New distribution limit of Clifford`s diadem snake Spalerosophis

Herpetology Notes, volume 6: 453-456 (2013) (published online on 23 September 2013)
New distribution limit of Clifford’s diadem snake Spalerosophis
diadema (Serpentes: Colubridae) in southern Morocco
Mohamed Mediani1,*, Soumia Fahd1, Franck Chevalier2, Abdeljebbar Qninba3, Mohamed Lamine Samlali4
Clifford’s diadem snake Spalerosophis diadema
(Schlegel, 1837) is a medium-sized snake with a large
distribution range stretching from the Atlantic Ocean
through the Middle East to central-western Asia and
India (Marx, 1959; Gasperetti, 1988). Four subspecies
have been described: three of them are limited to Asia,
while the fourth subspecies Spalerosophis diadema
cliffordi is distributed in North Africa, from the Atlantic
coast through the Sahara and northern areas of the
Sahel, reaching the western part of the Middle East
(Marx, 1959).
Spalerosophis diadema is a typical Saharo-Sindian
species, which was considered to reach the Atlantic
along a narrow coastal strip near the Souss Valley
(Marx, 1969), but after splitting of S. dolichospilus
(Werner, 1923) from S. diadema (Pasteur, 1967) these
localities were assigned to the newly split species (S.
dolichospilus). Later, S. d. cliffordi was discovered in
southern Morocco in Tarfaya and around the Khnifiss
lagoon (Beaubrun, Thévenot and Schouten, 1988).
Further investigations have added new localities to the
species’ distribution in the Saharan zone, near Laayoune
and Smara (Bons and Geniez, 1996), which increased
the number of recorded localities to eight (Fig. 1). Based
on the confirmed presence in northern Mauritania
(approximately 35 km to Atâr) from the Moroccan
border; in Geniez et al. (2004), it seemed possible that
1 Département de Biologie, Laboratoire “Diversité et Conservation
des Systèmes Biologiques”, Faculté des Sciences, Université
Abdelmalek Essaâdi, Tétouan, Morocco
2 Ferme Tawarta, BP 248-73000, Dakhla, Morocco
3 Université Mohammed V-Agdal, Institut Scientifique, Av. Ibn
Battouta, BP 703, 10090, Agdal, Rabat, Morocco
4 Association “Nature-Initiative”, Complexe culturel, Avenue El
Walaa, Ad-Dakhla, Morocco
* Corresponding author; [email protected]
S. d. cliffordi also occurs in the Oued Dahab-Lagouira
region. Also, there could be continuity of distribution
of this species from the region of Laayoune-Smara to
Mauritania.
Despite the herpetological research started in the
Oued Dahab-Lagouira region, the species has never
been seen in this region, on area of about 200 km2
(Bons and Geniez, 1996; Schleich, Kästle and Kabisch,
1996; Geniez et al., 2004; Trape and Mané, 2006). In
Morocco, S. diadema is usually found in the Saharan
habitats, arid and semi-arid, including rocky and sandy
deserts, and frequently occurs in cultivated areas and
oases of palm trees such as exist around the Bay of
Dakhla in particular. The coastal zone of Oued DahabLagouira, in general, presents favorable conditions for
this species, with high humidity and favorable habitat
for this species (Regs or stony plateau, occupied by
chamaephytes very sparse, especially Chenopodiaceae
and Zygophyllaceae. These regs, become silted inward
direction Awserd, present some sandbanks scattered a
few feet of Acacia, twisted by the wind).
The lack of knowledge of the reptilian fauna in the
southern Sahara is supposed to be mainly caused by
remoteness and by the area’s instability before the 1990s.
Since then, most of the Sahara became ����������������
inaccessible����
or
dangerous by the presence of landmines and unexploded
ammunition. As such, the main knowledge about the
presence and distribution of many species dates back
to the old references (e.g. Valverde, 1957). Despite
all these obstacles, Geniez et al. (2004) attempted to
synthesize all the known Saharan Atlantic observations
by referring to previous publications, unpublished
records and records from some expeditions to other less
risky areas (e.g. Geniez and Geniez, 1992 (part data in
1993); Mateo et al., 1999; Geniez et al., 2000; Geniez
et al., 2004; Brito et al., 2008). Since then, further
observations were made in the region that brought new
areas of species’ occurrence (e.g. Escoriza et al., 2011;
Qninba et al., 2013). Our observations were made in
454
Mohamed Mediani� et al.
Figure 1. Range of Spalerosophis diadema cliffordi in the Atlantic Sahara, Morocco. Red dots indicate localities from the
literature; green dot indicate new records reported in the present study
the same context, to better know the reptilian fauna
of the region of Oued Dahab-Lagouira and to present
and discuss the southern boundary of Spalerosophis
diadema in the Moroccan Atlantic Sahara.
Here, we report nine new distribution records of S. d.
cliffordi in the region of Oued Dahab-Lagouira, near
to Dakhla. Two sub-adult individuals were observed
dead on the road within 1km from the coast around the
Dakhla Bay on the road N1 heading towards El Argoub
(Locality 1, Table 1), and on the road N3 in the direction
to Awserd (Locality 2). The individual from the first
locality was observed during the month of June 2012
and from the second locality, in October 2012. Seven
further observations were made 30 to 40 km south
wards of the first observations at the farm Mijk (Grayer
Ahel Al Beydi, locality 3): five individuals were found
under stones and wood piles during the following dates:
September 2009, November 2010, August 2011, July
2012 and May 2013, and all were adults or subadults
except the first which was a young individual with a
total length of about 20 cm. In May 2009, another adult
was noticed freshly killed on the road about 8 km from
the Atlantic coast (Locality 4). On the southern side of
the road that separates the complex truck farming, one
subadult was noticed during December 2012 alive under
pieces of plastic inside the agricultural greenhouses of
(Locality 5). At 3 km to the south, two other inactive
adults were observed during the month of January 2010
and January 2013 inside the agricultural greenhouses
MDS2 (Locality 6). After 7 Km south, heading towards
the city of Al-Argoub, two other inactive subadults were
noticed during the daytime in the market gardening
MDS3 (NB see above comment, Locality 7). During
a recent expedition to the Awserd region on 26 April
2013, two other individuals were found: the first was a
large-sized male (total length 104 cm) freshly crushed
on the road about 2km after Sidi-Driss (locality 8)
and the second was a female distant about 7km from
New distribution limit of Clifford’s diadem snake Spalerosophis diadema
Table 1.Coordinates (Decimal degrees, datum WGS 84) of S. diadema cliffordi at Oued Dahab-Lagouira region
455
Table 1.Coordinates
(Decimal
degrees, datum WGS 84) of S. diadema cliffordi at Oued Dahab-Lagouira region (Atlantic Sahara,
(Atlantic Sahara,
Morocco).
Morocco).
Localities
Date
Locals
Longitude (W)
Number-state
Locatity 1
26-June-12
23,765
-15,746
1-found dead
Locatity 2
25-Aug.-12 Graret Lajrab
23,786
-15,706
1-found dead
26-Sept.-09 Mijk (Graret Oum As-Sgui)
23,699
-15,697
1-live
21-Nov.-10 Mijk (Graret Oum As-Sgui)
23,699
-15,697
1-live
7-Aug.-11
Mijk (Graret Oum As-Sgui)
23,699
-15,697
1-live
16-July-12
Mijk (Graret Oum As-Sgui)
23,699
-15,697
1-live
30-May-13
Mijk (Graret Oum As-Sgui)
23,699
-15,697
1-live
1-May-09
Road to Awsserd (near MDS1)
23,682
-15,738
1-found dead
1-live
Locatity 3
Locatity 4
Locatity 5
Road N1 to El Argoub
Latitude (N)
7-Dec.-12
Greenhouse farming MDS1
23,674
-15,748
20-Jan.-10
Greenhouse farming MDS2
23,648
-15,760
1-live
5-Jan.-13
Greenhouse farming MDS3
23,648
-15,760
1-live
18-Jan.-10
Greenhouse farming MDS3
23,607
-15,790
1-live
3-Dec.-11
Greenhouse farming MDS3
23,607
-15,790
1-live
Locatity 8
26-Apr.-13
2Km after Sidi-Driss
23,591
-15,701
1-found dead
Locatity 9
26-Apr.-13
10Km after Sidi-Driss
23,566
-15,641
1-live
Locatity 6
Locatity 7
the previous observation (locality 9). The habitat is
sandy, with the presence of sandstone rocks and small
tufts of Chenopodiaceae and Zygophyllaceae plants.
The climate of the region is very dry, but the oceanic
influences offset the dry climate which consequently
creates a relatively humid micro-climate in the area
where these specimens were observed. There are mild
temperatures and low amounts of precipitation (up to 35
millimeters) in September. Winds are frequent and strong
during the summer. In comparison, human activities at
the first seven localities are common, whereas at the last
two places, habitats are well preserved, except by the
presence of pastures where vegetation is abundant.
Our observations expand by c. 400 km to the south
the known distribution range of S. diadema, and suggest
also that the species may be relatively abundant in
particular habitats. The distribution of this species along
the South Atlantic coast of Morocco may be fragmented
and, as in the case of the new station discovery, limited
to depressions (graras) characterized by moderate winds
and wet climates, modulated by the influence of oceanic
currents. These conditions favor the development of
thicker vegetation, in comparison to the surrounding
desert plateaus (reg). During the driest months of the
year, snakes may find shelter in market gardening areas
in the region where food is present and where present
microclimates are favorable for reproduction.
Despite being characterized as a crepuscular and
nocturnal species, thus hard to detect, S. diadema has
often been considered as rare with little knowledge of its
status in southern Sahara areas (Bons and Geniez 1996;
Geniez et al., 2004; Schleich et al., 1996). This study
shows that this species has a distribution much broader
than previously thought, and suggests the existence
of a more or less continuous population along coastal
areas. Further herpetological explorations in the region
are required to search for possible new sub-populations
of S. diadema between the old records and our recent
observations, as well as south of Dakhla and inland. This
will also help to fill out the knowledge gaps regarding
the distribution of many other reptiles occurring in this
region.
Acknowledgements. We thank Tahar Slimani, Philippe Geniez
for their remarks about the manuscript, and José Carlos Brito and
Philip De Pous for their corrections in the earlier draft of this
manuscript. Our gratitude goes also to the members of “NatureInitiative” association of the city of Dakhla who handled the
logistics for field work, with special regards to Mr. Mohamed
Lamine Samlali, the president of the association.
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A
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D
Figure2.Specimens of Spalerosophis diadema cliffordi photographed in the Region of Oued Dahab-Lagouira. (A) subadult,
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