domingo, 23 de septiembre de 2012

Reviving the African Wolf Canis lupus lupaster in North and West Africa: A Mitochondrial Lineage Ranging More than 6,000 km Wide: Gaubert P, Bloch C, Benyacoub S, Abdelhamid A, Pagani P, et al. (2012)

A- Geographic distribution of the African Canisincluded in this study. B- The typical ‘wolf-like’ (left) and ‘jackal-like’ (right) phenotypes observed near Kheune, Senegal. (photographs: C. Bloch).

"The recent discovery of a lineage of gray wolf in North-East Africa suggests the presence of a cryptic canid on the continent, the African wolf Canis lupus lupaster. We analyzed the mtDNA diversity (cytochrome b and control region) of a series of African Canis including wolf-like animals from North and West Africa. Our objectives were to assess the actual range of C. l. lupaster, to further estimate the genetic characteristics and demographic history of its lineage, and to question its taxonomic delineation from the golden jackal C. aureus, with which it has been considered synonymous. We confirmed the existence of four distinct lineages within the gray wolf, including C. lupus/familiaris (Holarctic wolves and dogs), C. l. pallipesC. l. chanco and C. l. lupaster. Taxonomic assignment procedures identified wolf-like individuals from Algeria, Mali and Senegal, as belonging to C. l. lupaster, expanding its known distribution c. 6,000 km to the west. We estimated that the African wolf lineage (i) had the highest level of genetic diversity within C. lupus, (ii) coalesced during the Late Pleistocene, contemporaneously with Holarctic wolves and dogs, and (iii) had an effective population size of c. 80,000 females. Our results suggest that the African wolf is a relatively ancient gray wolf lineage with a fairly large, past effective population size, as also suggested by the Pleistocene fossil record. Unique field observations in Senegal allowed us to provide a morphological and behavioral diagnosis of the African wolf that clearly distinguished it from the sympatric golden jackal. However, the detection of C. l. lupaster mtDNA haplotypes in C. aureus from Senegal brings the delineation between the African wolf and the golden jackal into question. In terms of conservation, it appears urgent to further characterize the status of the African wolf with regard to the African golden jackal."

Bayesian phylogenetic analysis of the wolf-like clade based on cytochrome b and control region. The model HKY + I + Γ was applied to the coherent fragment “cytochrome b + control region”, assuming a constant size coalescent model. Values at nodes correspond to posterior probabilities ≥0.90. Clades were collapsed for better readability of the tree. Scale bar represents 2% sequence divergence.
"[...] The gray wolf is generally not considered to occur in Africa (reaching the Sinai Peninsula, northeastern Egypt), where it is ecologically ‘replaced’ by the golden jackal (Canis aureus Linnaeus, 1758), which itself ranges from the northern half of Africa to south-eastern Europe and Asia. However, it has long been emphasized that the so-called Egyptian jackal C. aureus lupaster Hemprich & Ehrenberg, 1832, distributed in North Africa, had cranial and dental sizes that overlapped with the smaller-sized wolves from Arabia and India, but clearly separated from the even smaller golden jackal. On these morphological grounds, Ferguson [9] proposed to consider lupaster as a subspecies of gray wolf, with a distribution restricted to Egypt and Libya. Supporting this view, two recent studies detected a divergent mitochondrial lineage of gray wolf in northern Egypt and Ethiopia that was eventually designated as the African wolf C. lupus lupaster. Wolves (from Ethiopia) were larger–but slender-looking–than the usual golden jackal phenotype, expanding the gray wolf’s range more than 2500 km south-east into the African continent."

Phenotypic and behavioral traits betweenCanis species near Kheune, Senegal. A- Aggressive posture of the African wolf towards golden jackals; B- Aggressive posture of a golden jackal towards congeners; C- Typical ‘wolf-like’ phenotype, sampled in this study (T1361); D- Typical ‘jackal-like’ phenotypes, sampled in this study (T1360); E- Food guarding of golden jackals on a dead carcass of cow; E- African wolf (left) fighting with golden jackal (right) to access the dead carcass; F- Simulated mating between two male golden jackals; G- Phenotype of the feral dogs living in sympatry with the African wolf and the golden jackal. (photographs: C. Bloch).
"The discovery of a distinct lineage endemic to Africa of such a flagship species as the gray wolf is critical in terms of conservation, especially since large African canids do not benefit from any specific conservation action, and are regularly persecuted to protect livestock. This discovery also raises a series of overlapping questions. First, how could a gray wolf lineage have passed undetected in Africa until recently? And how long and how far has it been ranging the continent? Feeding the debate, large forms of ‘jackals’ comparable to lupaster have been reported from the Middle to Late Pleistocene of Morocco. Second, how can the African phenotype of the gray wolf be defined? In other words, is there a clear phenotypic distinction between the gray wolf and the golden jackal, the latter also showing a wide spectrum of morphological and ecological variations throughout its distribution? And third, does the gray wolf’s African phenotype reflect adaptation to specific environmental conditions or rather result from potential hybridization with the golden jackal? Although no crosses between the two species have been reported to date, hybridization among Canis taxa has proved to be common and to involve significant phenotypic changes in hybrid generations, reaching fixation in several cases."
Phenotypic variation in the golden jackal and the African wolf near Kheune, Senegal. A- Typical ‘jackal-like’ phenotype; B- ‘Jackal-like’ phenotype tending towards C; C- ‘Intermediate’ phenotype between golden jackal and African wolf; D- ‘wolf-like’ phenotype tending towards C; E- Typical ‘wolf-like’ phenotype. (photographs: C. Bloch).

"In this study, we analyzed the mitochondrial DNA (mtDNA) diversity of a series of African Canis including wolf-like animals from North and West Africa (Fig. 1), to respond to the following questions: (i) is C. lupus lupaster confined to Egypt and Ethiopia?, (ii) does it constitute an ancient African lineage or a recent spread into the continent?, and (iii) does hybridization between the African wolf and the golden jackal occur? Our results suggest that (i) the distribution of the African wolf also includes North and West Africa, expanding its range 6,000 km to the west; (ii) C. l. lupaster is a distinct, relatively ancient and genetically highly diversified lineage of gray wolf endemic to Africa; and (iii) hybridization between the former and C. aureus may occur in West Africa, although the ‘golden jackal’ entity needs to be reassessed further. We also provide unique information on the morphology and behavior of sympatric African wolves and golden jackals from West Africa. We expect that further taxonomic."

Reviving the African Wolf Canis lupus lupaster in North and West Africa: A Mitochondrial Lineage Ranging More than 6,000 km Wide: Gaubert P, Bloch C, Benyacoub S, Abdelhamid A, Pagani P, et al. (2012) PLoS ONE 7(8): e42740. doi:10.1371/journal.pone.0042740 (Publicado por PLoS ONE: )

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