The Fingui white-toothed shrew Crocidura fingui, categorized as Data Deficient on the IUCN Red List, is endemic to Príncipe Island, Central Africa. It is currently known from < 10 sites and its ecology and any threats are largely unknown. We review its distribution and ecology, and any potential threats, based on camera-trap data, field observations and previously published and unpublished sightings. Crocidura fingui appears to have an island-wide distribution and to use a range of ecosystems, from native forests to urban areas. It is largely nocturnal and exhibits considerable spatiotemporal overlap with introduced mammals such as the African civet Civettictis civetta, domestic cat Felis catus and rats Rattus spp. The species has an area of occupancy < 500 km2 and is known from fewer than five locations, and its population is inferred to be affected by several introduced mammals. We recommend that it is recategorized as Endangered on the IUCN Red List.

Since it was first described in 1901, the Príncipe thrush Turdus xanthorhynchus has been rare and restricted to the native forest in the south of Príncipe Island. The Obô giant land snail Archachatina bicarinata, however, was widespread across the island and at least locally abundant until the 1990s. Since then its population has collapsed, and now, like the thrush, it is also restricted to the native forest in the south of the island. Using species distribution modelling, we show that both species are currently strongly associated with rugged and remote areas of native forest at high altitudes. We argue that their current distribution might be negatively affected by anthropogenic pressures, as both are harvested, and also because invasive alien species are expected to have deleterious effects on these species, although further studies are needed to clarify interactions between these native and introduced species. The diachronic stories of these species highlight an overlooked value of native ecosystems: their role in the conservation of widespread species that might be unable to use anthropogenic landscapes in the future. They also reinforce the need for protected areas that strive to exclude most human activities in the context of particularly sensitive biodiversity, as is often the case on oceanic islands.

The shrew Crocidura thomensis is a little-known species endemic to São Tomé Island. We review its distribution, ecology and conservation status based on nine published and 23 new records. The species has a wide distribution across São Tomé, preferring rugged forested areas with high rainfall. The location of new records coincides with that of historical records but the proportion of records in plantations has declined, possibly as a result of agricultural intensification, increased use of pesticides, and presence of exotic species. The shrew is restricted to a single island, its extent of occurrence is < 1,000 km2 and its habitat is declining in extent and quality, and thus its categorization as Endangered on the IUCN Red List remains appropriate. It is important to gain a better knowledge of population trends, ecological preferences and sensitivity to potential threats, but the effective protection of São Tomé Obô Natural Park and surrounding forests is the most important measure to ensure the long-term survival of this mammal.