Premium
Sky Islands of the Cameroon Volcanic Line: a diversification hot spot for puddle frogs ( P hrynobatrachidae: Phrynobatrachus )
Author(s) -
Zimkus Breda M.,
Gvoždík Václav
Publication year - 2013
Publication title -
zoologica scripta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.204
H-Index - 64
eISSN - 1463-6409
pISSN - 0300-3256
DOI - 10.1111/zsc.12029
Subject(s) - endemism , vicariance , biology , biological dispersal , ecology , montane ecology , biogeography , species richness , phylogeography , phylogenetics , population , biochemistry , demography , sociology , gene
The continental highlands of the Cameroon Volcanic Line ( CVL ) represent biological ‘sky islands’ with high levels of species richness and endemism, providing the ideal opportunity to understand how orogenesis and historical climate change influenced species diversity and distribution in these isolated A frican highlands. Relationships of puddle frogs ( P hrynobatrachus ) endemic to the CVL are reconstructed to examine the patterns and timing of puddle frog diversification. Historical distributions were reconstructed using both elevation and geography data. Puddle frogs diversified in the CVL via several dispersal and vicariance events, with most of the locally endemic species distributed across the northern part of the montane forest area in the B amenda‐ B anso H ighlands ( B amboutos M ts., M t. L efo, M t. M bam, M t. O ku and medium elevation areas connecting these mountains). Two new species, P . jimzimkusi sp. n. and P . njiomock sp. n., are also described based on molecular analyses and morphological examination. We find that these new species are most closely related to one another and P . steindachneri with the ranges of all three species overlapping at M t. O ku. P hrynobatrachus jimzimkusi sp. n. is distributed in the southern portion of the continental CVL, P . njiomock sp. n. is endemic to M t. O ku, and P . steindachneri is present in the northeastern part of the montane forest area. Both new species can be distinguished from all other puddle frogs by a combination of morphological characters, including their large size, ventral coloration and secondary sexual characteristics present in males. These results highlight the B amenda‐ B anso H ighlands, and specifically emphasize M t. O ku, as a centre of diversification for puddle frogs, supporting the conservation importance of this region. Our results also provide new insights into the evolutionary processes shaping the CVL ‘sky islands’, demonstrating that lineage diversification in these montane amphibians is significantly older than expected with most species diverging from their closest relative in the M iocene. Whereas climatic changes during the P liocene and P leistocene shaped intraspecific diversification, most speciation events were significantly older and cannot be linked to A frica's aridification in response to Pleistocene climate fluctuations.