Ichnotropis bivittata Bocage, 1866

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 bivittata Bocage, 1866

Figures 4 , 5 , 6 , 7 ; Table 3

Taxonomic note.

Bocage (1866) described Ichnotropis bivittatus ( = bivittata ) based on a series of specimens collected from Duque de Bragança [= Calandula], Malanje Province, Angola, despite Günther (based on material that Bocage had sent to him) considering them to be the same as I. capensis . Boulenger (1887) followed Günther and did not consider I. bivittata to be a valid species. This prompted Bocage (1895) to relegate I. bivittata into the synonymy of I. capensis . It was not until Boulenger (1921) reviewed the family Lacertidae that I. bivittata was reinstated as a valid species. This taxonomic revision was followed by most subsequent authors, except for a brief period when I. bivittata was regarded as a subspecies of I. capensis ( Laurent 1952; Hellmich 1957; Manaças 1963; Robertson et al. 1963). The above confusion led to much of the historical Angolan material being incorrectly assigned to I. capensis ( Marques et al. 2018) .

When Laurent (1964) described the subspecies I. b. pallida he distinguished it from the nominotypical form based on its duller dorsal colouration and differences in head scalation — specifically, its less pronounced keeled head striations, distinct interparietal shape, and small frontoparietals that were separated by the interparietal (see Ceríaco et al. 2020 a: fig. 30). However, colouration in Ichnotropis , as in many lacertids, is highly variable and influenced by factors such as substrate, age and sex, rendering it an unreliable taxonomic character — except when comparing adult breeding male material, where it can provide useful diagnostic insights. Furthermore, the head scalation observed in the holotype appears to be aberrant, as the scalation differs from a topotypic specimen from Humpata ( PEM R 17934 ; Fig. 7 ). Specifically, the configuration where the frontoparietals are separated by the interparietal, which in turn is in contact with the frontal, has not been observed in any other Ichnotropis specimens examined in this study, including the topotypic Humpata specimen. Although phylogenetic analyses reveal notable divergence between the Humpata specimen and other I. bivittata samples, further research is necessary before making definitive taxonomic decisions regarding the validity of I. b. pallida. Therefore, we currently treat I. b. pallida as a junior synonym of I. bivittata .

In the same paper, Laurent (1952) described Ichnotropis capensis nigrescens based on two specimens exhibiting darker ventral surfaces. Notably, the paratype ( BE_ RMCA _Vert.R.1869 ), originating from Luluabourg [= Kananga, Kasaï-Central Province, DRC], had previously been designated as a paratype in the description of Ichnotropis overlaeti by de Witte and Laurent (1942). The initial classification of nigrescens as a subspecies of I. capensis was guided by Boulenger’s (1921) key, which emphasised the separation of the prefrontal from the anterior supraocular. Subsequently, Loveridge (1933) synonymised this subspecies with I. capensis . Upon examining the type specimens, along with two additional specimens housed at RMCA ( BE_ RMCA _Vert.R.15925 and BE_ RMCA _Vert.R.16240 ) from Ndwa Village near Bolobo — proximate to the holotype’s locality — it was observed that they possess a short and rounded snout, a character consistent with members of the I. bivittata group (see Fig. 2 ). Consequently, these specimens are transferred to the I. bivittata group instead of I. capensis . Specifically, the holotype ( BE_ RMCA _Vert.R.14671 ) and the two additional specimens are assigned to I. bivittata sensu lato based on the presence of closely spaced pale spots (possibly yellow in life) above the forelimb, whereas the Kananga paratype ( BE_ RMCA _Vert.R.1869 ) is reassigned to I. tanganicana , based on shared morphological (supraocular in contact with supraciliaries) and colouration characteristics detailed in the species account below (evenly spaced white dorsolateral spots; described as being blue by de Witte and Laurent 1942). Given the substantial sequence divergence observed in our limited I. bivittata material, the name nigrescens may be applied to northern populations, particularly those from the Republic of the Congo, DRC and Gabon, should future studies support the recognition of a distinct species in this region.

Synonymy.

Ichnotropis capensis nigrescens Laurent, 1952: 201 (new synonymy); Ichnotropis bivittata pallida Laurent, 1964: 64 (new synonymy).

Syntypes.

BMNH 1946.9.3.47 –48 (1866.6. 11.3–4), ZMB 5827 [additional syntypes in Lisbon Museum were probably destroyed by a fire in 1978], collected from Duque de Bragança [= Calandula], Malanje Province, Angola by F. A. P. Bayão.

General description.

A medium-sized lacertid with a rounded snout and strongly striated head scales. Nostril pierced between three nasals; the supranasals in broad contact behind the rostral; single frontonasal as broad as long; paired prefrontal scales in broad contact medially; prefrontal mostly in contact with the anterior supraocular (separate in BE _ RMCA _ Vert. R. 40 [ I. overlaeti paratype], BE_ RMCA _Vert.R.14641 [ I. capensis nigrescens holotype] and NMZB-UM 16358 ), separated from the first supraciliary by a smaller scale (rarely in contact); two large supraoculars, which are separated from the supraciliaries by one row (or rarely two rows anteriorly) of small scales (7–9) and preceded by a cluster of 2–5 smaller scales; 1–3 smaller post-supraocular scales; paired frontoparietal scales in broad contact; two parietals separated by an interparietal; occipital scale not reaching much past parietals; two loreal scales present, the anterior one smaller than the posterior; posterior loreal is separated from the anterior supraocular by two smaller scales; subocular in contact with lip; 3–6 (mostly 4) supralabials anterior to the subocular and two posteriorly; 6–9 (mostly 6) infralabials; 5 (rarely 6) chin shields, with the anterior three (rarely four) in broad contact; 3–4 (mostly 4) supraciliaries; 29–40 midbody scale rows; 8–10 longitudinal rows of enlarged ventral plates; 22–31 transverse ventral scale rows; 17–24 subdigital lamellae under the 4 th toe; 10–14 femoral pores per thigh. Size: Adult specimens varied from 42.2–75.0 mm (mean: 63.2 mm) SVL and 85.0– 156 mm (mean: 109.7 mm) TAIL. Largest female: 71 mm SVL ( FMNH 74288 – Serra do Moco, Angola); largest male: 75 mm SVL ( NMZB-UM 16358 – Chitau, Angola). Colouration (Fig. 4 ): The dorsal side of the head, body and tail varies from brown to coppery red, sometimes with dark brown to black paired blotches. The flanks are dark brown to black, typically with two pale dorsolateral stripes. The upper stripe, usually two scales wide, originates behind the eye and extends onto the tail. The lower stripe begins anteriorly at the supralabials, tracing posteriorly through the ear, over the arm, and to the groin, though it may not be distinctly defined at midbody. Between these two stripes lies a broad band of coppery brown to black scales, interspersed with scattered black markings. Beneath the lower pale stripe there are scattered brown to black markings, sometimes accompanied by orange spots or blotches that extend onto the venter. During the breeding season, males exhibit more prominent orange flanks (extending onto the lower side of the tail), while the white stripes and lateral sides of the head become vividly yellow anteriorly. Diagnostic narrowly-spaced yellow or orange spots above the arm extend backwards for about a third of the body in both sexes. Dorsal tail with scattered white specks and black bars. The venter is typically plain white, although some individuals may have a grey venter or scattered fine grey to black specks.

Distribution.

Ichnotropis bivittata is known from Angola’s central plateau, with its range extending northward into western DRC, the Republic of the Congo, and southeastern Gabon (Fig. 3 ). Laurent (1964) reported both I. overlaeti de Witte & Laurent, 1942 and I. bivittata occurring sympatrically at Alto Cuilo, Lunda-Sul Province, Angola. During a recent field expedition to Alto Cuilo, the presence of I. bivittata was confirmed, and re-examination of historical DM (Dundo Museum) material attributed to I. overlaeti revealed it to be rather assignable to I. capensis sensu lato, based on a narrower and sharper head profile, the prefrontal in contact with the anterior supraocular and absence of any dorsolateral spots. In the present study, we also document the occurrence of I. aff. capensis — herein described as a new species — from Mona Quimbundo, approximately 62 km east of Alto Cuilo. These findings indicate that three distinct Ichnotropis species occur in the Miombo woodland of northeastern Angola. Historical records of I. bivittata from eastern Angola ( Manaças 1963) require re-evaluation, as they may be referable to the I. capensis group or possibly to I. tanganicana .

Habitat and Natural History.

Ichnotropis bivittata inhabits wet Miombo woodlands, preferring open, sandy areas suitable for thermoregulation and foraging. It is a diurnal, terrestrial species and an active forager, primarily preying on small arthropods such as ants, beetles, and termites ( Pietersen et al. 2021). Activity peaks during warmer periods and declines in cooler or wetter conditions.

Figures

Figure 2. Above: Scatterplots of the first two principal components for Ichnotropis, based on the full Dataset 1 (A) and reduced Dataset 2 (B). Arrows indicate the loadings of morphological variables (see Materials and Methods for abbreviations). The green star marks the holotype of Ichnotropis capensis nigrescens (BE _ RMCA _ Vert. R. 14641), and the brown star marks the holotype of Ichnotropis overlaeti (BE _ RMCA _ Vert. R. 9691). Below: Box plots showing C snout – vent length (SVL), D head width (HW), and E head height (HH). Species are represented by different colours, and species groups are enclosed by polygons, as indicated in the legend.

Figure 3. Records of specimens from the Ichnotropis bivittata 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: Ib – I. bivittata, Ibp – I. bivittata pallida, Ic – I. chapini, Im – I. microlepidota, Icn – I. capensis nigrescens, Io – I. overlaeti and It – I. tanganicana.

Figure 4. Photographs in life of Ichnotropis bivittata depicting the closely spaced yellow spots just posterior to the forelimbs. Specimens photographed at A Cuito town (PEM R 23530), Angola; B Cambau (FKH - 0833), Angola; C Cangandala National Park, Angola; D Luando Reserve (CHL 0675), Angola; and E Humpata (PEM R 17934 – I. b. pallida), Angola. Photographs: A – Werner Conradie; B, C, D – Pedro Vaz Pinto; E – William R. Branch.

Figure 5. Syntype (ZMB 5827) of Ichnotropis bivittata from Duque de Bragança [= Calandula], Malanje Province, Angola. Photographs of body in A dorsal and B ventral views, and head in C dorsal, D lateral and E ventral views. Scale bars represent 10 mm. Photographs: Frank Tillack.

Figure 6. Holotype (BE _ RMCA _ Vert. R. 14641) of Ichnotropis capensis nigrescens from Bolobo, Democratic Republic of the Congo. Photographs of body in A dorsal and B ventral views, and head in C dorsal, D lateral and E ventral views. Scale bars represent 10 mm. Photographs: Max Benito.

Figure 7. Topotypic (PEM R 17934) Ichnotropis bivittata pallida from Humpata, Huila Province, Angola. Photographs of body in A dorsal and B ventral views, and head in C dorsal, D lateral and E ventral views. Scale bars represent 10 mm. Photographs: Werner Conradie.