Psammophis ansorgii Boulenger, 1905

Branch, William R., Baptista, Ninda, Keates, Chad & Edwards, Shelley, 2019, Rediscovery, taxonomic status, and phylogenetic relationships of two rare and endemic snakes (Serpentes: Psammophiinae) from the southwestern Angolan plateau, Zootaxa 4590 (3), pp. 342-366 : 358-359

Psammophis ansorgii Boulenger, 1905

Ansorge’s Sand Snake

Psammophis ansorgii Boulenger 1905 , 16: 113, Pl. iv, Fig. 4.. A list of the batrachians and reptiles collected by Dr. W. J. Ansorge in Angola with descriptions of new species. Ann. Mag. Nat. Hist. (7) 16: 105–115.

Holotype: BMNH 1946.1 .8.49, a 700 mm male (W.J. Ansorge, end of 1904).

Type locality: “Benguella to Bihé”, Angola. Ansorge (in Boulenger 1905) describes Bihé as “A district in the north-east of the occupied portion of the Benguella province; roughly only the eastern half of the Benguella province is …nominally Portuguese.” It also notes “End of 1904”, which is presumed to be the time Ansorge was in the region. Ansorge’s vague locality description infers that the specimen was collected somewhere enroute between Benguella (= now Benguela) and Bihé (= now Bié). Both were administrative regions at the time of Ansorge’s travels, with Viye (of which Bihé is a corruption) a traditional Ovimbundu kingdom in Angola. There are no diaries documenting Ansorge’s journeys in Angola that give fuller details of his travels, but the American ornithologist James Chapin prepared a terse, unpublished summary of Ansorge’s itineraries in Angola (Chapin, undated). From Chapin’s summary it is apparent that in December 1904 Ansorge started heading back to Caconda (then in Benguela District) and reached it on Dec 22 nd. Whilst still in Bié, and just prior to reaching Benguela District, he was in the vicinity of Bulu-Bulu (12°05'S, 17°37'E, elevation 1316 m a.s.l.) on 9–10 December, at Chinguar (12°33'S, 16°20' E, elevation 1812 m a.s.l.) on 9–10 December, and at Cunhangamua River (12°56'S, 15°44'E, elevation 1600 m a.s.l.) on 16 December (dates from Chapin undated; co-ordinates from Crawford-Cabral & Mesquitela 1989). Based on this fuller understanding of Ansorge’s location at the “End of 1904” we take this opportunity to restrict the type locality for Psammophis ansorgii Boulenger, 1905 , to between Chinguar (12°33'S, 16°20'E, elevation 1812 m a.s.l.) and Cunhangamua River (12°56'S, 15°44'E, elevation 1600 m a.s.l.), Bié Province, Angola ( Fig. 6 ).

Synonymy:

Psammophis ansorgi Boulenger, 1905, p113 .

Psammophis jallae Peracca 1896 (part)— Loveridge, 1940, p. 6, 63.

Psammophis ansorgii Hellmich, 1957, p69 .

Psammophis ansorgii Broadley 1977b, p13 ; Broaldey 2002, p. 98.

Material examined. Psammophis ansorgii : NB560, montane grassland south of observatory, Tundavala region of the Humpata Plateau, near Chela Escarpment (14°48'37"S, 13°24'13"E, 2286 m a.s.l.), Huíla Province, Angola, 10 February 2017; NB600, montane grassland near Vieque village , Tundavala region of the Humpata Plateau, near Chela Escarpment (14°49'3.4''S, 13°25'6.6''E, 2262 m a.s.l.), Huíla Province, Angola. 13 July 2017 .

Description. A medium-sized sand snake (maximum 75cm). Nostril pierced between 2 or 3 nasals; preocular 1, usually separated from frontal; postoculars 2; temporals usually 2+2+3 (sometimes 2+1); supralabials 7, the third & fourth entering orbit (sometimes 2–3 or 2–4); infralabials 8–9, the first 4 in contact with anterior sublinguals; dorsal scales in 15-15-13 (sometime 15-15-11) rows; ventrals 152–161; cloacal shield divided; subcaudals 70–78. Dorsum grey-brown to reddish brown, usually uniform but sometimes with a fine ‘ladder’ pattern on the forebody due to black-edged dorsal scales. Head uniform grey-brown on crown, but with characteristic ivory-coloured pre- and post-oculars and a black-edged ivory-cream stripe on supralabials. Ventrum unpatterned with a white-edged yellowish centre, and brighter yellow below tail.

Scalation details of specimen are summarized in Table 3 .

Size: Maximum size: 555 + 195 = 750 mm ( Hellmich 1957 —Bela-Vista, Angola).

Habitat. See habitat characterization for Ps. ocellatus . An illustration of the habitat is shown in Figure. 3C .

Distribution. Endemic to the central highlands of Angola, from Bela-Vista (= Catchiungo, 12°33'29.45"S, 16°13'32.66"E), Huambo Province (previously the only precise locality), to Tundavala on the Humpata Plateau, Huíla Province ( Fig. 6 ). The Tundavala material represents a 400+km southwest range extension to the edge of the plateau, and an altitudinal increase from approximately 1800 m to 2286 m a.s.l.

Ecology: NB600 was collected while active during the day in montane grassland in rocky soil, near a patch of dwarf miombo, in the middle of the dry season (13 th of July, 2017). This female snake was gravid, containing nine eggs (three in the left oviduct and six in the right) that measured 22–31 mm in length.

Conservation: P. ansorgii and Ps. ocellatus are two of only five known endemic Angolan snakes ( Branch 2018), that occur sympatrically in the Tundavala region of the Humpata plateau, a region highlighted as a centre of herpetofaunal endemism ( Laurent 1964, Baptista et al. 2018). Although the distributions of both species are still poorly known, and inland records indicate that both are not restricted to montane grassland habitat, their cooccurrence in the Tundavala region reinforces the need for its protection, which has been previously highlighted ( Huntley & Matos 1994) but still lacks implementation ( Baptista et al. 2018). The areas where both species were found undergo man-made fire every year. It is not known how this habitat disturbance affects these species. More surveys are required to assess the conservation status of both Angolan endemics, and other localized and potentially endemic lizards such as Chamaeleo anchietae , Eumecia anchietae and Rhoptropus montanus .

Figures

FIGURE 3. Psammophis ansorgii NB 560, Tundavala montane grassland, Huíla province; A: whole body dorsal coloration showing the characteristic reddish brown body; B: Lateral view of head showing scalation and distinctive ivory-coloured pre- and postoculars and dark-edged, pale upper labial stripe; C: Habitat—montane grasslands, Tundavala, Huíla Province; D: Illustration from Boulenger’s (1905) description of P. ansorgii showing uniform body coloration, and pale upper labial stripe and pale pre- and postoculars. All photos by N. Baptista.

FIGURE 4. Psammophis ansorgii NB 600, Tundavala montane grassland, Huíla province. A: whole body, showing a subdued grey-brown body and distinctive head coloration, with ivory pre- and postoculars and dark-edged upper labial stripe; B: ventral coloration with a central broad light yellow band bordered by white edges, and the ventral surface of the tail brighter yellow without white border; C: unusual dorsal coloration showing dark edges to scattered dorsal scales; and D: these dark scale edges forming an indistinct ‘ladder-like’ effect on the forebody that was not noted in type description. All photos by N. Baptista.

FIGURE 6. Distribution of Psammophylax ocellatus (green) and Psammophis ansorgii (blue). Right (A): Africa with location of Angola in blue. Middle (B): Topographic map of Angola, showing relief and central localities, and red square outlining the location of the Humpata Plateau, adjacent to the Chela Escarpment. Localities: 1–2 Catchiungo—Chinguar (blue star) type locality of Psammophis ansorgii; 3, Cunhangamua; 4, Tundavala; 5, Estação Zootécnica; 6, Chibemba (green star) type locality of Psammophylax ocellatus; 7, Humbe; 8, Calueque, near Ruacaná. Left (C): zoomed in region of Humpata Plateau.