Cordylus namakuiyus, Stanley, Edward L., Ceríaco, Luis M. P., Bandeira, Suzana, Valerio, Hilaria, Bates, Michael F. & Branch, William R., 2016

Stanley, Edward L., Ceríaco, Luis M. P., Bandeira, Suzana, Valerio, Hilaria, Bates, Michael F. & Branch, William R., 2016, A review of Cordylus machadoi (Squamata: Cordylidae) in southwestern Angola, with the description of a new species from the Pro-Namib desert, Zootaxa 4061 (3), pp. 201-226 : 212-217

Cordylus namakuiyus sp. nov.

( Figs. 1–6 , Table 2 )

Holotype. CAS 254912, an adult female collected from a large rock outcrop near Caraculo, on the road from Lubango and Namibe, Namibe province, Angola [15°0'59.40"S, 12°38'31.30"E; 503 m elevation], collected by E. L. Stanley, S. de Sá, S. Bandeira, H. Valerio, A. L. Kuhn, J. V. Vindum and L. Ceríaco, on 6 December 2013.

Paratypes. Eight specimens: CAS 254913–14, two fetuses taken from the holotype, with the same data; CAS 256529, one juvenile collected at the same locality as the holotype [15°0'57.3"S, 12°38'32.6"E; 509 m elevation] by the same collectors; CAS 254754, adult female, CAS 254755, adult male, CAS 256530, juvenile, CAS 256531, adult female, all collected on the outskirts of Pico Azevedo [15°28'33.2"S, 12°27'45.7"E; 421 m elevation] by the same collectors of the holotype on 7 December 2013; PEM R18005, adult female, collected in a low rock outcrop bordering the road between Namibe and Omahua lodge [15°59'48.5"S, 12°24'24.6"E; 308 m elevation], Namibe Province, Angola, by W. R. Branch, K. A. Tolley and G. J. Measey on 20 January 2009.

Additional material. Forty-nine specimens. One specimen: TM 40430, adult female from 49 km ESE of Tombua, Namibe Province, Angola [15°53'S, 12°16'E], collected by W. D. Haacke on 31 March 1971; and a series of 48 specimens collected by A. S. Vernay, H. Lang and R. Boulton between 25 April and 4 August 1925, locality “ Angola ”: Adult females: AMNH R47274, 47276, 47278, 47279, 47282–84, 47286, 47287, 47289-95, 47297, 47298, 47299, 47304, 47305, and 47315. Adult males: AMNH R47275, 47277, 47280, 47281, 47285, 47288, 47296, 47300–03, 47306–09, and 47311. Juveniles: AMNH R47310, 47312–14, and 47316–23.

Diagnosis. A relatively large species of Cordylus , identified to genus by the following combination of characters: four-limbed, rupicolous, viviparous, strongly depressed triangular head and body, osteoderms present, rhomboidal, imbricate and keeled dorsal scales present, occipitals non-spinose, and spinose caudal and limb scales enlarged ( Branch 1998; Broadley and Branch 2002; Stanley et al., 2011). Cordylus namakuiyus sp. nov. differs from all other species in the genus except for C. vittifer and C. machadoi , by the presence of a transverse row of elongated dorsal scales immediately posterior to occipitals (vs. absence); from C. vittifer by possessing an incomplete row of pre-occipital scales between posterior parietal and occipital scales (absent in C. vittifer ), and by having infralabials that are moderately-deeply corrugated (vs. usually smooth); from C. machadoi by having a large, keyhole-shaped interparietal in broad contact with frontoparietals, thereby separating anterior parietals (vs. small, diamond-shaped interparietal not in contact with frontoparietal, thereby never completely separating anterior parietals), temporal scales that are strongly keeled (vs. weakly keeled), fewer transverse gular rows (14–17 vs. 17– 24), light brown dorsal body coloration (vs. darker brown), and by the absence of dark speckles on throat and ventral body surfaces (vs. presence), presence of osteoderms on throat and ventral surfaces (vs. absence); from C. angolensis (based on original description; Bocage 1895) by having fewer ventral transverse scale rows (21–24 vs. 27), light brown dorsal body coloration (vs. brown with blackish speckles over paler dorsal ground coloration), and by the absence of longitudinal series of whitish speckles along dorsal surface (vs. presence of two longitudinal series of small whitish speckles along dorsum), and presence of a loreal (vs. absence).

Description of holotype. SVL 101 mm. Head and body depressed. Head 1.2 × as long as broad. Nasals in median broad contact; frontonasal lozenge-shaped, as broad as long, separated from frontal by enlarged prefrontals (in median contact, forming a suture), separated from rostral by nasals, separated from loreal by prefrontals; frontal in contact with first and second supraoculars, followed by a pair of large frontoparietals in broad, median contact; a distinctive keyhole-shaped interparietal in broad contact with the frontoparietals, separating anterior parietals; parietal eye visible; a row of 10 rugose occipitals. A row of 11 elongated nuchal scales. Four supraoculars and three supraciliaries. Nasals large, with nostril pierced centrally on upper margin. Loreal in contact with preocular, nasal and first two supralabials; three suboculars, well separated from the lip by the fourth and fifth supralabials. Rostral twice as broad as deep; supralabials five; infralabials five; chin shields five. Mental twice as broad as long; gulars smooth, enlarged and forming transverse rows posteriorly, with 16 gulars between the posterior extent of the jaws. Dorsal scales rectangular, rugose, obtusely keeled, mucronate and serrate posteriorly; dorsals and laterals in 25 transverse and 24 longitudinal rows; ventrals squarish, smooth, in 21 transverse and 15 longitudinal rows. Scales on limbs above large, strongly keeled and spinose; subdigital lamellae under fourth toe 14; femoral pores five; generation glands absent. Tail with whorls of large, elongate, strongly keeled, spinose and serrated scales, spines directed posteriorly and largest superolaterally.

Cranial osteology. The parietal is pentagonal with a well-developed, unbifurcated medio-posterior process that extends past the postero-lateral processes. The premaxilla is unpaired and contains seven pleurodont teeth and five foramina, with a dorsal process that extends posteriorly to be clasped by the nasals, which themselves insert into an unpaired frontal. The maxilla is typically scinciform, with a deeply grooved crista dentalis and 16 pleurodont teeth. No palpebral is present, though the prefrontal has a small, flattened, laterally projecting tubercle that supports the anterior-most superorbital osteoderm in much the same way. The jugal is triangular in crosssection and asymmetrically T-shaped, with a tapering anterior process and a broad, truncated posterior process that extends along and past the posterior edge of the maxilla. The lacrimal bone is small, flattened and extends along the postero-ventral boundary of the maxilla and prefrontal. Edentate pterygoids extend back to connect with the quadrates, becoming C-shaped in cross-section posterior to the epipterygoid condyle. The squamosal is curved and blade-like, circular in cross-section anteriorly, becoming flattened posteriorly, where it articulates with the cephalic condyle of the quadrate and the braincase. Supratemporals are flattened, reniform and fused to the paroccipital processes. The supraoccipital has a strong sagittal crest that extends posteriorly to contact the ventral surface of the medio-posterior process of the parietal. The prootic bears an extended alar process and a well-developed, rhomboid christa prootica, and a very weak supratrigeminal process. Basipterygoid processes are well developed and flattened. The lower jaw possesses a large adductor fossa, a highly flattened and medially extended retroarticular process, a medially open meckelian canal and a dentary with a strong subdental shelf, 21 mandibular teeth, and nine dentary foramina.

Postcranial osteology. The holotype possesses 25 presacral and 17 postsacral vertebrae with the last 21 mm (roughly 20%) of the tail made up of regenerated cartilage. There are five cervical ribs, three sternal ribs, two xiphisternal ribs, five long asternal ribs with ossified costal cartilage, and eight short asternal ribs. The first three cervical ribs are distally flattened with bifid cartilaginous projections. Sacral vertebrae are fused asymmetrically, with the left diapophysis formed from the fused sacral ribs, while the right diapophysis is formed by the fusing of the second sacral and first caudal ribs. The next two pairs of caudal ribs are well developed and angled anteriorly, with subsequent ribs becoming increasingly smaller and posteriorly angled. Pelvic girdle is well developed and flattened. No iliac tubercle is present. There is a well-developed, ventrally angled pubic tubercle directly anterior to the obturator foramen. Both hypoischium and hyperischium are well developed. Pubic bones are well separated by triangular prepubic cartilage. The sternal plate is broad and lacks a fontanelle. Interclavicle cruciform, clavicles rod-like and flattened dorsally. The epicoracoid is narrow and curved, connecting the scapular ray to the primary and secondary coracoid rays, but not to the anterior process of the scapular. Limb bones well developed. Digits display the typical squamate phalangeal arrangement of 3–5–4–3–2. A large sesamoid is found in the palm of the hands. The fifth metatarsal possesses an elongated medial process at midbody.

Osteoderms. Scales of the dorsal and temporal regions of the skull and the ventrolateral aspects of the jaws are underlain with rugose osteoderms. These osteoderms fuse to the proximal parietal, frontal and postorbital bones, although the mesokinetic and metakinetic joints appear unobstructed and flexible. The entire body is covered in robust osteoderms, with only the femoral pores and the axillary, inguinal and cloacal regions unarmoured. Large, rectangular, imbricate osteoderms protect the dorsal and lateral aspect of the trunk, becoming more keeled and mucronate laterally. Unkeeled, imbricate osteoderms cover the entire venter, from the gulars to the cloaca, rectangular on the throat and abdomen, becoming rhomboid around the sternum and cloaca. Several abdominal osteoderms appear to be fractured. Caudal osteoderms are thick, sharply spined and arranged in imbricate transverse whorls. Limbs covered by imbricate circular/rhomboid osteoderms, keeled and mucronate dorsally, plate-like ventrally.

Colouration of holotype. Dorsal coloration is medially brown, blending to a straw-yellow laterally. Head yellow-brown; supra and infralabials yellowish; a dark-brown bar extends from the posterior aspect of the eye to the temporals. The base of the tail is medially brown, surrounded by a straw-yellow coloration that extends towards the tip and eventually dominates the tail; the dorsal aspect of the limbs is brown. Laterally a dark-brown line, similar to the eye-mask coloration, extends from the neck towards the insertion of the forelimbs. The venter is yellowish-white, cream on the tail; the underside of the hind limbs, cloacal region and tail are cream, grading into yellowish on the anterior half of the tail.

Variation. Variation in scalation and body measurements of C. namakuiyus sp. nov. are reported in Tables 2 and 3. The sole male paratype CAS 254755 has 12 generation glands on the ventral surface of each thigh. One female paratype (CAS 254754) differs from the holotype in having the loreal and preocular fused. The medioposterior parietal process is slightly bifurcated distally in CAS 254754, CAS 265529 and PEM R18005, and does not extend back beyond the posterolateral processes in CAS 25630. Five premaxillary foramina are present in all type specimens except CAS 254754 (two) and CAS 256531 (four). Specimens CAS 254755 and PEM R18005 have 15 maxillary teeth, and CAS 256531 has 17. All paratypes have 21 mandibular teeth, except CAS 254754 (20), CAS 256530 (18), and CAS 254755 and CAS 256529 (16). The supratemporals are not fused to the paroccipital processes in CAS 254754, CAS 256529, and CAS 256530. Five of the paratypes have full, unautotomised tails: CAS 254755 has 29 postsacral vertebrae, CAS 25474, CAS 256529 each have 27, and the two fetuses, CAS 254913 and CAS 254914, have 25 and 26 respectively. One specimen, CAS 256531, has 26 presacral vertebrae. CAS 254755, CAS 256529 and CAS 256530 each possess four pairs of long asternal ribs, while CAS 256529 and PEM R18005 each have seven short asternal ribs. None of the paratypes exhibit the asymmetrical sacral fusion of the holotype, but rather display the normal condition of having the sacral diapophyses formed from the sacral ribs. The hyperischium of CAS 254755 extends anteriorly to connect with the prepubic cartilage.

Etymology. The specific epithet “ namakuiyus ” is the masculine latinised form of namakuiya, which means “thorny” in the Herero language, referring to the sharp spines on the limbs and tail of this species. Suggested common name: Kaokoveld Girdled Lizard.

Distribution. Currently, the new species is known only from the south and central parts of Namibe Province, Angola, southwest of the Leba escarpment, at elevations of 215–509 m a.s.l.

Localities. Angola: AMNH R47274–47321. Namibe Province, outskirts of Caraculo: CAS 254912–14 [15°0'59.4"S, 12°38'31.3"E; 503 m elevation], CAS 256529 [15°0'57.3"S, 12°38'32.6"E; 509 m elevation]; outskirts of Pico Azevedo: CAS 254754–55, 256530, 256531) [15°28'33.2"S, 12°27'45.7"E; 421 m elevation]; Road from Namibe to Omahua lodge PEM R18005 [15°59'48.5"S, 12°24'24.6"E; 308 m elevation]; 49 km ESE of Tombua: TM 40430 (15°53'S, 12°16'E; 215 m elevation).

Habitat and natural history notes. This species is found in gently sloping crevices of granite outcrops in the arid Kaokoveld. When approached, specimens retreat into their fissure as far as possible, wedging themselves head-first and protecting their head and flanks with their spiny tails. As with all other cordylines, C. namakuiyus sp. nov. is viviparous; the holotype contained two large fetuses (SVL 49.5% of the holotype). The fetuses appear to be approaching full-term, suggesting a spring/early summer parturition period. Although these fetuses lack any body osteoderms, the slightly larger neonates (SVL 55.6–56.4% of the holotype) possess significant dermal ossification, suggesting that the young rapidly accumulate osteodermal armour following parturition. One of the Pico Azevedo specimens was found occupying the same rock crack as an adult Chondrodactylus pulitzerae (Schmidt) , and PEM R18005 from Iona National Park inhabited the same crack as an adult Chondrodactylus fitzsimonsi (Loveridge) .

Figures

FIGURE 1. Head and body diagrams of Cordylus sp. (AMNH 47301, “ Angola ”) from an unpublished species description by Charles M. Bogert, illustrated by Alma W. Froderstrom, reproduced with the permission of the Department of Herpetology at the American Museum of Natural History

FIGURE 2. Map showing localities for Cordylus in Angola and Namibia. Cordylus namakuiyus sp. nov. 1) Iona national park: PEM R 18005, 2) Pico Azevedo: CAS 254754, 254755, 256529 – 31, 3) Caraculo: CAS 254912, 256529, 4) Iona National Park: TM 40430. C. machadoi: 5) Humpata environs: PEM R 18006 – 8, 19782, 19784, 6) Nasecute do Tchiviuguira: PEM R 18009, 7) NMN 7002, 8) TM 40131 – 3, 9) TM 40095, 40096. C. cf. machadoi: 10) Otjihipa Mountains: NCN – FN 377, 378, 11) Baynes Mountains: TM 57561, NCN-FP 402, 403, 12) Sera de Neve (sight record, P. Vaz Pinto), 13) C. angolensis, Caconda: type locality, and 14) Mombolo: AMNH 47331 – 35.

FIGURE 3. Maximum likelihood phylogeny of 11 - gene dataset of Cordylus. Bootstrap support for MP and ML shown above branches, Bayesian posterior probabilities below. The new species, Cordylus namakuiyus sp. nov., is highlighted for reference. The numbered circles to the right of the Angolan specimens correspond to the numbered localities in Figure 2.

FIGURE 4. Dorsal, lateral, and ventral views of A) Cordylus namakuiyus sp. nov. (CAS 254912, holotype) and B) C. machadoi (PEM R 18006).

FIGURE 5. High-resolution Computed Tomography reconstructions showing the ventral aspects of (top) Cordylus namakuiyus sp. nov. (CAS 254912, holotype) and (bottom) C. machadoi PEM R 18006. Osteoderms are shown in green. A – F tomograms showing cross-sections of the throat (A + D), torso (B + E), and hind limb (C + F).

FIGURE 6. PCA plots of A) 32 meristic and continuous and B) 22 meristic characters from 73 specimens of Cordylus. Green dots = C. namakuiyus sp. nov. (N = 10), red dots = C. machadoi (N = 13), yellow dots = AMNH C. cf. namakuiyus collected on the 1925 Vernay expedition (N = 48), purple star = C. cf. machadoi (TM 57561) from northern Namibia. Polygons with solid lines show morphospace of adult specimens, those with dotted lines represent morphospace of adults + juveniles.