The morphology and distribution of Xenopus vestitus (Anura: Pipidae) in Central Africa

Amphibians of Rwanda: Diversity, Community Features, and Conservation Status

The diversity and distribution of the amphibians in Rwanda was critically reviewed to provide a reliable species inventory for informed conservation management. The checklist of the amphibian species of Rwanda is based on results of our own fieldwork, historical records compiled from the literature, and examination of voucher specimens in museum collections. A total of 62 species are recorded, and 22 further species listed in field guides and open-access data bases are discussed, identified as erroneous records, and consequently not included in the country list. We provide diagnostic characters of external morphology and the advertisement call for each validated species, and a short synopsis of geographic distribution, altitudinal range, occurrence in the provinces of Rwanda, and habitat preference. We provide keys to all genera, and all taxonomically described species based on morphological characters and additional keys based on features of the advertisement calls. We discuss features of amphibian communities including local community structure and delimitation of altitudinal metacommunities. Based on the IUCN red list assessment and our field surveys, we propose for the first time a national red list of amphibians in Rwanda.

Description of a new octoploid frog species (Anura: Pipidae: Xenopus) from the Democratic Republic of the Congo, with a discussion of the biogeography of African clawed frogs in the Albertine Rift

We describe a new octoploid species of African clawed frog (Xenopus) from the Lendu Plateau in the northern Albertine Rift of eastern Democratic Republic of the Congo. This species is the sister taxon of Xenopus vestitus (another octoploid), but is distinguished by a unique morphology, vocalization and molecular divergence in mitochondrial and autosomal DNA. Using a comprehensive genetic sample, we provide new information on the species ranges and intra-specific diversity of African clawed frogs from the Albertine Rift, including the details of a small range extension for the critically endangered Xenopus itombwensis and previously uncharacterized variation in Xenopus laevis. We also detail a new method for generating cytogenetic preparations in the field that can be stored at room temperature for up to 3 weeks. While extending our understanding of the extant diversity in the Albertine Rift, this new species highlights components of species diversity in ancestral African clawed frogs that are not represented by known extant descendants.

The morphology and biology of Xenopodistomum xenopodis from the gall bladder of the African clawed toad, Xenopus laevis

Xenopodistomum xenopodis Macnae, Rock and Makowski, 1973 was recovered from the gall bladder of Xenopus laevis laevis imported from the Cape Peninsula, South Africa, during 1967 – 1978. The overall incidence amongst 396 toads was 2.8%, and while the maximum intensity was 8 worms per host, most carried single infections. The parasite was not represented in 570 specimens of 8 other Xenopus taxa from East, Central and West Africa. The internal anatomy of X. xenopodis is of a plagiorchild type, but the adult body form is unusual with marked division into a slender very extensible neck and a broad oval hindbody. Although apparently confined within the gall bladder, the parasite can extend its neck along the bile duct and into the duodenum: host gut contents or intestinal epithelium may therefore supplement the diet of bile fluid. The original description and generic diagnosis have been amplified and amended. X. xenopodis apparently lacks close affinities with other known genera, a characteristic common to many of the parasites which infect the clawed toads.

Studies on the biology ofProtopolystoma xenopodis(Monogenoidea): the oncomiracidium and life-cycle

Protopolystoma xenopodis(Price, 1943) Bychowsky, 1957 is a parasite of the African clawed toads, species ofXenopus. Adult worms in the host's urinary bladder produce up to 15 eggs/24 h; these are voided with the urine and hatch after 20–24 days (at 26 °C). The swimming oncomiracidia enter the cloaca of the toad and travel via the urinary ducts to the kidneys. Larval development in the kidneys lasts 8–12 weeks (at 22 °C) and the juvenile parasites then migrate to the urinary bladder where maturity is reached after a further 3–4 weeks,i.e. 3–4 months after invasion. Egg production is continuous and parasite longevity has been found to exceed1½ years. Rarely, the adult worms may undertake a return migration from bladder to kidneys.

The morphology of the oncomiracidium is described and compared with available accounts of other polystomatid genera. Consideration of data for the genusPolystomasuggests that the arrangement of the epidermal ciliary cells is relatively constant at the inter-specific level. Comparison ofProtopolystomawithPolystoma,DiplorchisandOculotremareveals that whilst the ciliary cell patterns are clearly related there are important differences in both cell number and disposition at the inter-generic level. Differences are also evident in the distribution of epidermal sensillae inProtopolystomaandPolystoma.Protopolystomais distinguished from all other polystomatids infecting anuran hosts by the presence of two pairs of haptoral hamuli.

Two new polyploid Xenopus species from western Uganda

2 new species of the anuran genus Xenopus have been found in western Uganda: X. ruwenzoriensis sp.n. with the hexaploid chromosome number of 108 in the Semliki Valley, west of the Ruwenzori, and X. species nova with the tetraploid chromosome number of 72 in and near lake Bunyoni.