This member of the Apocynaceae family was given this name by S.H.J.V. Rapanarivo in 1999. It is found on Isalo mountains between 300 and 1000 m. It grows on sandstone escarpment with some humus. The shape of the caudex looks like a more or less regular balloon, up to 50 centimetres in diameter. The stem will grow up to two centimetres in diameter and reach a height of 60 centimetres. The leaves are lanceolate and smaller than other rosulatum.
The genera name from Greek; pachys; 'thick' and Greek podion; 'small foot' for the thick caudiciform trunk, formed by some species. The species name means 'slender'. Flower photo by Ferdinand Poilodan.

