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Diversity, distribution and conservation of crocodiles (Order: Crocodylia) in Guinea-Bissau, West Africa

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Pizzigalli, Cristian, Regalla, Aissa, Palmeirim, Ana Filipa, Palma, Luís, Lopes-Lima, Manuel, Razgour, Orly, Godinho, Raquel, Intipe, William Alexandre, Brito, José Carlos·2025·Scientific Reports
DOI 10.21203/rs.3.rs-6183800/v1PMC PMC12241385

Preprint — published as 10.1038/s41598-025-08789-3 · Paper page

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Abstract

Challenges in freshwater organism conservation in West Africa are worsened by significant knowledge gaps, even for charismatic species like crocodiles. This study addresses these gaps by assessing crocodile diversity, distribution, and conservation threats in Guinea-Bissau, where existing data is outdated. We used visual surveys, inquiries, molecular barcoding, camera trapping, and bibliographic reviews to investigate crocodile populations. Notably, we found evidence suggesting the Nile crocodile (Crocodylus niloticus), previously thought extinct in West Africa since about 200 years, may persist in the Cacheu region (Guinea-Bissau). We also confirmed the presence of the West African crocodile (Crocodylus suchus) in major river basins and coastal lagoons, including the Bijagós Archipelago, and the West African dwarf crocodile (Osteolaemus cf tetraspis) in the southern mainland and the Bijagós Archipelago. Habitat loss and deliberate killings were identified as major threats. Standardized surveys and genetic sampling are essential to assess population size, connectivity, and genetic diversity, informing evolutionary studies and conservation planning. Conservation efforts should prioritize habitat protection through community-managed reserves and restoration initiatives. Additionally, engaging local communities to raise awareness and develop conflict mitigation strategies is crucial, particularly in areas with human-crocodile interactions.

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Fig. 1 Placement of study samples within the African crocodilian phylogenetic tree. Colours of the branches refer to the species found in Guinea-Bissau in this study, namely: the Nile crocodile (C. niloticus in green), the West African crocodile (C. suchus in yellow), and the West African dwarf crocodile (O. cf. tetraspis in purple). Red dots at the nodes represent highly supported nodes (> 95% pp), coloured dots next to the branch description represent the samples collected for this study. The red rectangle in the inset map of Africa represents the geographic location of Guinea-Bissau. This figure and maps within it, were produced using QGIS version 3.36 (QGIS Development Team, 2024; https://qgis.org).
Fig. 1 Placement of study samples within the African crocodilian phylogenetic tree. Colours of the branches refer to the species found in Guinea-Bissau in this study, namely: the Nile crocodile (C. niloticus in green), the West African crocodile (C. suchus in yellow), and the West African dwarf crocodile (O. cf. tetraspis in purple). Red dots at the nodes represent highly supported nodes (> 95% pp), coloured dots next to the branch description represent the samples collected for this study. The red rectangle in the inset map of Africa represents the geographic location of Guinea-Bissau. This figure and maps within it, were produced using QGIS version 3.36 (QGIS Development Team, 2024; https://qgis.org).CC BY · PubMed Central
Fig. 2 Distribution of crocodile data collected in Guinea-Bissau. Symbols with red strokes represent barcoded genetic samples.
Fig. 2 Distribution of crocodile data collected in Guinea-Bissau. Symbols with red strokes represent barcoded genetic samples.CC BY · PubMed Central
Fig. 3 Map of the toponymies in the study area. Triangles indicate the major cities, whose names are adjacent to them. Numbers in bold indicate the protected areas: (1) Tarrafes do Rio Cacheu National Park, (2) Boe National Park, (3) Tchetche Natural Corridor, (4) Dulombi National Park, (5) Salifo-Xitole Natural Corridor, (6) Cuntabani-Quebo Natural Corridor, (7) Cantanhez National Park, (8) Lagoas de Cufada Natural Park and (9) Grupo de Ilhas de Orango National Park. The red rectangle in the inset map of Africa represents the geographic location of Guinea-Bissau. This figure and maps within it, were produced using QGIS version 3.36 (QGIS Development Team, 2024; https://qgis.org).
Fig. 3 Map of the toponymies in the study area. Triangles indicate the major cities, whose names are adjacent to them. Numbers in bold indicate the protected areas: (1) Tarrafes do Rio Cacheu National Park, (2) Boe National Park, (3) Tchetche Natural Corridor, (4) Dulombi National Park, (5) Salifo-Xitole Natural Corridor, (6) Cuntabani-Quebo Natural Corridor, (7) Cantanhez National Park, (8) Lagoas de Cufada Natural Park and (9) Grupo de Ilhas de Orango National Park. The red rectangle in the inset map of Africa represents the geographic location of Guinea-Bissau. This figure and maps within it, were produced using QGIS version 3.36 (QGIS Development Team, 2024; https://qgis.org).CC BY · PubMed Central

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Metadata

Authors
Pizzigalli, C., Regalla, A., Palmeirim, A. F., Palma, L., Lopes-Lima, M., Razgour, O., Godinho, R., Intipe, W. A., & Brito, J. C.
Affiliations
  • Universidade do Porto (PT)
  • Instituto da Biodiversidade e das Áreas Protegidas (IBAP)
  • University of Lisbon (PT)
  • CIBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, Campus de Vairão, Universidade do Porto, 4485-661 Vairão, Portugal
  • University of Exeter (GB)
Corresponding author
Pizzigalli, Cristian
ORCID
Venue
Scientific Reports
Publisher
Springer Science and Business Media LLC
Published
2025-03-31
Volume
15
Issue
1
Pages
24703-24703
ISSN
2045-2322 (ISSN-L)
DOI
10.21203/rs.3.rs-6183800/v1
PMC
PMC12241385
OpenAlex
W4412150710
Cited by
5
References
1
Citations by year
2026: 4 · 2025: 1
FWCI
2.05
Type
journal article
Language
en
Open access
Licence
Locations
  • Scientific Reports (publishedVersion, cc-by)
  • Research Square (acceptedVersion, cc-by)
  • Europe PMC (PubMed Central) (publishedVersion, cc-by)
  • PubMed Central (publishedVersion, cc-by)
  • PubMed (publishedVersion)
  • DOAJ (DOAJ: Directory of Open Access Journals) (submittedVersion, cc-by-sa)
Funders
  • European Commission (854248)
  • Fundação para a Ciência e a Tecnologia (CEECINSTLA/00020/2022, 2022.07926.CEECIND, FCT - InBIO Programático FUI 2020-2023 (UIDP/50027/2020), 2020.05054.BD, CEECINST/00014/2018/CP1512/CT0001)
Topics
  • Life Sciences › Agricultural and Biological Sciences › Ecology, Evolution, Behavior and Systematics › Amphibian and Reptile Biology
  • Physical Sciences › Environmental Science › Ecology › Wildlife Ecology and Conservation
  • Physical Sciences › Environmental Science › Nature and Landscape Conservation › Fish Ecology and Management Studies
Keywords
crocodiles, crocodilians, species diversity, species distribution, conservation threats, Nile crocodile, Crocodylus niloticus, Osteolaemus tetraspis, habitat loss, human-crocodile conflict, freshwater conservation, Guinea-Bissau, Bijagós Archipelago
MeSH terms
Alligators and Crocodiles, Animals, Conservation of Natural Resources, Guinea-Bissau, Ecosystem, Biodiversity

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CoChat. (2026). Citation check: Diversity, distribution and conservation of crocodiles (Order: Crocodylia) in Guinea-Bissau, West Africa. https://app.cochat.ai/papers/10.21203/rs.3.rs-6183800/v1
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Pizzigalli, C., Regalla, A., Palmeirim, A. F., Palma, L., Lopes-Lima, M., Razgour, O., Godinho, R., Intipe, W. A., & Brito, J. C. (2025). Diversity, distribution and conservation of crocodiles (Order: Crocodylia) in Guinea-Bissau, West Africa. Scientific Reports. https://doi.org/10.21203/rs.3.rs-6183800/v1