PSAMMOPHIS SUDANENSIS Werner, 1919

Northern Stripe-bellied Sand Snake, Psammophis soudanien, Sudanesische Sandrennnatter

Psammophis subtaeniatus (not Peters) Boulenger, 1896: 161 (part); Tornier, 1896: 82 (part, Arusha); Corkill, 1935: 22; Loveridge, 1936a: 38, 193; Uthmoller, 1937: 119; Pitman 1938: 155, Pl. K, fig. 2; Böhme, 1975: 39 (Makolo); Hedges 1983: 30, fig. 39; Chippaux, 1999: 166; 2006: 179.

Psammophis sibilans (not Linnaeus) Hedges 1983: 30, fig. 29.

Psammophis subtaeniatus var. sudanensis Werner, 1919: 504. Type locality: Kadugli, Sudan. Lectotype NMW 19086.

Psammophis sibilans sibilans (not Linnaeus) Bogert, 1940: 79 (part); 1942: 3 (Voi); Villiers 1951: 827 (part), Fig. 3; Broadley & Howell, 1991: 28.

Psammophis subtaeniatus sudanensis Loveridge, 1940: 50 (part); 1956: 49 (part); 1957: 280 (part); Mertens, 1955: 59; Broadley, 1966: 5 (part); Spawls, 1978: 8 (part).

Psammophis cf. rukwae (not Broadley) Böhme, 1978: 402, fig. 17 (left); Joger, 1982: 332, fig. 8.

Psammophis leucogaster Spawls, 1983: 11. Type locality: Wa, Ghana. Holotype BMNH 1980.261.

Psammophis rukwae (not Broadley) Böhme, 1986: 172 (part); Böhme & Schneider, 1987: 259.

Psammophis subtaeniatus subsp. Böhme, 1987: 85 (Darfur).

Psammophis subtaeniatus orientalis (not Broadley) Brandstätter, 1995: 194 (part).

Psammophis sudanensis Hughes 1999: 67; Spawls, et al., 2002: 407; Trape & Mané, 2002: 149, 2015: 45; Trape, 2005: 142; Villiers & Condamin, 2005: 144; Trape & Baldé, 2014: 323.

Psammophis sudanensis leucogaster Trape & Mané, 2006: 156.

Description. (114 specimens examined) Nostril pierced between 2 nasals; preocular 1, in short contact with or separated from frontal; postoculars 2 (very rarely 1 or 3); temporals basically 2+2+3, but with frequent fusions; supralabials 8 (very rarely 7 or 9), the 4 th & 5 th (rarely 3 rd & 4 th or 4 th, 5 th & 6 th) entering orbit; infralabials usually 10 (rarely 9 or 11), the first 4 (very rarely 3 or 5) in contact with anterior sublinguals; dorsal scales in 17-17-13 rows; ventrals 150–180; cloacal divided (entire in type of leucogaster); subcaudals 93–122. Dorsum dark brown, top of head with a black-bordered pale median stripe extending far back on the frontal before forking (Fig. 18), transverse pale markings on back of head; labials immaculate white or speckled with black; vertebral stripe ill-defined in the east, strongly marked in the west, broadening on the nape; pale dorsolateral stripes on scale rows 4 and 5; lower half of outer scale row and ends of ventrals whitish, often separated by a pair of well defined black ventral lines (occasionally ill-defined or absent in West and Central Africa) from a yellow mid-ventral band.

Size. Largest male (MCZ 53449 – Torit, South Sudan) 820 + 390 = 1210 mm; largest female (FMNH 58389 – Torit, South Sudan) 920 + 405 = 1325 mm.

Remarks. The type of P. leucogaster from Ghana appears to be a highly aberrant specimen of P. sudanensis. Populations from Chad are probably similar genetically to those in Kordofan, the type locality, which is close geographically and ecologically. The sequences of P. sudanensis from Tanzania and Kenya of Kelly et al. (2008) belong to a distinct clade, suggesting that they may belong to a cryptic species. However, the pattern of a Kenyan specimen illustrated by Spawls et al. (2002) is similar to those of our specimens from West Africa and Chad (Fig 19). Some rare specimens from Chad are uniformly beige dorsally (e.g. IRD 2871.N and 2884.N).

Habitat. In eastern Africa, coastal thicket, moist and dry savanna and high grassland, from sea level to 2,700 m (Spawls et al. 2002). In Chad it was the most common colubrid snake that JFT collected in almost all moist and dry savanna areas of the country (17% of 1,010 colubrids collected between 7°N and 14°N). In West Africa, it is a very rare species: only three specimens out of 9,000 snakes in Senegal, all in the Sahel north of 14°N (Trape & Mané unpublished), one specimen out of 1,714 in Niger (Trape & Mané 2015), none out of 4,906 in Guinea (Trape & Baldé 2014), and none out of 5,224 in Mali (Trape & Mané 2017). A single specimen of P. sudanensis was present in Roman’s collection of 5,000 snakes from Burkina Faso (Trape 2005). Psammophis sudanensis reports from Sangaredi area (Guinea) by Chirio (2012) and from southern Benin by Ullenbruch et al. (2010, see Figs 16 & 17 p. 44) are in fact attributable to specimens belonging to the lineated phase of P. afroccidentalis sp. nov.

Distribution. East Africa from southern Sudan, south through eastern Uganda and Kenya to northern Tanzania, west through the Central African Republic, Cameroon, Nigeria, Niger, Burkina Faso, Ghana, Senegal. Sympatric with P. orientalis at Morogoro in Tanzania, with P. rukwae in Chad and Cameroon, and with P. afroccidentalis sp. nov. in West Africa.