Ichnotropis robusta, Conradie & Keates & Greenbaum & Lobón-Rovira & Tolley & Benito & Vaz Pinto & van Breda & Verburgt, 2025

Conradie, Werner, Keates, Chad, Greenbaum, Eli, Lobón-Rovira, Javier, Tolley, Krystal A., Benito, Max, Vaz Pinto, Pedro, van Breda, Reuben V. & Verburgt, Luke, 2025, Systematics of African rough-scaled lizards, with description of two new species from eastern Angola (Squamata: Lacertidae: Ichnotropis Peters, 1854), Vertebrate Zoology 75, pp. 627-672 : 627-672

Ichnotropis robusta sp. nov.

Figures 17 , 18 ; Tables 4 , 5

Chresonymy.

Ichnotropis cf. grandiceps – Conradie et al. (2022 a: 198); Ichnotropis aff. grandiceps – Benito et al. (2025: 893).

Holotype.

PEM R 23420 (field number WC-4816), adult male, collected from Cuando River source ( –13.0035°, 19.1275°, 1343 m a. s. l.), Moxico Province, Angola by Werner Conradie and James Harvey on 21 November 2016 .

Paratypes.

4 specimens: a) PEM R 23361 (field number WC-4063) and PEM R 23362 (field number WC-4056), adult females, collected on the road between Cuanavale River source camp and Samanunga village ( –13.0380°, 18.8298°, 1605 m a. s. l.), Moxico Province, Angola by Werner Conradie and Luke Verburgt on 13 March 2016 ; b) PEM R 23421 , adult male, same collection details as holotype ; c) PEM R 23482 (field number WC-4804), adult male, collected from Cuando River source , trap 4 ( –13.0016°, 19.1296°, 1372 m a. s. l.), Moxico Province, Angola by Werner Conradie and James Harvey on 15 November 2016 .

Additional juvenile material.

12 specimens: a) PEM R 23279 –80; INBAC (no number), collected from Cuanavale River source lake ( –13.0933°, 18.8940°, 1367 m a. s. l.), Moxico Province, Angola by Werner Conradie on 1 March 2016 ; b) PEM R 23299 –300, grassland west of Cuanavale River source en route to Samanunga village ( –13.0751°, 18.8848°, 1366 m a. s. l.), Moxico Province, Angola by Werner Conradie and Luke Verburgt on 16 March 2016 ; c) PEM R 23303 –9, trap 4 km upstream from Cuanavale River source lake ( –13.0508°, 18.8973°, 1380 m a. s. l.), Moxico Province, Angola by Werner Conradie from 28 February to 15 March 2016 .

Etymology.

The species name robusta is the feminine form of the Latin adjective robustus, meaning ‘ robust’ or ‘ sturdy’, in reference to the large, heavy-built adults of this species.

Diagnosis.

Assigned to Ichnotropis due to the absence of a well-defined collar, digits not serrated or fringed, subdigital lamellae keeled, and subocular bordering the lip. A large Ichnotropis with a single frontonasal; subocular bordering the lip; a single anterior loreal; feebly developed head shield striations; prefrontals well separated from the anterior supraocular; and supraciliaries separated from the supraoculars by a series of smaller scales.

The new species can be distinguished from other Ichnotropis species based on a combination of the following characters: Prefrontals well separated from the anterior supraocular (versus mostly in contact in I. bivittata , I. microlepidota and I. tanganicana ); high number of midbody scale rows (43–48 versus 25–42 in I. capensis sensu lato); large, robust head and rounded snout (versus small depressed head and pointed snout in I. capensis sensu lato); four (46 %) to five (50 %) supralabials anterior to the subocular (versus mostly four in I. capensis sensu lato); distinctive large trapeziform occipital wedged between the parietals, not protruding past parietals (versus occipital usually extending posteriorly, well beyond the level of the parietals in I. capensis sensu lato).

The new species resembles I. grandiceps in its large size, robust, rounded head; prefrontals well separated from anterior subocular; high midbody scale rows (43–48 versus 44–47) and genetic similarity. Due to the lack of comparative adult material of I. grandiceps , no clear morphological and colouration differences could be observed between the two species. However, the two species exhibit clear differences in habitat preferences. All I. grandiceps material have either been found in drier Zambezian Baikiaea woodlands or Combretum-Vachellia bushveld ( Broadley 1967 b; Haacke 1970; Pietersen et al. 2017) at lower elevations (less than 1000 m a. s. l.), while the new species is associated with the higher elevations (above 1300 m a. s. l.) of the Angolan Plateau, which consists of moister Angolan Miombo woodland.

In the phylogenetic analysis, the uncorrected p distances show that the new species differs by> 6.7 % for 16 S and> 16.3 % for ND 4 sequence divergence from other Ichnotropis species (Table 2 ).

Holotype description (Fig. 18).

Adult male measuring 73.5 mm SVL and 96 mm TAIL (regenerated). Body moderately depressed; head not depressed, 1.7 times as long as broad ( HL 18.9 / HW 11.1 mm), its length equivalent to 25.7 % of snout – vent length, expanded in the temporal region and very distinct from the neck. Adpressed hind limb reaches the anterior ear opening. The foot length is almost equal to the head length (FL 18.3 / HL 18.9 mm).

Upper head shields very feebly striated and keeled; nostril pierced between three nasals, the supranasals in broad contact behind the rostral; frontonasal slightly broader than long (2.6 × 2.4 mm); prefrontals much longer than broad (4.3 × 1.7 mm), in broad contact medially, not reaching the anterior supraoculars (separated by a small keeled scale), and separated from the anterior loreal by a small keeled scale; frontal twice as long as its maximum width between the posterior tips of the prefrontals (6.2 × 3.0 mm), rounded anteriorly and strongly narrowed posteriorly; frontoparietals longer than broad; parietals longer than broad (5.4 × 2.8 mm), extending posteriorly, widely separated by a large interparietal and occipital, the latter small and its posterior margin level with the posterior borders of the parietals; an elongate keeled upper temporal shield borders the parietal; two supraoculars, the anterior supraocular longer than its distance from posterior loreal ( 2.3 mm vs. 1.8 mm), and in contact with posterior half of frontal; the second is smaller, separated from the supraciliaries by nine (right) / eight (left) small keeled scales (except the 4 th supraciliary on the left side, which is in narrow contact with the second supraocular); two post-supraocular scales; five supraciliaries, the first two much longer than the others and forming a long oblique suture. Lower nasal in contact with the rostral, first supralabial and anterior loreal; postnasal small, in contact with the other two nasals, frontonasal, and anterior loreal; two loreals, the posterior one much larger; four supralabials anterior to the subocular, whose lower border on the lip is much shorter (2.5 ×) than the upper; three supralabials posterior to the subocular; temporal scales strongly keeled; a narrow tympanic shield on the upper anterior edge of the vertically elongate ear opening; lower eyelid scaly with a median series of vertically elongate scales. Six infralabials; four (right) and five (left) large chin shields, the first two (right) and three (left) in median contact; gular scales imbricate; no collar.

Dorsal scales rhomboid, strongly keeled and imbricate, lateral scales smaller and feebly keeled, passing gradually into the smooth, rounded ventral plates, which are broader than long; 44 scales around the middle of the body; ventral plates in 10 longitudinal and 29 transverse rows between fore- and hind limbs; preanal scales irregular; scales on upper surfaces of limbs rhomboid, strongly keeled, and imbricate; 12 femoral pores on each side; subdigital lamellae pluricarinate and spinulose, 21 under the 4 th toe; caudal scales strongly keeled above and below, except those just posterior to the vent, which are smooth.

Colouration.

(In life, breeding colouration; similar to Fig. 17 A ): Above uniform reddish-brown, with small black spots on the lower body and anterior third of tail; dorsolateral bands as in preserved colouration, but more vivid; gular, chin shields and posterior section of white dorsolateral band bright yellow to anterior of the forelimb insertion, fading to just behind the arm; front limbs brick red dorsally, hind limbs dark grey anteriorly and brick red posteriorly; venter (except gular) white. Colouration (in preservative; Fig. 18 ): Above pale grey-brown, with a few scattered dark brown to black spots (not covering more than one scale) on lower body and upper tail; a well-defined broad (covering 3–4 scales at midbody) black dorsolateral band extends from the tip of the snout to the groin; below this black dorsolateral band is a second narrow white band (covering 1–2 scales at midbody) which also extends from the tip of the snout to the groin; below this white band is another narrow black band extending from the mental, along the edge of the jaw (edge of supra- and infralabials), to just behind the forelimb insertion, where it fades to fine specks towards the groin. Limbs dorsally brown and ventrally white; venter white.

Paratype variation.

The paratypes are in general agreement with the holotype in most regards, differing only in: Two large supraoculars, which are separated from the supraciliaries by a single row of smaller scales (7–10) and preceded by a cluster of smaller scales (3–5) (except in PEM R 23482 , the 1 st supraciliary is in narrow contact with the anterior supraocular on the right side); 1–3 post-supraocular scales; large occipital scale that separates the two interparietals and extends well past their posterior edge; two loreal scales present, which are separated from the anterior supraocular by 1–2 scales; 4–5 (mostly 5) supralabials in front of the subocular; 6–7 (mostly 6) infralabials; five chin shields, with the anterior three in broad contact; five supraciliaries; 43–48 (average: 45.0) midbody scale rows; 26–30 (average: 27.8) transverse ventral scale rows; 20–23 subdigital lamellae under the 4 th toe; 11–14 femoral pores per thigh. Size: Adult specimens varied from 71.9–78.8 mm (mean: 75.3 mm) SVL and 121–140.0 mm (mean: 133.0 mm) TAIL. Largest female: 78.8 mm SVL + 136 mm TAIL ( PEM R 23361 ); largest male: 73.5 mm SVL + 96.0 mm truncated tail ( Holotype). Colouration (Fig. 17 B ): Females with numerous scattered black scales on back and tail, scattered white scales along the upper edge of the dorsolateral dark brown band, continuing onto the tail. Lower dorsolateral black band broken from behind the head to the tail.

Additional juvenile material variation.

Prefrontal separated from the anterior supraocular by 1–2 smaller scales (in contact in PEM R 23300 and R 23299 – both sides; PEM R 23309 – left side only) and separated from supraciliaries by a smaller scale (except PEM R 23305 and PEM R 23299 ); two large supraoculars, which are separated from the supraciliaries by one row (two in PEM R 23280 and R 23303) of small scales (7–10) and preceded by a cluster of smaller scales (2–7) (except in PEM R 23300 , where the 1 st supraciliary is in narrow contact with the anterior supraocular on the right side; in narrow contact on the left side in PEM R 23306 ; in PEM R 23307 , the 2 nd and 3 rd supraciliaries are in contact with the posterior supraocular on the right and anterior supraocular on the left); 1–2 post-supraocular scales; two loreal scales present, which are separated from the anterior supraocular by 1–2 scales; subocular in contact with the lip; 4–6 (mostly five) supralabials in front of the subocular; 6–7 (mostly six) infralabials; five chin shields, with the anterior three in broad contact; 5–6 (mostly five) supraciliaries; 43–47 (average: 45.0) midbody scale rows; 9–10 longitudinal rows of enlarged ventral plates; 30–33 (average: 32.4) transverse ventral scale rows; 20–25 subdigital lamellae under the 4 th toe; 11–13 femoral pores per thigh. Size: Juvenile specimens varied from 35.6–51.1 mm (mean: 44.6 mm) SVL and 68.0– 100.9 mm (mean: 88.2 mm) TAIL. Colouration (Fig. 17 C, D ): In juveniles, the dorsum is grey anteriorly and orange posteriorly, with scattered black and white specks, and a narrow mustard coloured dorsolateral band. The dorsum of the tail is orange with scattered black and white scales. The venter is white.

Distribution.

Only recorded from the headwaters of the Okavango (Cuito and Cuanavale Rivers) and Cuando Rivers in central Angola (Fig. 14 ).

Habitat and Natural History.

Ontogenetic colour differences have been observed between juveniles and adults. Breeding colouration males and gravid females were collected in November 2016, while non-breeding females and juveniles were found in February – March 2016. Juveniles were only observed on sandier areas around the source of the Cuanavale River, while two adult females were found on the elevated grassland ridges surrounding the river. Found in sympatry with I. capensis sensu lato.

Figures

Figure 14. Records of the Ichnotropis grandiceps group, based on all literature records (open circles), examined material (closed circles) and genetically analysed material (white centres). Respective type localities are indicated by arrows: Ig – I. grandiceps, and Ir – I. robusta sp. nov.

Figure 17. Photographs in life of Ichnotropis robusta sp. nov. Photographs of A adult male (PEM R 23482) from Cuando River source, Angola; B adult female (PEM R 23362) from the road between Cuanavale River source camp and Samanunga village, Angola; C juvenile (PEM R 23304) from 4 km upstream of Cuanavale River source lake, Angola; and D juvenile (PEM R 23300) from the road between Cuanavale River source camp and Samanunga village, Angola. Photographs: A, B, C – Werner Conradie; D – Luke Verburgt.

Figure 18. Holotype (PEM R 23420) of Ichnotropis robusta sp. nov. from Cuando River source, Moxico Province, Angola. Photographs of body in A ventral and B dorsal views, and head in C dorsal, D lateral and E ventral views. Scale bars represent 10 mm. Photographs: Werner Conradie.