Ichnotropis tanganicana Boulenger, 1917

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 tanganicana Boulenger, 1917

Figures 11 , 12 , 13 ; Table 3

Taxonomic note.

This species was described from the ‘ East Coast [of] Lake Tanganyika’ in modern-day Tanzania based on a single subadult specimen that was collected in 1896. When Boulenger (1917) described I. tanganicana , he ascribed the holotype to a subadult male. However, after our examination of high-resolution photographs of the type specimen it was not possible to sex it, so we regarded it as an unsexed subadult specimen. Since its description, no additional material has been documented. However, due to the vague description provided by Boulenger (1917), the taxonomic status of this species has been questioned by some authors ( Mayer 2013). On the other hand, based on some diagnosable head scalation features (i. e., supraoculars in contact with supraciliaries), this species was preliminary retained as valid in subsequent years ( Spawls et al. 2002, 2018; van den Berg 2017; Uetz et al. 2025).

In this study, an adult female specimen collected from the mid-elevation Miombo woodlands west of the Kabobo Plateau, DRC ( MTSN 9947 ; Fig. 11 E ) agreed with the description of I. tanganicana based on the supraocular arrangement, (i. e., anterior supraocular in direct contact with the supraciliaries), and the colouration (bronzy olive dorsum with three fine black stripes on nape). However, Boulenger (1917), in his description of the type specimen after 20 years of preservation, did not document the unique, evenly-spaced blue dorsolateral spots observed in the new DRC specimen (Fig. 11 E ). Based on this new information about the dorsal colouration, we revisited the literature, examined known museum specimens (previously ascribed to I. bivittata in eastern DRC and adjacent Zambia and Tanzania) and consulted online citizen science platforms.

Of special interest is the case of the first specimens of I. bivittata from Ipemi, Udzungwa Mountains, Tanzania, documented by Loveridge (1933). He states that, in comparison to the type, he regards his specimens as conspecific with I. bivittata and distinct from I. tanganicana , of which he also examined the type. However, he provides no further details. In his description of the specimens’ colour, he offered a detailed account of the colouration as follows: ‘ … series of blotches which is rather more black than chestnut-brown having the appearance of ocelli by reason of a blueish-white central spot in each … ’. Examination of high resolution images of the two Ipemi specimens in the Museum of Comparative Zoology ( MCZ R 30836 –7) confirmed the presence of the unique blue lateral spots (although faded to white in preservative) and the dorsal colouration, but the supraoculars were not in contact with the supraciliaries, as reported in the type specimen ( BMNH 1946.9.3.49 ) of I. tanganicana . This difference might have been the reason why Loveridge (1933) considered his material to be conspecific with I. bivittata rather than I. tanganicana .

Additionally, de Witte and Laurent (1952) again mentioned these unique dorsolateral blue spots in the colour description of I. overlaeti : “ … from this place it is sometimes replaced by a series of small blue spots more or less bordered with black, extending to the base of the hind limbs; blue spots are also present on the upper band, between the front and hind limbs. ” (translation from French to English). When we examined the type specimens of I. overlaeti at the RMCA (Fig. 13 ), we not only confirmed the remnants of blue lateral spots and the nape colouration, but we also confirmed the presence of contact between the supraoculars and the supraciliary scales, in agreement with I. tanganicana . Nevertheless, this feature was only present in the holotype ( BE_ RMCA _Vert.R.9691 ) and one of the original paratypes ( BE_ RMCA _Vert.R.1869 , later used as a paratype for I. nigrescens ). However, the other paratype material conformed morphologically to either I. bivittata (see above) or I. capensis sensu lato (see below).

Other published sources showing photographs of I. bivittata (sic) with blue spots include de Witte (1933: plate 2, fig. 1) from southeastern DRC, Spawls et al. (2018: 202, bottom right) from southwestern Tanzania, and Phadima et al. (2024: 22; also on iNaturalist 146895735) from northwestern Malawi. Additional records were also found on iNaturalist (191773297, 146684850, 147210660, 87417155) and ReptileMap (169500) from DRC, Malawi and Zambia

Based on the combined evidence, all the above material can thus be confidently assigned to I. tanganicana . We therefore take this opportunity to expand on the original description of I. tanganicana and synonymise I. overlaeti with I. tanganicana .

Synonymy.

Ichnotropis overlaeti de Witte & Laurent, 1942: 173 (new synonymy).

Holotype.

BMNH 1946.9.3.49 (96.5.14.14), collected from ‘East Coast [of] Lake Tanganyika’ , Tanzania, presented to the museum by Mr. WH. Nutt in 1896 .

General description.

A medium-sized lacertid with a robust, rounded snout. Head scalation weakly to 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 mostly in contact with the anterior supraocular (n = 29 in contact, seven not in contact; three in contact on one side only) and separated from supraciliaries by a smaller scale; two large supraoculars, which are either in direct contact (n = 15) or separated (n = 18) from the supraciliaries by a series of small scales; those that are not in contact are separated by one row of small scales (3–9) and preceded by a cluster of 1–6 (1.7 average) smaller scales; one post-supraocular scale; two loreal scales present, which are separated from the anterior supraocular by two scales; subocular in contact with lip; 3–5 (mostly 4) supralabials in front of subocular; 5–7 (mostly six) infralabials; five chin shields, with the anterior three in broad contact; 4–5 (mostly four) supraciliaries; 28–42 (average: 36.0) midbody scale rows; 8–10 (average: 8.4) longitudinal rows of enlarged ventral plates; 20–27 (average: 22.8) transverse ventral scale rows; 17–22 subdigital lamellae under the 4 th toe; 10–15 femoral pores per thigh. Size: Adult specimens varied from 41.0–60.0 mm (mean: 53.9 mm) SVL and 55.6–107.9 mm (mean: 81.7 mm) TAIL. Largest female: 60 mm SVL ( NMZB-UM 24433 – Misuku Hills, Malawi); largest male: 56 mm SVL ( NMZB-UM 24432 – Misuku Hills, Malawi). Colouration (Fig. 11 ): The top of the head and the anterior part of the body are coppery red, sometimes with three clearly defined black stripes on the nape. The anterior part of the dorsum is grey with scattered brown paired blotches with black edging, extending onto the tail. The flanks are dark brown to black, typically with interrupted white dorsolateral stripes. The upper stripe originates behind the eye and extends onto the neck and then breaks up into smaller white blotches. The lower stripe begins anteriorly at the supralabials, tracing posteriorly through the ear and over the arm, breaking into smaller white blotches on the anterior third of the body. Between these two stripes lies a broad dark brown to black band. Diagnostic, evenly-spaced green to blue spots start above the arm and extend posteriorly to the groin in both sexes. Beneath the lower interrupted white stripe / blotches lies another narrow band of brown to black scales, sometimes accompanied by orange spots or blotches extending onto the venter. During the breeding season, males exhibit more prominent orange flanks, while the lower white stripe and lateral head become vivid yellow anteriorly. The specimen from the DRC ( MTSN 9947 ) exhibits a bright orange lower jaw. The venter is typically plain white but can have light grey colouration.

Distribution.

Known from western Tanzania, south to northern Malawi, and eastward to northern Zambia and southern DRC (Fig. 3 ).

Habitat and Natural History.

The Lukwati specimen was discovered in grassland adjacent to Brachystegia woodland. This specimen exhibited peculiar leg-tucking behaviour, wherein it raised its body and folded its legs to the sides ( Spawls et al. 2018; Lloyd-Jones pers. comm.). A gravid female was observed laying eggs in January (iNaturalist 146684850). Shelled eggs in the oviducts of one specimen measured 13.5 mm × 6.5 mm ( Robertson et al. 1963). Stomach contents were documented to contain Acrididae , Mantidae, Isoptera , and Araneae ( Robertson et al. 1963) .

Figures

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 11. Photographs in life of Ichnotropis tanganicana from across its range, depicting the evenly spaced dorsolateral blue spots. Photographs from A Rukwa, Tanzania; B Cambua, Democratic Republic of the Congo; C Rumphi, Malawi (https://www.inaturalist.org/observations/146895735); D Nyika National Park, Malawi (https://www.inaturalist.org/observations/146684850); E Kindingi, Lake Tanganyika (MTSN 9947), Democratic Republic of the Congo; and F Upemba National Park, Democratic Republic of the Congo (https://www.inaturalist.org/observations/249778421). Photographs: David Lloyd-Jones; B – Colin Tilbury, C – Marc Henrion, D – Tim Brammer, E – Wandege Muninga, D – Naftali Honig.

Figure 12. Holotype (BMNH 1946.9. 3.49) of Ichnotropis tanganicana from ‘ East coast of Lake Tanganyika’, Tanzania. Photographs of body in A ventral and B dorsal views, and head in C dorsal, D lateral and E ventral views. Photographs: Patrick Campbell.

Figure 13. Holotype (BE _ RMCA _ Vert. R. 9691) of Ichnotropis overlaeti from Kapanga, Haut-Katanga Province, Democratic Republic of the Congo. Photographs of body in A ventral and B dorsal (note the evenly spaced white dorsolateral spots indicated by the arrows) views, and head in C dorsal, D lateral and E ventral views. Scale bars represent 10 mm. Photographs: Max Benito.