentation; legs reddish-orange with black patches covering nearly half of each leg ( Figure 7 ).

Description of holotype.

SVL – 58mm; HeadL – 14.4mm; HLL – 23mm; FLL – 15mm; ILL – 35mm; TailL – 88mm; LorH:W –.91; MidB – 22; Lam4Toe – 24; VentS – 48; NasSS – Yes; PrefSS – Yes; SOS – 4; SOSContact – 2; SupCil – 8; Palp – 11; UppLab – 8; EarL – 3; EarLPos – 2.

Variation. Table 6 presents the morphological variation for the 19 characters measured. Juveniles show the same overall colour patterns, but with somewhat finer black blotching on legs. There appears to be little geographic variation.

Habitat. Specimen WAM R119059 was found under a banksia log in open eucalypt woodland over Banksia attenuata and Banksia grandis on white sand. Specimen WAM R73591 was found in Corymbia calophylla over heath in sandy soil. The species seems to have a preference for sandy substrates with low vegetation with open Eucalyptus woodland over Banksia (B. Maryan, pers. comm.)

Distribution. This species appears to be restricted to the SWA coastal plain west of the Darling Range, south of Perth, Western Australia. In addition to the specimens examined and listed in Table 1, we examined photographs of specimens from Lake Clifton on the Swan Coastal Plain and these appear to also represent C. ora (WAM R17966-68). It is known to occur as far north as Pinjarra and south as far as Yallingup Brook, where it occupies coastal dunes. Across its range it occurs in very low densities, in contrast to neighbouring C. labillardieri populations, which are found in great abundance throughout the Darling Range (B. Maryan, pers. comm.).

Etymology. ora is Latin for “coast”, “seaside” or “shore” and is in reference to the coastal distribution of the species.

Similar species. Despite large morphological variation within C. labillardieri in color patterns, C. ora can be readily distinguished by its smooth copper-brown dorsum and absence of white specks above the dorsolateral line. All C. labillardieri (with the exception of Clade 2) shared varying degrees of melanism on the dorsal surface scales, creating either an unconnected pattern of dark flecks, or a connected set of one or two vertebral stripes ( Figure 5 ). Furthermore, C. ora lacks the heavily speckled flanks present in all C. labillardieri clades, with the exception of C. labillardieri Clade 2. Instead, both C. ora and C. labillardieri Clade 2 possess two dark brown and one white ventrolateral stripes with Clade 2 being distinguished from C. ora by the most ventral brown zone much more solid and defined. In addition, C. labillardieri Clade 2 lacks any white specks between the dorso-lateral and mid-lateral stripes, giving these individuals a uniquely “immaculate” appearance overall, in contrast to the subtle white speckling in C. ora . Finally, the ventral surface of C. ora is whitish and clean where C. labillardieri Clade 2 individuals have dark flecks under the chin and throat.

Figures

FIGURE 5. Back patterns in the Ctenotus labillardieri species group. A – D illustrate geographic variation in C. labillardieri and E – J show representative back patterns in the other species in the group. The variation shown within C. labillardieri is not confined to the clades illustrated. A) C. labillardieri (R 135665; lineage 6), B) C. labillardieri (R 117354, lineage 1), C) C. labillardieri (R 142908, lineage 2), D) C. labillardieri (166085, lineage 7), E) C. catenifer (R 163143), F) C. delli (R 13444), G) C. gemmula (R 150245), H) C. lancelini (R 18874), I) C. youngsoni (R 66208), J) C. ora sp. nov. (R 131983). Scale bars are all 1 cm.

FIGURE 7. Photograph in life of Ctenotus ora sp. nov. from Pinjarra, Western Australia (WAM R 119059).