The “ Cobra-preta ” of São Tomé Island, Gulf of Guinea, is a new species of Naja Laurenti, 1768 (Squamata: Elapidae)
Author
Bauer, Aaron M.
text
Zootaxa
2017
2017-09-26
4324
1
121
141
journal article
31987
10.11646/zootaxa.4324.1.7
baa4c68d-aca9-4ca8-872b-6f50a172dbf3
1175-5326
997103
6E545Fda-E061-49D9-Ba68-79C2Acabe5F4
Naja (Boulengerina) peroescobari
sp. nov.
Figs 4–5
Naja haje
(
Greef 1884
: 47
;
Bocage 1886
: 69
;
Bocage 1895a
: 24
)
Naja haje
var.
nigra
(
Bocage 1866
: 51
; 1879: 87; 1889: 34;
Vieira 1886
: 237
)
Naja haje
var.
melanoleuca
(Bedriaga 1982: 299, 440)
Naja melanoleuca
(
Bocage 1905
: 94
;
Manaças 1973
: 228
;
Nill 1993
: 71
;
Hofer 2002
: 78
, 89;
Schatti & Loumont 1992
: 31
;
Themido 1941
: 6
)
Naja melanoleuca melanoleuca
(
Capocaccia 1961
: 299
;
Manaças 1958
: 190
)
Naia melanoleuca
. (
Boulenger 1906
: 215
;
Ferreira 1902
: 133
)
Holotype
.
MUHNAC
/MB03–001065 (
Fig. 4
), adult male collected in the vicinity of Praia Inhame (
0.028636° N
,
6.523203° E
, WGS-84;
17 m
above sea level),
São Tomé
Island, Republic of
São Tomé
e
Príncipe
, by Luis Ceríaco, Mariana Marques and Ana
Carolina Sousa
on
24 February 2016
. The specimen was chopped in half by a local man with a machete, and collected minutes after this event. The choice of this particular specimen as
holotype
is justified as it is the source of the comparative molecular data.
Paratypes
.
All
specimens from the
Island of
São Tomé
,
Republic of
São Tomé
and
Príncipe
. Eight specimens:
IICT 18-1972
, adult male collected in
Ribeira Peixe
(
0.090278° N
,
6.615278° E
, this and all following coordinates use map datum WGS-84;
17 m
above sea level
) by an unknown collector on
24 December 1972
;
IICT 20-1967
, adult female collected in
Santa Josefina
(
0.247882° N
,
6.738315° E
;
69 m
above sea level
) by an unknown collector on
October 1967
;
IICT 2-1966
, adult female, without specific locality (
São Tomé
island) by an unknown collector on
20 February 1966
;
ZMH
R10526, unsexed adult, without specific locality (
São Tomé
island) collected by
Carl Weiss
in the late 1840s
;
ZMH
R10527, unsexed adult, without specific locality (
São Tomé
island) collected by
Richard Greef
in 1879/1880
;
MHNG 2518.41
and
MHNG 2518.42
, both unsexed adults collected in
Rio Angra Toldo
(
0.156881 N
,
6.668792° E
;
75 m
above sea level
) by Tilman Nill in
3 April 1991
;
MHNG 2462.43
, adult male collected in the environs of
Neves
(
0.353192 N
,
6.634972° E
;
281 m
above sea level
) by Heft and Fahr on
8 August 1989
.
Diagnosis.
Naja peroescobari
is placed in the subgenus
Boulengerina
(as defined by
Wallach
et al.
2009
) on the basis of having 2–4 maxillary teeth, the penultimate supralabial height reaching eye level the combination of one preocular and one anterior temporal, rostral much broader than deep, internasals shorter than the prefrontals, dorsal scales smooth and fangs not modified for spitting. Morphologically,
N. peroescobari
differs from other members of the subgenus
Boulengerina
by a combination of coloration and scalation patterns. It differs from
N.
(
Boulengerina
)
chrysti
in having 19 dorsal scale rows (
17 in
chrysti
), three infralabials contacting the chinshields (four in
chrysti
), and by its homogeneous dark coloration (brownish in
chrysti
).
Naja
(
Boulengerina
)
chrysti
is considered to be strictly aquatic (
Chippaux 2006
), whereas
N. peroescobari
is mainly terrestrial. It also differs from
N.
(
Boulengerina
)
annulata
by the lower number of dorsal scales (
19 in
peroescobari
versus
21 to 25 in
annulata
), and by its coloration, as
annulata
has between 21–23 dark bands (the first 3–5 simple, subsequent bands double) over a yellow or brown dorsum (contrasting with the homogeneous black of
peroescobari
), and the ventral coloration (uniformly dark brown in
annulata
,
versus
white banded throat, followed by homogeneous black of
peroescobari
).
Naja peroescobari
differs from
N.
(
Boulengerina
)
multifasciata
in its size (
260 cm
maximum in
peroescobari
versus maximum total length reported for
multifasciata
76 cm
;
Chippaux 2006
), by having two postoculars (three in
multifasciata
), in having 19 dorsal scale rows (
15–17 in
multifasciata
), a higher number of subcaudals (
30 to 39 in
multifasciata
versus
52 to 70 in
peroescobari
), a higher number of ventral (
153 to 175 in
multifasciata
versus
208 to 215 in
peroescobari
), and by its coloration (
multifasciata
is uniformly light yellow on the ventral side, and the dorsal scales are yellow in the anterior part and black in the posterior, with a dark head, separated by the rest of the body by a white collar;
Chippaux 2006
).
Naja peroescobari
differs from the more closely related West African
N. melanoleuca
,
with which it was formerly confused, having a combination of white and black bands, but the white bands are always confined to the first 22 ventral scales, whereas in
N. melanoleuca
these white bands extend throughout the first two thirds of the venter, usually between the 80th to the 100th scale (max. 125th scale, min. 50th scale; in the
type
series the last white ventral scale of
syntype
ANSP 6878 corresponds to the 81
st scale
, the other having it on the 83th (ANSP 6876), 86th (ANSP 6875) and 90th (ANSP 6879). This is even more evident when comparing the new species with
N. subvulva
, which has whitish scales mottled with dark spots extending all across the venter. Also the dorsal coloration of
N.
peroescobari
is uniformly shiny black, never exhibiting the whithish/yellow markings of the dorsal neck area common in
N. melanoleuca
. In terms of scalation, the most striking difference between
N. peroescobari
and
N. melanoleuca
is the contact of the posterior sublinguals. In
N. peroescobari
the posterior chin shields are mostly never in contact due to the intrusion of a large scale between them, whereas in
N. melanoleuca
these are always in contact, either fully across their extent or at least in the anterior part (
Meirte 1992 considered this character [
souslinguales postérieures se touchent
] as the way to differentiate
N. melanoleuca
in the key to African snakes
). These differences were already mentioned by
Capocaccia (1961)
and are here confirmed with a larger sample of both taxa.
FIGURE 4.
Holotype of
Naja
(
Boulengerina
)
peroescobari
sp. nov.
(MUHNAC/MB03–001065).
Description of
holotype
.
Body dimensions: Snout-vent length
1700 mm
, tail length
380 mm
, dorsal head length (snout to end of parietal suture)
46.2 mm
, lateral head length (snout to posterior end of lower jaw articulation)
61 mm
. Head width across supraocular
24.8 mm
, maximum overall width of head
45.5 mm
. Head broad, hearth-shaped from above. Eye moderate, diameter half the distance from mouth or from nostril. Body scalation: 208 ventrals, 66 subcaudals, all paired, anal scale entire, the intact tail terminates in a spine. Dorsal scale rows: 24 on the neck, 19 at midbody, 14 one head length ahead of vent. Head scalation: preoculars 1/1, postoculars 3/3, supralabials 7/7 the third and fourth of which contact the orbital rim, infralabials 8/8 of which the first three contact the anterior chin shields. Cuneate scale absent. Anterior temporals 1/1, posterior temporal 2/2. Two temporals and nuchals contact the lateral and posterior edges of parietals. Rostral 1.3 times wider than high, visible from above. Anterior chin shields adjacent to each other, posterior chin shields separated by one elongate scale. Nasal scale entirely divided into a prenasal and a postnasal scale by the large, vertically elongate nostril. Frontal slightly longer than wide (11.7
x
11
mm), longer than distance from rostral (
11.4 mm
), shorter than supraoculars (
14.2 mm
), widest along anterior edge; shape pentagonal, anterior edge slightly concave, posterior edge ends in obtuse angle, border with supraoculars straight. Color and pattern: Head uniformly black dorsally, lateral side cream with large black marking on the anterior/posterior borders of the supralabials and infralabials. Underside of head uniformly pearly white. Dorsal color of the total length of body uniformly shiny black. Interstitial skin black. Throat scales and ventral pattern (
Fig. 4
): first ten scales uniformly white, except the seventh scale, which presents a small dark blotch at the left side of the scale. Eleventh ventral scale black on the half left, and white with small scattered black dots on the right. Twelfth ventral scale uniformly black. Ventrals 13–15 white, except the fourteenth scale, which has a small dark blotch at the left side of the scale. Ventrals 16–17 uniformly black. Ventrals 18–19 white, but the latter with some black intrusion on the posterior edge. The remainder of the ventral and subcaudal scales are uniformly black, and the distal lateral edges of these are continuous in color with the lower dorsal scale rows.
Variation.
Variation in scale counts and body measurements of the
paratypes
of
N. peroescobari
are reported in
Table 3
. Midbody scale rows 19–21; Neck scale rows 21–25; Tail scale rows 13–16. Due to the limited number of
N. peroescobari
specimens for which sex was confirmed, no sexually dimorphic differences could be found in the subcaudal scales of the species, which range from 52 to 70 (
52 to 69 in
females, n= 4;
57 to 70 in
males, n= 3). The same applies to ventral scales, which range from 208 to 215 (
208 to 214 in
females;
208 to 211 in
males). The posterior sublinguals are always separated by the intrusion of a scale, however in
paratype
MHNG 2518.42 the intrusion of this scale between the posterior sublinguals is not evident, as in the other specimens, and both scales contact narrowly in the anterior part. All the
paratypes
have one anterior temporal followed by two posterior temporals. However in MCHNG 31002a,
Capocaccia (1961)
reported three posterior temporal instead of two. The anal scale is usually entire in all the
type
series, with the exception of the
paratype
IICT 18-1972, where it is divided. Supralabials always 7, whereas the number of infralabials varies between 7 and 9. Largest male examined (MUHNAC/MB03–001065, Praia Inhame,
São Tomé
) 1700 + 380 =
2080 mm
; largest female (IICT 20-1967, Santa Josefina,
São Tomé
) 2180 + 420 =
2600 cm
. All specimens examined were homogenous black on the dorsal areas, entirely agreeing with the
holotype
, while in the ventral pattern, despite small variations on the arrangement of the white scales (see
Fig. 2
), no specimen had any white scales distal to the 22th ventral.
Etymology.
The species is named after Pêro (also known as Pedro) Escobar (?–?), one of the 15th -century Portuguese navigators who discovered
São Tomé
Island on
December 21, 1471
,
Annobon
Island on
January 1, 1472
, and
Príncipe
island on
January 17, 1472
, and participated in the discovery of the ocean route from
Portugal
to
India
under the command of Vasco da Gama (
circa
1460–1524
) in 1497, as well as in the expedition of Pedro Álvares Cabral’s (
circa
1467–
circa
1520) that “discovered”
Brazil
in 1500. We adopt the Portuguese local common name “Cobra-preta” and suggest the English common name “
São Tomé
cobra” for this species.
Distribution.
The species appears to be widely distributed through the island, except the drier savanna areas in the northeast (
Fig. 6
).
Greef (1884)
noted that the species was confined to high areas, from 300 to up
900 m
in the northeast “Cordilheira”, and that it was much more common on the southeastern part of the island, near Angra de São João (
0.1167° N
,
6.6500° E
;
134 m
above sea level), but it has subsequently been found elsewhere: Roça Minho (
0.266667° N
,
6.633333° E
;
712 m
above sea level;
Bocage 1905
), Roça Saudade (
0.288319° N
,
6.636209° E
;
815 m
above sea level;
Bocage 1905
), Água-Izé (
0.218727° N
,
6.727969° E
;
19 m
above seal level;
Boulenger 1906
,
Capocaccia 1961
), Roça
Porto
Alegre (
0.033333° N
,
6.533333° E
;
16 m
above sea level;
Manaças 1958
), Roça Santa Josefina (
0.247882° N
,
6.738315° E
;
69 m
above sea level;
Manaças 1973
), “Cascata” and surroundings (
0.2854722° N
,
6.6254416° E
;
929 m
above sea level;
Nill 1993
); Angra Toldo, also referred as Rio Angra Toldo (
0.156881° N
,
6.668792° E
;
75 m
above sea level;
Nill 1993
), Rio Quicha (location unknown;
Nill 1993
) and Generosa (
0.348305° N
,
6.551019° E
;
81 m
above sea level;
Nill 1993
). Two specimens from the California Academy of Sciences collections (CAS 219402 and CAS 219403) are from Bom Sucesso (
0.288394° N
,
6.612155° E
;
1154 m
above sea level) and Morro Esperança (
0.299743° N
,
6.616667° E
;
998 m
above sea level), respectively. The species is also known from Roça
Bombaim
(
0.246481° N
,
6.632732° E
;
465 m
above sea level; LMPC & MPM pers. obs.). The
type
locality represents the southernmost known record of the species, and also the lowest elevation recorded (
21 m
). The species is not known from the neighboring Rolas Islet.
TABLE 3.
Variation in size and scalation characters displayed in São Tomé’s “Cobra preta”,
Naja peroescobari
sp. nov.
, and continental
Naja melanoleuca
. Values are organized as mean (minimum–maximum; standard deviation). Measurments are rounded off to the closest 1 mm.
“Cobra preta” (n= 15) |
Continental
Naja melanoleuca
(n= 47)
|
Snout-vent length |
1250 (790–2180; 40.3) |
1105 (370–1920; 46.9) |
Tail length |
280 (110–420; 8.7) |
235 (80–435; 10.4) |
Ventrals |
210 (208–215; 2.2) |
218 (200–231; 6.4) |
Sub-caudals |
69 (52–70; 5.9) |
64 (33–71; 5.6) |
Neck scale rows |
24 (21–25; 1.5) |
24 (22–29; 1.9) |
Midbody scale rows |
19 (19–21; 0.7) |
19 (16–21; 0.9) |
Tail scale rows |
13 (13–16; 1.3) |
13 (12–16; 0.8) |
FIGURE 5.
Live picture of
Naja
(
Boulengerina
)
peroescobari
sp nov. from near Santa Josefina. Specimen not collected. Photo by Tiziano Pisoni.
Medical relevance and folklore.
There is currently no available information on the venom of this snake. Local people (as well as historical reports) refer to the snake as highly venomous, causing death in a few hours, but no credible reports about the symptomology were recorded during our expeditions to the island (L.M.P.C & M.P.M pers. obs.).
Vieira (1886)
mentions that the species is highly venomous (even recording the local saying: “
homem mordido, homem perdido
”, meaning “man bitten, man lost”), but only bites when attacked or stepped on. Local informants claim that when bitten, patients usually cut the afflicted limb off, and there are also reports of people who are on the top of palm trees to extract palm wine who simply toss themselves to the ground to avoid being bitten whenever they encounter a snake. The manuscript report of José Gonçalves Correia (
1888–1954
), Portuguese naturalist who collected birds in
São Tomé
for the American Museum of Natural History in 1928/1929, mentions that after a bite, the afflicted area should be burnt with a hot iron in the first 24 hours (
Correia 1928
). Further studies on the venom and also on the symptomology and bite incident records are needed to understand the potential medical relevance of this species to the human population. A possible island effect in the venom should also not be discounted, as snake venom is known to be highly affected by ecological and geographic conditions (
Chippaux
et al.
1991
). In some parts of the island, namely around Roça
Bombaim
, the species is captured by locals to serve as a local delicacy, and the meat is sold in the capital city market (L.M.P.C & M.P.M pers. obs.). The recent development of political ties between
São Tomé
and
Príncipe
and
China
, and the expected arrival of Chinese workers to the country, is a potential cause of concern, as snakes from the genus
Naja
are commonly used in the Chinese Traditional Medicine (
Zheng & Zhang 2000
) and gastronomy (
Zhou & Jiang 2005
), and conservation problems related to the exploitation of wildlife by Chinese workers have been reported for other parts in Africa (
Munson & Ronghui 2012
;
Bersacola
et al.
2014
).
Habitat and Natural History notes.
Bocage (1895)
reports a skull of a Least Weasel (
Mustela nivalis
) in the stomach contents of one specimen. Specimen IICT 18-1972 had an invasive Black rat (
Rattus rattus
) in its stomach, but knowledge on the trophic ecology of the species is limited.
Vieira (1886)
mentions that the species prefer shaded and moist habitats. The snake is mostly seen in forested areas in the southern half of the island, being absent in the northeast regions. It is commonly seen on roads basking during the day.