Abstract
We report on the search and rediscovery of the Liberian Nimba toad, Nimbaphrynoides liberiensis, 30 years after its original description. A small surviving population could be traced in the surroundings of the type locality Mount Alpha, Liberia. The type locality was meanwhile destroyed by open cast mining. Similar to the Guinean Nimba toad, Nimbaphrynoides occidentalis, the Liberian toad lives exclusively in open, savanna like habitats above 1200 m a.s.l. The presumably few surviving individuals and the small and patchy distribution classify the Liberian toads as Critically Endangered (Stuart et al. 2008). A morphological, acoustical and genetic comparison of Liberian and Guinean populations revealed only minor, but distinct morphological (size, colour) differences. Genetically and acoustically the two taxa were indistinguishable. We therefore propose to consider the two populations as conspecific and to consider Nimbaphrynoides liberiensis (Xavier, 1978) as junior synonym of Nimbaphrynoides occidentalis (Angel, 1943). Because of the morphological differences we propose to treat the Liberian population as a subspecies of the Guinean toad and herein introduce the new name: Nimbaphrynoides occidentalis liberiensis.References
Angel, F. (1943) Description d’un nouvel amphibien anoure, ovo-vivipare de la Haute-Guinée Française (Materiaux de la mission Lamotte, au Mont-Nimba) (2e note). Bulletin du Muséum national d’Histoire naturelle, 15, 167–169.
Angel, F. & Lamotte, M. (1944) Un crapaud vivipare d’Afrique Occidentale Nectophrynoides occidentalis Angel. Annales des Sciences naturelles, Zoologie, 6, 63–89.
Angel, F. & Lamotte, M. (1948) Nouvelles observations sur Nectophrynoides occidentalis Angel. Remarques sur le genre Nectophrynoides. Annales des Sciences naturelles, Zoologie, 11, 115–147.
Babik, W., Szymura, J.M. & Rafinski, J. (2003) Nuclear markers, mitochondrial DNA, and male secondary sexual traits variation in a newt hybrid zone (Triturus vulgaris x T. montandoni). Molecular Ecology, 12, 1913–1930.
Bossuyt, F. & Milinkovitch, M.C. (2000) Convergent adaptive radiations in Madagascan and Asian ranid frogs reveal covariation between larval and adult traits. Proceedings of the National Academy of Sciences, USA, 97, 6585–6590.
Brown, J.L. & Twomey, E. (2009) Complicated histories: three new species of poison frogs of the genus Ameerega (Anura: Dendrobatidae) from north-central Peru. Zootaxa, 2049, 1–38.
Dubois, A. (1987 ‘1986’) Miscellanea taxinomica batrachologica (I). Alytes, 5, 7–95.
Hillers, A., Loua, N.-S. & Rödel, M.-O. (2008) Assessment of the distribution and conservation status of the viviparous toad Nimbaphrynoides occidentalis on Monts Nimba, Guinea. Endangered Species Research, 5, 13–19.
Lamotte, M. (1959) Observations écologiques sur les populations naturelles de Nectophrynoides occidentalis (Fam. Bufonidae). Bulletin Biologique, 4, 355–413.
Lamotte, M. (1983) The undermining of Mount Nimba. Ambio, 12, 174–179.
Lamotte, M. (1998) Le mont Nimba. Réserve de la biosphère et site du patrimoine mondial (Guinée et Côte d'Ivoire). Initiation à la géomorphologie et à la biogéographie. UNESCO publishing, Paris, 153 pp.
Lamotte, M. & Roy, R. (2003) Le peuplement animal du Mont Nimba (Guinée, Côte d'Ivoire, Liberia). Mémoires du Musée national Histoire naturelle, 190, 1–724.
Lamotte, M. & Sanchez-Lamotte, C. (1999) Adaptation aux particularités climatiques du cycle biologique d’un anoure tropical, Nectophrynoides occidentalis Angel, 1943 (Bufonidae). Alytes, 16, 111–122.
Palumbi, S.R. (1991) Nucleic Acids II: the Polymerase Chain Reaction. In: Hillis, D.M., Moritz, C. & Mable, B.K. (Eds) Molecular Systematics. 2nd edition, Sinauer Associates, Sunderland, pp. 205–247.
Rödel, M.-O., Boateng, C.O., Penner, J. & Hillers, A. (2009) A new cryptic Phrynobatrachus species (Amphibia: Anura: Phrynobatrachidae) from Ghana, West Africa. Zootaxa, 1970, 52–63.
Rödel, M.-O. & Ernst, R. (2004) Measuring and monitoring amphibian diversity in tropical forests. I. An evaluation of methods with recommendations for standardization. Ecotropica, 10, 1–14.
Rödel, M.-O., Kosuch, J., Veith, M. & Ernst, R. (2003) First record of the genus Acanthixalus Laurent, 1944 from the Upper Guinean rain forest, West Africa, with the description of a new species. Journal of Herpetology, 37, 43–52.
Schiøtz, A. (1964) The voices of some West African amphibians. Videnskabelige Meddelelser fra Dansk Naturhistorisk Forening, 127, 35–83.
Shimada, T., Matsui, M., Yambun, P., Lakim, M. & Mohamed, M. (2008) Detection of two cryptic taxa in Meristogenys amoropalamus (Amphibia, Ranidae) through nuclear and mitochondrial DNA analyses. Zootaxa, 1843, 24–34.
Stuart, S., Hoffman, M., Chanson, J., Cox, N. Berridge, R. Ramani, P. & Young, B. (2008) Threatened amphibians of the World. Lynx Editions, Barcelona, 758 pp.
Swofford, D.L. (2002) PAUP*: Phylogenetic Analysis Using Parsimony (and Other Methods). 4.0 Beta for UNIX or OpenVMS. Sinauer Associates, Sunderland, Massachusetts.
Tamura, K., Dudley, J., Nei, M. & Kumar, S. (2007) MEGA 4: Molecular Evolutionary Genetics Analysis (MEGA) software version 4.0. Molecular Biology and Evolution, 24, 1596–1599.
Vences, M., Thomas, M., Bonett, R.M. & Vieites, D.R. (2005) Deciphering amphibian diversity through DNA barcoding: changes and challenges. Philosophical Transactions of the Royal Society, B Biological Sciences, 360, 1859–1868.
Vieites, D.R., Wollenberg, K.C., Andreone, F., Köhler, J., Glaw, F. & Vences, M. (2009) Vast underestimation of Madagascar’s biodiversity evidenced by an integrative amphibian inventory. Proceedings of the National Academy of Sciences, USA, 106, 8267–8272.
Xavier, F. (1978) Une espèce nouvelle de Nectophrynoides (Anura, Bufonidae) des Monts Nimba, N. liberiensis n.sp. I – description de l’espèce. Bulletin de la Société Zoologique de France, 103, 431–441.
Xavier, F. (1986) La reproduction des Nectophrynoides. In: Grassé, P.-P. & Delsol, M. (Ed) Traité de Zoologie, anatomie, systématique, biologie. Tome XIV, Batraciens, fascicule IB. Masson, Paris, pp. 497–513.