Naja ashei, Wüster, Wolfgang & Broadley, Donald G., 2007

Wüster, Wolfgang & Broadley, Donald G., 2007, Get an eyeful of this: a new species of giant spitting cobra from eastern and north-eastern Africa (Squamata: Serpentes: Elapidae: Naja), Zootaxa 1532, pp. 51-68 : 58-64

publication ID	https://doi.org/ 10.5281/zenodo.177729
DOI	https://doi.org/10.5281/zenodo.5631790
persistent identifier	https://treatment.plazi.org/id/F20287EB-FF92-FF91-C7F7-F8EBFB028749
treatment provided by	Plazi
scientific name	Naja ashei
status	sp. nov.

Treatment

Naja ashei sp. nov. — Ashe’s spitting cobra

Holotype. National Museums of Kenya NMK S/3993, a female specimen from Watamu, Kenya (3º 21’S: 40º 01’E), coll. Royjan Taylor, maintained in captivity at Bio-Ken Snake farm until 29/09/2004 with reference number BK 10030 (Fig. 4,5).

Paratypes (three males and two females):

BMNH 1955.1.12.4a and 4b (Kilifi, Kenya) BMNH 1963.456 (Kiboko, Kenya); BMNH 2005.1604 (Baringo, Kenya); NMZB 3349 (Ex USNM 40954) (Guaso Nyiro [=Ewaso Ng’iro], Kenya).

Diagnosis. Naja ashei differs from all other African spitting cobras in possessing a unique clade of mtDNA haplotypes. From the data presented here, we identified 12 fixed nucleotide differences that differentiate N. ashei from the other eastern African spitting Naja . These correspond to positions 105, 169 and 315 of the ND4 sequence of the holotype ( DQ897706 View Materials ), and to positions 60, 108, 153, 201, 348, 381, 507, 630 and 676 of the cytochrome b sequence of the same specimen ( DQ897749 View Materials ), the diagnostic bases at these positions being C, T, G, C, G, T, T, T, A, C, T and A, respectively.

Morphologically, N. ashei differs from East African N. nigricollis in a number of characters relating to adult colour pattern and scalation. In particular, its midbody and posterior ventral colour is predominantly light, with dark pigment encroaching mostly from the sides of the body (venter normally largely or entirely dark in N. nigricollis ), it lacks any red, orange or pink pigment under the throat (usually pronounced in N. nigricollis ), and the head is the same olive-brown colour as the rest of the body (often black above and below in East African N. nigricollis ). Scalation does not provide any absolutely diagnostic characters for N. ashei , but mean scale counts and the range differ clearly from those of East African N. nigricollis ( Table 4 View TABLE 4 ). In particular, N. ashei can be distinguished from most eastern African N. nigricollis by the combination of high ventral scale and dorsal scale row counts. Most N. ashei have over 195 ventrals and at least 21 and typically more scale rows around the neck, whereas most N. nigricollis with 195 or more ventrals have at most 21, and usually 19 or fewer scale rows around the neck, whereas higher scale row counts around the neck tend to be found in specimens with fewer ventral scales.

Naja ashei differs from the more closely related N. mossambica in lacking any dark edges on the labial scales and ventral scales, in having a less complex ventral banding pattern, and in having higher average ventral scale counts, but lower dorsal scale row counts. Naja pallida and N. nubiae differ in having higher midbody dorsal scale row counts (usually 25, compared to 21–23 in N. ashei ). In addition, N. pallida differs from N. ashei in having a single, very clearly defined and clean-edged throat band (which very obviously crosses the neck except in older, darker specimens), in usually having higher ventral scale counts, and in the frequent presence of a single preocular and seven supralabials. Naja nubiae also has a cleaner, neater throat pattern, and two dark bands across the neck and two or three across the throat; a characteristic black tear-drop marking (consisting of dark edges to the supralabial suture below the eye) is almost invariably present; moreover, N. nubiae has almost consistently higher ventral scale counts, and often has seven supralabials and/or a single preocular (see Wüster & Broadley, 2003). Naja katiensis has consistently lower ventral and subcaudal scale counts ( Table 4 View TABLE 4 ), a much smaller adult size, and lacks cuneate scales. Among the non-spitting cobras, N. ashei is most likely to be confused with N. haje , on account of its drab brownish coloration and large size. However, N. haje differs in having a single preocular, a row of suboculars separating the eyes from the supralabials, a greatly enlarged sixth supralabial, a single anterior temporal, and in lacking spitting adaptations to the fangs ( Bogert, 1943), and thus being incapable of spitting venom. Naja melanoleuca similarly differs from N. ashei in having a single preocular, no suboculars, an enlarged sixth supralabial and a single anterior temporal.

Description of holotype. Body dimensions: Snout-vent length 1268 mm, tail length 239 mm, dorsal head length (snout to end of parietal suture) 33.3 mm, lateral head length (snout to posterior end of lower jaw articulation) 51.7 mm. Head width across supraoculars 19.7 mm, maximum overall width of head 39.7 mm.

Head broad, heart-shaped from above. Eye small to moderate, diameter much less than distance from mouth or from nostril.

Body scalation: 197 ventrals, 55 subcaudals, all paired except for the first, the intact tail terminates in a spine. Dorsal scale rows: 23 on neck, 21 at midbody, 15 one head length ahead of vent.

Scale rows at midbody

Subcaudals - Females

Dorsal scale row reduction formula: 25 5+6(2) 24 7+8(4) 23 4+5(12/13) 21 4+5/5+6(21) 19 +6(30/ 30) 21 4+5/5+6(122) 19 4+5/5+6(131) 17 4+5(151/154) 15 3+4(186) 14 +4(187) 15 4+5(191/194) 13 +3(195/195) 15

Caudal scale reduction formula: 11 2+3(2) 10 2+3(3/3) 8 4+5(5) 7 3+4(6) 6 2+3(16/17) 4

Head scalation: Preoculars 2/2, postoculars 2/2, supralabials 6/6, third enters eye, infralabials 8/9, first four contact anterior chin shields. On the left, infralabials 5 and 6 are homologous to the cuneate scales of Asiatic cobras ( Wüster, 1998), whereas on the right hand side, infralabials five and seven are cuneates ( Fig. 5 View FIGURE 5 ). Anterior temporals 2/2, posterior temporals 5/5. Seven temporals and nuchals contact the lateral and posterior edges of the parietals. Rostral 1.5 times wider than high, visible from above. Posterior chin shields separated by two rows of smaller, elongate scales. Nasal scale entirely divided into a prenasal and a postnasal scale by the large, vertically elongate nostril. Frontal longer than wide (9.0 x 7.1 mm), slightly shorter than distance from rostral (10.3 mm), shorter than supraoculars (12.0 mm), widest along anterior edge; shape pentagonal, anterior edge straight, posterior edge ends in obtuse angle, border with supraoculars slightly concave.

Colour and pattern in life: Head uniformly brownish olive on top, paler and greyer in supralabial region and around eye. Underside of head very finely dusted with brownish grey pigment, scale bases cream, overall impression light brownish grey. Dorsal colour generally olive-brown. Neck immediately posterior to head darker than top of head or the remainder of the dorsum. Otherwise, overall appearance largely uniform. Most dorsal scales with a slightly lighter lower basal edge. Interstitial skin mostly dark grey, with indistinct lighter variegations, visible especially when exposed by inflation of the body. Dorsal scales within lighter variegations have more pronounced light bases, giving an indistinct mottled appearance. Throat and ventral pattern ( Fig. 5 View FIGURE 5 ): first seven ventrals heavily mottled with greyish brown, scale bases creamy-white, light area sharply demarcated from darker pigment. Ventrals 8–10 similarly patterned, but with a slightly darker, more saturated brown pigment, covering 85–90% of each scale except the base near the middle of the scale. Ventrals 11–13 as ventrals 1–7. Ventrals 14–20 almost entirely covered with pigment of intermediate density, with only a few lighter flecks on some scale bases. The remainder of the ventral and subcaudal scales are creamish with isolated blotches of greyish-brown pigment. Distal lateral tips of the ventrals also covered in greyish brown pigment, which forms a continuation of the colour of the lower dorsal scale rows. There are no dark scale bases or edges on the ventral surface.

Variation for all material examined. Variation in scale counts in N. ashei and other African spitting cobras is given in Table 4 View TABLE 4 . In addition to the characters listed there, N. ashei is notable for frequently having only two postocular scales, rather than three. Among the specimens included in our principal components analysis, eight out of fifteen N. ashei had two postoculars on at least one side, compared to one out of twentynine N. nigricollis . Variation in colour and pattern concerns especially the ventral pattern. The first ventrals may be largely light or more or less heavily suffused with dark pigment, but the transition from these to the main dark throat band normally remains distinguishable. Juveniles have a lighter dorsal ground colour, often with a faint “herring-bone” pattern, but the top and upper sides of the head and the neck are dark greyish brown ( Fig. 6 View FIGURE 6 ). The darker colour on the neck is more intense on the sides (where it merges into the dark throat band), and gradually merges into the dorsal body colour, without there being a clearly defined band.

Size. This appears to be the largest spitting cobra, at least in terms of average size. Largest male examined ( NMK / O 2401—Nguni, Kitui District, Kenya) 1750 + 360 = 2110 mm; largest female ( NMK, unnumbered, “ Kenya ”) 1800 + 350 = 2150 mm. However, giant specimens are generally underrepresented in collections. Specimens measuring 2 metres are not rare along the Kenyan coast, and a number of specimens of well over 2 metres in total length have been recorded. Pitman (1974) records males with total lengths of 2743 and 2311 mm from the Baringo region of Kenya, which are almost certainly referable to N. ashei . However, a record specimen measuring 2819 mm (Seronera, Serengeti National Park, Tanzania—Pitman, 1974) cannot confidently be attributed to N. ashei , as there are no records of the species from the park, and some northern Tanzanian N. nigricollis also reach very large sizes (W.W., pers. obs.).

Etymology. We dedicate this species to the memory of the late James Ashe (1925–2004), in recognition of his contributions to East African herpetology, of the inspiration he gave to others working on the herpetofauna of this part of the world (see Spawls, 2004), of his early recognition of the distinctiveness of the species that now bears his name, and in gratitude for his support for this work.

Distribution. Naja ashei appears to be sympatric with N. pallida over much of its range, i.e. dry lowland regions of northern and coastal Kenya, extending south along the coast to at least Diani Beach and north into southern Somalia and south-eastern Ethiopia. It occurs in northeast Uganda at Amudat in Karamoja District (BMNH 1954.1.12.46, 1974.5145–7). It probably also occurs in the far north and/or northeast of Tanzania, but there appear to be no confirmed records. It should be looked for in the Serengeti National Park and the northernmost parts of the Tanzanian coast. The brown-headed and often very large spitting cobras from the Usambara Mountains and the central coastal region of Tanzania are referable to N. nigricollis , as demonstrated by our molecular analyses here. The northern and western distributional limits of N. ashei remain somewhat unclear. Some specimens of N. nigricollis from southern Sudan, northern Uganda and north-eastern Congo are also brownish above, but differ from N. ashei as highlighted in the diagnosis. However, the precise distributions of these forms require further investigation. The isolated population of spitting cobras assigned to N.

nigricollis by Wüster & Broadley (2003), from Jebel Marra, Darfur Province, Sudan, where it occurs sympatrically with N. nubiae , also superficially resembles N. ashei due to its colour pattern, but clusters with N. nigricollis in our multivariate analyses. Further genetic studies are required to ascertain the status of this form.

Medical relevance. As always, the discovery of a new species of venomous snake raises the question of whether existing antivenoms provide adequate protection ( Wüster & McCarthy, 1996; Fry et al., 2003). The question is particularly relevant as large Naja ashei can secrete prodigious quantities of venom. A large specimen milked at the Bio-Ken snake farm in Watamu, Kenya, produced 6.2 ml of liquid venom, weighing 7.1 g ( Fig. 7 View FIGURE 7 ). Dry weight was not recorded, but if the ratio of 34.6–41.3% solids by weight obtained by Mirtschin et al. (2006) from a selection of four species of Naja applies to N. ashei , then this suggests venom yields of up to 3 grams of dry venom, a record-breaking yield emphasising the potential danger of this species. Case histories have not been documented specifically for N. ashei , but bites by African spitting Naja typically result in severe necrosis ( Warrell et al., 1976; Tilbury, 1982), but often limited systemic symptoms.