(Figs 19–20, Table 3; Supporting Information, Fig. S7; Table S8)

Zoobank registration: https://zoobank.org/ F64BBDF9-A337- 4130-A65D-B3E2481112D4

Lygodactylus picturatus gutturalis: Schmidt (1919) [part]; Pasteur (1964) [part]; Wermuth (1965) [part].

Lygodactylus gutturalis: Röll (2005) [part]; Spawls et al. (2018) [part]; Behangana et al. (2020)

Lygodactylus karamoja sp. nov. is known from the northern Albertine Rift in the Lendu Plateau of DRC and several highlands of Uganda, and it is the sister taxon to L. kibera sp. nov. in clade (B1), from which it differs by c. 6.07% for the 16S mitochondrial gene (Table 2) and a lack of nuclear haplotype sharing in RAG1 (Fig. 2B–C). The new species differs from L. gutturalis and L. depressus by c. 12.49% and 10.45%, respectively, for the 16S (uncorrected p-distance) mitochondrial gene (Table 2) and a lack of nuclear haplotype sharing in RAG1 (Fig. 2B–C).

Holotype: UTEP 22590 (DFH 593), male with original tail, collected on a large tree at the edge of a village at Agoro Town, Imatong Foothills, Northern Region, Uganda, N03.83156, E33.01974, 1193 m a.s.l. on 5 July 2015 by Daniel F. Hughes, Wilber Lukwago, and Mathias Behangana.

Paratypes (six specimens): UTEP 22588–89 (DFH 591–92) and UTEP 22591 (DFH 594), males, with same collection data as the holotype; UTEP 22592 (DFH 641), female, collected at Agoro Town, Imatong Foothills, Northern Region, Uganda, N03.80548, E32.98836, 1153 m a.s.l. on 5 July 2015 by Daniel F. Hughes, Wilber Lukwago, and Mathias Behangana; UTEP 22593 (DFH 130), juvenile, and UTEP 22594 (DFH 131), female, collected at Nakapiripirit, Mount Kadam, Northern Region, Uganda, N01.82270, E34.74603, 1730 m a.s.l. on 31 May 2015 by Daniel F. Hughes and Mathias Behangana.

Diagnosis: Lygodactylus karamoja sp. nov. is the sister taxon of L. kibera sp. nov. that is also a large-sized Lygodactylus [maximum SVL 37.7 mm (mean 34.4 ± 2.9 mm)] and shares the gular patterning of the L. gutturalis subgroup. Seven to eight supralabials and 5–7 infralabials. Dorsal pholidosis with granular scales that become flattened, larger, and imbricate on original tails. Large triangular mental followed by usually two (or occasionally three) symmetric postmental scales (Supporting Information, Fig. S7). Ventral pholidosis with large, flattened, and imbricate scales. Ventral scales usually denticulated posteriorly. Six terminal scansors on the tail tip. Digits elongated with five terminal scansors on the fourth toe (Table 3).

Like other Lygodactylus within the gutturalis group, this species can be easily differentiated from members of the L. angularis group by its characteristic ∩ - shaped gular chevrons (vs. V-shaped gular chevrons in L. angularis group), and from other members of the L. picturatus group based on dorsal coloration (light brown with five or six laterodorsal cream ocelli vs. usually blueish dorsum with yellow to white head in L. picturatus group).

Lygodactylus karamoja sp. nov. can be differentiated from other species within the gutturalis subgroup by only minor morphometric and meristic data, reflecting its cryptic nature. However, we provide some characters that are putatively diagnostic. Lygodactylus karamoja sp. nov. differs from L. dysmicus by its larger size (maximum SVL 37.7 mm vs. 27.6 mm); fewer precloacal pores (8 vs. 9); nostril not in contact with rostral scale (vs. nostril contacting rostral); and lower number of ventral scales across the body (16–18 vs. 21 in L. dysmicus). It can be easily distinguished from L. kibera sp. nov. by the gular pattern that comprises two or three thinner ∩ -shaped chevrons that never extend beyond the posterior part of the lower jaw vs. three thick ∩ -shaped chevrons reaching the chest; there are usually two symmetrical postmental scales vs. usually three smaller postmental scales; and a proportionally smaller orbital diameter (OD /HL 0.19–0.23 vs. 0.22–0.26 in L. kibera sp. nov. ). Also, L. karamoja sp. nov. can be differentiated in the same way as L. gutturalis from L. depressus, based on gular patterning (always two or three ∩ -shaped chevrons vs. one ∩ -shaped followed by one posterior central mark).

Etymology: The name ‘ karamoja ’ is a noun in apposition and refers to the Karamoja region in north-eastern Uganda where many individuals of this species have been found. The species is named in honour of this arid region, which is occupied by the Karamojong people who are mostly nomadic pastoralists related to the Maasai in Kenya.

Description of the holotype (Fig. 19): Measurements and meristic characters of the holotype are presented in Supporting Information, Table S8. Adult male, with a snout–vent length (SVL) of 34.3 mm and an original tail length slightly larger (TL = 36.1 mm). Body slender, nape moderately distinct. Head as broad as body and moderate head length (HW /HL 0.72). Canthus rostralis not prominent. Eye diameter 1.9 mm with circular pupil. Ear to eye distance twice the orbital diameter (3.2 mm). Snout rounded and slightly pointed. Granular scales on frontal area larger than occipital scales, with 22 small granular scales between the eyes. Dorsal scales granular from rostral to tail. Rostral undivided, in contact with 1st supralabial, prenasals, and one large internasal scale. Eight supralabials and 5–6 infralabials. Prenasal scale present and in contact with 1st supralabial. Nostril circular, bordered by 1st supralabial, prenasal, and one supranasal. Postnasal not contacting nostril, separated by 1st supralabial, which it contacts posteriorly. Four rows of scales between supralabials and orbit. Mental large, triangular, and rounded, bordered posteriorly by two large rounded symmetric postmental scales. Six asymmetrical post-postmental scales. Gular scales granular, rounded, and slightly smaller than ventral scales. Ventral scales imbricate, rounded, and larger than dorsal scales, with 16 scales rows across the venter. Body relatively robust and slightly elongated (TRL / SVL 0.42). Tail with 34 enlarged transverse scales and six pairs of terminal scansors at the tip. Eight precloacal pores. Fore- and hind limbs moderately short, stout; forearm medium-sized (FL / SVL 0.16); tibia short (CL/ SVL 0.17). Digits elongated and unwebbed with 5–6 terminal scansors. Thumb rudimentary with a small terminal claw. Relative length of digits: I <II = V <III <IV (manus); I <II <V <III <IV (pes).

Coloration: In life (Fig. 20), dorsal coloration from light to dark brown to greyish or almost black (Fig. 20D), with lighter cream-beige lines with five or six lighter cream dots surrounded by black flanks. Some specimens have lighter cream-beige dots along the vertebral line, giving them a granitic appearance (Fig. 20A). Black line from nostril to the anterior insertion of the forelimb. Gular region white and two or three black, ∩ -shaped chevrons. Venter uniformly orange or white. Tip of tail and digits dark brown. In preservative (holotype; Fig. 19): dorsum dark brown and venter with uniform light cream coloration.

Variation: The meristic and morphometric data are summarized in Supporting Information, Table S8. Coloration of this species seems to be consistent, with gular coloration slightly lighter in females. Number and shape of postmentals and internasals vary between specimens (Supporting Information, Fig. S7).

Habitat and distribution (Figs 6, 20 ): Lygodactylus karamoja sp. nov. has been recorded from mid-elevation savannahs of the northern Albertine Rift to the Karamoja Region, eastern Uganda, an arid area characterized by mostly woodland savannah habitat with several isolated mountain ranges. This suggests that specimens from western Kenya and southern South Sudan also belong to this species. If confirmed, this species would have a distribution that is similar to the lacertid Adolfus jacksoni (Greenbaum et al. 2018). However, we recommend caution until molecular data become available.

Natural history: A diurnal and arboreal species that is always found on trees. UTEP 22592, a gravid female, was found in July on a tree at night. UTEP 22593–94 were found during the day on trees trunks c. 1 m above ground in an open clearing of grass and rocky outcrops that were surrounded by dry forest (Fig. 20F).