A NEW SPECIES OF CARDIOGLOSSA (AMPHIBIA: ANURA: ARTHROLEPTIDAE) ENDEMIC TO MOUNT MANENGOUBA IN THE REPUBLIC OF CAMEROON, WITH AN ANALYSIS OF MORPHOLOGICAL DIVERSITY IN THE GENUS

A new frog species of the genus Cardioglossa, that is probably restricted to less than 10 km2 of gallery forest near the summit of Mount Manengouba in the Republic of Cameroon, is described. Unlike all other Cardioglossa, in life the coloration of the new species is typically brownish red, with no dorsal markings, but with a pair of thin, golden white lines that extend posteriorly from the tip of the rostrum and terminate just above and behind the tympanum. This new species is morphologically similar to C. oreas, another high-altitude species endemic to the Cameroonian mountains: both have small tympana and lack the hypertrophied third manual digit typical of males of other Cardioglossa. The tadpole of the new species is similar to that of C. occidentalis, the only other Cardioglossa for which the tadpole is fully described, but differs in having a broad anterolaterally projecting supraoral labium, lacking ventral pigmentation, and having a relatively longer spiracular tube. Several features of tadpole morphology are convergent with the unusual fossorial tadpole of the microhylid Otophryne and suggest a similar convergence in ecology. Principal components analysis of morphometric data, followed by discriminant function analysis, was used to explore patterns of morphological similarity within Cardioglossa. These analyses provide support for five species groups: (1) C. aureoli (distinct from other Cardioglossa); (2) C. escalerae, C. gratiosa and C. nigromaculata; (3) C. gracilis, C. melanogaster and C. schioetzi; (4) C. sp. nov. and C. oreas; and (5) C. cyaneospila, C. pulchra, C. venusta and C. trifasciata. The inclusion of C. cyaneospila in the last group supports previous suggestions of past biotic connections between the Albertine Rift mountains and those of the Cameroon Volcanic Line. The description of this new species further emphasizes Mt Manengouba as a centre of anuran endemism within the Cameroonian mountains and reaffirms the importance of this ecoregion within sub-Saharan Africa. © 2008 The Linnean Society of London, Zoological Journal of the Linnean Society, 2008, 154, 611–630.