Tytthoscincus kakikecil, Grismer & Wood & Jr. & Quah & Anuar & Ngadi & Izam & Ahmad, 2018

TYTTHOSCINCUS KAKIKECIL View in CoL SP. NOV.

FRASER’S HILL FOREST SKINK

MENGKARUNG HUTAN BUKIT FRASER

( FIG. 11; TABLE 9)

Holotype: Adult male ( LSUHC 11769 ) collected along Richmond Road , Frasers’s Hill, Pahang, Peninsular Malaysia (N 03°42.590′, E 101°44.236′; 1271 m in elevation) by Evan S. H. Quah on 27 September 2013. GoogleMaps

Paratypes: LSUHC 11770 and 11772 collected on the Telecom Loop Road , Fraser’s Hill, Pahang, Peninsular Malaysia (N 03°43.112′, E 101°45.158′; 1305 m in elevation) by Evan S. H. Quah and L. Lee Grismer on 27 September 2013 GoogleMaps . LSUHC 12754 collected at Ulu Kali , Genting Highlands, Pahang, Peninsular Malaysia (N 03°25.759′, E 101°47.328′; 1670 m in elevation) by Evan S. H. Quah and L. Lee Grismer on 22 June 2016 GoogleMaps .

Additional specimens examined: FMNH 19945 from Ulu Kali, Genting Highlands and ZRC 2.5944 from Telom Valley, Cameron Highlands, Pahang, Peninsular Malaysia.

Diagnosis: Tytthoscincus kakikecil sp. nov. can be differentiated from all other species of Tytthoscincus in the montane clade by having the combination of 8`1, 9`1 or 9`2 superciliaries; a shallow, pigmented tympanic depression; enlarged pectoral scales; 30–33 midbody scales; 67–73 paravertebral scales; 65–69 ventral scales; keeled, subdigital lamellae; six subdigital lamellae on the third finger; ten subdigital lamellae on the fourth toe; TD/HL = 0.10–0.12; HL/SVL = 0.18– 0.21; AXG/SVL = 0.52–0.65; FL/SVL = 0.18–0.23; HDL/SVL = 0.30–0.34; and a maximum SVL of 36.2 mm ( Table 6). All non-ratiometric characters are scored across all other Tytthoscincus and species of Sphenomorphus suspected of being Tytthoscincus in Grismer et al. (2016a: 237) and Karin et al. (2016: 416).

Description of holotype: Adult male, SVL 30.8 mm; original tail 33.9 mm; AXG 19.9 mm; HL 6.2 mm; head width 3.4 mm; snout to anterior margin of foreleg 10.6 mm; rostral wider than long, in broad contact with frontonasal; frontonasal wider than long; prefrontals large, in broad contact on midline; frontal elongate, diamond-shaped, in contact with first two supraoculars; four supraoculars; frontoparietals in contact posterior to frontal, contacting second, third and fourth supraoculars anterolaterally and parietals and interparietal posteriorly; frontoparietals non-overlapping; interparietal diamond-shaped, large, slightly projecting posteriorly, eyespot in posterior projection; parietals large, in medial contact posterior to interparietal, contacting fourth supraocular anteriorly; enlarged nuchal scales absent; nasals small, widely separated, trapezoidal, contacting rostral anteriorly, frontonasal dorsally, first loreal posteriorly, first supralabial ventrally; nostril in centre of nasal; supranasals absent; two loreals taller than wide, posterior loreal smallest; upper and lower preocular present; lower preocular followed by a series of suboculars; nine superciliaries, posterior superciliary elongate and projecting dorsomedially; six supralabials, third, fourth and fifth below eye; two postsupralabials; three primary temporals; three secondary temporals, uppermost not contacting parietals; lower eyelid transparent, scaly, no enlarged central window; mental twice as wide as long; single, large postmental, contacting first infralabial on each side; two enlarged pairs of chin shields posterior to postmental, anterior pair contacting medially, posterior pair widely separated posteriorly by a single scale; anterior and posterior chinshield pairs contacting first, second and third infralabials; five infralabials; external ear opening 0.6 mm less than one-half diameter of eye, subcircular, lacking anterior lobules; tympanum very shallow, pigmented.

Body scales smooth, cycloid, imbricate; ventral scales slightly larger than dorsal scales; 33 longitudinal scale rows around midbody; 73 paravertebral scales; 65 ventral scales; slightly enlarged precloacal scales; tail slightly compressed laterally; subcaudals same size as dorsal caudals; limbs very thin, short (FL/ SVL = 0.22; HDL/SVL = 0.32), widely separated when adpressed; scales of dorsal surface slightly larger than those of ventral surface; palmar and plantar scales slightly raised; and digits short, scales of dorsal surfaces in a single row, subdigital lamellae bicarinate, ten on fourth toe; six on third finger.

Coloration: Overall dorsal ground colour of head, body, limbs and tail brown; head speckled with light-coloured markings; labials bearing light centres; dorsum, posterior portion of flanks and tail bearing small, light-coloured spots; limbs mottled; anterior of flanks to posterior margin of jaws dull-orange bearing irregularly shaped speckles and elongate markings; all ventral surfaces dull-yellow, immaculate; lateral margin of gular region stippled with dark brown; and palmar and plantar surfaces, subtibial, subforearm and subcaudal regions heavily stippled with dark brown.

Variation: The paratypes closely approach the holotype in all aspects of coloration except LSUHC 12754 is considerably darker in overall in dorsal coloration ( Fig. 11). Meristic variation is presented in Table 9.

Distribution: Tytthoscincus kakikecil sp. nov. is known from the town of Fraser’s Hill at Richmond Road and the Telecom Loop and from the upper elevations of Genting Highlands at Ulu Kali, Pahang, Peninsular Malaysia ( Fig. 9).

Natural history: Tytthoscincus kakikecil sp. nov. inhabits leaf-litter in hill dipterocarp and mossy forests from at least 1305–1670 m in elevation ( Fig. 12). All specimens at Fraser’s Hill were collected by raking leaves that had accumulated on earthen banks along the road or by turning rocks and logs buried in leaf-litter. LSUHC 12754 from Genting Highlands was found abroad at night in a dirt parking lot next to a rubbish

AXG, axilla–groin length; FL, forelimb length; HDL, hind limb length; HL, head length; SVL, snout–vent length; TD, tympanum diameter.

pile on the edge of a mossy forest that we presume to be its natural habitat (as opposed to the rubbish pile).

Etymology: The specific epithet kakikecil is derived from the Malay words kaki meaning leg or foot and kecil meaning small and refers to this species’ diminutive limbs.

Comparisons: Tytthoscincus kakikecil sp. nov. can be differentiated from all other species of Tytthoscincus of the montane clade ( Table 6), except its sister species T. jaripendek sp. nov., by having a shallow, pigmented tympanic depression vs. a well-developed, deeply recessed, weakly pigmented tympanum. From T. jaripendek sp. nov., it differs by having 67–73 vs. 63–65 paravertebral scales; 65–69 vs. 60–62 ventral scales; having as opposed to lacking enlarged pectoral scales; and having statistically significant differences in the mean number of PV, VS, 3TL and FL/SVL ( Tables 6, 7). Tytthoscincus kakikecil sp. nov. also bears statistically significant mean differences of all ten characters in varying combinations across all other species ( Table 6). Meristic and body shape trends of these characters among species in the montane clade are presented in Figures 4 and 5.

Remarks: Tytthoscincus kakikecil sp. nov. is known from separate populations at Fraser’s Hill (LSUHC 11769–70, 11772) and Ulu Kali, Genting Highlands (LSUHC 12754, FMNH 19945), ~ 38 km apart ( Fig. 8). We were unsuccessful in obtaining DNA sequences from FMNH 19945, also from Ulu Kali. Sly (1976) considered this specimen to be T. butleri but provided no character evidence and Grismer (2011), who did not examine the specimen, considered it to be T. bukitensis based on the fact that T. butleri occurs in different mountain range and T. bukitensis occurs 38 km to the north across habitable terrain (multiple point measurements made from Google Earth along an elevation profile) at Fraser’s Hill in the same mountain range. FMNH 19945 plotted next to a sequenced specimen of T. kakikecil sp. nov. from Ulu Kali (LSUHC 12754) in the PCAs and DAPCs. Furthermore, based on probability estimates generated from retained posteriors from the concatenated DAPC, FMNH 19945 clustered with T. kakikecil sp. nov. with a 72% probability. However, these populations (Fraser’s Hill and Ulu Kali) differ discretely in their numbers of midbody scales (33 vs. 30 or 31, respectively), TD (TD/HL = 0.10–0.11 vs. 0.12, respectively), HL (HL/SVL = 0.19–0.21 vs. 0.18, respectively) and HDL (HDL/SVL = 0.30–0.32 vs. 0.34, respectively). But, based on a Welch two-sample t -test, only the means of the HDL/SVL ratios are significantly different (P = 0.035). In the absence of molecular data, it would be tempting to consider these populations as separate species regardless of their small sample sizes – an error that has been made before with species of Tytthoscincus (e.g. Grismer, 2007, 2008). However, the molecular data estimate these two populations have only a 1.9% sequence divergence between them and they cluster tightly together in the concatenated PCA and DAPC ( Fig. 2). This shallow divergence across ~ 38 km of habitable terrain is in stark contrast to the 6.2% divergence found between individuals of T. martae sp. nov. (LSUHC 12749, 12751) and T. bukitensis (LSUHC 12750) found only a few meters apart at Awana Road, Genting Highlands (see below).This suggests gene flow still exists between these populations and the morphological differences are due to small sample sizes (n = 3 for Fraser’s Hill and n = 2 for Genting Highlands) and/or sampling error. We predict that data from additional specimens from both localities and the intervening regions will most probably eclipse their current morphological differences.