Nucras aurantiaca, Bauer & Childers & Broeckhoven & Mouton, 2019

Bauer, Aaron M., Childers, Jackie L., Broeckhoven, Chris & Mouton, P. Lefras N., 2019, A new Nucras Gray, 1838 (Squamata: Lacertidae) from the Strandveld of the Western Cape, South Africa, Zootaxa 4560 (1), pp. 149-163 : 154-157

Nucras aurantiaca sp. nov.

Lambert’s Bay Sandveld Lizard

Figs. 2–3 , 4D .

Holotype: NMB (National Museum, Bloemfontein) R11626, adult female. Republic of South Africa, Western Cape Province, Lamberts Bay, Bosduifklip Restaurant (32°05’04.36”S, 18°21’26.9 E). Collected in 2005 by farm workers and sent to Cape Nature Conservation by Kobus Engelbrecht and thence to the University of Stellenbosch.

Paratype: NMB (National Museum, Bloemfontein) R11627, gravid adult female, same data as holotype .

Diagnosis: A moderately sized (SVL at least 75 mm) Nucras distinguished from all congeners by having an attenuate body with 28 presacral vertebrae and an extremely long tail (to at least 3.2 times SVL), 39–41 dorsal scale rows across midbody, enlarged plates on the preaxial face of the forearm, parietal window in interparietal scale absent or very tiny, 25 subdigital lamellae under digit IV of the pes, a total of 27 femoral pores with a diastema of 1–2 poreless scales separating left and right series, dorsal coloration orange (limbs) to orangey-brown (trunk), with no longitudinal stripes and a series of very pale gray transverse marks along the vertebral midline.

It differs from N. lalandii in having enlarged plates on the preaxial face of the forearm, from N. boulengeri in having more than 24 subdigital lamellae and granules present between the suborbital and supraciliary scale rows; from N. taeniolata ( Smith, 1838) and N. livida in a lower number of midbody scale rows (39–41 versus 42–52 and 44–56, respectively; data from Broadley 1 972); from N. caesicaudata and N. taeniolata in larger size (to at least 75 mm SVL versus maxima of 65 mm and 70 mm, respectively); from N. scalaris Laurent, 1964 in lacking a bold pattern of dark crossbands on the trunk; and from all other congeners in lacking any trace of spots, dashes, reticulations, or longitudinal color pattern elements. Vertebral counts have not been previously reported for Nucras spp., but among the few species sampled, N. aurantiaca sp. nov. can be distinguished by its presacral count of 28 (see Osteology and Discussion).

Description: Measurements (holotype, followed parenthetically by paratype): SVL 75.2 (67.2) mm, TrW 8.4 (7.6) mm, TailL (regenerated) 157.0 (88.4, broken) mm, TailW 5.4 (5.8) mm, AGL 46.3 (39.2) mm, HumL 5.4 (5.9) mm, ForeaL 12.6 (damaged, not recorded), FemL 6.9 (8.3) mm, CrusL 8.5 (9.2), PesL 14.1 (damaged, not recorded), HeadL 12.5 (12.6) mm, HeadW 7.9 (7.7) mm, HeadD 7.0 (6.4) mm, CSn 18.2 (18.4) mm, OrbD 2.2 (2.1) mm, NEye 4.2 (4.1) mm, EyeE 4.7 (5.9) mm, EarH 2.4 (2.0) mm., EarW 1.2 (1.1).

Both the holotype and paratype were kept alive in captivity for some period and damage to the digits ( Fig. 2 ) was probably sustained during this time. In the holotype digits II and III of the left manus, I–III of the right manus, and digit V of the right pes are affected. All digits in the paratype damaged except digit V of right pes. Both specimens with an abdominal incision from the fixation process, holotype with incision in left thigh from tissuing.

Body slender and elongate (AGL/SVL 0.62), trunk much longer than hind limbs (AGL/FemL 1.57), tail more than twice as long as SVL (TailL/SVL 2.09), slender and tapering (a photograph of a wild individual [ Fig. 2B ] shows an apparently original tail at least 3.2 times SVL). Limbs short, pes longer than shank or femur (PesL/FemL 2.04; PesL/CrusL 1.69). Head small (HeadL/SVL 0.17), distinct from neck, slightly elongate (HeadW/HeadL 0.63), not strongly depressed (HeadD/HeadL 0.56). Snout blunt, short (NEye/HeadL 0.34), about twice eye diameter (NEye/OrbD 1.91). Eye relatively large (OrbD/HeadL 0.18); 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 twice diameter of eye (EyeE/OrbD 2.14).

Ear opening vertical, taller than wide (EarH/EarW 2.0), without projecting lobules, bordered posteriorly by a series of tiny granules and anteriorly by a series of larger, elongate scales and anterior to this a vertical row of enlarged juxtaposed scales; tympanic shield oval, 8–10 times the size of cheek granules. Rostral wider than deep; loreal region flat to very slightly concave. Supralabials 7/7 (7/6), first shortest, fifth largest and in subocular position, 2–4 subequal in height and intermediate between first and fifth. Infralabials 6/6 (6/6), all longer than tall.

Nostrils subcircular, surrounded by enlarged supranasal, and two postnasals, each approximately one third the size of supranasal. Two loreal scales, anterior rhomboidal, bordering both postnasals, second and third supralabials, prefrontal, frontonasal and posterior loreal, which is roughly hexagonal, four times larger than anterior loreal, and borders the prefrontal, first supraciliary, two preocular scales, supralabials three and four (loreals fused on left side of paratype). Supranasals in broad contact with one another; frontonasal shield-shaped, roughly semicircular anteriorly, gabled posteriorly, wider than long; prefrontals in contact with one another anteriorly. Frontal scale nearly twice as wide anteriorly as posteriorly, lateral terminus of frontal-frontoparietal suture coincident with border between second and third supraorbitals. Supraorbital scales four, second and third much larger than first and fourth, 10 supraciliary scales, smallest at midorbit. Parietals roughly rectangular with slight forward projection wedging between frontoparietal and fourth supraciliary. Interparietal scale narrow and elongate, separating posterior half of frontoparietals from one another and completely separating left and right parietals (elongate but 3– 4 times broader anteriorly than posteriorly, not extending anteriorly to separate frontoparietals, which are in broad median contact with one another); parietal window tiny (absent); occipital scale very small, pentagonal, only about 4–5 times size of nuchal granules. Surface sculpturing evident on dorsal head shields from midorbit posteriorly. 4/5 (3/2) supratemporal scales, anteriormost thin and elongate, posterior ones only slightly larger than granular scales of cheek region, but more elongate.

Mental subtriangular, broader than deep, bordered posteriorly by a pair of small chin shields in midline contact with one another and bordering first and narrowly second infralabials. Second set of chin shields larger and also in contact with each other medially and second and third infralabials laterally; third pair larger still and separated from one another posteriorly by several small throat scales (in point contact with each other anteriorly but otherwise separated from one another by two narrow scales), bordering infralabials three and four. Fourth pair of chin shields twice 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 longitudinally elongate and angled medially; scales between gular fold and collar chiefly transversely elongate. Collar border comprising a series of enlarged scales, the largest in median position and rhomboidal in shape.

Dorsal pholidosis homogeneous, comprising 39 (41) longitudinal rows of small granules, 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. 29 (28) transverse rows of ventral plates between axilla and groin.

Femoral pores 13 on left thigh and 14 on right thigh, with left and right series separated by a diastema of a single poreless scale in the holotype and two scales in the paratype. Scales in row immediately posterior to femoral pore row oval, approximately same size as pore-bearing scales. Scales of rows anterior to pores much larger, one (distal) to three (proximal) rows between pore-bearing scales and enlarged preaxial plates. Large, roughly circular patch of precloacal plates anterior to cloaca, constituent scales extremely large, largest bordering posterior margin, bordered laterally and anteriorly by five (four) scales each approximately one eighth to one third as large, a semicircular series of much smaller scales bordering the precloacal plates laterally and anteriorly.

Preaxial surface of forelimb with a series of transversely enlarged scales; postaxial surface covered by smaller, flattened juxtaposed to subimbricate scales. Preaxial aspect of thigh with large transverse plates, continuing on to shank and dorsum of pes, postaxial aspect with small flattened juxtaposed scales, granular on shank. Scales on the sole small, smooth,granular. Digits of pes 4>3>5>2>1, all clawed, bearing a series of smooth narrow subdigital lamellae: (L/R) I–8 /8, II–13/13, III–18/18, IV–25/damaged, V–14/14.

Posterior 94.1 mm of tail regenerated. Original portion tail of holotype with approximately 30 elongate rectangular scales per whorl at level of knee of adpressed hindlimb. Dorsal scales strongly keeled, becoming more weakly keeled ventrolaterally. Mid-ventral subcaudals with pointed, posteriorly directed apex and strongly unicarinate, but bordered by a series of smoother scales laterally. Posterior to this level all caudal scales strongly keeled and approximately equal in size; scalation of regenerate similar to original.

Coloration (in life) (based on photographs, Fig. 3 A–B). Dorsum pale orangey-brown, with greyish overtones on forebody, nape and occiput. A series of weakly delineated, short, transverse grey markings along the vertebral midline of forebody. Flanks a pale creamy orange, abruptly changing to white at ventrolateral margins of trunk. Head pale greenish-brown with darker irregular blotches; lateral surfaces of head lighter greyish brown. Labial scales chiefly white, rostral with orangey tinge, anterior labial scales with a diffuse light brown marking in posterodorsal quadrant. Dorsal surfaces of fore- and hindlegs bright orange. Original portion of tail pale orangeybrown, distal regenerated portion of tail greyish. A photograph of a wild individual ( Fig. 3B ) shows an original tail that is bright orange and the overall body coloration is much more vibrant than in the captive life photo of the holotype ( Fig. 3A ), suggesting that the duller appearance may be an artifact of captivity. However, such differences could also reflect sexual dimorphism (although the sex of the camera trapped individual is not known).

Coloration (in preservative). Holotype ( MNB 11626). Pale orange to straw, suffused with grey from just posterior of forelimb insertions to dorsum of head. Venter cream. Limbs orangey-red with scattered darker pigment flecking. Tail more-or-less uniform pale orange. Lateral surfaces of head pale greyish, labials cream . Paratype (NMB 11627) similar except nape, crown and occiput a darker grey.

Osteology: The female holotype of Nucras aurantiaca sp. nov. possesses 28 presacral vertebrae in comparison to 26 for the scanned representatives of its closest relatives, N. livida and N. tessellata , and 31 for N. lalandii , the next most closely related taxon ( Fig. 4 ). There are 19 caudal vertebrae in the original portion of the tail.

Etymology: The specific epithet auriantiaca refers to the conspicuous, mostly unmarked orange dorsal coloration of the new species.

Distribution and Natural History: In addition to the type locality, a specimen of the new species was photographed by a Reconyx PC900 HyperFire (Reconyx, Inc., Holmen, Wisconsin, USA) camera trap set by one of us (CB) on the Farm Fonteintjie (-31.935, 18.41067), ~ 20 km NNE of Bosduifklip, Western Cape on 8 December 2011 at 14h20 at 32° C ( Fig. 3B ). The two localities for Nucras aurantiaca sp. nov. fall within the Lambert’s Bay Strandveld vegetation type ( Mucina & Rutherford 2006) in the Fynbos Biome ( Figs. 5–6 ), although both records are close to the western border of the Leipoldtville Sand Fynbos vegetation type. Lambert’s Bay Strandveld occupies a relatively small (451 km 2) area of mostly consolidated sand dunes supporting evergreen sclerophylous shrubs and an understory of succulent shrubs. The region, stretching from Donkin’s Bay in the north to Elands Bay in the south, is below 180 m elevation and receives 125–200 mm of winter rainfall. Nucras tessellata has been characterized as being associated with rocky terrain ( Burger 2014) or “hard substrates” ( Broadley 1972), so the occurrence of N. aurantiaca sp. nov. on loose, sandy substrates is a potential ecological difference between the two. Branch (1998) depicted the range of N. tessellata as including that of N. aurantiaca sp. nov., but the quarter degree square maps of Visser (1984) and Burger (2014) show no records from the particular quarter degree squares from which the new species has been recorded ( Fig. 5A ).

Figures

FIGURE 2. Preserved type specimens of Nucras aurantiaca sp. nov. A) Holotype specimen NMB R11626 in oblique dorsal (left) and ventral (right) views. B) Paratype specimen in oblique dorsal view.

FIGURE 3. Life photos of Nucras aurantiaca sp. nov. A) Holotype specimen NMB R11626 from Lambert’s Bay in captivity. B) Camera trap photo of a wild individual from Farm Fonteintjie. Note the brighter orange coloration of the wild specimen and the extremely elongate original tail.

FIGURE 4. Micro-CT-scans of the skeletons of selected Nucras spp. A) N. tessellata, USEC/H 1559 (26 presacral vertebrae). B) N. lalandii, USEC/H 3892 (31 presacral vertebrae). C) N. livida, USEC/H 5787 (26 presacral vertebrae). D) N. aurantiaca sp. nov., NMB R11626 (28 presacral vertebrae). Scale bars = 10 mm. Note the variation in trunk length and presacral vertebral number across taxa.

FIGURE 5. Map of A) the distribution by quarter degree squares of Nucras tessellata in South Africa—yellow squares circles (from Bates et al. 2014, including virtual records but excluding questionable records) and Nucras aurantiaca sp. nov.—red squares; and B) close-up of the region of Lambert’s Bay Strandveld vegetation type (teal coloration) occupied by N. aurantiaca (based on Mucina & Rutherford 2006). Red star is the type locality of N. aurantiaca sp. nov., red dot is the camera trap locality for the species.

FIGURE 6. Habitat of Nucras aurantiaca sp. nov. near camera trap recording site on Farm Fonteintjie, Western Cape Province. Photo by Chris Broeckhoven.