Nucras margaritae Bauer, Childers & Burger, 2025, sp. nov.

Nucras margaritae sp. nov. (Figs. 7–8) Holotype: NMB (National Museum, Bloemfontein) R11574 (field number MBUR [Marius Burger] 01427), adult female (confirmed by epiphyseal fusion in long bones in radiographs). Zambia, Northern Province, 5.3 km WSW of Senga Hill, -9.386°, 31.19683°, 1650 m elevation. (see Distribution below). Collected by Marius Burger, 27 November 2005. Diagnosis: A moderately sized (SVL to at least 65 mm) Nucras distinguished from all congeners by having 46–48 dorsal scale rows across midbody, enlarged plates on the preaxial face of the forearm (Fig. 7B), two granules between the supraocular and supraciliary scales on each side (Fig. 8B), a tiny parietal window evident in interparietal scale (Figs. 7C–D), 26 subdigital lamellae under digit IV of the pes, 28 femoral pores (14 on each side with a diastema of two poreless scales medially), nape and forebody bearing three pale stripes, no stripes on flanks, distinct barring on lateral surface of head and neck (Fig. 8B), and flanks bearing more-or-less vertically oriented pale spots surrounded by thick black borders (Figs. 7A, 8A). Nucras margaritae sp. nov. differs from N. lalandii in having enlarged plates on the preaxial face of the forearm, from N. boulengeri in having more (26 versus 24) subdigital lamellae under digit IV of the pes and granules present between the supraocular and supraciliary scale rows; from N. scalaris and N. aurantiaca in having a color pattern with longitudinal elements (versus crossbands only and a more-or-less uniform/patternless dorsum, respectively); and from N. intertexta in lacking pale dorsal spots or reticulations. In having three pale dorsal stripes on the nape, N. margaritae sp. nov. is distinguished from N. tessellata (usually two or four stripes on nape), N. livida (six stripes on nape), N. broadleyi (four stripes on nape), and N. taeniolata (four or five stripes on nape). It shares three stripes on the nape with N. caesicaudata, N. holubi, N. damarana, and N. ornata (although the vertebral stripe may be lacking in the last of these), but differs from N. caesicaudata in having fewer pale stripes on the body dorsum (three versus seven), lacking a bright blue tail, and in its larger body size (65 versus 57 mm maximum SVL). Nucras margaritae sp. nov. is most similar to N. ornata, N. damarana, and N. holubi. Nucras margaritae sp. nov. differs from N. holubi and N. damarana in possessing a distinct barring pattern on the temporal region and neck and having the pale markings of the anterior flank arranged vertically (versus lateral pattern of neck and trunk comprising pale spots in one or two more-or-less horizontal rows). It differs from N. ornata in possessing a visible parietal window (Figs. 7C–D) in the interparietal scale (usually absent in N. ornata, including northern specimens; D.G. Broadley, unpubl. data—the consistency of this character in N. margaritae sp. nov. can only be evaluated when more specimens are available), and in its smaller size (65 versus 95 mm maximum SVL). The head also appears to be more depressed, but due to variation in the position of fixation we were not able to confirm this impression. Broadley (1972) considered that variation in several scale characters, including the number of transverse rows of ventral scales, was uninformative in the N. tessellata group, but his comparisons were confounded by the fact that his taxonomy resulted in the lumping of some now-accepted species. It may or may not be of note that the holotype of N. margaritae sp. nov. has 29 transverse rows of ventral scales between the collar and groin. While this falls within the range of N. ornata from Zambia, Malawi and Mozambique (n = 39; range 28–35; mean 31.3), only three individuals had a count below 30, and among 107 specimens of “ N. ornata ” from Zimbabwe (Broadley’s concept of N. ornata included N. holubi as well), the mean was 31.1. Of course, the reliability of putative diagnostic features in N. margaritae sp. nov., as for all taxa known from a single individual, must be considered tentative until such time as variability in the species can be assessed. Finally, N. margaritae sp. nov. can be excluded as the undescribed species illustrated by Broadley and Berry (2004), as the only photograph of the latter species reveals four pale stripes on the nape and on the sides of the neck, and a pale-yellow longitudinal stripe extending to the shoulder, where it breaks up into a series of spots. Moreover, the photographed individual lacks any trace of barring on the neck and temporal region. Description: Measurements: SVL 65.2 mm, TrW 9.6 mm, TailL (regenerated) 77.4 mm, TailW 6.2 mm, AGL 34.7 mm, HumL 6.2 mm, ForeaL 13.8 mm, FemL 11.4 mm, CrusL 11.2 mm, PesL 16.2 mm, HeadL 16.4 mm, HeadW 9.2 mm, HeadD 8.0 mm, CSn 21.1 mm, OrbD 3.4 mm, NEye 4.8 mm, EyeE 5.5 mm, EarH 3.5 mm., EarW 1.5 mm. The holotype is intact and in good condition except that the distal portion of the regenerated tail had been taken for tissue. Body moderately slender and elongate (AGL/SVL 0.53), trunk shorter than hind limbs (AGL/[FemL + CrusL + PesL] 0.89), regenerated tail longer than SVL (TailL/SVL 1.19), moderately slender and tapering. Limbs short, pes longer than shank or femur (PesL/FemL 1.42; PesL/CrusL 1.47). Head large (HeadL/SVL ratio 0.25), distinct from neck, slightly elongate (HeadW/HeadL 0.56), not strongly depressed (HeadD/HeadL 0.49). Snout blunt, short (NEye/HeadL 0.29), less than 1.5 times eye diameter (NEye/OrbD 1.41). Eye relatively large (OrbD/ HeadL ratio 0.21); lower eyelid scaly, with four large translucent/semi-opaque scales surrounded by a rim of small granules. Margin of eyelids pigmented dark brown. Eye to ear distance more than 1.5 times diameter of eye (EyeE/ OrbD 1.62). Ear opening vertical, much higher than wide (EarH/EarW 2.33), without projecting lobules, bordered posteriorly by a series of tiny granules and anteriorly by a series of slightly larger, elongate scales and anterior to this a vertical row of enlarged juxtaposed scales; tympanic shield narrow, 2.5 times the size of cheek scales. Rostral approximately as wide as deep, strongly gabled, separating supranasals for most of their length; loreal region flat to very slightly concave. Supralabials 8/8, increasing in size posteriorly to the fifth, which is largest and in subocular position. Infralabials 7/7, all much longer than high. Nostrils semicircular, surrounded by enlarged supranasal and bordered posteriorly by two postnasals, each approximately a quarter the size of supranasal. Two loreal scales, anterior trapezoidal, bordering posterior loreal, postnasals, second and third (point contact only) supralabials, and, narrowly, both prefrontal and frontonasal; posterior loreal seven-sided, posterior face much higher than anterior, 4–6 times larger than anterior loreal (Fig. 8B), and bordering the prefrontal, first supraciliary, three preocular scales, supralabials three and four (and in point contact with supralabial five on the left side). Supranasals in contact with one another posteriorly; frontonasal roughly hexagonal, wider than long, with lateral apices projecting posteriorly, gabled anteriorly; prefrontals in broad contact medially. Frontal scale approximately 1.5 times wider anteriorly than posteriorly, lateral terminus of frontalfrontoparietal suture lies posterior to border between second and third supraoculars. Four supraocular scales, second and third much larger than first and fourth; seven supraciliary scales, smallest at midorbit, where there are two small granules separating the supraoculars from the main row of supraciliaries. Parietals six-sided, much longer than wide, with slight forward projection wedging between frontoparietal and fourth supraciliary. Interparietal scale narrow and elongate, separating posterior-most portion of frontoparietals from one another and completely separating left and right parietals; parietal window present but tiny; occipital scale very small, pentagonal, narrower anteriorly than posteriorly, only about 4–5 times size of nuchal granules (Fig. 7C). 2/2 supratemporal scales, anterior narrow and elongate, posterior less than half the size of anterior, but much larger than scales of cheek region. Mental roughly semicircular, broader than deep, much wider than rostral, bordered posteriorly by a pair of small chin shields in midline contact with one another and bordering first and second infralabials (Fig. 8C). Second set of chin shields larger and also in contact with each other medially and second and third infralabials laterally; third pair larger still, in point contact with each other anteriorly but otherwise separated from one another by a narrow longitudinal row of throat scales. Fourth pair of chin shields 1.5 times as large as third and widely separated from one another, bordering infralabials four through six. A relatively indistinct gular fold present, scales anterior to this roughly hexagonal and becoming longitudinally elongate and angled medially at approximately the level of the angle of the jaws; scales between gular fold and collar enlarged and rectangular. Collar border comprising a series of enlarged scales, the largest in median position and rhomboidal in shape, decreasing in size laterally and anteriorly. Dorsal pholidosis homogeneous, comprising 46–48 longitudinal rows of small granules (Figs. 7A, 8A), becoming slightly larger and more flattened on flanks. Six longitudinal rows of transversely widened ventral plates plus one ventrolateral row of smaller plates on each side (= 8 longitudinal ventral rows sensu Broadley 1972; Fig. 7B), and 29 transverse rows of ventral plates between collar and groin. Femoral pores extending to knee, 14 on each thigh, with left and right series separated by a diastema of two small poreless scales (Fig. 7B). Scales in row immediately posterior to femoral pore row oval, approximately one-half size of pore-bearing scales. Scales of rows anterior to pores much larg