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.

Dietary Partitioning in Two Co-occurring Caecilian Species (Geotrypetes seraphini and Herpele squalostoma) in Central Africa.

Trophic interactions among fossorial vertebrates remain poorly explored in tropical ecosystems. While caecilian species can co-occur, whether and how sympatric species partition dietary or other resources are largely unknown. Based on specimens collected during field surveys in southern Cameroon, we conducted a dietary analysis of two co-occurring caecilian species, Geotrypetes seraphini and Herpele squalostoma. We find a negligible overlap in the adult diets of these two species. Earthworms dominated the diet of adult G. seraphini, whereas we found that mole crickets were the most frequent prey items in adult H. squalostoma. The dietary breadth of adult G. seraphini is smaller than that of H. squalostoma, which consumes a variety of hard-bodied prey including mole crickets, cockroaches, beetles, and crabs. Juvenile diets were similar between these species and mostly contained earthworms and ants. We did not detect significant ontogenetic dietary shifts in either species, though adults generally consumed a broader diversity of prey. As adults, G. seraphini and H. squalostoma may partition prey categories by consuming soft-bodied and hard-bodied prey, respectively. Because most caecilians are likely opportunistic predators, we expect that sympatric species partition dietary resources either by preference for different soil layers or ability to consume different prey categories.