Johannes Penner

The next generation of site-based long-term ecological monitoring: Linking essential biodiversity variables and ecosystem integrity

Global change effects on biodiversity and human wellbeing call for improved long-term environmental data as a basis for science, policy and decision making, including increased interoperability, multifunctionality, and harmonization. Based on the example of two global initiatives, the International Long-Term Ecological Research (ILTER) network and the Group on Earth Observations Biodiversity Observation Network (GEO BON), we propose merging the frameworks behind these initiatives, namely ecosystem integrity and essential biodiversity variables, to serve as an improved guideline for future site-based long-term research and monitoring in terrestrial, freshwater and coastal ecosystems. We derive a list of specific recommendations of what and how to measure at a monitoring site and call for an integration of sites into co-located site networks across individual monitoring initiatives, and centered on ecosystems. This facilitates the generation of linked comprehensive ecosystem monitoring data, supports synergies in the use of costly infrastructures, fosters cross-initiative research and provides a template for collaboration beyond the ILTER and GEO BON communities.

Batrachochytrium dendrobatidis in amphibians of Cameroon, including first records for caecilians

Amphibian chytrid fungus Batrachochytrium dendrobatidis (Bd) has been hypothesised to be an indigenous parasite of African amphibians. In Cameroon, however, previous surveys in one region (in the northwest) failed to detect this pathogen, despite the earliest African Bd having been recorded from a frog in eastern Cameroon, plus one recent record in the far southeast. To reconcile these contrasting results, we present survey data from 12 localities across 6 regions of Cameroon from anurans (n = 1052) and caecilians (n = 85) of ca. 108 species. Bd was detected in 124 amphibian hosts at 7 localities, including Mt. Oku, Mt. Cameroon, Mt. Manengouba and lowland localities in the centre and west of the country. None of the hosts were observed dead or dying. Infected amphibian hosts were not detected in other localities in the south and eastern rainforest belt. Infection occurred in both anurans and caecilians, making this the first reported case of infection in the latter order (Gymnophiona) of amphibians. There was no significant difference between prevalence and infection intensity in frogs and caecilians. We highlight the importance of taking into account the inhibition of diagnostic qPCR in studies on Bd, based on all Bd-positive hosts being undetected when screened without bovine serum albumin in the qPCR mix. The status of Bd as an indigenous, cosmopolitan amphibian parasite in Africa, including Cameroon, is supported by this work. Isolating and sequencing strains of Bd from Cameroon should now be a priority. Longitudinal host population monitoring will be required to determine the effects, if any, of the infection on amphibians in Cameroon.

Light shines through the spindrift - Phylogeny of African torrent frogs (Amphibia, Anura, Petropedetidae)

Torrent frogs of the genus Petropedetes Reichenow, 1874 as currently understood have a disjunct distribution with species endemic to West, Central or East Africa. We herein present a phylogenetic analysis including all but one of the currently described 12 species of the genus. Maximum Likelihood and Bayesian analyses of combined nuclear (rag1, SIA, BDNF) and mitochondrial (16S, 12S, cytb) genes of more than 3500 base pairs, revealed clades corresponding to the three sub-Saharan regions. Molecular results are confirmed by morphological differences. Surprisingly, the three geographic clades do not form a monophyletic group with respect to closely related families Pyxicephalidae and Conrauidae and therefore require taxonomic changes. We resurrect Arthroleptides Nieden, 1911 for the East African taxa. The Central African taxa remain in the genus Petropedetes. The West African members are placed in the new genus Odontobatrachus gen. nov. The taxonomic position of the new genus remains incertae sedis as it was not assigned to any of the four families included in our analyses. Potential new species have been detected within all three major clades, pointing to a still not fully clarified diversity within African torrent frogs.

Terrestrial reproduction as an adaptation to steep terrain in African toads

How evolutionary novelties evolve is a major question in evolutionary biology. It is widely accepted that changes in environmental conditions shift the position of selective optima, and advancements in phylogenetic comparative approaches allow the rigorous testing of such correlated transitions. A longstanding question in vertebrate biology has been the evolution of terrestrial life histories in amphibians and here, by investigating African bufonids, we test whether terrestrial modes of reproduction have evolved as adaptations to particular abiotic habitat parameters. We reconstruct and date the most complete species-level molecular phylogeny and estimate ancestral states for reproductive modes. By correlating continuous habitat measurements from remote sensing data and locality records with life-history transitions, we discover that terrestrial modes of reproduction, including viviparity evolved multiple times in this group, most often directly from fully aquatic modes. Terrestrial modes of reproduction are strongly correlated with steep terrain and low availability of accumulated water sources. Evolutionary transitions to terrestrial modes of reproduction occurred synchronously with or after transitions in habitat, and we, therefore, interpret terrestrial breeding as an adaptation to these abiotic conditions, rather than an exaptation that facilitated the colonization of montane habitats.

Two new Phrynobatrachus species (Amphibia: Anura: Phrynobatrachidae) from the Republic of the Congo

We describe two new species of puddle frogs, genus Phrynobatrachus, from the south-western Republic of the Congo. One of them, P. horsti sp. nov., occurs also in neighbouring Gabon and is morphologically most similar to the Cameroonian P. ruthbeateae. It differs from the latter species by smaller males with longer thighs and shanks. The new species comprises various colour morphs but always has less conspicuous black borders between flanks and belly than P. ruthbeateae. The distinct and large black axillary blotch of P. ruthbeateae is either much smaller in P. horsti sp. nov., or broken into numerous irregularly shaped smaller dots. Similarly, a black transversal line at the anterior ventral border of thighs and the black face mask is less distinct and irregularly delimitated in P. horsti sp. nov. when compared to P. ruthbeateae. The mean genetic difference in the sampled region of the 16S rRNA gene between P. horsti sp. nov. and 40 other western African congeners range from 3.66-18.10%. The second new species, P. mayokoensis sp. nov., differs from all other known congeners by the combination of a compact and warty body, the absence of a spiny eyelid tubercle and pedal webbing, a conspicuous black triangle on throat and anterior part of the belly, and a distinct large red blotch on the anterior-proximal surface of the thighs. It exhibited a mean genetic difference in the 16S rRNA to 40 other western African congeners ranging from 1.34-16.98%. The genetically most similar sequence stems from a GenBank entry of a Gabonese frog, determined as P. ogoensis. A comparison of the new species with P. ogoensis syntypes confirmed their specific distinctiveness, most convincingly underlined by the absence of pedal webbing in the new species and the pronounced pedal webbing in P. ogoensis. The GenBank entry thus most likely is based on a misidentification and P. mayokoensis sp. nov. may also occur in neighbouring Gabon. The discovery of the two new frog species is further evidence of the huge gap in our knowledge concerning the species richness in the Guineo-Congolian rainforests.

Diversity and biogeography of frogs in the genus Amnirana (Anura: Ranidae) across sub-Saharan Africa

Frogs in the genus Amnirana (family Ranidae) are widely distributed across sub-Saharan Africa and present a model system for exploring the relationship between diversification and geography across the continent. Using multiple loci from the mitochondrial (16S) and nuclear genomes (DISP2, FICD, KIAA2013, REV3L), we generated a strongly supported species-level phylogeny that provides insights into the continental biogeography of African species of Amnirana, which form a monophyletic group within the genus. Species delimitation analyses suggest that there may be as many as seven additional species of Amnirana in Africa. The biogeographic history of Amnirana is marked by several dispersal and vicariance events, including dispersal from the Lower Guinean Forest into the Congo Basin. In addition, phylogeographic patterns within two widespread species, A. albolabris and A. galamensis, reveal undescribed cryptic diversity. Populations assigned to A. albolabris in western Africa are more closely related to A. fonensis and require recognition as a distinct species. Our analyses reveal that the Lower and Upper Guinean Forest regions served as important centers of interspecific and intraspecific diversifications for Amnirana.

Phylogeny and biogeography of the African burrowing snake subfamily Aparallactinae (Squamata: Lamprophiidae)

Members of the snake subfamily Aparallactinae occur in various habitats throughout sub-Saharan Africa. The monophyly of aparallactine snakes is well established, but relationships within the subfamily are poorly known. We sampled 158 individuals from six of eight aparallactine genera in sub-Saharan Africa. We employed concatenated gene-tree analyses, divergence dating approaches, and ancestral-area reconstructions to infer phylogenies and biogeographic patterns with a multi-locus data set consisting of three mitochondrial (16S, cyt b, and ND4) and two nuclear genes (c-mos and RAG1). As a result, we uncover several cryptic lineages and elevate a lineage of Polemon to full species status. Diversification occurred predominantly during the Miocene, with a few speciation events occurring subsequently in the Pliocene and Pleistocene. Biogeographic analyses suggested that the Zambezian biogeographic region, comprising grasslands and woodlands, facilitated radiations, vicariance, and dispersal for many aparallactines. Moreover, the geographic distributions of many forest species were fragmented during xeric and cooler conditions, which likely led to diversification events. Biogeographic patterns of aparallactine snakes are consistent with previous studies of other sub-Saharan herpetofauna.