Reflexions about potential distribution of Echis leucogaster in North Africa

by Gabriel Martínez del Mármol Marin (gabrimtnezmarmol@yahoo.es), Baudilio Rebollo Fernández (budilord@gmail.com) & Tomas Mazuch (somalia@seznam.cz)

Genus Echis Merrem, 1820, is one of the most complex genera of snakes in Africa. Recent genetic analysis has shown that the genetic variability among Echis leucogaster and Echis pyramidum group is very low and some authors suggest the existence of a single species with several subspecies (Arnold et al., 2009).

Echis leucogaster or Echis pyramidum leucogaster is probably the rarest snake in Morocco (Aymerich et al., 2004). In 1996 in Morocco the only known populations were Aouinet Torkoz (now called Aouinet Lahna) and Ait-Semgane-n-el-Grara (originally attributed to Echis carinatus by Sochurek but later classified as Dasypeltis scabra by Stemmler, 1971)(Bons & Geniez, 1996).

Over the years both populations have been confirmed: in Aouinet Lahna the population is relatively abundant (Aymerich et al., 2004; K. Lazghem, pers. comm.; G. Martinez del Marmol Marín, pers. obs.) and it has also been found in nearby regions such as Tiglit (F. Cuzin in Herrmann et al., 2000). South of Ouarzazate the number of citations has also increased with up to 6 specimens found in 2009 in the area between Ait Semgane-n- el-Grara and Tasla (Escoriza et al., 2009; Aymerich, 2010) and other nearby points such as Amazer (J. Maran & Maran in Geniez, 1999) and Allougoum (Pook et al., 2009).

As the populations are more than 300 Km apart there was a question that there could be intermediate populations between both nucleuses, especially as there are many sites potentially favourable for the species (Brito et al., 2011).
During a herpetological trip to Morocco on April 30, 2012, some of the authors found a juvenile of this species (Martinez del Marmol & Rebollo Fernandez, 2012) on the outskirts of the town of Tata.

Echis leucogaster
Figure 1: Photograph of the Echis leucogaster specimen found in Tata. Photo: © Baudilio Rebollo Fernández.
Habitat of Echis leucogaster
Figure 2: Photograph of the exactly habitat where it was found. Photo: © Baudilio Rebollo Fernández.

The importance of this record is that it shows that the distribution of Echis leucogaster in Morocco is not limited to two isolated nuclei. This report shows that Echis leucogaster has a much wider distribution than that previously thought and confirms the possibility of a continuous population.

Distribution map Echis leucogaster in Morocco

Figure 3: Map showing the known distribution of Echis leucogaster in Morocco. Indicated as dark red dots known locations (according to Aymerich et al., 2004; Escoriza et al., 2009; Pook et al., 2009; Aymerich, 2010). The last record as yellow dot (Martinez del Marmol Marin & Rebollo Fernandez, 2012). The potential distribution for authors is drawn with a soft red coloration.

Prior to this sighting, some of the authors had prospected around Assa, Foum el Hisn and Akka but without success. These and other places as Tisgui-El-Haratine, Icht, Tissint or Foum Zguid are locations where this species could possibly occur as they contain similar characteristics.

Akka
Figure 4: Foum Zguid landscape. Photo: © Gabri Mtnez.

In the last genetic analysis the E. pyramidum haplotypes are in turn subdivided into western (Mauritania, Senegal, Morocco, western Mali) and eastern (Tunisia, Niger, eastern Mali) clades (Pook et al., 2009). Those two groups are in the beginning of the diversification and at this moment and knowledge they don’t deserve any taxonomic unit (e.g. subspecies). The Echis vipers found in Biskra, Algeria (Jiri Hales-Tomas Mazuch, pers. comm.), should belong to Echis leucogaster species, as the specimens from both sides (Morocco, Tunisia) of this locality according to DNA (Pook et al., 2009), coloration (dorsal patterns, white venters) and morphology analysis (D 29, V165, Scd 36, thus certainly not from the complex ocellatus).

Echis leucogaster
Figure 5: Echis leucogaster. Aouinet Lahna (Morocco). Photo: © Gabri Mtnez.
Echis leucogaster
Figure 6: Echis pyramidum?. Biskra (Algeria). Photo: © Jiří Haleš.
Echis leucogaster
Figure 7: Echis pyramidum. Bou Hedma (Tunisia). Photo: © F. Kovařík.

If we would speculate to which populations belong (eastern vs. western) Biskra specimens may belong to the eastern clade, because this population is closer and without any geographical barrier. Whereas the E. pyramidum and “E. leucogaster” meeting area is in somewhere in Libya (and probably further south in the Chad and western Sudan; T. Mazuch, unpublished), the possibility of a contact area between both E. pyramidum clades is uncertain due to the scarcity of Algerian and Moroccan records. Maybe there are some populations between Ait Semgane and Biskra (Tazzarine, Figuig, Beni Ounif, Brezina or Laghouat are good examples where “Echis leucogaster” could occur). Although a morphology analysis shows that an animal from Biskra (Natural History Museum, London: BMNH 1907.4.6.55) has a distinctive hemipenis and may represent yet another taxon (Arnold et al., 2009), there are no other reasons (geographically or phylogenetically) to recognize this population as another taxon.

Figure 8: Map showing the potential distribution of Echis pyramidum in North Africa following Pook et al., 2009.
Eastern clade in yellow colour:

  1. Sidi Toui (Karen, 2003, in Kaupia Journal)
  2. Matmata (Pook et al., 2009)
  3. Bou Hedma (Joger, 2003, in Kaupia Journal)
  4. Near (Djebel Attig) Gafsa (Olivier, 1896)
  5. Tadjera, near Mettamer (Boulenger, 1890, also as reference for (6) Biskra population)
  6. NE and SE of Biskra (Chirio L. & Blanc C . P ., 1997 – Statut et distribution des Reptiles dans le massif de l’Aurès (Algérie) – Rev. Zool. afr., Tervuren, 111: 205-233.) Here is what wrotte Laurent Chirio to Tomas Mazuch: “I worked during 2 years in Khenchela (1984-86), north-east of Biskra, and made a thesis about reptiles of Aures montane. I found only one dead (and dry) specimen of Echis leucogaster in Hammam-Salahine, just near Biskra, and a piece of another dead one south-east of Biskra. This entire specimen is now in Paris Museum (MNHN).”

Western clade in red colour:

  1. Ait Semgane (Bons & Geniez, 1996 ; Escoriza et al., 2009 ; M. Aymerich, pers. comm.)
  2. Amazer (Aymerich et al., 2004)
  3. Allougoum (Pook et al., 2009)
  4. Tata (Martinez del Marmol & Rebollo Fernandez, 2012)
  5. Aouinet Lahna (Bons & Geniez, 1996; Aymerich et al., 2004 ; G. Martinez del Marmol, pers. obs.)
  6. Tiglit (Herrmann, Herrmann and Geniez, 2000)
Errachidia
Figure 9: Errachidia landscape, E. leucogaster habitat?. Photo: © Gabri Mtnez.
Bou Hedma
Figure 10: Habitat of E. pyramidum in Bou Hedma (Tunisia). Photo: © Tomas Mazuch.

To cite this page:
Gabriel Martínez del Mármol Marin, Baudilio Rebollo Fernández & Tomas Mazuch: Reflexions about potential distribution of Echis leucogaster in North Africa.
Published on July 26, 2012. Available from http://blog.moroccoherps.com/en/reflexions-about-potential-distribution-of-echis-leucogaster-in-north-africa/. Accessed June 25, 2017.

To cite www.moroccoherps.com as a whole:
Amphibians & Reptiles of Morocco and Western Sahara.
Available from www.moroccoherps.com. Accessed June 25, 2017.

Bibliography: