Research Article |
Corresponding author: Violaine Nicolas ( vnicolas@mnhn.fr ) Academic editor: Clara Stefen
© 2021 Haithem El-Farhati, Mourad Khaldi, Alexis Ribas, Mohamed Wassim Hizem, Saïd Nouira, Violaine Nicolas.
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation:
El-Farhati H, Khaldi M, Ribas A, Hizem MW, Nouira S, Nicolas V (2021) Evolutionary history of the two North African hedgehogs (Mammalia: Erinaceidae) Atelerix algirus and Paraechinus aethiopicus based on phylogeography and species distribution modelling. Vertebrate Zoology 71: 799-811. https://doi.org/10.3897/vz.71.e70989
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Abstract
Two species of hedgehogs are known to occur in northern part of Africa: the Algerian hedgehog Atelerix algirus and the Ethiopian hedgehog Paraechinus aethiopicus. Within each species several subspecies were described based on morphometrical data and pelage coloration, but all these subspecies have enigmatic and unclear definitions. We investigated the phylogeographical history and taxonomy of these two species based on mitochondrial DNA data covering the entire geographical distribution of A. algirus and the North African distribution of P. aethiopicus. We also used climatic niche modelling to make inferences about their evolutionary history. Low genetic diversity was recovered in both species. While no phylogeographic pattern was found in P. aethiopicus, two haplogroups were identified within A. algirus. This could be explained by the fact that continuous high or moderate climatic suitability occurred throughout most of the Saharan desert since the LGM (Last Glacial Maximum) for the first species, while during the LGM there were several disconnected areas of high climatic suitability for A. algirus: one in South-West Morocco, one at the coastal Moroccan-Algerian border and one in Tunisia-coastal Libya. Our genetic results confirm that A. algirus recently colonized Spain, Balearic and Canary Islands, and that this colonization was probably mediated by humans. Suitable climatic conditions occurred throughout most of the Southern and Eastern Iberian Peninsula during the last 6,000 years which could have favored the spatial expansion of the Algerian hedgehog after its arrival in Europe. According to our molecular results subspecific recognition within North Africa is unwarranted for both species.
Climatic niche modelling, haplotype network, mammal, mitochondrial DNA, North Africa, phylogeny, taxonomy
Two species of hedgehogs are known to occur in northern part of Africa (Fig.
Within each species several subspecies and forms were described based on morphometrical data and pelage coloration. According to
Until recently, virtually nothing was known on the genetic variability within these two species. However, during the last five years, several studies were published. Based on one mitochondrial (Cytochrome b) and one nuclear (BFIBR) genes
The aim of this study is to investigate the phylogeographical history and taxonomy of these two species based on improved sampling covering the entire geographical distribution of A. algirus and the North African distribution of P. aethiopicus. New samples from Morocco, Algeria, Tunisia, peninsular Spain, and Balearic and Canary Islands were included. We also used ecological niche modelling to make inferences about the evolutionary history of these lineages and the potential impact of paleoclimatic events on the current genetic variability and distribution of each species.
A total of 126 new samples (See supplementary file 1) were collected in the field, either from road-killed animals or live-trapping or from museum collections (Museum of Natural Science of Barcelona) and stored in 96% ethanol. These specimens come from Tunisia (72 specimens), Algeria (32), Morocco (2 specimens), Spain (15), Balearic (2) and Canary Islands (3). Geographical coordinates for the collected samples were recorded with a Global Positioning System. Species identification in the field was based on morphological characteristics, namely ventral, leg and facial color patterns, as well as ear length (
Whole genomic DNA was extracted using the QIAamp DNA Mini Kit (QIAGEN), following the manufacturers’ protocols. We amplified a fragment of 456–465 bp of the mitochondrial control region (CR) using the primers developed by
Chromatograms were checked and sequences manually corrected in CodonCode Aligner 8.0.2. In our phylogenetic analyses, we included all the newly sequenced specimens and all specimens of Atelerix and Paraechinus available in the GenBank database for which the control region was sequenced. We also added several references sequences for the hedgehog species Erinaceus europaeus, E. roumanicus and E. concolor. Sequences were aligned with ClustalW implemented in Geneious 4.6.4., and the alignment was corrected by eyes. The final alignment comprised 283 sequences (see supplementary file 1 for specimens list, and see supplementary file 2 for sequence alignment). Sequences of 423 bp were retained for the final analyses as they were available for most specimens.
We estimated evolutionary relationships among sequences by constructing phylogenetic trees using maximum-likelihood (ML) and Bayesian inference (BA). The computer program MrModeltest ver.2 (
A haplotype network for each species (See supplementary file 3 for A. algirus sequences alignment, and see supplementary file 4 for P. aethiopicus sequences alignment) was constructed in TCS 1.2.0 (
Nucleotide diversity, haplotype diversity (
Inferences of population expansion were made using two different methods: the Fs statistic (
To evaluate current and past habitat suitability for the two species of hedgehogs (A. algirus and P. aethiopicus) we produced distribution models under three different climatic conditions (current, mid-Holocene and Last Glacial Maximum [LGM]) using a distribution modeling approach. Species occurrence data were assembled from the literature (
As environmental layers, we used available climatic data from the WorldClim database (
The final alignment contained 283 sequences of 423 pb long with 32 sites with alignment gaps. ML and BA analyses resulted in a well resolved tree (Fig.
The 204 specimens of A. algirus lineage I resulted in 58 haplotypes (Table
The 45 specimens of P. aethiopicus resulted in 19 haplotypes. Nucleotide diversity is 0.01086 ± 0.00050, haplotype diversity is 0.905 ± 0.026 and the average number of nucleotide differences is 4.386. A higher number of haplotypes is found in Algeria, but this is probably due to the greater sample size in this country (Fig.
Diversity and neutrality estimates for the two species and main haplogroups identified in the Statistical parsimony haplotype networks. Significant values are indicated by asterix (* for P < 0.05, ** for P < 0.01, *** for P < 0.001). Number of sequences (N), number of distinct haplotypes (Nh), haplotype diversity (Hd), nucleotide diversity (Pi), average number of nucleotide differences (k) and results of the Fu’s Fs and R2 tests are given.
N | Nh | Hd | Pi | k | Fu’s Fs | R2 | |
All A. algirus lineage I | 204 | 58 | 0.924 ± 0,008 | 0.00745 ± 0,00037 | 3.010 | –28,426*** | 0.057 |
Haplogroup 1 | 25 | 13 | 0.827 ± 0.067 | 0.00514 ± 0.00069 | 2.077 | –3.555* | 0.110 |
Haplogroup 2 | 179 | 43 | 0.904 ± 0.010 | 0.00592 ± 0.00030 | 2.399 | –19.395*** | 0.053 |
All P. aethiopicus | 45 | 19 | 0.905 ± 0.026 | 0.01086 ± 0.00050 | 4.386 | –3.846 | 0.133 |
We built species distribution models for the two African hedgehog species based on the known presence localities. The AUC values were 0.935 and 0.808 for A. algirus and P. aethiopicus, respectively. Thus, they are considered to correspond to a useful predictive model.
Under present-day climatic conditions the model revealed climatic suitability for A. algirus across all the Mediterranean Basin (Fig.
Species distribution modeling of Atelerix algirus as estimated by Maxent for present-day conditions (current), for Holocene and the Last Glacial Maximum (LGM) based on the Model for Interdisciplinary Research on Climate (MIROC) and on the Community Climate System Model (CCSM) paleoclimatic models. Warmer colors show areas with higher probability of presence.
For P. aethiopicus, in North Africa, the model revealed continuous high climatic suitability under present-day bioclimatic conditions in Western part of the Sahara desert from Mauritania to Morocco limited by the Anti-Atlas and the High Atlas (Fig.
Species distribution modeling of Paraechinus aethiopicus as estimated by Maxent for present-day conditions (current), for Holocene and the Last Glacial Maximum (LGM) based on the Model for Interdisciplinary Research on Climate (MIROC) and on the Community Climate System Model (CCSM) paleoclimatic models. Warmer colors show areas with higher probability of presence.
One of the most remarkable finding from this study is the discrepancy between our results and those published by
Our A. algirus lineage I corresponds to the two sister lineages A. algirus 1 and A. algirus 2 of
To sum up, our results are congruent with the study of Khaldi et al. (
Our genetic results confirm that the Algerian hedgehog recently colonized Spain, Balearic and Canary Islands, and that this colonization was probably mediated by humans, as already suggested by several authors (
Our study shows no phylogeograhic structure in North African P. aethiopicus. This is consistent with our climatic niche modeling results showing a more or less continuous high or moderate climatic suitability for this species throughout most of the Saharan desert since the LGM (except in the most central parts). This study significantly increases our knowledge of the distribution of P. aethiopicus expanding currently recognized ranges (IUCN, 2015; Best, 2018). An extension of its distribution range in Atlantic Sahara was already proposed by
Several subspecies have been described for Atelerix algirus, either from the mainland or islands, Atelerix algirus algirus from North Africa, A. algirus vagans from Spain, Minorca and Balearic Islands and A. algirus girbaensis from Djerba Island (Tunisia). Given that the differential diagnosis is mainly based on pelage variations (hairs, spines), the validity of these subspecies has been regularly questioned (
In the two studied hedgehog species low genetic diversity was found in North Africa. However, while no phylogeographic pattern was found in P. aethiopicus, two haplogroups were identified within A. algirus. This could be explained by the fact that a more or less continuous high or moderate climatic suitability occurred throughout most of the Saharan desert since the LGM for the first species, while during the LGM there were several disconnected areas of high climatic suitability for A. algirus: one in South-West Morocco, one in coastal Moroccan-Algerian border and one in Tunisia-coastal Libya. Our genetic results confirm that the Algerian hedgehog colonized recently Spain, Balearic and Canary Islands, and that this colonization was probably mediated by humans. Suitable climatic conditions occurred throughout most lowland Southern and Eastern Iberian Peninsula during the last 6000 years which could have favored the spatial expansion of the Algerian hedgehog after its arrival in Europe.
Several subspecies have been described within the two African hedgehog species. Our results do not show any strong genetic discontinuity within either species in North Africa, suggesting that subspecific recognition within this region may be unwarranted. Additional sampling in Djerba Island (for both species), Soudan, Ethiopia and in the Middle East (for P. aethiopicus) is needed to test the genetic differentiation of other proposed subspecies.
Our phylogeographic and taxonomic conclusions are only based on short mitochondrial fragment, which could explain the low bootstrap support of several important nodes in our phylogeny. Increasing the amount of genetic data frequently allows resolution of even the most problematic phylogenetic relationships (
Molecular analyses were performed at the Service de Systématique Moléculaire (UMS 2700 Acquisition et Analyse de Données pour l’Histoire naturelle, 2AD, Paris, France). We are indebted to many local authorities for providing permits to carry out the research, especially ‘Direction Générale des forêts’ (Tunisia), ‘Haut Commissariat aux Eaux et forêts et lutte contre la desertification’ (Morocco). For help in the field and with logistics, we acknowledge A. Lalis, C. Denys, M. Benyettou, G. Barech, P. Foronda and M. Alcover. We thank the curator of the Museum of Natural Science of Barcelona for access to the tissue samples from Spain.
List of specimens
Data type: .xlsx
Explanation note: List of specimens included in the mitochondrial DNA phylogenetic.
Sequence alignment – phylogenetic tree analyses
Data type: .csv
Explanation note: Sequence alignment used for the phylogenetic tree analyses.
Sequence alignment used for haplotype network analysis of A. algirus
Data type: .csv
Explanation note: Sequence alignment used for haplotype network analysis of A. algirus.
Sequence alignment used for haplotype network analysis of P. aethiopicus
Data type: .csv
Explanation note: Sequence alignment used for haplotype network analysis of P. aethiopicus.
Species occurrence data
Data type: .xlsx
Explanation note: Species occurrence data used in our climatic niche modelling analyses.