Testing recurrent ecological speciation processes in microendemic Madagascan reptiles and amphibians of the isolated Amber Mountain

• Applicant: Professor Dr. Miguel Vences
• Subject Area: Evolution, Anthropology ; Ecology and Biodiversity of Animals and Ecosystems, Organismic Interactions
• Term: from 2016 to 2019
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 322418141

• Final Report Year: 2020

Final Report Abstract

In this project, we aimed to study the potential for a common underlying ecological cline to drive ecological speciation in multiple independent lineages diversifying across it. The study was focussed on Amber Mountain, an isolated volcanic massif in the north of Madagascar. We conducted population-level sampling of two chameleons and two frogs on Amber Mountain, as well as herpetofaunal community assessment, over the course of a three-month research expedition from November 2017 to January 2018. Using various genetic and genomic approaches (newly developed microsatellites, mitochondrial sequences, and sequence capture), we established that our four focal taxa each shows signs of population structure across the mountain. In one frog taxon, Mantidactylus ambreensis, we discovered that the assemblage on the mountain had actually originated through a vicariant speciation event and not in-situ diversification, but that the one lineage that is an Amber Mountain microendemic nevertheless shows signs of some population structure across its distribution. The other lineages appeared all to have diversified in situ, but ranged from five genetic clusters in the frog M. bellyi, to just two populations in the chameleon Calumma linotum. Despite strong genetic structure in M. bellyi, there is no consistent relationship between genetic cluster and morphological or bioacoustic differences, except that individuals from higher elevations were smaller and called at higher frequency. The strongest break in all focal taxa occurs around 1200 m a.s.l., coupled with a change in herpetofaunal richness. With our findings, we can establish Amber Mountain as a new system for studying parallel ecological speciation in diverse clades. As a by-product of our work, this project was also able to result in and contribute to several taxonomic outcomes, including several new species descriptions, and natural history notes.

Publications

• (2017) Describing the smaller majority: Integrative taxonomy reveals twenty-six new species of tiny microhylid frogs (genus Stumpffia) from Madagascar. Vertebrate Zoology, 67(3):271–398
  Rakotoarison A, Scherz MD, Glaw F, Köhler J, Andreone F, Franzen M, Glos J, Hawlitschek O, Jono T, Mori A, Ndriantsoa SH, Raminosoa Rasoamampionona N, Riemann JC, Rödel MO, Rosa GM, Vieites, DR, Crottini A, Vences M
  
• (2018) Computational molecular species delimitation and taxonomic revision of the gecko genus Ebenavia Boettger, 1878. The Science of Nature, 105:49
  Hawlitschek O, Scherz MD, Ruthensteiner B, Crottini A, Glaw F
  (See online at https://doi.org/10.1007/s00114-018-1574-9)
• (2018) Polymorphism and synonymy of Brookesia antakarana and B. ambreensis, leaf chameleons from Montagne d’Ambre in north Madagascar. Salamandra 54(4): 259–268
  Scherz MD, Glaw F, Rakotoarison A, Wagler M, Vences M
  
• (2018) Tadpole predation by Mantidactylus bellyi Mocquard, 1895 with brief description of the site and morphological measurements of the specimen. Herpetology Notes 11: 747–750
  Rasolonjatovo SM, Scherz MD, Raselimanana AP, Vences M
  
• (2018) Two new Pandanus frogs (Guibemantis: Mantellidae: Anura) from northern Madagascar. European Journal of Taxonomy 451: 1–20
  Lehtinen RM, Glaw F, Vences M, Rakotoarison A, Scherz MD
  (See online at https://doi.org/10.5852/ejt.2018.451)
• (2019) Comparative phylogeography and patterns of deep genetic differentiation of two gecko species, Paroedura gracilis and Phelsuma guttata, across north-eastern Madagascar. Salamandra 55(3): 211–220
  Mohan AV, Gehring P-S, Scherz MD, Glaw F, Ratsoavina FM, Vences M
  
• (2020) Diamond frogs forever: a new species of Rhombophryne Boettger, 1880 (Microhylidae, Cophylinae) from Montagne d’Ambre National Park, northern Madagascar. Zoosystematics and Evolution 96(2): 313–323
  Scherz MD
  (See online at https://doi.org/10.3897/zse.96.51372)
• (2020) Sympatric lineages in the Mantidactylus ambreensis complex of Malagasy frogs originated allopatrically rather than by in-situ speciation. Molecular Phylogenetics and Evolution 144: 106700
  Rasolonjatovo SM, Scherz MD, Hutter CR, Glaw F, Rakotoarison A, Razafindraibe JH, Goodman SM, Raselimanana AP, Vences M
  (See online at https://doi.org/10.1016/j.ympev.2019.106700)