Causus cf. rasmusseni Broadley, 2014

Conradie, Werner, Bills, Roger & Branch, William R., 2016, The herpetofauna of the Cubango, Cuito, and lower Cuando river catchments of south-eastern Angola, Amphibian & Reptile Conservation (e 126) 10 (2), pp. 6-36 : 23

Causus cf. rasmusseni Broadley, 2014

Rasmussen’s Night Adder

Material: PEM R 21488 (57).

Comment: An adult female from riverine habitat on the Rio Longa, and with a diffuse color pattern ( Fig. 9e, f ) and only 132 ventrals. It conforms in coloration and low ventral count with the newly-described C. rasmusseni ( Broadley 2014) but has a lower subcaudal count (31) than that of the only female (39) in the type series from north-west Zambia. As noted by Rasmussen (2005), the status of night adders in Angola has been confused with many “ rhombeatus ” of earlier authors now assigned to other species, e.g., C. maculatus and C. bilineatus (Piri Dembos; Hellmich 1957a) and C. resimus (Libolo-Luali, Hellmich 1957b) . Ventral counts are typically higher (143‒145) for blotched females of C. rhombeatus from the eastern half of Angola ( Laurent 1964). A molecular phylogeny of Causus (Tolley et al. in prep.) shows that the Rio Longa specimen is only weakly differentiated from South African C. rhombeatus . However, topotypic material is not available for C. rasmusseni and its taxonomic status thus remains equivocal. If the specific validity of Rasmussen’s night adder is confirmed the Rio Longa specimens would be the first Angolan record for the species, and a southern range extension of approximately 740 km from the Zambian series ( Broadley 2014). If, however, it is only a plain color morph of C. rhombeatus it would be the first record for south-east Angola.

Figures

Fig. 9. Selective amphibians and reptiles from south-easternAngola.A. Ptychadena taeniocelis; B. Xenopus petersii; C. Ptychadena cf. grandisonae; D. Ichnotropis spp; E. Causus cf.rasmusseni; F.Causus cf.rasmusseni; G. Boaedon cf.angolensis; H. Trachylepis cf. spilogaster.