Museomics and integrative taxonomy reveal three new species of glandular viviparous tree toads (Nectophrynoides) in Tanzania’s Eastern Arc Mountains (Anura: Bufonidae)

For the last century, herpetologists have referred to any Nectophrynoides Noble, 1926 toad characterized by a large, robust body, with large, distinct parotoid glands, as Nectophrynoides viviparus (Tornier, 1905). Consequently, Nectophrynoides viviparus is also considered to have the broadest distribution of all its congeners, with populations ranging from the Tanzanian Southern Highlands, close to the Tanzania-Malawi border, through the Udzungwa and Mahenge Mountains in the south to Uluguru, Rubeho, and Nguru Mountains in the central part of the Eastern Arc Mountains.

However, there is underappreciated morphological diversity within what is generally referred to as N. viviparus, and various populations are isolated by large distances and geographical barriers. Recent molecular studies have shown that N. viviparus from the Southern Highlands, the type locality, is genetically distinct from all other N. viviparus populations in the Eastern Arc Mountains, suggesting the existence of a species complex warranting taxonomic revision.

Here, we present an integrative taxonomic assessment of southern populations by supplementing the genetic results with the analysis of morphometric and morphological data for 257 specimens assigned to N. viviparus, including museomic data for name-bearing types. Based on the results, we describe three new species from the N. viviparus species complex, covering the southern Eastern Arc Mountains populations. Together with a revised morphological key to the genus and a gazetteer of known populations, we provide Extent of Occurrence and Area of Occupancy for N. viviparus sensu stricto and the new species to investigate their conservation status compared to other members of the genus.