The description of Mediorhynchus africanus n. sp. (Acanthocephala: Gigantorhynchidae) from galliform birds in Africa

Abstract

Mediorhynchus africanus n. sp. is described from specimens collected from the helmeted guinea fowls, Numida meliagris Linn. 1758 in Kruger National Park and elsewhere in subSaharan Africa from the same and other galliform birds. These specimens were previously assigned to Mediorhynchus gallinarum Bhaleroa (Proc Zool Soc Lond Ser B Syst Morph 107:199-203, 1937) described from chickens, Gallus gallus L. in India and subsequently reported from other Asian countries. The identification of the African forms as M. gallinarum was based on similarities in the structure and measurements of the proboscis, proboscis armature and receptacle, lemnisci, and reproductive organs. A detailed study of specimens from South Africa and descriptions reported from elsewhere in Africa revealed marked differences that clearly distinguish the African material as new species. The African specimens are pseudo-segmented and flattened, the proboscis has two prominent apical pores, sensory pits are prevalent throughout the trunk, the posterior end of the female is broad with dorso-terminal dome-like extension opposite the subterminal gonopore, and the eggs are large. The Asian specimens from Indonesia and elsewhere are cylindrical and non-segmented, the proboscis lacks prominent apical pores, sensory pits are rare on the trunk, the posterior end of the female is pointed with a terminal gonopore, and the eggs are markedly smaller. We used DNA sequence from one mitochondrial gene (cytochrome oxidase subunit I) and one nuclear gene (18S ribosomal RNA) to infer the phylogenetic relationships of M. africanus and M. gallinarum and selected Acanthocephala. Medioryhnchus is monophyletic and M. africanus and M. gallinarum are allopatric sister species (9.7% sequence divergence). All findings indicate that M. africanus should be ranked as a separate species.