Acanthocercus cf. cyanocephalus (Falk, 1925)

Conradie, Werner, Keates, Chad, Verburgt, Luke, Baptista, Ninda L., Harvey, James, Júlio, Timóteo & Neef, Götz, 2022, Contributions to the herpetofauna of the Angolan Okavango-Cuando-Zambezi River drainages. Part 2: Lizards (Sauria), chelonians, and crocodiles, Amphibian & Reptile Conservation (e 322) 16 (2), pp. 181-214 : 183

Acanthocercus cf. cyanocephalus (Falk, 1925)

Angolan or Western Tree Agama ( Figs. 1–2 , Map 1 ) Material (9 specimens): PEM R 23267, Cuanavale River source, -13.09330° 18.89396°, 1,367 m asl; PEM R 23318, Cuito River source, -12.68935° 18.36012°, 1,435 m asl; PEM R 23480, Cuando River source, -13.00164° 19.12960°, 1,372 m asl; PEM R 23503, Sombanana village, -12.31082° 18.62392°, 1,403 m asl; PEM R 23517, near Cuito River source, -12.68563° 18.36686°, 1,460 m asl; PEM R 23529, INBAC: WC-4588, drive back from Quembo River source, -13.10543° 19.01698°, 1,555 m asl; PEM R 23560, old hunters camp near Quembo River source, -13.13167° 19.09639°, 1,290 m asl; PEM R 27387, Luvu River camp, -13.71200° 21.83538°, 1,082 m asl. Description: The absence of an enlarged occipital scale and its arboreal habits allow the distinction between sympatric congeners and Agama spp. Large agamid with blue head, chest, and shoulders, mostly in males; 122–148 (133) dorsal scale rows at midbody; 68–74 (71) transverse ventral scales; 78–95 (87) transvers dorsal scales; 11–13 supralabials; 11–15 infralabials; 22–26 (24) subdigital lamellae under 4 th toe; 17–35 precloacal pores in 2–3 rows. Largest female: 174.0 + 192.0 mm ( PEM R 23560); largest male: 137.0 + 162.0 mm ( PEM R 27387). The new material presented here represents the largest recorded sizes of both male and female for the species ( Pietersen et al. 2021; Wagner et al. 2021). Habitat and natural history notes: Juveniles were collected in February from the bases of large trees in miombo woodland, while gravid females were collected in October. Adult specimens were found very close to holes in trees, into which they retreated when approached. Comments: Wagner et al. (2018) initially assigned all Angolan Acanthocercus material to A. cyanocephalus , and although they provided a detailed account of Falk’s work in Angola, they assigned a specimen from northern Zambia as the neotype, and only examined three Angolan specimens from a single locality. Numerous records of Acanthocercus are known across the entire extent of Angola, and recent studies ( Marques et al. 2018; Butler et al. 2019) allude to the fact that cryptic species are present in Angola. Follow-up studies ( Wagner et al. 2021; Marques et al. 2022b) focused primarily on Namibian and Angolan material and further subdivided this group into three species: A. margaritae , ranging from northern Namibia northwards into central and western Angola, A. ceriacoi from northwestern Angola, and A. cyanocephalus from eastern Angola. While these studies made use of integrative taxonomy, they only used a single gene (a fragment of the 16S rDNA) and a small morphological dataset to support their results. The genetic differences among the Acanthocercus atricollis group, which includes A. atricollis , A. branchi , A. ceriacoi , A. cyanocephalus , A. margaritae , A. gregorii , and A. ugandaensis , are very small (<5%) and additional phylogenetic work is needed to support the current taxonomy. Based on geographic proximity, we tentatively assign our material collected from the eastern side of our study area to A. cyanocephalus , pending the results of further phylogenetic work.

Figures

Map 1. Distribution of Acanthocercus cf. cyanocephalus in Angola. Historical records are indicated by white dots while all new records are indicated by black dots. Axis values are in degrees (°). Purple polygon – Okavango River basin, blue polygon – Cuando River basin, brown polygon – Zambezi River basin.

Fig. 1. Adult female Acanthocercus cf. cyanocephalus (PEM R23560) from Quembo River source. Photo by Werner Conradie.

Fig. 2. Adult male Acanthocercus cf. cyanocephalus (PEM R27387) from Luvu River camp. Photo by Chad Keates.