Ichnotropis chapini Schmidt, 1919

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 chapini Schmidt, 1919

Figure 8 ; Table 3

Taxonomic note.

When I. chapini was described, it was differentiated from its congeners based on the presence of an anterior supraloreal, thus having two anterior loreal scales ( Schmidt 1919). However, additional material collected from Adra in northeastern DRC does not possess any anterior supraloreal ( de Witte 1933; Laurent 1952). Despite the limited material available, the scalation observed in the type specimen appears to be anomalous. This is further supported by the fact that we have only recorded this condition (an anterior supraloreal) once for all of the other Ichnotropis specimens examined (n = 432). As in the previous species, I. chapini was assigned to the I. capensis group based on the observation that the prefrontal is separated from the anterior supraocular ( Boulenger 1921). Examination of high-resolution photographs of the holotype (Fig. 8 ) and physical examination of additional material from RMCA showed that this species belongs to the I. bivittata group, based on the more rounded head (Fig. 2 ). This species also seems geographically well isolated from other species in the genus, but this might just be an effect of under-sampling. The seasonality of Ichnotropis species makes them hard to observe outside or the breeding season. Consequently, coupled with the absence of any modern material and thus molecular data, we retain this species as valid until more data become available.

Holotype.

AMNH 10674 , adult female, collected from Aba , Haut-Uele Province, DRC in July 1911 .

General description.

A medium-sized lacertid with a robust, rounded snout. Head scalation moderately striated. Nostril pierced between three nasals; the supranasals are in broad contact behind the rostral; single frontonasal, as broad as long; paired prefrontal scales in broad contact medially; prefrontal not in contact with anterior supraocular and separated from the supraciliaries by a smaller scale; two large supraoculars, which are separated from the supraciliaries by one row of small scales (6–8) and preceded by a cluster of 2–3 (3 median) smaller scales; one post-supraocular scale; two loreal scales present, which are separated from the anterior supraocular by two scales (except in the holotype, where the anterior loreal is divided to form a supraloreal on both sides and on the left side of BE_ RMCA _Vert.R.3657 ); subocular in contact with lip; 4–5 (mostly 4) supralabials in front of subocular; 6–7 (mostly 6) infralabials; five chin shields, with the anterior 2–3 in broad contact (in the holotype only the first two chin shields are in contact, while in BE_ RMCA _Vert.R.3657 the third chin shield is in narrow contact anteriorly); 3–5 (mostly 4) supraciliaries; 34–35 midbody scale rows; 8–10 longitudinal rows of enlarged ventral plates; 24–25 transverse ventral scale rows; 18–20 subdigital lamellae under 4 th toe; 8–9 femoral pores per thigh. Size: Adult specimens varied from 53.8–58.0 mm (median: 55.0 mm) SVL and 77 mm TAIL (all specimens’ tails missing or truncated; this measurement is based on Schmidt 1919). Largest female: 58 mm SVL ( AMNH 10674 – holotype); largest male: 55.0 mm SVL ( BE_ RMCA _Vert.R.3656 – Adra, DRC). Colouration (based on preserved specimens; Fig. 8 ): Dorsal surface uniformly greyish brown, with scattered darker brown to black scales. A distinct lateral white stripe originates at the subocular region, bordered both dorsally and ventrally by narrow black lines; this stripe extends over the forelimbs but does not reach the hind limbs in females ( AMNH 10674 and BE_ RMCA _Vert.R.3657 ), but reaches the hind limbs in the male ( BE_ RMCA _Vert.R.3656 ). A second faint dorsolateral line is present above the lower white stripe, and only extends to just posterior of the forearms in females, while in the male this stripe is more prominent and extends to just above the hind limbs. Between these lines are a series of transverse black spots in the females, each spanning 2–3 scales in width and approximately half a scale in length, located at the tips of the scales. In the male the space between the two white stripes forms a prominent black band with scattered black scales. This band extends onto the temporal and snout area. Dorsally, two similar series of transverse black markings flank the vertebral region, extending laterally to the dorsolateral stripe. Ventral scales and chin shields are white with subtle grey margins. The two outermost ventral rows are punctuated with small brown dots in females, but form a continuous narrow black band between the limbs in the male and extends onto the supralabials. Supralabials and infralabials are irregularly mottled with light and dark pigmentation. Limbs greyish brown dorsally, transitioning to a lighter tone on the ventral surfaces.

Distribution.

Only known from northeastern DRC in the vicinity of Aba (Fig. 3 ). Given this locality’s proximity to the border with South Sudan (< 10 km), it is likely to occur in the latter country.

Habitat and Natural History.

Very little is known about this species, but it is expected to have similar habitat requirements to other Ichnotropis species.

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 8. Holotype (AMNH 10674) of Ichnotropis chapini from Aba, Haut-Uele Province, 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: Lauren Vonnahme.